The discovery of a “virus that 'kills off' prostate cancer cells” has been described in the Daily Mail. It reported that scientists injected six prostate cancer patients with a ‘tame’ virus and found it killed cancer cells while sparing healthy tissue.

The research article reports both pre-clinical studies on cancer cells and mice in the laboratory as well as an early clinical trial in six patients with advanced prostate cancer. The virus was injected into their cancers three weeks before their prostates were due to be removed. The infected cancer cells showed evidence of cell death and there were signs of an immune system response and cell changes, suggesting that the virus could be an effective cancer treatment.

This is an early report of a new type of treatment for prostate cancer. Based on these results, the researchers hope to go on to the first stage of full trials of the viral treatment in more people with advanced prostate cancer. These trials will go some way to indicating how useful this treatment might be, compared with existing treatments for prostate cancer.

 

Where did the story come from?

The research was carried out by Dr Chandini M. Thirukkumaran and colleagues from the University of Calgary and other institutions in Canada. The study was supported by grants from the Prostate Cancer Research Foundation of Canada, the National Cancer Institute of Canada, the Canadian Cancer Society and Oncolytics Biotech, Inc. (the Canadian company developing the treatment). The paper was published in the peer-reviewed medical journal Cancer Research.

The Daily Mail correctly highlights that these are early days for the treatment and that “much larger trials are needed to make sure it works, and even then it would take a decade for the treatment to be widely available”.

 

What kind of research was this?

The journal article reports on several studies in cells, animals and humans that all focussed on a new viral treatment for cancer. The treatment is based on a ‘reovirus’ (short for respiratory, enteric, orphan virus). This virus is common and usually causes very minor flu symptoms, and often no symptoms at all, in humans. The virus appears to kill cancerous cells over healthy cells. It has already been shown to have potential for treating other cancers such as bowel, colon, ovarian, breast, and bladder cancer.

 

What did the research involve?

The aim of this research was to provide the necessary preclinical data for a full phase I clinical trial of a treatment utilising the virus in men with advanced prostate cancer.

The researchers report on three studies, each at a different stage of the process towards developing a treatment. In the first study, normal human prostate cells and prostate cancer cells grown in the laboratory were exposed to either dead or live reovirus, to see what effect it had. The researchers also tested how much virus the infected cells were producing up to 72 hours after infection. The second study involved injecting human prostate cancer cells into the hind legs of mice. The researchers then measured the growth of any tumours that developed and took various cellular measures of cancer behaviour, both with and without the injection of the virus.

For the clinical parts of the study, six patients were recruited from local prostate cancer referral clinics in Calgary, Canada. All six had advanced cancer confined to the prostate gland, which means that the study was not testing the treatment for prostate cancer that had spread beyond the prostate gland. The patients had been given a biopsy confirming prostate cancer, and were booked for surgery called radical prostatectomy, in which the whole of their prostate would be removed. They were otherwise healthy and not taking any drugs to suppress their immune system.

Patients were then treated with the reovirus by injection. The methods were said to have been developed in a previous phase I study. Guided by an ultrasound probe, 1 mL of the virus solution was injected directly into an identified cancerous region and a metal marker left at the injection site so that the cells nearest to the injection could later be identified for analysis after the prostatectomy. Patients were then tested weekly for three weeks for signs of toxicity and evidence of viral shedding (or spread) in the urine, faeces and blood, and monitoring of prostate-specific antigen levels (a marker of cancer activity) before their prostatectomy. The prostatectomy went ahead as planned, and the entire prostate was removed.

After the planned surgical removal of the prostate gland, the tissue was examined for signs of inflammation and cell death.

 

What were the basic results?

In the preclinical part of the study, the researchers found that the live reovirus was able to infect human prostate cancer cells and kill them. Human prostate cancer tumours grown in mice shrank when injected with the virus.

In the clinical part, the researchers found that the treatment was well tolerated, except for a mild flu–like illness seen in four of the six patients. Patients recovered from these symptoms within 24 hours without needing treatment. Cancer activity, as indicated by prostate-specific antigen values, did not change greatly over the course of the study. Three patients showed signs of the virus in their urine at week one, but had negative blood tests for the virus.

There was a rise in antibodies to the virus within one week of the injection, suggesting that there had been an immune response to the new virus and that this may have limited the viruses spread to other areas of cancer in the gland. Analysis of the prostate tissue also suggested that the reovirus did not infect healthy noncancerous tissue, possibly also inhibiting its spread to other cancerous areas. There were signs that cells near to the injection site were dying, and that immune system cells were infiltrating the area.

 

How did the researchers interpret the results?

The researchers say that this is the first study to provide evidence of an effect of the new reovirus
treatment for prostate cancer in both preclinical and clinical settings.

They suggest the potential value of their finding is that patients may be able to avoid some of the problems of current treatments for localised prostate carcinoma, such as erectile dysfunction,
bowel and bladder problems. In addition, they say, “Those patients in which radical radiotherapy or radical prostatectomy are contraindicated may well be candidates for reovirus therapy.”

 

Conclusion

This is early research on a new treatment for prostate cancer. It is worth noting that:

• The virus has already been tested, and shown some success, in treatment for other cancers. This means that the route to clinical use may be shorter for this treatment indication but it will not get around the fact that many more patients will need to be tested in rigorous trials to see if the treatment is better than current alternatives.
• The treatment seemed to have very few side effects, which is a positive sign for a cancer treatment.
• The researchers acknowledge that it is unfortunate that the reovirus did not seem to infect non-cancerous tissue after the injection as this means that it is unlikely that the virus could spread to other areas of the prostate cancer and kill these, in the same patient.

Overall, this report shows another type of cancer that may respond to the reovirus treatment. More studies in many more patients will be needed to decide if the new treatment has a place and where that place might be among existing treatments for prostate cancer.

Links To The Headlines

Virus that 'kills off' prostate cancer cells: Volunteer patients injected with 'tame' bug. Daily Mail, March 10 2010

Links To Science

Thirukkumaran CM, Nodwell MJ, Hirasawa L. Oncolytic Viral Therapy for Prostate Cancer: Efficacy of Reovirus as a Biological Therapeutic. Cancer Research 2010; Published online first March 9

“A technique that ‘washes out’ the brains of severely ill premature babies may aid survival,” says the BBC. Their article says that the treatment, called DRIFT (drainage, irrigation and fibrinolytic therapy), could help around 100 babies per year.

The research behind the news looked at whether DRIFT could reduce the risk of death and disability in premature infants that had a type of bleeding that enlarged the fluid-filled spaces in the centre of the brain. This condition is very serious and can lead to death or severe disabilities such as cerebral palsy. Although DRIFT was associated with more secondary bleeding than standard care, subsequent follow-up showed that DRIFT reduced the proportion of infants that died or had severe disabilities by the age of two. The researchers suggest that modifications to the DRIFT process used in the trial could reduce the risk of second bleeds.

Overall, this study suggests that the DRIFT technique could help premature babies with this very serious condition. Further studies should look at whether modifications to the technique can, as claimed, reduce the risk of second bleeds while maintaining the benefits seen in this study.

 

Where did the story come from?

Dr Andrew Whitelaw and colleagues from the University of Bristol, Frenchay Hospital in Bristol, and research centres in Poland carried out this research. The study was funded by the Cerebra charity and the James and Grace Anderson Trust. The study was published in the peer-reviewed medical journal Pediatrics.

The Daily Mail, Daily Express and BBC News have covered this study. The BBC provides the most detailed coverage of the study, and reports the findings accurately. The Mail and Express concentrate on the story of one boy who took part in the trial.

 

What kind of research was this?

This was a randomised controlled trial comparing DRIFT (drainage, irrigation and fibrinolytic therapy) with the standard care for premature infants with a dangerous condition called posthemorrhagic ventricular dilatation (PHVD).

PHVD is caused by bleeding into the fluid-filled spaces in the centre of the brain (ventricles) that causes them to expand, putting pressure on the brain. Bleeding occurs due to the fragile, immature blood capillaries in the premature baby’s brain being unable to withstand changes in blood flow and pressure in the brain following birth. Babies at the greatest risk of PHVD are those who are more severely premature (born at less than 32 weeks) or of very low birth weight.

Developing PHVD as a baby can lead to serious cognitive, motor, and sensory disability, for example the development of cerebral palsy. The DRIFT technique is designed to reduce the excess pressure and build-up of leaked blood in the ventricles soon after bleeding, and aims to reduce the chances of brain damage and death from PHVD. The technique involves draining excess fluid and replacing it with artificial cerebrospinal fluid containing antibiotics while maintaining a steady, normal pressure in the ventricles.

This was a randomised controlled trial, the best way of comparing the effects of two treatments. Randomly assigning individuals into groups (randomisation) is the best way to ensure that the groups are well balanced for factors that could affect results. However, when the numbers of individuals randomised is small, such as in this study, randomisation may not work that well. In these situations researchers should check key factors to make sure that they are balanced, a step that was performed in this study.

 

What did the research involve?

The researchers recruited 77 preterm infants with bleeding into their ventricles: 54 from Bristol, 20 from Katowice in Poland, two from Glasgow and one from Bergen in Norway. Eligible infants whose parents agreed to participate were randomly assigned to receive either DRIFT or standard care (39 in DRIFT group, 38 in standard care). The infants were then followed up for two years to determine if they survived and whether they had any cognitive, motor or sensory disabilities.

Infants were eligible if they were no more than 28 days old, had been diagnosed with bleeding into their ventricles with ultrasound and showed progressive enlargement of the ventricles in both hemispheres of the brain.

Standard care was to not offer any intervention unless the infant showed signs of having raised pressure within the brain (such as irritability, persistent vomiting or reduced consciousness), or if the infant showed excessive head enlargement (over 2mm expansion in a day). If infants showed these signs, they were given a lumbar puncture to release cerebrospinal fluid and reduce pressure in the brain. The process was repeated as needed.

Treatment with DRIFT involved inserting tubes (catheters) into the ventricles and injecting an anticlotting agent to prevent blockage of the catheters with blood clots. The catheters were used to drain bloody fluid from ventricles and replace it with artificial cerebrospinal fluid containing antibiotics, while maintaining a steady normal pressure in the ventricles. Treatment with DRIFT was administered until the fluid being drained became clear, indicating that all leaked blood had been removed. Treatment with DRIFT continued for an average (median) of three days. If enlargement of the ventricles and excessive head growth did not stop in infants who had received DRIFT, they also received lumbar puncture.

In clinical trials such as this, there is often an external safety monitoring group that looks at the ongoing results of the trial to determine if the treatments being administered are safe. If they judge that the treatments are not safe, they can stop the trial. The safety monitoring group stopped the DRIFT trial because there was an increase in secondary bleeding into the ventricles in the DRIFT group. While DRIFT treatment was discontinued, the children in the study were still followed up to see what their outcomes were.

The children were assessed at an average of 25 months after their expected delivery date. The researcher assessing them did not know whether they had received DRIFT or standard care. The assessment used a standard scale to assess cognitive ability and development. Severe sensory and motor disabilities were defined as:

• inability to walk
• inability to walk unaided
• inability to sit without support
• inability to control head without support
• inability to use hands to feed self
• blindness or only light perception
• hearing loss uncorrected by hearing aid
• inability to communicate by speech

The researchers then compared the overall rate of death or severe disability between the group that received DRIFT and the group that received standard care. They carried out unadjusted analyses, as well as analyses that took into account how child gender, birth weight and severity of bleeding may have affected the results.

 

What were the basic results?

The researchers found that the DRIFT group and standard care group were similar, except that:

• there were more boys in the DRIFT group than the standard care group (29% vs. 24%)
• the DRIFT group had slightly lower birth weight (1050g vs. 1130g)
• babies in the drift group were born slightly earlier (27 weeks vs. 28 weeks)
• the DRIFT group had a greater proportion with the most severe bleeds, which have a very high mortality and complication rate (grade IV bleeds: 20% vs. 18%)

The researchers were able to assess what happened to all 77 children enrolled in the trial.

• Three children in the DRIFT group and five children in the standard care group had died before the age of two.
• Eighteen of the DRIFT group and 22 children in the standard care group had severe disabilities (cognitive, motor or sensor) by the age of two.
• This equated to 51% of the DRIFT group and 71% of the standard care group having either died or become severely disabled by the age of two. This difference was statistically significant once gender, birth weight and severity of bleeding into their ventricles were taken into account (odds ratio 0.25, 95% confidence interval 0.08 to 0.82).

Survivors in the DRIFT group were less likely than those in the standard care group to have severe cognitive disabilities at the age of two (31% vs. 59%). There was a trend for lower rates of individual sensory/motor disabilities in the DRIFT group, but this difference did not reach statistical significance.

 

How did the researchers interpret the results?

The researchers concluded that, “despite an increase in secondary intraventricular bleeding, DRIFT reduced severe cognitive disability in survivors and overall death or severe disability”.

 

Conclusion

This small study suggests that, compared to standard care, DRIFT reduces the risk of the combined outcome of death or severe disability in premature infants with enlargement of the ventricles in the brain due to bleeding. There are a number of points to note:

• The study was relatively small, with 39 children in the DRIFT group and 38 in the standard care group. The trial was also stopped early due to safety concerns. The researchers note that these factors mean the results should therefore be interpreted cautiously.
• While larger studies are preferable, the severity of the condition, its relatively uncommon nature and the difficulties associated with carrying out trials in infants mean that larger studies may not be feasible.
• There were some differences between the groups at the start of the study, but the researchers took these into account in their analyses. However, there could be other unmeasured differences between the groups that could have affected the results.
• The researchers believe that the increase in secondary bleeds into the ventricles with DRIFT treatment was likely to be caused by the use of an anticlotting agent called tPA. They say that if DRIFT is used in future that they would not recommend using this anticlotting agent routinely, but would only use it if there was a need to clear a clot blocking the drainage tubes.

Links To The Headlines

Brain 'wash out' may help premature babies. BBC News, March 7 2010

'Brain washing' technique cuts risk of premature babies suffering severe disabilities. Daily Mail, March 7 2010

Miracle of ‘brainwash’ boy. Daily Express, March 8 2010

Links To Science

Whitelaw A, Jary S, Kmita G et al. Randomized Trial of Drainage, Irrigation and Fibrinolytic Therapy for Premature Infants with Posthemorrhagic Ventricular Filatation: Developmental Outcome at 2 years. Pediatrics [Published online] March 8 2010

“What women eat while they are in the early stages of pregnancy influences the sex and health of their unborn baby”, The Daily Telegraph reported. It said that eating breakfast and a high fat diet around the time of conception made it more likely the offspring would be a boy.

The newspaper article is actually reporting two different studies. The findings about the effect of a high fat diet and breakfast on a child’s gender are from a study in humans that the newspaper says was published two years ago.

The new study that has prompted this report was in mice, and it did not aim to look at whether a high fat diet during pregnancy affects the sex of offspring. The researchers’ main aim was actually to investigate whether the amount of fat in the diet of pregnant female mice affected gene activity in the placenta, and whether this varied depending on the gender of the fetus. Such research could potentially help to explain how maternal diet in pregnancy has an effect on offspring health.

There are many differences between mice and humans and these findings may not be representative of what happens in people. Further study in humans would be needed to establish if this were the case. Pregnant women should aim to have a healthy balanced diet to maintain good health in themselves and their offspring.

 

Where did the story come from?

Dr Jiude Mao and colleagues from the University of Missouri and GenUs BioSystems, Inc. carried out this research. The study was funded by the National Institutes of Health. The study was published in the peer-reviewed medical journal Proceedings of the National Academy of Sciences of the USA.

The Daily Telegraph reported this study. The article presents the study’s findings and does say that the current research is in mice. It also refers to a previous study looking at the effect of diet on baby gender in humans, but this study is not assessed here. The reporting of the findings of this previous study, which had different aims to the current research, could lead to confusion about what the new research has found.

 

What kind of research was this?

This research in pregnant female mice examined how maternal diet affected the activity of genes in the cells of the placenta that was supporting each male or female foetus. The researchers say that diet during pregnancy affects the future health of offspring, and that the effects differ for foetuses of different genders. Therefore, they wanted to look at whether they could find differences in gene expression in the placenta that could potentially account for these effects.

Studies such as this are useful in that they help scientists to understand how certain environmental conditions might affect health. However, differences between the species may mean that results obtained in mice may not be representative of what happens in humans.

 

What did the research involve?

The researchers fed female mice one of three diets from the age of five weeks: a very high-fat diet, a low fat, high in carbohydrate diet, or a chow diet with a level of fat between these two extremes. These mice were mated at 35 to 40 weeks of age and the pregnant mice studied further. The researchers then looked at the activity of a large panel of genes in the placentas of the mice at 12.5 days of pregnancy. They looked at whether the pattern of activity was affected by diet and by the gender of the foetus.

 

What were the basic results?

The three maternal diets affected the activity of 1,972 genes in the placentas, with the differences in activity at least double between at least one pair of diets. The differences were more pronounced in female foetuses than in males. Each diet showed a distinct pattern of gene activity depending on the gender of the foetus.

The genes that were affected by diet are usually involved in kidney function and in sensing odours.

The researchers report that there was a tendency for more female offspring in the low-fat, high-carbohydrate diet group, but that there were too few offspring in the very high-fat diet group to determine the statistical significance of this.

 

How did the researchers interpret the results?

The researchers conclude that gene activity in the placenta of mice is affected by maternal diet and foetal gender. The placentae of female foetuses are more sensitive to maternal diet than the placentae of male foetuses.

 

Conclusion

This study investigated how the mother’s diet in pregnancy might have an effect on the developing foetus. The researchers aimed to identify alterations in the activity of genes in the placenta that could potentially contribute to this effect. They found a number of changes in gene activity as a result of different maternal diets in mice, and that these changes were also affected by the gender of the foetus. However, differences between the species may mean that results obtained in mice may not be representative of what happens in humans.

This study did not aim to investigate whether maternal diet in pregnant mice affects the gender of their offspring.

The developing foetus obtains nutrition and oxygen, and also eliminates waste, via the placenta. Therefore changes in the placenta, such as changes in placental gene activity due to diet and foetus gender, could potentially influence foetus health and possibly survival. However, as the authors themselves acknowledge: “The reason why a maternal high-fat (low-carbohydrate) diet favours survival of sons while a maternal low-fat (high-carbohydrate) diet results in more daughters continues to elude us.”

Links To The Headlines

Eating breakfast and fatty diet during early pregnancy increases chances of having a boy. The Daily Telegraph, March 9 2010

Links To Science

Mao J, Zhang X, Sieli PT, et al. Contrasting effects of different maternal diets on sexually dimorphic gene expression in the murine placenta. PNAS 2010; Published online before print

“Women who like a glass of wine after work are less likely to gain weight than those who stick to mineral water,” according to The Times, which claims that moderate female drinkers have a lower risk of obesity than teetotallers.

The research behind these claims asked a group of middle-aged American women of a healthy weight about their alcohol consumption. The women were sent follow-up questionnaires over the next 13 years to track how their weight changed. Over the course of the study most of the women gained weight, but on average those who originally consumed at least four units per day gained around 2kg less than their non-drinking counterparts.

While this study has found that higher alcohol consumption was associated with slightly lower weight gain over time, there are a number of limitations to the research. Equally, the study did not look at potential mechanisms by which alcohol could have an effect on weight, although it suggests that drinkers may have replaced dietary calories with calories from alcohol. However, the negative health effects of regular alcohol consumption are well-known, and women are advised to limit alcohol consumption to two to three units per day.

 

Where did the story come from?

This research was conducted by Dr Lu Wang and colleagues from Brigham and Women’s Hospital and Harvard University. The study was funded by the US National Institute of Health and published in the peer-reviewed medical journal Archives of Internal Medicine.

Several newspapers have reported on this research, with some suggesting that alcohol may aid weight loss. However, the research did not directly prove that alcohol consumption prevents weight gain, instead showing that the dietary and exercise habits of drinkers versus non-drinkers differed. Some news sources also reported on a theory that alcohol may be broken down in the liver to create heat rather than fat. That theory was not tested by this research.

 

What kind of research was this?

This was a prospective cohort study following a group of American women of normal weight to look at how their drinking habits affected the likelihood of them becoming overweight or obese over time.

The researchers say that alcohol contains 7.1 calories per gram and that the extra calories it contributes to the daily diet may increase weight gain. They add that studies have not provided consistent evidence that alcohol consumption is a risk factor for obesity. The researchers therefore used data from a large prospective cohort study in women to see whether there was any association between alcohol consumption and obesity in women.

 

What did the research involve?

The researchers drew participants and data from the Women’s Health Study, a randomised clinical trial that evaluated the effects of low-dose aspirin and vitamin E in the prevention of cancer and cardiovascular disease. The trial involved 39,876 female healthcare professionals aged 39 to 89 who were free of cancer and cardiovascular disease. For this subsequent alcohol study the researchers included 19,220 women with a body mass index (BMI) ranging from 18.5 up to 25, which is considered to be within the healthy range.

At the start of the study the participants were given a questionnaire asking how many alcoholic drinks they consumed. The frequency was graded in nine possible responses that ranged from “never or less than once per month” to “more than six times a day”. Their alcohol consumption was calculated according to the alcohol content in each type of beverage. The researchers defined one alcoholic unit as containing 8g of pure alcohol.

At the start of the study the researchers also collected baseline information on each participant’s age, smoking status, physical activity level, menopausal status, postmenopausal hormone use, multivitamin use, history of diabetes, hypertension (high blood pressure) and high cholesterol levels. The participants also completed a food frequency questionnaire that assigned a portion size for each specified food item. These were used to calculate an estimate of each participant’s calorie intake.

Information on the participants’ body weights was updated using follow-up questionnaires given 2, 3, 5, 6 and 9 years after the first questionnaire. In addition 16,322 of the women agreed to be followed up for a further four years, providing a dataset spanning 13 years from the initial questionnaire.

The women had their BMI calculated and categorised as normal (18.5-25), overweight (25-30) or obese (over 30). If a participant became overweight or obese while being followed up, the year in which this event occurred was recorded. If a woman developed diabetes, the date of the diagnosis was also recorded.

When the researchers performed their initial analysis they only adjusted their data to account for the women’s ages. As additional factors may have affected the women’s weight, the researchers made further adjustment to account for BMI at baseline, non-alcoholic energy intake and the type of food they ate (such as fruit and vegetables, meat, refined or whole grains, fibre and dairy produce). They also adjusted for the amount of exercise they did, their smoking status, hormone status, and any history of high cholesterol or high blood pressure.

 

What were the basic results?

The women’s baseline characteristics at the time of the first questionnaire showed that those who drank greater amounts of alcohol were more likely to be older, white, current smokers, postmenopausal, have high blood pressure and have a lower baseline BMI. They also found that although the total energy intake was greater in women who drank lots of alcoholic beverages, these women took in fewer calories from food than the non-drinkers.

Alcohol intake was associated with a greater intake of red meats, poultry and high-fat dairy products but a lower intake of whole grains, refined grains, low-fat dairy products, fats, carbohydrates and fibre. Women who consumed an intermediate amount of alcohol did more exercise than those who did not drink, or those who drank greater amounts. On average, all women put on weight over the follow-up period. However, the greatest average weight gain was in the women who did not drink alcohol.

The drinking and non-drinking groups had varied in a number of dietary and lifestyle factors at the start of the study, leading the researchers to perform a set of analyses that were adjusted to account for the influence of these variations. After these adjustments, they found that the relationship between weight gain and low alcohol consumption was stronger.

The researchers also found that 41.3% of the women had become overweight or obese during the follow-up period. When using a BMI of 30 as a cut-off, 3.8% of the women had become obese. The mean weight gain during 12.9 years of follow-up was 3.63kg for women who did not consume alcohol, compared to 1.55kg for those who consumed 30g per day or more. (95% confidence interval [CI], was 3.45-3.80kg vs 0.93-2.18KG).

 

How did the researchers interpret the results?

The researchers concluded that light-to-moderate alcohol consumption was associated with less weight gain and a lower risk of becoming overweight and/or obese over 12.9 years of follow-up in middle-aged women.

They suggested that other studies have shown that in British men, an equivalent increase in alcohol consumption was associated with increased BMI. They suggest that “male drinkers tend to add alcohol to their daily dietary intake, whereas female drinkers usually substitute alcohol for other foods without increasing total energy intake”.

 

Conclusion

This large cohort study that followed middle-aged women for almost 13 years found that there was an association between greater alcohol consumption and slightly slower weight gain over this period.

Despite the tone of press coverage, it should be remembered that this type of study can only show associations between factors, and cannot say how or whether alcohol directly causes the slower weight gain. There are also a number of limitations to this research, some of which the researchers have highlighted:

• The participants self-reported their weights and alcohol consumption, which may have resulted in a misclassification or underestimation of these values.
• The study used a single measurement of alcohol consumption taken at the start of the study. It is likely that the participants’ drinking habits changed over the 13-year study period.
• The questionnaire used in the study did not collect sufficient detail on some aspects of the women’s drinking habits. For example, it did not differentiate between women who drank a small amount on most days of the week and those who drank multiple drinks on one day of the week. These drinking patterns may have different effects on the body’s metabolism.
• The women in this study were predominantly white, female healthcare professionals who may differ in their socioeconomic status from other women, so these findings may not apply to the population as a whole or to men.
• The women included in this study were all originally in the healthy BMI range. This means the study has not looked at how the weight of women outside this range changes in relation to alcohol intake or whether alcohol may have contributed to existing weight problems.
• The average difference in weight gain between the groups was relatively small, at just over 2kg.

Given the limitations of this research, it is not possible to say whether alcohol consumption directly reduces the chances of weight gain. However, the data from this study contributes to our understanding of how related lifestyle factors such as alcohol consumption and eating habits can contribute to weight gain.

Excessive alcohol consumption is known to be bad for our health in several ways. For example, it can increase the risk of cancer and depression. Women are recommended to drink no more than two to three units a day. The daily limit for men is three to four units.

Links To The Headlines

Wine doesn't make women fat, report claims. The Daily Telegraph, March 8 2010

Drink up girls: wine isn't fattening. The Times, March 8 2010

Cheers, girls! The odd glass of wine is less fattening than water. Daily Express, March 8 2010

Links To Science

Wang L, Lee IM, Manson JAE et al. Alcohol Consumption, Weight Gain, and Risk of Becoming Overweight in Middle-aged and Older Women. Archives of Internal Medicine 2010;170(5):453-461 [Awaiting publication]

The Daily Telegraph has reported that “vitamin D 'triggers and arms' the immune system”. It said that researchers believe that vitamin D plays a key role in boosting the immune system.

The study looked at human T cells in the laboratory, and found that vitamin D was part of a complex process in which T cells become 'primed' and help to fight infection. While these findings suggest that people with vitamin D deficiency are more susceptible to infection or that vitamin D supplements might boost immunity, such theories need to be tested further before drawing any firm conclusions.

It is important to have enough vitamin D to maintain a healthy body. Vitamin D forms in our skin in response to sunlight. However, care should be taken to avoid burning or over-exposure. Vitamin D is also found in foods such as oily fish, eggs, fortified margarines, some breakfast cereals and vitamin supplements.

 

Where did the story come from?

Dr Marina Rode von Essen and colleagues from the University of Copenhagen and Bispebjerg Hospital in Denmark carried out this research. The study was funded by the Danish Medical Research Council, the Lundbeck Foundation, the Novo Nordisk Foundation, the King Christian the 10th Foundation and the A.P. Møller Foundation for the Advancement of Medical Sciences. Some of the chemicals used in the study were provided by the manufacturer Bayer Schering Pharma AG. The paper was published in the peer-reviewed scientific journal Nature Immunology.

The study was reported in The Daily Telegraph, Daily Mail, and Metro. The newspapers give reasonable coverage of this complex research. Metro includes the study’s sensible warning that sunburn should be avoided.

 

What kind of research was this?

This laboratory research investigated what happens to human T cells when they respond to foreign molecules (called antigens). T cells are immune-system cells that recognise antigens (for example molecules on the surfaces of viruses) and kill infected cells. In particular, the researchers looked at the 'priming' of the T cells, a process by which T cells prepare to respond to antigens. When exposed to an antigen, primed T cells are able to multiply in number faster and produce more chemicals to help promote further immune response than naive T cells. They looked at the role of a protein called phospholipase C, which is involved in sending signals within cells. They also looked at how vitamin D and the vitamin D receptor are involved in this process.

This type of laboratory study helps researchers to unravel the complex events that occur in individual cells in the immune system. A better understanding of how the immune system works could suggest ways of boosting immune responses. In this case, if vitamin D was found to play a role in the immune system, this would suggest that people with vitamin D deficiency might be more susceptible to infection or that vitamin D supplements might boost immunity. Such theories would have to be tested in human research before any firm conclusions could be drawn.

 

What did the research involve?

The researchers took 'naive' (unprimed by exposure to antigens) human T cells from freshly drawn blood and grew them in the laboratory. They grew some in solutions containing immune system molecules: conditions that 'primed' them for activation.

The characteristics and behaviour of the 'primed' T cells were then compared with the 'naive' T cells. This included the cells’ response to being 'restimulated' through re-exposure to the immune system molecules that originally primed their activation.

The researchers were especially interested in how much the cells produced a particular form of phospholipase C, called phospholipase C-γ1, and how this was linked to the presence of the vitamin D receptor. They also looked at what happened if they blocked the cells from responding to vitamin D. They carried out experiments to investigate how the cells switched on the production of the vitamin D receptor.

 

What were the basic results?

The researchers found that 'naive' T cells that had not been primed produced only a small amount of phospholipase C-γ1. However, following priming by exposure to the activator immune system molecules, the T cells began to produce far more phospholipase C-γ1. For this to occur, the T cells needed to be in the presence of vitamin D and the vitamin D receptor.

They also found that naive T cells did not produce the vitamin D receptors, and that these receptors were only produced when the T cells were primed.

 

How did the researchers interpret the results?

The researchers conclude that T cells produce vitamin D receptors when they are primed to respond to antigens. Vitamin D then acts via the receptor to stimulate production of phospholipase C-γ1. These changes are necessary for the T cells to be activated.

 

Conclusion

This research indicates that vitamin D is involved in the activation of the T cells of the immune system. It is important to note that this is a laboratory study, and it is useful in helping researchers to understand what happens in specific immune system cells when exposed to foreign entities such as bacteria or viruses. It does not tell us how variations in vitamin D levels might affect people’s susceptibility to infection, or what the ideal level of vitamin D is for supporting immune system responses to infection.

Other studies will no doubt look into these questions. However, as with other vitamins, it is clearly important to have sufficient vitamin D to maintain a healthy body. Vitamin D forms in our skin in response to sunlight, but care should still be taken to avoid burning or over-exposure. Vitamin D is also found in foods such as oily fish, eggs, fortified margarines, some breakfast cereals and vitamin supplements.

Links To The Headlines

How sunshine can help your body fight disease. Daily Mail, March 8 2010

Vitamin D 'triggers and arms' the immune system. The Daily Telegraph, March 8 2010

Sunshine linked to immune system boost. Metro, March 8 2010

 

Links To Science

Rode von Essen M, Kongsbak M, Schjerling P, et al. Vitamin D controls T cell antigen receptor signaling and activation of human T cells. Nature Immunology 2010; published online March 7 2010

Children’s eyes could be seriously damaged by capsules of laundry detergent, doctors have warned.

Capsules of concentrated detergent first went on sale in 2001, designed to be less messy and inconvenient than washing powders and liquids. However, hospital records suggest that curious children can be injured if they burst the brightly coloured sacks and release the cleaning agents inside.

In a letter to the British Medical Journal, ophthalmologists from the Western Eye Hospital, London, say that the corrosive substances in the cleaning capsules can cause severe burns if they get into the eyes of toddlers. The doctors reported that the capsules contribute to 40% of the chemical eye burns they treat infants for.

 

What did the report say?

The doctors say that detergent capsules were linked to 40% of the chemical eye injuries they treated in children under the age of five. The average age of those treated was two. The doctors also consulted Guy’s and St Thomas’ Hospital Poisons’ Unit in London, finding that it had received 192 enquiries in 2007-8 and 225 during 2006-7 relating to the capsules. One-fifth of these enquiries were related to children who had the detergent in their eyes.

Of the 13 children the doctors treated for detergent in their eyes, 12 experienced chemical burns to their cornea, the clear layer covering the iris and pupil. For these children, the lining of the cornea took up to three days to heal.

However, one child only had their eye washed with water on arrival at hospital. The child sustained total burns to the cornea in both eyes, taking the corneal lining seven days to heal.

 

What is the danger from these products?

According to the authors, detergent capsules contain concentrated alkaline solutions such as detergents that can cause severe chemical injuries to the eyes. They say that alkali burns are the most serious form of chemical injury to the eye, potentially causing irreversible damage that can have lifelong ramifications.

The brightly coloured contents and unusual texture of the capsules may also make them tempting playthings for exploring toddlers, who might burst them by squeezing them or placing them in their mouths. While other forms of cleaning product can also harm children, concentrated liquid capsules may be more likely to cause accidents than bottled or powdered detergents if left within a child’s reach.

 

What should I do if my child gets detergent in their eye?

If detergent gets into a child’s eyes, it is important to take action as soon as possible in order to limit further damage:

• Wash their eyes out under large amounts of cold, running water for at least 10 minutes.
• While washing, gently hold the eyelids open to help flush out as much of the detergent as possible.
• Seek medical advice promptly. You can call NHS Direct on 0845 4647.

Sterile saline solution can also be used to wash out the eyes, although it is unlikely to be available in most homes.

If the detergents are ingested (swallowed), parents should seek medical advice promptly.

 

How should I store these products if I use them?

Detergents and other cleaning products are often stored in cupboards under sinks, within easy reach of curious toddlers. Instead, store your products in a sealed container on a high shelf or within a childproof cupboard. Using baby safety gates to block doorways can also keep children out of the kitchen, where a high proportion of accidents occur.

 

Where can I get more advice on preventing and treating accidents?

Emergencies such as chemical burns to the eyes should always be referred to trained medical professionals. However, knowing how to prevent and deal with accidents are important skills to have and many organisations offer reliable advice for parents. More information is available at:

• NHS Live Well: first aid
• British Red Cross 
• Royal Society for the Prevention of Accidents (RoSPA)
• RoSPA Safe At Home

“Common painkillers ‘increase the risk of hearing loss’”, reported The Daily Telegraph.

This story is based on research on whether frequent use of aspirin, ibuprofen, and paracetamol increase the risk of hearing loss in men. It found that men who took any of these drugs more than twice a week had a small increased risk of hearing loss. This type of study can only find associations, and it does not prove that the painkillers caused the hearing loss in these men. It also did not assess why the men were taking painkillers, and it is possible that the cause of their underlying pain may have had an effect on their hearing.

Hearing loss is already an established, potential side effect of these drugs, but only regular, high doses were thought to increase risk. This study indicates there may be increased risk, albeit a small one, with lower doses as well. Further work is needed to see if this is the case and to accurately quantify the dosage and duration of use that most poses a risk to hearing. In any case, anyone who is regularly taking painkillers for any unexplained long-term pain should consult with their GP.

 

Where did the story come from?

This research was carried out by Dr Sharon G Curhan and colleagues from Harvard University Brigham and Women’s Hospital and Harvard School of Public Health. The study was funded by the National Institutes of Health and Massachusetts Eye and Ear Infirmary Foundation. The paper was published in the peer-reviewed The American Journal of Medicine.

The research was clearly and accurately covered by the Telegraph. However, the paper did not emphasise that this study only showed an association between hearing loss and frequent painkiller use and did not demonstrate that frequent painkiller use causes hearing loss through a toxic effect.

 

What kind of research was this?

This cohort study investigated whether the use of painkillers is associated with hearing loss. The researchers suggest that painkillers have been shown to cause hearing loss when taken in high doses (several grams per day). As painkillers are widespread and regularly used by a large proportion of the population, the researchers wanted to see whether taking them frequently, even at a low dose, would be associated with hearing loss.

 

What did the research involve?

The researchers used data from a large cohort study (The Health Professionals Follow-up Study). This study began in 1986 and enrolled 51,529 male health professionals, aged 40 to 75 years, and followed them for a further 18 years. Every alternate year, the participants completed questionnaires on their diet, medical history and medication use. Painkillers questioned included aspirin, NSAIDs (such as ibuprofen) and acetaminophen (paracetamol). If the participants took these medications two or more times a week, this was defined as regular use. The 2004 questionnaire asked the men whether they had been diagnosed with hearing loss.

The researchers excluded anyone who had been diagnosed with hearing loss before 1986, or who had cancer and therefore may have been treated with drugs that could affect their hearing. As hearing loss is common with increasing age, they also excluded men as they reached the age of 75 in the follow-up. This left the researchers with data from 26,917 men.

In the analysis, the results were adjusted for other factors that may affect hearing. These included age, race, body mass index, alcohol intake, folate intake, physical activity, smoking, hypertension, diabetes, cardiovascular disease, elevated cholesterol and the use of furosemide (a type of diuretic).

 

What were the basic results?

Within the 20-year study period, 3,488 of the men were diagnosed with hearing loss. After adjustment for other factors that can affect hearing loss, men who regularly took painkillers had a higher risk of developing hearing loss than men who took them less than twice per week. Each type of painkiller was associated with a different increase in risk:

• 12% increase in the risk of developing hearing loss in men who took two or more aspirin a week (hazard ratio [HR] 1.12, 95% confidence interval [CI] 1.04 to 1.20);
• 21% risk increase in men taking two or more NSAIDs per week (HR 1.21, 95% CI 1.11 to 1.33);
• 22% risk increase in men taking two or more paracetamol per week (HR 1.22, 95% CI 1.07 to 1.39).

The researchers then looked at the length of time that the participants had regularly used painkillers and whether this had an effect on the risk of hearing loss. They compared the risk of hearing loss in participants that had taken painkillers regularly for four or more years, with those who were not regular users.

Long-term regular users of aspirin were 28% more likely to develop hearing loss than non-regular users. Regular NSAID users were 33% more at risk, the same result as for paracetamol users.

Age had an effect on risk, with a lower risk for men who were over 60 compared with younger men. For example, in the under 50 group the risk to hearing of regular aspirin use compared to non-regular use was 33% (hazard ratio); however, in the over 60s this relative risk was 3% (and was not significant). All three painkillers were associated with a lower risk in older men.

 

How did the researchers interpret the results?

The researchers conclude, “regular analgesic use was independently associated with an increased risk of hearing loss. The increased risk of hearing loss seen with regular analgesic use was greatest among younger men”.

They added, “given the high prevalence of regular analgesic use and health and social implications of hearing impairment, this represents an important public health issue”.

 

Conclusion

This study found an association between regular use of three types of painkiller and a small increased risk in hearing loss. This type of study can only find associations, it cannot demonstrate that these painkillers caused the hearing loss. The researchers highlight some limitations of their study:

• Men were categorised as having hearing loss based on their own admission in the questionnaire on whether it had been diagnosed by a professional. Participants who did not report hearing loss were considered to not be impaired. The best way to assess hearing would have been through standard pure-tone audiometry, but this could not be performed due to cost and logistics reasons.
• The researchers did not have information on the participants’ lifetime noise exposure or the reasons why they took painkillers. It may be the case that the underlying cause of the pain affected the men’s hearing. In addition, there may have been differences between the regular or non-regular users of painkillers in how likely it would be for them to consult a doctor for a hearing test.
• The research was carried out in a population of predominantly white, male health professionals, and it may not be appropriate to generalise the results outside of this population.
• The three types of painkillers assessed in this research work in different ways to ease pain. The researchers did not test potential mechanisms for the increased risk in this study.

This study found painkillers to be associated with a small increased hearing loss. Certain groups of medications are already known to be associated with hearing loss, and this includes aspirin and NSAIDs along with certain antibiotics, chemotherapy drugs and diuretic (‘water’) medications. However, aspirin and NSAIDs are only thought to increase risk with high daily doses taken on a regular basis. Painkillers should always be used within the recommended dose and only as required. Anyone using these painkillers for any unexplained long-term pain should consult their GP.

Links To The Headlines

Common painkillers 'increase risk of hearing loss'. The Daily Telegraph, March 3 2010

Links To Science

Curhan SG, Eavey R, Shargorodsky J, Curhan GC. Analgesic Use and the Risk of Hearing Loss in Men. The American Journal of Medicine 2010; 123: 231-237

A handheld device could ‘zap away’ headaches according to several newspapers. They say that the device, which delivers a magnetic pulse to the back of the head, could be an alternative to drug treatments for sufferers.

The news is based on a well-conducted randomised controlled trial and has found promising results when using a ‘single-pulse transcranial magnetic stimulation’ device to treat people who frequently suffer from migraine with visual distortions (aura). Within two hours of the onset of symptoms more people were pain-free when using the handheld device than those who had used an identical dummy device.

Although the study has reliable results, there are some points to consider when putting these findings into context. Importantly, the results will need to be verified in larger trials that directly compare the technology to other active treatments for migraine, principally medication. Therefore, the news reports are premature in announcing this treatment as an ‘alternative’ to pain medications. Further issues of optimal use, effectiveness and safety also need to be explored when further researching this promising technology.

 

Where did the story come from?

This research was conducted by Dr Richard Lipton and colleagues from Einstein College of Medicine, New York and other institutions across the US. The study was funded by Neuralieve, the medical technology company that makes the prototype device being tested. The study was published in the peer-reviewed medical journal The Lancet.

 

What kind of research was this?

This was a phase 2 randomised, ‘sham’-controlled trial testing the use of a prototype ‘single-pulse transcranial magnetic stimulation’ (sTMS) device using magnetic fields to treat certain types of migraine. The study was termed a ‘sham trial’ as it compared a real device against an identical mock device that actually performed no function.

A randomised controlled trial is the best way of examining the safety and efficacy of a treatment. However, results of this trial will need follow-up in larger phase 3 trials that compare sTMS use to other active treatments for migraine (eg replace the sham sTMS device with suitable drugs) and in larger groups of people.

News coverage has generally reflected the findings of this well-conducted trial, although most reports have jumped too far ahead in hailing this as a new treatment for migraine ‘at the press of a button’. The current stage of this research, plus the fact that it hasn’t been compared to any active treatment, mean that questions still remain over its safety and efficacy.

 

What did the research involve?

This research was carried out at 18 different locations across the US and studied people who experienced migraines accompanied by aura - visual distortions that precede the pain of migraines. Aura symptoms usually last less than an hour and can include visual disturbances (such as flashing/flickering spots of lights, zigzag lines or even temporary blindness), numbness, tingling sensations and slurred speech.

All eligible adults met diagnostic criteria of having at least 30% of their migraines accompanied by aura. Their migraines also had to occur at least once a month and to be associated with moderate or severe headache in 90% of those attacks. People were excluded if their migraine was suspected to be caused by, or associated with, overuse of painkillers, use of other medications, or underlying disease or trauma.

Before the treatment phase began, the recruited participants were trained in the use of an electronic headache diary, which they used for one month to verify that they had a suitable diagnosis of migraine for the trial. Sixty-six people dropped out in this phase, after which the remaining 201 individuals were randomly allocated by computer to either sham stimulation (99 people) or sTMS (102 people). Training was given in the use of the devices before the trail.

The sTMS machine tested was a handheld device that could be positioned against bone at the base of the skull. It delivers two magnetic pulses, 30 seconds apart, when the ‘treat’ button is pressed. The ‘sham’ stimulator device was identical to the real device, even buzzing and vibrating in the same manner. Neither researchers nor participants knew which device each person was using.

Participants were instructed to treat up to three attacks over a three-month period at the onset of aura. The main outcome was being pain-free within two hours of the attack, and with secondary outcomes being no difference between the sTMS device and sham device in terms of reports of  symptoms of nausea, oversensitivity to light, and oversensitivity to sound within two hours of the attack. All participants were allowed to use their usual migraine medication throughout the trial.

 

What were the basic results?

The researchers excluded the results on 37 people who did not treat a single migraine attack during the trial. This left 164 patients (82 sTMS and 82 sham). Significantly more people treated with sTMS were pain-free within two hours (39% v 22%; 17% difference, 95% CI 3 to 31%).

At 24 and 48 hours after using the device, sustained pain-free response rates were also better in the treatment group.

There were also no differences between the sTMS and sham groups in rates of associated nausea, sensitivity to light, or sensitivity to sound. No device-related serious adverse effects were observed.

 

How did the researchers interpret the results?

The researchers conclude that early treatment of migraine with aura using sTMS resulted in increased freedom from pain at two hours compared with sham stimulation, and sustained absence of pain at 24 and 48 hours. They say that sTMS this could be a promising new treatment for migraine with aura.

 

Conclusion

This well-conducted, double-blind, randomised controlled trial has found promising results when using single-pulse transcranial magnetic stimulation (sTMS) to treat people who frequently suffer from migraine with visual aura. Within two hours of the onset of symptoms, more people were pain-free when using the handheld device than those who had used an identical ‘sham’ device.

Although the study has reliable results, there are a couple of things to consider when putting these findings into context:

• This was a phase 2 trial, which has so far compared sTMS only with no treatment in a relatively small number of people (164 completed the study). Results will need follow-up in larger phase 3 trials that compare sTMS to other active treatments for migraine (eg actual drugs rather than sham sTMS) and in larger groups of people.
• People in this trial were allowed to use medications to treat their migraine as normal, so at this stage it is difficult to extract the extent of the effect that sTMS alone is having, for example how people would feel if they used sTMS as their sole treatment for migraine. Therefore, the news reports are premature in announcing this treatment as an ‘alternative to pain medications’.
• Although no significant adverse effects of this device were observed, a greater number of people who had used this device for much longer than three months (the period of this study) would need to be observed in order to see whether there were any longer-term adverse effects or health risks of sTMS.
• As the researchers say, they have not yet explored the possible range of sTMS doses that could be given, or the optimum timing of treatment (at what stage in the headache, for example).
• The device at the current time would only be suitable for people who experience migraine with visual aura.

Overall, the findings of this study are promising, and further trials are awaited.

Links To The Headlines

New device offers hope for migraine sufferers: research. The Daily Telegraph, March 4 2010

Hand-held device on trial for migraine sufferers. BBC News, March 4 2010

The migraine zapper that can head off pain at the press of a button. Daily Mail, March 4 2010

New hope for migraine sufferers. Daily Mirror, March 4 2010

Migraine: machine that can zap the pain. Daily Express, March 4 2010

 

 

Links To Science

Lipton RB, Dodick DW, Silberstein SD et al. Single-pulse transcranial magnetic stimulation for acute treatment of migraine with aura: a randomised, double-blind, parallel-group, sham-controlled trial. The Lancet Neurology; early online publication, March 4 2010

"Vitamin pills are useless within a week of opening," the Daily Mail reported. It said that the high levels of humidity in kitchens and bathrooms make them simply dissolve even if the bottle’s lid is screwed on.

This research studied the breakdown of two common forms of vitamin C under different temperatures and humidities in the laboratory, and found that high humidity seemed to have the greatest effect.

Though the effect seen in this lab study may also occur in supplements used at home, it is not clear if the different forms of vitamin C will degrade at the same rate. Supplements usually contain other nutrients, minerals and ingredients, some of which are preservatives. For example, silica, which absorbs water, is often included.

Further research into the best storage conditions for vitamins is likely. The most useful would be testing the rate of vitamin C degradation in different formulations, and under conditions found in the home. For now, the best way to store vitamins is in their original container in a cool, dry place. Kitchens and bathrooms may not be the best storage places.

 

Where did the story come from?

The research was carried out by Ashley Hiatt and colleagues from Purdue University, Indiana, US. The research was supported by grants from the US Department of Agriculture and from Lilly Endowment, Inc. – a private philanthropic foundation set up through gifts of stock in Eli Lilly, a pharmaceutical company. The paper was published in the peer-reviewed Journal of Agricultural and Food Chemistry.

The newspapers have generally reflected these findings, without going into the complexities of the laboratory research. However, Metro’s headline that stored vitamins “go off in a week” may be misleading, as the research looked at how vitamin C breaks down, and its positive effects on the body, and not that it becomes harmful or 'goes off'. This research was also in raw vitamin C – sodium ascorbate and ascorbic acid – and not in vitamin supplements. Supplements tend to contain other ingredients, which may alter the rate at which vitamin C breaks down.

 

What kind of research was this?

This laboratory study aimed to model the degradation (breakdown) of vitamin C and to investigate how variations in humidity and temperature affect this. Vitamin C is one of the most widespread nutrient supplements, but is also highly unstable and quickly degraded by exposure to heat, light and air. As such, vitamin C is commonly monitored when determining shelf life.

The researchers say that a study looking at the degradation of vitamin C though exposure to heat and humidity would be valuable. In particular, it would help to understand the process by which vitamin C in storage absorbs moisture from the atmosphere to form a solution, known as deliquescence (when a substance melts or becomes liquid).

 

What did the research involve?

The researchers studied the two most common forms of vitamin C, sodium ascorbate and ascorbic acid, which have different deliquescence points. Complex laboratory methods were used to analyse both forms. This involved storing the vitamin C in a chamber above different saturated salt solutions to give different humidity exposures and exposing it to temperatures ranging from 4C to 40C.

After the different exposures, the researchers measured the breakdown of vitamin C using colourimetry, a form of photometric analysis that indicates the concentration of vitamin C present. The amount of moisture that had been absorbed was measured using a different type of analysis (known as gravimetric sorption analysis). The two forms of vitamin C were also analysed over an extended period of eight weeks at different temperature and moisture conditions, and regularly assessed to see at which point they achieved 50% degradation – their half-life.

 

What were the basic results?

Both humidity and temperature significantly affected the stability of vitamin C, but humidity had the greatest effect.

In brief:

• At a given temperature, sodium ascorbate absorbed moisture more readily than ascorbic acid.
• At 25C, ascorbic acid was stable in all humidity conditions for up to eight weeks, while sodium ascorbate would break down completely at the highest humidity levels (85% and 98% humidity).
• Both forms of vitamin C were stable when stored in dry conditions for up to eight weeks (0% humidity), even at temperatures of up to 40C.

The researchers say this indicates that the two forms of vitamin C are affected by different combinations of humidities and temperatures. Moisture absorption appeared to precede extensive breakdown, and was considered to be a good predictor of vitamin C loss.

 

How did the researchers interpret the results?

The researchers conclude that it is important to consider the phases of transformation that vitamin C goes through during storage when considering the shelf life of a nutrient supplement. They say that it is important to ensure it is maintained in the solid state “for enhanced stability”.

 

Conclusion

This research examined the breakdown of two common forms of vitamin C under controlled temperature and humidity conditions in the laboratory. It found that, of temperature and humidity, high humidity seemed to have the greatest effect on vitamin C breakdown. Generally, ascorbic acid was more stable than sodium ascorbate under the conditions tested in this study.

The breakdown of vitamin C does not mean that it becomes harmful or past its use-by date, but it does raise the question of whether or not the nutrients remain beneficial. This research was in two ‘raw’ forms of vitamin C, sodium ascorbate and ascorbic acid, studied in the laboratory. It is well-established knowledge that vitamin C is an unstable and easily degradable substance.

Often in supplements, vitamin C will be formulated with other nutrients and vitamins, in addition to other ingredients, some of which are preservatives (for example silica, which absorbs water). Though the effect found in this study may be replicated in bathroom cabinets and kitchens, it is not clear if vitamin C will degrade at the same rate when formulated with other ingredients and under home conditions.

Further research into the best storage conditions for vitamins is likely to occur. For now, the best way to store vitamins is in their original container in a cool, dry place. Kitchens and bathrooms often do not meet these requirements so may not be the best storage places.

Links To The Headlines

Vitamin pills 'are useless within a week of opening'. Daily Mail, March 4 2010

Stored vitamins go off in a week. Metro, March 4 2010

Hiatt AN, Taylor LS and Mauer LJ. Influence of Simultaneous Variations in Temperature and Relative Humidity on Chemical Stability of Two Vitamin C Forms and Implications for Shelf Life Models. Journal of Agricultural and Food Chemistry 2010; February 17 2010

 

 

 

Osteoporosis pills may cut the risk of breast cancer, the Daily Express has reported. A study suggests that women who take the drugs, called bisphosphonates, to treat brittle bones may reduce their risk of breast cancer.

The research compared almost 3,000 women who were diagnosed with breast cancer to a similar number of women without the disease. The researchers looked for characteristics in the two groups that might explain an increased cancer risk, including whether they had taken bisphosphonates. The women who had used the drugs for the longest time (two years) were found to be 40% less likely to develop breast cancer than women who had never used the pills.

These results will need to be confirmed with randomised trials that assess whether the drug really can prevent breast cancer. These trials are needed to ensure that the reduced cancer risk was not due to any other unmeasured or unknown factors that differed between the groups. Overall, there appears to be a plausible biological explanation for the effect seen, which justifies further research in this area.

 

Where did the story come from?

This study was conducted by Dr Polly Newcomb and colleagues from the University of Wisconsin in the US. The study was supported by the National Cancer Institute of the US National Institutes of Health and published in the peer-reviewed British Journal of Cancer.

Other newspapers also reported the findings, including the Daily Mirror, which quoted Dr Lesley Walker of Cancer Research UK. She was said to have welcomed the results, but said: "Before a drug can be recommended, thorough testing needs to be completed."

 

What kind of research was this?

This was a case control study in which the researchers evaluated whether the use of bisphosphonate medication for osteoporosis is associated with breast cancer. Animal studies and research using human cells in the laboratory have found some signs that the growth of cancers sampled from tumours that have spread to the bones (bone metastases) may be slowed by the drugs. These test also show that that the drugs may influence several phases of tumour growth and progression.

Among the strengths of this study are its large size and its careful, thorough adjustment to account for the influence of important confounding factors that may have affected the results. Some of the confounders adjusted for were body mass index, postmenopausal hormone use and smoking. Results from case control studies such as this one need to be confirmed in randomised trials to avoid the problem of confounding factors, a point that the authors acknowledge.

 

What did the research involve?

The researchers used Wisconsin’s mandatory cancer registry to identify new diagnoses of invasive breast cancer from 2003 to 2006. The identified women, who were 20 to 69 years old, were matched to similarly aged women from the general population who did not have a history of breast cancer. The women without cancer were randomly selected using state driving licence lists.

All women were asked a series of questions during structured interviews. Specific attention was given to any bisphosphonate use (the type of drug, duration and how recently it was used). The women were also asked if a doctor had made a diagnosis of osteoporosis, if they had experienced any fractures, or if their height had changed since the age of 18 (all indicators of brittle bones). Other risk factors for breast cancer were also covered in the interview.

The researchers used a complex statistical analysis technique called multivariable logistic regression in their final analysis. This analysis method was appropriate for this type of study. After excluding 55 women with incomplete data, the final analysis included 2,936 women with new diagnoses of breast cancer and a control group of 2,975 women without breast cancer to compare them against.

In their analysis, the researchers adjusted for the following risk factors, which are known to increase the risk of breast cancer or to be linked to osteoporosis:

• age
• year of interview
• number of children (0-1, 2, 3, 4 or more)
• age at first child
• strong family history of breast cancer
• body mass index one year before the study started
• menopausal status
• age at menopause
• number of screening mammograms over the past five years
• a physician diagnosis of osteoporosis
• smoking
• height change from the age of 18

 

What were the basic results?

The researchers report a link between use of bisphosphonates and breast cancer risk. They say that current use of bisphosphonates was associated with a 33% reduction in breast cancer risk compared with non-use (odds ratio 0.67, 95% confidence interval 0.51 to 0.89).

Increasing the duration of use was associated with a greater reduction in risk. The researchers say this risk reduction was observed in women who were not obese. Women with a BMI of over 30 showed a reverse trend, in which use of bisphosphonates was linked to a non-significant increased risk of breast cancer.

 

How did the researchers interpret the results?

The researchers say that use of bisphosphonates was associated with an approximately 30% reduction in breast cancer risk, and that this decrease in risk was greatest for longer durations of use and among leaner women.

They also say the link was not due to the 'primary indication for use', ie the drug’s ability to reduce bone density loss and fractures, which have been shown to be risk factors for breast cancer.

 

Conclusion

This study has several strengths and weaknesses:

• As a large case control study based on population sampling, the confidence in the results is increased.
• The researchers adjusted for several confounders in their analysis. These confounders were considered and included in the study design before the results were known. This is also a strength of the study.
• Measurements of bone mineral density were not available, so the researchers relied on patient reports of clinical symptoms and of doctors’ diagnoses of osteoporosis. Bone density is one major factor that might contribute to an increased risk of breast cancer in women taking these drugs. This means that it would have been better to have used a more accurate measurement of bone density.
• A ‘dose-response’ was seen in this study, which means that women who took the drugs for longer had a consistently reduced risk. This also suggests that the observed link is genuine.

The major problem with all case control studies is the possibility that unmeasured or unknown confounding factors may have been present, for which adjustment was not possible. For example, women who are healthier in general may have been more likely to seek treatment for osteoporosis and to have a lower breast cancer risk. Diet, physical activity and socioeconomic factors were also not adjusted for.

This was a robust study that has found a plausible link between bisphosphonate use and reduced breast cancer risk. However, as Dr Walker of Cancer Research UK has said, the link cannot be confirmed without further testing.

 

Links To The Headlines

Bone pills may cut breast cancer risk. Daily Express, March 3 2010

Bone drug cuts breast cancer risk. Daily Mirror, March 3 2010

Links To Science

Newcomb PA, Trentham-Dietz A and Hampton JM. Bisphosphonates for osteoporosis treatment are associated with reduced breast cancer risk. British Journal of Cancer (2010) 102, 799–802