Blog – Helen Jaques

Competing interests at medical journals: industry sponsored trials boost impact factors

November 12, 2010 1 Comment

These days medical journals are rigorous when it comes to getting researchers to declare any associations with industry that might influence how a trial is reported. Before agreeing to publish a paper, many of the top medical journals require authors to sign a comprehensive conflicts of interest form that outlines any financial or personal relationships that could be perceived as inappropriately influencing the authors’ actions with regard to the research.

But what about the journals themselves, how do they fare when subjected to the same rigorous transparency they impose on their authors? Not too well according to a study published recently in PLoS Medicine. Industry supported trials published in six major medical journals were cited more often than trials not sponsored by industry, and had a considerable bolstering effect on the journals’ impact factors – a measure of the “importance” of a journal.

The authors of this study looked at 1,353 randomised controlled trials published in six general medical journals in 1996-7 and 2005-6: Annals of Internal Medicine, Archives of Internal Medicine, BMJ, Journal of the American Medical Association, Lancet, and New England Journal of Medicine. When they categorised these trials they found that a third (32%) of trials published in NEJM in 1996-7 were industry sponsored, compared with roughly one in 10 (13%) published in BMJ. These proportions dropped for all journals by 2005-6 except for NEJM, so the same proportions nine years later were 32% and 7%.

They then looked at citations for these trials, in 1998 for the 651 published 1996-7 and in 2007 for the 702 from 2005-6. For all journals, there was a significant association between the degree of industry support among the studies published in 2005-6 and the number of citations. This was most pronounced for Annals, Archives, and Lancet, where industry sponsored trials were cited more than twice as often as trials not supported by industry.
Citations are important because they indicate how much a paper has affected a field – the more it has been cited by other authors, the more it has influenced research in the field. Having a high number of citations thus reflects well on the journal that published the study, suggesting that it is featuring the most important research.

The authors then calculated approximate impact factors for the journals by dividing the number of citations by the number of trials published in order to figure out how often the “average” article would be cited. When they removed industry sponsored trials from these equations, the impact factors dropped notably, in particular for NEJM (13-15%) and Lancet (6-11%).

Lastly, editors in chief were contacted and asked to provide information on what proportion of the journal’s total income was from sales of advertisements, reprints, and industry supported supplements. Only BMJ and Lancet provided this data.

Almost half (41%) of Lancet‘s income was from article reprints, which are often bought up by drug companies that sponsored a particular trial to promote the efficacy of their product. A further 1% of the journal’s total income was from display adverts. On the other hand, only 3% of the BMJ‘s income was from reprints and 16% was from display adverts. Neither made much money from industry supported supplements.

Then the authors got cunning. To get financial data for the three American journals – Annals, Archives, and NEJM – they dug up publicly available tax information for the journals’ parent companies. The Massachusetts Medical Society, owner of NEJM, earned 23% of its income from adverts, whereas no data was available on reprints and supplements.

For the American Medical Association, publisher of JAMA, 53% of its income was from adverts and 12% from reprints (no data on supplements). Richard Smith, former editor of the BMJ, reported that reprint sales from a single trial may lead to an income of US$1 million for a journal, so the 12% figure for JAMA is quite noteworthy. The Internal Revenue Service data did not specify the income for the American College of Physicians, publisher of Annals.

So what do all these findings mean? It seems that publishing industry sponsored trials boosts the reputation of journals, some more than others. Of course, it is important that industry data does get published rather than sit in a drawer somewhere, and it seems a bit misplaced to criticise journals for benefiting from this process. Instead perhaps journals should make clear to what degree they benefit from publishing industry supported trials – financially and status wise.

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Lundh A et al. (2010) Conflicts of Interest at Medical Journals: The Influence of Industry-Supported Randomised Trials on Journal Impact Factors and Revenue – Cohort Study. PLoS Medicine 7 (10). DOI: 10.1371/journal.pmed.1000354.

Clinical trials

What’s in placebos? No one’s telling…

October 26, 2010 No Comments

Placebos – the inert substances taken by control groups in clinical trials – are often assumed to be harmless sugar pills or something along those lines. New research has found that actually it’s impossible to know what’s in placebos because there’s precious little documentation of what exactly is used in clinical trials.

Out of 176 research studies published in four of the biggest international medical journals, only one in five fully disclosed the composition of the placebo treatment. This lack of transparency suggests that all sorts of things could be being used, some of which might be having some sort of physiological effect and compromising the validity of findings on the study drug.

Placebo controlled clinical trials investigate the effects of a particular drug on a disease by comparing people who receive the treatment against patients receiving a placebo, which looks, smells, and tastes the same as the study drug but has no active ingredients. This design accounts for the placebo effect – the possibility that people in a trial may experience a health benefit because they’re taking a drug, not because the study drug they’re taking is effective.

In this study, the authors searched for randomised, placebo controlled trials published from January 2008 to December 2009 in four top medical journals – New England Journal of Medicine, JAMA, The Lancet, and Annals of Internal Medicine. A total of 176 trials were eligible for inclusion in the study – six studies of placebo pills, 65 studies of placebo injections, and 25 studies of other treatment methods (for example, nasal spray).

Only 40 (23%) of the 176 trials studied fully disclosed the composition of the placebo treatment, and 120 (68%) did not disclose any information on the placebo at all. The remainder partially disclosed what was in the placebo treatment.

Less than one in 10 (9.3%) studies that used pills disclosed the placebo, compared with 33.8% of studies that used injections and 40.0% that assessed other treatments. When papers that referred to previous publications for their primary findings or study design were excluded, these figures fell to 8.24%, 26.3%, and 27.8%, respectively.

By not paying attention to what’s in the placebo, researchers could be burying cases where the placebo has some sort of effect that’s similar to the effect of the study drug. The authors cite the example of trials of cholesterol lowering drugs that use olive oil and corn oil as the placebo. The monounsaturated and polyunsaturated fatty acids of these “placebos,” and their antioxidant and anti-inflammatory effects, could potentially reduce lipid levels and heart disease, just like the study drug, causing researchers to underestimate the effect of the cholesterol lowering drug.

“A positive or negative effect of the placebo can lead to the misleading appearance of a negative or positive effect of the drug,” author Beatrice Golomb, associate professor of medicine at the University of California, San Diego School of Medicine, told Science Daily. “And an effect in the same direction as the drug can lead a true effect of the drug to be lost. These concerns aren’t just theoretical. Where the composition has been disclosed, the ingredients of the placebo have in some instances had a likely impact on the result of the study – in either direction (obscuring a real effect, or creating a spurious one). In the cases we know about, this is not because of any willful manipulation, but because it can in fact be difficult to come up with a placebo that does not have some kind of problem.”

The authors highlight what a huge effect this lack of transparency regarding placebos could have on medical research. “Because inferences from clinical trials propagate to clinical practice, failure to report placebo composition compromises the foundation on which medical decisions are based, and on which the fate of lives may rest,” they write.

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Golomb BA et al. (2010) What’s in placebos: who knows? Analysis of randomized, controlled trials. Annals of Internal Medicine 153 (8): 532-5 PMID: 20956710

Public health

Schemes that promote cycling seem to have limited benefit

October 21, 2010 1 Comment

City wide programmes that promote cycling – such as London’s new bike hire scheme – seem a great way to get the public active and tackle the obesity epidemic. But new research published in the BMJ suggests that interventions to promote cycling don’t have much discernible effect after all.

Public health programmes that specifically aimed to increase cycling in a population found increases the the proportion of trips made by bike or the number of bike trips per person of 3.4 percentage points at the most, whereas there was little evidence that cycling increased physical activity or reduces obesity population wide.

Adults in the UK are supposed to at least 150 minutes of moderate intensity physical activity or 75 minutes of vigorous physical activity a week, but few manage. Cycling can fit relatively easily people’s daily routines as a means of travel from place to place, so people might be more inclined to adopt and maintain this type of physical activity than something like running or swimming. Also, if people cycle rather than take the bus or get in their cars, they’re helping to reduce harmful traffic pollution – so cycling could help the environment as well as provide a double whammy of health benefits.

The authors of this paper looked at 25 controlled or “before and after” studies on the effect of various different cycle schemes, such as free bike programmes, building new cycle routes, and promoting cycling to families. The studies were from seven countries, including the UK and the US.

Six studies assessed programmes that specifically aimed to promote cycling, of which four – an intensive one-to-one scheme for obese women, improvements to a cycle route network, and two multifaceted cycle promotion initiatives at town or city level – were found to be associated with increases in cycling. For example, one study found that improving the connectivity of the cycle route network in the Dutch city of Delft increased the proportion of household trips made by bicycle from 40% to 43% over a three year period compared with a change from 38% to 39% over the same period in an area where no improvements had been made.

A further 16 studies evaluated individualised marketing of “environmentally friendly” modes of transport (walking, cycling, and public transport) via marketing and incentives such as free bus tickets. On average this approach increased the number of cycling trips each individual made by eight a year.

Three other studies examined the effects of efforts to change travel behaviour in general, such as car sharing schemes. Two of these trials found small increases in the proportion of trips made by bicycle or the frequency of cycle trips per person (+1.1 and +0.17 a week, respectively), whereas the third actually found a decrease in the proportion of bike trips of almost 12%.

Only two of the 25 studies assessed looked at the health benefits of schemes to promote cycling, one of which reported a small but positive shift in the amount of overall physical activity in the population studied.

Discussing their less that glowing findings, the authors write that “There is nevertheless a strong case for promoting cycling on health grounds,” pointing to evidence that at an individual level cycling to work or school has been shown to improve cardiorespiratory fitness and reduce mortality. “Promoting cycling is, therefore, a viable approach to improving health,” they conclude.
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Yang L et al. (2010) Interventions to promote cycling: systematic review. BMJ 341:c5293. DOI: 10.1136/bmj.c5293

Diet and nutrition

Sleep starved dieters might be thwarting their fat loss plans

October 15, 2010 No Comments

A small study from the United States has suggested that getting too little sleep might prevent dieters from losing as much body fat as they would have had they slept properly.

When individuals slept for five and a half hours a night, they lost half as much body fat as when they were allowed to sleep for eight and a half hours a night and 50% more lean body mass. These results highlight the importance of human sleep for the loss of body fat when dieting.

Many people today are overweight or obese – the prevalence of obesity in England is thought to be 33% and 28% for men and women, respectively. Furthermore, 42% of men and 30% of women are expected to be overweight in 2010.

Losing weight by dieting is one sensible way of addressing this epidemic and thus reducing the poor health associated with being overweight or obese. However, emerging data suggest that insufficient sleep might affect the response of our hormones to reduced food intake and negatively influence the metabolic effects of eating less.

A total of 12 overweight, non-smoking, middle aged (range 35 to 49 years) individuals were enrolled in this study, of whom 10 (three women and seven men) took part. Alarmingly, one woman was withdrawn from the study because the combination of calorie and sleep restriction caused heart palpitations, whereas another woman dropped out for reasons unrelated to the study.

Participants spent two 14 day stints in the University of Chicago sleep laboratory, with three months inbetween to recover. To start with six were allowed 8.5 hours of sleep a night, while the other four were only allowed 5.5 hours. Then the groups switched over so that those who had been enjoying 8.5 hours a sleep a night were only allowed 5.5, and vice versa.

Before and after each study period, fasting body weight, adiposity, fat-free body mass, and the levels of various hormones related to metabolism were measured. Participants ate their normal diet during each 14-day intervention period, but its calorie content was 10% than what they would usually eat.

Interestingly, both the sleep situations – 5.5 hours a night and 8.5 hours a night – were associated with about 3kg of weight loss. However, when people were sleeping 8.5 hours a night, roughly half of the weight loss (1.4kg) was down to reduction in fat, compared with only about a quarter (0.6kg) when people had 5.5 hours of sleep (55% less fat loss in the sleep reduction group). When sleep was restricted to 5.5 hours a night, people lost more fat-free body mass instead, which is largely made up of muscle and water (60% increase in fat-free weight loss).

People were also hungrier and had higher concentrations of the hormone ghrelin when they only got 5.5 hours of sleep a night. Ghrelin has been shown to reduce energy expenditure, stimulate hunger and food intake, and promote retention of fat. People also had a lower resting metabolic rate during the 5.5 hours a night study period – all the better to ensure the finite amount of energy available would stretch to cover the longer waking hours.

The authors suggest that in the sleep deprived state, the body concentrates increasing amounts glucose in fat tissue to support the more prolonged energy needs of the glucose hungry brain. When energy intake is reduced in this situation, the body “holds on” to fat stores to make sure enough energy is available for the drawn out waking hours and instead uses energy stored in muscle – the fat-free body mass.

The authors also suggest that people trying to lose weight who don’t get enough sleep could find it harder to stick to their diet and might be more susceptible to piling on the pounds if they do slack off. “The enhanced metabolic, neuroendocrine, and behavioral compensation in the form of increased hunger and reduced energy expenditure that develop in response to combined caloric and sleep restriction can disrupt adherence to a lower-energy diet and promote efficient weight regain once it is discontinued,” they write.

Writing in an editorial on the topic, Shahrad Taheri of the University of Birmingham, UK, and Emmanuel Mignot from Stanford Sleep Medicine Center in California suggest that sleep should be included as part of the lifestyle package for weight loss, which traditionally has focused on diet and exercise instead.

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Nedeltcheva AV et al. (2010) Insufficient sleep undermines dietary efforts to reduce adiposity. Annals of Internal Medicine 153 (7): 435-41. PMID: 20921542

Sexual health

“Do it yourself” tests for chlamydia could be missing around 80% of cases

October 5, 2010 No Comments

Commercially available home tests for chlamydia could be failing to identify between 75% and 83% of people infected when compared with the “gold standard” biochemical lab test, according to new research from the Netherlands.

The study of 772 women found that three “point of care” tests available on the internet and in pharmacies only correctly identified 17-25% of women who had chlamydia according to nucleic acid amplification testing commonly used by GPs and sexual health clinics.

Chlamydia is the most common sexually transmitted infection in the United Kingdom. More than 200,000 people were diagnosed in 2009, the majority of whom were aged 15-24. Around 50% of men and 70-80% of women who get chlamydia will have no symptoms, yet left undiagnosed chlamydia cause infertility.

Point of care tests for chlamydia usually involve the woman taking a vaginal swab herself and sending the sample to a laboratory to be tested, then going for an appointment with her doctor to get the result. Currently testing involves one doctor’s appointment to have a sample taken and a second 1-2 weeks to get the result, which is a much more time consuming approach.

The authors of this study assessed all women over the age of 16 who applied for a consultation at a sexual health clinic in Maastricht between September 2007 and April 2008. A total of 772 women with a median age of 23 were included in the final study.

When nucleic acid amplification testing was used, 11% of these women were found to be infected with Chlamydia trachomatis.

The authors then assessed whether three tests commercially available and certified in Europe – Handilab-C, Biorapid CHLAMYDIA Ag test, and QuickVue Chlamydia test – could identify which women had chlamydia.

The three tests only picked up 17.1-25.0% of women who had chlamydia (sensitivity) and correctly excluded 93.7-99.7% of those who didn’t (specificity). World Health Organization criteria indicate that point of care tests should have a sensitivity of between 43% and 65% and a specificity of 98%.

The sensitivity of two of the tests improved slightly if they were performed within 72 hours of the women taking a vaginal swab. As little as 19.8% of women who tested positive actually had chlamydia, although about 90% of those who tested negative were free from disease.

The results of this study indicate that many infections would have been missed had these point of care tests been used on their own, allowing women to go untreated and potentially spread the infection, and people with false positive results could have been treated unnecessarily.

On this basis the authors state: “In our opinion, the chlamydia point of care tests we have evaluated are not ready for widespread use.”

In an editorial on the topic, Dr Sue Skidmore from the Department of Microbiology at Princess Royal Hospital, Telford, agrees. “It is widely agreed that rapid tests for sexually transmitted infections with high sensitivity and specificity would provide advantages,” she writes, “although the introduction of their use, particularly for home use, needs to be rigorously evaluated and controlled with an assurance that robust quality assurance is in place when appropriate.”

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van Dommelen L et al. (2010) Alarmingly poor performance in Chlamydia trachomatis point-of-care testing. Sexually Transmitted Infections 86:355-359. DOI: 10.1136/sti.2010.042598

Imaging

Unexpected findings on medical imaging are usually harmless

September 28, 2010 No Comments

Imagine you go for an MRI or an x ray and the radiologist spots something they didn’t anticipate on your scan – you would be worried, right?

Well, maybe you don’t need to be. A study of more than 1,400 scan found that almost 40% showed at least one such “incidental finding” but only 2.5% were thought to show a genuine medical problem and required further clinical action.

Although spotting something by accident on a medical scan can mean that a disease or disorder is detected and treated early, the extra scans and tests that follow might be painful or dangerous if the incidental finding turns out to be clinically harmless. As such, it’s important that radiologists have some kind of idea which findings are worth acting on and which represent innocuous anatomical quirks.

The authors of this study raked through the medical records of patients at Mayo Clinic in Minnesota who had taken part in imaging research between January and March 2004.

Of the 1,426 scans for which three years of follow-up was reported, 567 (38.9%) had at least one incidental finding. Out of these people whose scan had an incidental finding, 35 (6.2%) underwent further clinical action such as follow-up imaging or invasive diagnostic tests like broncoscopy.

Four people turned out to have diseases or disorders that were medically serious or even life threatening, which would have gone undetected had they not been in an imaging study. Only one person was found to have minimal or trivial disease, which presumably would not have merited the further investigations conducted.

Six (1.1%) people with an incidental finding had treatment that resolved or improved the newly detected disorder or disease, whereas only three underwent medical or surgical treatment that resulted in lack of improvement. In the rest of the participants with an incidental finding the medical benefit or burden of the subsequent treatment was unclear.

The likelihood of an incidental finding varied considerably depending on the type of scan used – nearly two thirds (61%) of people who had computed tomography of the abdomen and pelvis had an incidental finding on their scan, compared with only 4% of people who underwent some sort of nuclear medicine procedure. However, only computed tomography and MRI of the head yielded incidental findings that received further investigation.

It seems that people whose incidental finding does represent serious disease are being checked out and few people whose odd findings on imaging are harmless are being pursued. However, the authors say: “the clinical investigation of a suspicious incidental finding that results in a benign diagnosis is not necessarily without clinical value or avoidable when presented with potentially life-threatening consequences (e.g. a solid renal mass).”

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Orme N et al. (2010) Incidental Findings in Imaging Research: Evaluating Incidence, Benefit, and Burden. Archives of Internal Medicine 170:1525-1532. DOI: 10.1001/archinternmed.2010.317

Education, Mental health

Medical students keep quiet about depression because of fear of stigma

September 15, 2010 1 Comment

Not only are a considerable proportion of medical students depressed, those who are believe they’ll lose the respect of their peers and their tutors if they speak out, according to new research in published in Journal of the American Medical Association.

The study of 505 medical students in Michigan found that more than one in 10 (14.3%) of them were depressed, almost three times as many as in the general population of the United States (prevalence 5.4%).

More than half of those who were depressed felt that telling a counselor would be risky and that fellow medical students would respect their opinions less if they knew (53.3% and 56.0%, respectively), whereas far fewer of their non-depressed peers held these views (16.7% and 23.7%).

The authors of this research invited all 769 medical students enrolled at the University of Michigan Medical School in September-November 2009 to do an anonymous internet survey on depression and their attitudes to the disease.

Women were more likely than men to have moderate to severe depression (18.0% vs 9.0%), and students who were depressed were nearly eight times more likely to have considered leaving medical school than had those with minimal depression (43.1% vs 5.6%). As many as 68% of those with depression had seriously considered committing suicide, although the overall number of students with “suicidal ideation” was small (22/505 (4.4%)).

Medical school is mentally and academically demanding, so it’s not surprising that rates of depression, burnout, and suicide are higher in medical students than in the general population. Yet despite no doubt being familiar with mental health issues given their training, medical students with depression are notoriously bad at seeking treatment. In this study, for example, approximately 70-80% of students with moderate to severe depression had not received a diagnosis or treatment for depression.

As well as worrying about what their tutors and peers thought of them, medical students with moderate to severe depression were more likely than those not depressed to think that asking for help would mean their coping skills were inadequate (61.7% vs 33.5%). They also felt that others would consider them unable to handle their medical school responsibilities (83.1% vs 55.1%).

It wasn’t just the students who were depressed who believed stigmas associated with the disease: those without depression were more likely to think that depressed medical students would be a danger to patients (25.7% vs 13.6%).

The fact that so many medical students seem to hold negative views of depression is rather worrying, not least because one study found that 30% of first year and second year medical students with depression cited stigma as a barrier to seeking treatment. It does seem counter-intuitive that this group exposed to health messages pretty much non-stop thanks to their course of study seems to sign up to negative stigmas surrounding depression.

The authors suggest that rather than the emphasis on academic excellence and professionalism scaring medical students out of reporting depression, medical education programmes could be tweaked so that students perceive looking after the mental health of themselves and their peers as a key aspect of being an outstanding doctor.
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Schwenk T, Davis L, & Wimsatt L (2010) Depression, Stigma, and Suicidal Ideation in Medical Students. JAMA: The Journal of the American Medical Association 304 (11): 1181-1190. DOI: 10.1001/jama.2010.1300

Public health

Hosting big sports events might not benefit the local population

May 24, 2010 5 Comments

Hosting an international sporting event like the Olympic Games or the Commonwealth Games is an expensive business. The London 2012 Olympic and Paralympic Games, for example, will cost a total of £9.35bn, equivalent to £150 for every man, woman, and child in the United Kingdom.

Such costs are generally justified in terms of collateral benefits for the population of the host city, both during the event and for years after – the so called “legacy” of the event.

However, Researchers in Glasgow – host of the 2014 Commonwealth Games – have searched through the sparse published and unpublished research on the topic and found little overall evidence that major multi-sport events provide health or socioeconomic benefits for the population of the host city.

They looked for studies on the long term effects of major sports events held between between 1978 and 2008 and came across very few papers – only 54 poor quality studies.

Five studies looked at the benefits on the host population in terms of health; more specifically, rates of suicide, paediatric health service demand, presentations for asthma in children (two studies), and problems related to illicit drug use. Overall, the data did not show a clear cut negative or positive health impact of major multi-sport events.

Of the studies that looked at whether sports participation in the population was affected, one found a decrease in the Manchester after the 2002 Commonwealth Games, whereas another reported upward trend in sports participation from the early 1980s to 1994 in association with the 1992 Olympic Games in Barcelona, Spain.

More studies – 18 in total – looked at whether big sports events improved economic factors, which in turn might have a positive effect on the health of the population; for example, by giving people the cash flow to pay their dentist’s fees or make healthy eating choices. But again the overall effect was unclear. Most studies did associate big sports events with an increase in economic growth and employment, but the studies often used lots of estimated data and didn’t collect the data very long after the event, so are hardly water tight. The more robust studies weren’t any more conclusive when looked at collectively – inflation increased in Barcelona and Atlanta in the run up to hosting the Olympic Games, but not in Sydney.

“The available evidence does not refute expectations of a legacy, positive or negative, but it does establish that very little is known about the impacts of previous large multi-sport events and, therefore, the possible impacts of future events,” conclude the authors. “This contrasts with official documentation used recently to promote such events,” they add curtly.

However, we Brits may not be throwing money down the drain by financing the next Olympic Games. As the authors of this study acknowledge, the research on the legacy benefits of major multi-sports events is patchy to say the least, hence why they were unable to draw any clear positive or negative conclusion. The London 2012 Olympics will be the first for which long term health and socioeconomic impacts will be explicitly measured, so should hopefully clear up whether or not hosting these big events really does benefit the local population.

Editorialist Mike Weed isn’t so sure that this effort will give us the evidence we need though, as he feels the measures being used for the 2012 event are not detailed enough. “The risk for the UK population is not that we will not get the benefits we want for our £150 a head investment in London 2012, but that there will be no robust evidence of what we have paid for,” he says.

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McCartney G et al. (2010). The health and socioeconomic impacts of major multi-sport events: systematic review (1978-2008). BMJ 340. DOI: 10.1136/bmj.c2369

Children

Mary Poppins was right: a spoonful of sugar DOES help the medicine go down

May 19, 2010 2 Comments

A new study has found that giving children up to one year old a sweet solution before jabs reduces the pain of the immunisation, providing a scientific basis for Mary Poppins’ maxim that “a spoonful of sugar helps the medicine go down.”

The meta-analysis looked at fourteen randomised controlled trials that assessed the effects of oral sucrose, glucose, or another sweet solution compared with placebo (water) or no treatment during 1674 injections in infants aged 1-12 months.

Thirteen (92.9%) of the trials found that the sweet solutions reduced various behavioural indicators of pain, such as crying, during and after immunisation compared with placebo. In the fourteenth study, the effects of a sucrose solution were only evident during a single immunisation and not for the second and third injections. The pain reduction was largely seen after the procedure had been completed rather than during the procedure.

Although the sweet solutions reduced behavioural signs of pain, they had less of an effect on physiological signs: none of the studies found that glucose or sucrose solutions reduced heart rate in infants during immunisation. On the other hand, one study found that infants who received a glucose solution (and were allowed to suck on a dummy) had lower levels of cortisol, the stress hormone,in their saliva after immunisation than infants who received water (with or without a dummy).

When data from the studies were pooled, sweet solutions were found to reduce the incidence of crying by 20%, the proportion of crying time by 10%, and the duration of crying time by 12 seconds compared with placebo.

The 14 studies all used different volumes and concentrations of sucrose and glucose, so the authors were not able to determine an optimal dose of sweet solution to be used in infants during immunisation. However, the findings did imply that more concentrated sugar solutions – for example, 50% sucrose in water – are more effective.

The authors recommend that “sucrose or glucose along with other recommended physical or psychological pain reduction strategies, such as non-nutritive sucking [e.g. using a dummy], breast feeding or effective means of distraction, should be consistently utilised for immunisation.”

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Harrison D et al. (2010) Efficacy of sweet solutions for analgesia in infants between 1 and 12 months of age: a systematic review. Archives of Disease in Childhood DOI: 10.1136/adc.2009.174227

Public health

Hookah smokers more likely to use marijuana or other illicit drugs

May 17, 2010 No Comments

Young people who smoke tobacco through a water pipe – also known as a hookah, shisha, or goza – are more likely to use illicit drugs than their non-smoking contemporaries, according to a study of young Canadians. Most notably, hookah smokers were much more likely to smoke marijuana: 74% of water-pipe users reported marijuana use, compared with 35% of non-users.

A hookah or shisha comprises an upright device with a small platform where tobacco, often flavoured, is burned, a metal body, a base half-filled with water, and a tube with a mouthpiece for inhaling.

Smoking tobacco using water pipes is an old Arabic tradition that is becoming more popular in the Western world, with an estimated 40% of US college students and 38% of British university students having ever used a hookah.

The rise in popularity is thought to be linked to the perception that smoking tobacco through a water pipe is harmless. However, water pipe smoke may contain greater amounts of tar and heavy metals, such as lead, than cigarette smoke and has been linked to lung cancer, heart disease, and infectious diseases.

In this study, the authors posted questionnaires to 1,208 18-24 year olds who lived in the Montreal area of Canada, 878 (73%) of whom responded and 871 (72%) of whom were included in the analyses.

A total of 204 participants (23%) reported having smoked tobacco using a water pipe in the past year. Among these water-pipe users, 78% smoked water-pipes less than once per month, 19% smoked 1-3 times per month, and 3% smoked 1-6 times per week. None used a water pipe every day.

Individuals who had used a hookah were younger, more likely to be male and not living with their parents, and had a higher household income than those who hadn’t, leading the authors to suggest that “Water-pipe users may represent an advantaged group of young people with the leisure time, resources, and opportunity to use water-pipes.” So hookah smokers are nice middle class kids with too much time on their hands then?

Compared with people who hadn’t used a water pipe in the previous year, those who had were more likely to have also used cigarettes and other tobacco products like chewing tobacco or snus and to have used alcohol, including having up to five or more drinks on one occasion (i.e. to a binge drinking level). Interestingly, a third of water-pipe users had not smoked cigarettes in the past year, perhaps using a hookah as a perceived “healthier” alternative.

Water-pipe users were more likely to have used marijuana (74% vs 35%) or other illicit drugs like speed or cocaine (33% vs 11%) in the past year, suggesting perhaps that smoking tobacco through a water pipe may act as a “gateway” to using more harmful substances. Nevertheless, the authors point out that the design of their study means no cause and effect inferences can be drawn between using a hookah and illicit drug use.
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Dugas E et al. (2010) Water-Pipe Smoking Among North American Youths. Pediatrics DOI: 10.1542/peds.2009-2335

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