Research highlights – 22 October 2010

Research questions “Research highlights” is a weekly round-up of research papers appearing in the print BMJ. We start off with this week’s research questions, before providing more detail on some individual research papers and accompanying articles.

Neighbourhood ethnic mix and mental health
Last week the UK Equality and Human Rights Commission (which the government hasn’t thrown on to the bonfire of the quangos but which, it reckons, needs “substantial reform”) reported that “Pakistani and Bangladeshi groups are more likely to experience poor mental health, more likely to report a disability or limiting long term illness, and more likely to find it hard to access and communicate with their GPs than other groups…It is unclear how far these worse than average outcomes are related to Pakistani, Bangladeshi, and Muslim people’s relatively poor socioeconomic position.”

Jayati Das-Munshi and colleagues provide some of that missing detail in their multi-level logistic regression analysis of the ethnic minorities psychiatric illness rates in the community (EMPIRIC) survey, a cross sectional, nationally representative survey of adults in England in 2000. They looked at self reported ethnicity in “middle layer super output areas,” survey speak for geographical areas with a mean population of about 7200 people. For each 10 percentage point rise in “own group ethnic density” in these areas—which, for an individual, is the percentage of people of the same ethnic group living in the same area—there was a decreased risk of common mental disorders for all local people from ethnic minorities (odds ratio 0.94, 95% CI 0.89 to 0.99) after adjustment for age, social class, educational level, sex, marital status, and level of deprivation in the area. The reduced risk was most striking for Bangladeshi and Irish groups. Living in areas of higher own group density was also associated with fewer reported experiences of discrimination or racism and with improved social support and improved social networks for some groups.

Editorialist Helen Lester says we’ve known for nearly a century that living in areas with people of the same ethnicity may be protective for mental health. The strengths of this study, says Professor Lester, include its nationally representative data and the ways it highlights “the messy complexity of the relationship between ethnic density and mental health.” The authors agree that “There were no neat conclusions from our analyses [and] we were not able to definitively unpack the meaning of ethnic density.” For more discussion of this intriguing work, listen to our podcast interview with Dr Das-Munshi at

Interventions to promote cycling
The Mayor of London’s cycle hire scheme, which provides (almost) free bicycles for 30 minute journeys in the city, was launched amid much fanfare in July this year. However, mayor Boris Johnson might be dismayed to read Lin Yang and colleagues’ systematic review of interventions to promote cycling in seven countries, including the United Kingdom and the United States.

Of the 25 published and unpublished studies assessed, those that evaluated interventions to promote cycling at population level reported net increases of only 3.4 percentage points in the population prevalence of cycling or the proportion of trips made by bicycle. Whether interventions resulted in an increase in overall physical activity or changes in anthropometric measures was unclear.

Student BMJ has also covered the topic of interventions to promote cycling, looking specifically at the London bike hire scheme. Authors Harry Rutter and Nick Cavill question whether the public health benefits of the scheme outweigh the associated risks of injury and long term exposure to traffic related air pollution.

Nevertheless, editorialists Nanette Mutrie and Fiona Crawford argue that an increase in everyday cycling could generate a considerable public health gain and that “better measurement of the impacts of interventions on levels of cycling and physical activity is necessary…to strengthen the case that promoting cycling represents extremely good value for money for both individual and public health.”

Research online: For this and other new research articles see

Antidepressants and publication bias
Last week we published a meta-analysis reporting that the antidepressant reboxetine is ineffective and potentially harmful, and that the published literature on the drug is skewed by publication bias. The research has received considerable coverage in the press and online, much of it focusing on the “serious obstacles” the authors encountered when they tried to get unpublished clinical trial information from the drug company Pfizer, which sells the drug in Europe (BMJ 2010;341:c5641, doi:10.1136/bmj.c5641).

“Scientists accuse Pfizer of holding back studies which reveal drug sold as Edronax to be ineffective and potentially harmful,” wrote the Guardian, while the BBC stated that the public had been “‘misled’ by drug trial claims.”

Perhaps surprisingly, given that reboxetine has not been licensed in the United States, the research also got plenty of coverage across the pond. American writer Scott Hensley describes reboxetine as “the crummiest antidepressant you’ve never heard of” in his health blog on the National Public Radio website, whereas Genetic Engineering and Biotechnology News asks “Did sneaky publication tactics help Pfizer’s reboxetine slip through to market?”

The responses to this research certainly indicate how concerned people are about pharmaceutical companies sitting on data about their drugs, but what can be done? The BMJ has taken the first steps to uncovering the extent of the problem and will devote a special theme issue to the topic in late 2011.