Abstracts

Encouraging families to move from poor neighbourhoods reduces obesity

Encouraging people to move out of poor neighbourhoods had a discernible effect on their risk of obesity and diabetes in a randomised social experiment from the USA.

The experiment began in 1994 in public housing developments where more than 40% of families were living below the US government’s poverty threshold. Just under 4500 women with young children agreed to take part, and roughly a third were given vouchers to subsidise their rent on the condition that they moved to a more affluent neighbourhood. Another third were given similar vouchers with no strings attached, and the final third (controls) received nothing.

Between 10 and 15 years later, 31.1% of the women encouraged to move had a body mass index of 35 or more compared with 35.5% of control women — a significant difference. Rent vouchers for more affluent neighbourhoods were also associated with a slightly but significantly lower prevalence of severe obesity (body mass index of at least 40), and diabetes (glycated haemoglobin of at least 6.5%). Women given the rent subsidy to use wherever they wanted also looked healthier than controls at the end of follow-up, but the differences were smaller and not statistically significant.

We know that being poor is a risk factor for obesity and diabetes. This novel social experiment suggests that the environment of poor neighbourhoods is probably part of the problem, and that giving families the opportunity to move out can help, say the authors. Roughly half of the families took advantage of the opportunity in this study.

Ludwig J et al. N Engl J Med 2011;365:1509-1519.

Bridget Farham