Public health programmes to prevent type 2 diabetes generally target those at high risk of the disease, and while this can be effective for the individuals who are targeted, the potential to reduce the occurrence of diabetes in the whole population is limited. Public health strategies that aim to prevent weight gain across the whole adult population can potentially prevent type 2 diabetes, but how large is the shift in weight gain needed to cause a substantial reduction?

To investigate this, Dr Adina Feldman and colleagues from the MRC Epidemiology Unit analysed data from 33,184 people aged 30-60 years who attended two health examinations 10 years apart as part of the Västerbotten Intervention Programme. Compared with people who maintained their weight, those who gained more than 1 kg/m² had a 52% higher risk of diabetes. In their study, published in BMC Public Health, the researchers estimated that if everyone who gained weight had maintained their weight, regardless of their starting weight, one in five of all type 2 diabetes cases in the population could have been prevented, compared with just one in ten cases prevented by strategies that target individuals at high risk.