BMI cut-offs for obesity and overweight need to be lowered for certain ethnicities to optimise type 2 diabetes prevention and management, according to a group of epidemiologists and clinicians.

The team, led by the University of Oxford, says making care conditional on BMI values recommended by the World Health Organization (WHO) is not optimal for people who are Black, south Asian, Chinese or Arab.

The study of almost 1.5 million adults in the UK’s Clinical Practice Research Datalink database of primary care patients is the most extensive yet to associate BMI with the incidence of type 2 diabetes (T2DM).

Participants were registered with an English GP at some point between 1990 and 2018, had at least a year of follow-up data, and did not have diabetes when their first BMI was recorded.