Excess body weight is a much more powerful risk factor for developing type 2 diabetes than genetics, according to a new study. Bringing weight below an individualized “trigger” threshold could prevent or even reverse the disease, investigators say. 

Data from more than 440,000 adult participants in the UK Biobank study was grouped according to genetic risk of diabetes, and body mass index (a measurement of weight adjusted to height). The group with the highest BMI had 11 times the risk of diabetes compared with participants in the lowest BMI group. The highest BMI group also had a greater likelihood of developing diabetes than all other BMI groups, regardless of genetic risk. 

In addition, being overweight for a longer period of time had no effect on risk, the researchers found. This result suggests that when a certain BMI threshold is crossed, the odds of developing diabetes increase and remain high — no matter how long an individual is overweight, said Brian Ference, M.D., an epidemiologist from the University of Cambridge, England, and University of Milan, Italy.

“The findings indicate that most cases of diabetes could be avoided by keeping BMI below the cut-off which triggers abnormal blood sugar,” Ference said. “This means that to prevent diabetes, both BMI and blood sugar should be assessed regularly. Efforts to lose weight are critical when a person starts to develop blood sugar problems,” he concluded.

The study was presented Monday at the European Society of Cardiology Congress 2020.