Body mass index (BMI) appears to have a threshold, rather than a cumulative, effect on the risk of diabetes, meaning most cases of diabetes could be prevented or reversed by keeping BMI below the threshold that causes insulin resistance for each individual, said researchers during an ESC Congress 2020 Late-Breaking Science session focused on diabetes and the heart.

The study, which aimed to address how BMI and polygenic scores (PGS) could be integrated to estimate lifetime risk and identify optimal treatment targets to prevent or reverse diabetes, also found that while PGS can moderately improve estimates of lifetime risk of diabetes, BMI is "a much more powerful" risk factor for diabetes. "Together, these two findings have implications relevant for screening, preventing, treating and potentially even reversing type 2 diabetes," said the study's principal investigator, Brian A. Ference, MD, MSc, FACC, of the University of Cambridge, UK, and University of Milan, Italy.

The study included 445,765 participants from the UK Biobank of whom the mean age was 57.2 years and 54% were female. Researchers assessed Inherited risk of diabetes using 6.9 million genes, while height and weight were measured at enrollment to calculate BMI in kg/m2. Participants were divided into five groups according to genetic risk of diabetes, as well as five groups according to BMI. Participants were followed-up until an average age of 65.2 years.

Over the course of follow-up, 31,298 participants developed type 2 diabetes. According to Ference and colleagues, patients in the highest BMI group (average 34.5 kg/m2) had an 11-fold increased risk of diabetes compared to participants in the lowest BMI group (average 21.7 kg/m2). The highest BMI group also had a greater likelihood of developing diabetes than all other BMI groups, regardless of genetic risk.

Using statistical methods, researchers also looked at the likelihood of diabetes being more likely in those with a high BMI over a long period of time. Upon analysis, Ference said the duration of elevated BMI did not appear to have an impact on the risk of diabetes, "suggesting that when people cross a certain BMI threshold their risk of diabetes goes up and stays at the same level of high-risk regardless of how long they are overweight."

These findings could have important implications for preventing and treating diabetes. According to Ference, both BMI and blood sugar should be assessed regularly to prevent diabetes, while efforts to lose weight are also critical when a person starts to develop blood sugar problems. "It may also be possible to reverse diabetes by losing weight in the early stages before permanent damage occurs," he said.

Clinical Topics: Diabetes and Cardiometabolic Disease, Prevention

Keywords: ESC Congress, ESC20, Metabolic Syndrome, Primary Prevention, Diabetes Mellitus

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