Type 2 diabetes has long been known to be associated with many different risk factors — some of which you can control, some of which you can’t. One risk factor that no one can control is the genes they inherit, which have been shown in previous studies to play a substantial role in whether you develop diabetes.
But there are many established risk factors for type 2 diabetes other than your genes, including exposure to certain chemicals and how much physical activity you get. One risk factor that may have something to do with your genes — but isn’t exclusively genetic — is your body weight. And new research shows that it may play an important role in whether you develop diabetes.
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Comparing genetic risk and body weight
The latest study, presented at the European Society of Cardiology (ESC) Congress 2020, was conducted by researchers at the University of Cambridge in England and the University of Milan in Italy. Its goal was to identify people, based on their genetic risk and body weight, who were at highest risk for developing type 2 diabetes to help doctors focus on preventing the condition in this population.
The researchers analyzed the genetic risk of developing diabetes in all participants based on 6.9 million genes, and divided participants into five groups based on low to high diabetes risk. They also measured each participant’s body-mass index (BMI, a measure of body weight that takes height into account), and divided participants into a separate set of five groups based on low to high BMI.
During a follow-up period that averaged about 8 years, over 30,000 participants developed type 2 diabetes. Overall, BMI was found to have a bigger impact than genetic risk on developing diabetes. Participants in the highest BMI group were 11 times as likely to develop diabetes as those in the lowest BMI group. In fact, members of this group had the highest diabetes risk regardless of where they fell in terms of genetic risk.
The researchers also found, based on a statistical analysis, that it didn’t seem to matter how long someone was at a higher BMI for their diabetes risk to increase. As soon as someone reached a certain BMI, their diabetes risk increased accordingly.
Weight threshold for diabetes?
According to the lead researcher, the results of this study suggest that each person may have a BMI threshold for developing type 2 diabetes. In other words, once a person reaches a certain body weight, their risk of diabetes increases dramatically. At what body weight this happens will be different for each person, based on their genetic risk for diabetes, lifestyle and other factors.
Staying below your personal BMI threshold for heightened diabetes risk could be an important way to prevent diabetes, if this theory holds true. This threshold may become clear based on regular measurement of blood glucose levels, showing how weight gain contributes to elevated blood glucose — even if these levels aren’t high enough to indicate diabetes.
Reversing weight gain in these early stages, the researchers note, may also help reverse diabetes risk and prevent a person from developing diabetes. There is likely to be a window of time — and body weight — where weight loss plays a critical role in reducing diabetes risk. In fact, it may be possible to prevent most cases of type 2 diabetes by losing weight at this critical stage.
More research is needed to learn what role, if any, genetic risk factors might play in determining a person’s BMI threshold for elevated diabetes risk.