Poor diet associated with increased diabetes risk across all gradients of genetic risk

A poor diet, irrespective of genetic risk factors, is associated with a 30% increased risk of diabetes. Genetic risk factors and diet quality are independently associated with type 2 diabetes; a healthy diet is linked to lower diabetes risk across all levels of genetic risk. That concludes a study of more than 35,000 United States (U.S.) adults publishing recently in PLOS Medicine by Jordi Merino of Massachusetts General Hospital, U.S., and colleagues.

Both genetic and lifestyle factors are known to contribute to individual susceptibility to type 2 diabetes. Previous studies have shown that adherence to a healthy lifestyle is associated with reduced risk of type 2 diabetes across genetic profiles, but whether genetic profiles, in part, interact with lifestyle factors was unclear.

In the new study, researchers analysed data from three extensive cohort studies, including 35,759 U.S. health professionals followed for 902,386 person-years of follow-up.

The team found that irrespective of genetic risk, a low diet quality, as compared to high diet quality, was associated with a 30% increased risk of type 2 diabetes. The relative risk of type 2 diabetes was 1.29 per standard deviation increase in the global polygenic score.

In addition, the joint association of low diet quality and increased genetic risk was similar to the sum of the risk for each factor alone, further supporting independent associations. That said, one limitation of the study was that the cohort sampling might not necessarily generalise to other populations.

The researcher adds, "This study provided evidence that the risk of type 2 diabetes attributed to increased genetic risk and low diet quality is similar to the sum of the risks associated with each factor alone. Such knowledge could serve to inform and design future strategies to advance the prevention of diabetes."