The incidence and prevalence of diabetes mellitus is on the rise. Lifestyle modifications such as weight loss, increased physical activity, and dietary change have all been shown to decrease rates of incident diabetes; however, some people will still progress from prediabetes to overt diabetes despite achieving weight loss, physical activity goals, or dietary changes. This pattern was observed in the Diabetes Prevention Program, a randomized trial that included an intensive lifestyle intervention arm. An understanding of how personal characteristics affect how an individual reacts to lifestyle modifications could assist in targeting diabetes prevention. A recent study from the Colorado School of Public Health examined how genetic risk for diabetes modifies the association of successful lifestyles changes with incident diabetes.
Sridharan Raghavan and Dana Dabelea from the Colorado School of Public Health, in collaboration with researchers from the Milken Institute School of Public Health, Harvard Medical School, Johns Hopkins School of Medicine, Lund University, and the National Institute of Diabetes and Digestive and Kidney Diseases, evaluated over 800 study subjects randomly assigned to the intensive lifestyle intervention arm of the Diabetes Prevention Program who were free of diabetes one year after enrollment. They examined the interactions of a diabetes genetic risk score and the achievement of three intensive lifestyle interventions (>= 7% weight loss, >= 150 minutes/week of moderate leisure-time physical activity, and/or a goal for self-reported total fat intake). They followed the participants over three years to monitor incidence of diabetes and examined both additive and multiplicative interactions. Additive interactions look at absolute diabetes incidence across populations (broken out by their diabetes genetic risk scores). Multiplicative interactions quantifies whether the combination of the diabetes genetic risk and lifestyle changes impacts diabetes risk in an individual.
Public health impact
The number of diabetes cases prevented by lifestyle modifications was greater in individuals at high genetic risk for diabetes than in individuals at lower genetic risk. Additive interactions between the genetic risk score and achievement of each or all of the lifestyle interactions proved to be significant, suggesting that genetic risk could help identify subgroups for which successful lifestyle modification could reduce diabetes risk.
