Purpose: Both duration of obesity and degree of obesity are critical risk factors for incident diabetes, and are increasing among younger generations of US individuals. Our objective was to project future type 2 diabetes (T2D) rates for the US population accounting for these trends.
Methods: Using data from the National Health and Nutrition Examination Surveys, we estimated cumulative excess body mass index (BMI) years, a composite measure of the degree to which a person’s BMI exceeds their ideal body weight and the duration for which they carry this weight over their lifetime, for current US birth cohorts. To simulate the overall burden carried over a lifetime (2 to 100 years), cumulative excess BMI years were estimated into the future for younger birth cohorts based on current trajectories. Age-specific probabilities for developing T2D based on cumulative excess BMI years.were derived from the National Longitudinal Survey of Youth. We then constructed a state transition model projecting diabetes prevalence across US birth cohorts. Model results were calibrated against existing diabetes prevalence data from NHANES.
Results: In this model which was based on weight trends for the US population, younger birth cohorts had higher cumulative excess BMI years, resulting in higher diabetes prevalence rates. For example, by age 20, diabetes prevalence rates were 20% higher for the 1996-2005 birth cohort compared with the 1946-1956 birth cohort. These differences magnified as the cohorts aged; by 60 years of age, rates were 60% higher (24.9% vs. 15.7%), and by 80 years of age, rates were 80% higher (60.4% vs. 33.1%). These estimates are higher than previous projections of a 1 in 3 lifetime risk of diabetes for the US population, which did not account for degree and duration of obesity among younger US birth cohorts.
Conclusions: The increasing cumulative excess BMI years carried by younger generations due to the recent childhood obesity epidemic will result in even greater rates of T2D than previously projected. The model will be further expanded to examine the impact of these birth cohort trends on rates of diabetes complications and mortality for the US population, which will provide clinicians and policymakers with critical information for guiding future health policy focused on treatment and prevention of T2D.
See more of: The 32nd Annual Meeting of the Society for Medical Decision Making