Projected Trends of Obesity throughout the Life Course According to Sex, Race, and Birth Cohorts in the United States

BackgroundMost research on obesity trends and projections has focused on changes across calendar years. However, as the risk of disease increases with cumulative exposure to obesity, it is crucial to characterize the obesity landscape through a life-course perspective and across birth cohorts. ObjectiveTo enhance the accuracy of obesity epidemic projections throughout life course and across birth cohorts in the US. DesignCross-sectional and cohort study. SettingUnited States ParticipantsIndividuals participated in three National Health Examination Surveys (NHES) from 1959 to 1970 and 18 National Health and Nutrition Examination Surveys (NHANES) from 1971 to 2020. MeasurementsBody mass index (BMI) distributions by sex, race, and birth cohort. ResultsBy leveraging over 40 years of cross-sectional and longitudinal data from nationally representative surveys, we developed models to estimate historical and future BMI distributions in the US for both children and adults throughout their life course. We also calculated life-years of exposure to overweight and obesity, according to sex, race, and birth cohort. Our findings reveal significant increases in these metrics among birth cohorts since 1965 and highlight differential trends by sex and race for the 1965, 1985, and 2005 cohorts. LimitationsAssumption that model parameters will hold in the future. ConclusionOur approach significantly expands upon previous models by projecting life course with continuous BMI distributions informed by longitudinal trajectories, explicitly accounting for variations in birth cohorts. Primary Funding SourceNational Institutes of Health.