Obesity and Mortality Risk: New Findings from BMI Trajectories

Hui Zheng, Ohio State University
Dmitry Tumin, Ohio State University
Zhenchao Qian, Ohio State University

Little research has addressed the heterogeneity and mortality risk of BMI trajectories among older populations. Applying latent class trajectory models to 9,538 adults aged 51 to 77 from HRS Survey (1992-2008), we capture six latent BMI trajectories. Survival analysis finds that people in the “overweight upward” trajectory have the highest survival rate, followed by “overweight-obesity”, “normal weight upward”, “class I obese upward”, “normal weight downward”, and “class II/III obese upward” trajectories. Results are robust after controlling for demographic and socioeconomic characteristics, smoking status, ADL limitations, a wide range of chronic illnesses, and self-rated health. Further analysis suggests BMI trajectories are more predictive of mortality risk than static BMI status. Attributable risk analysis finds about 7.6% of deaths after age 51 among the 1931-1941 birth cohort are due to obesity upward trajectories. This suggests trajectories of increasing obesity past age 51 pose a substantive threat to future gains in life expectancy.