Abstract 18563: Unraveling the Interplay Between Age, Obesity, and Mortality Across Adulthood: Insights From National Health and Nutrition Examination Survey 1999-2018

Introduction: Obesity is a major public health concern in the US, but the specific effects on mortality by age remain unclear. This study examined the complex relationship between age, obesity, and mortality.

Methods: We analyzed data from the National Health and Nutrition Examination Survey (1999-2018) and linked mortality of adults aged 18 to 80 years. We examined interactions between age and obesity measures (body mass index [BMI], waist circumference, and weight) in relation to all-cause and cardiovascular mortality using Cox regression models.

Results: The study included 44,041 adults (mean age: 44.8; SD=16.2). Among them, 50.5% were female, 12.2% were Black, 72.4% were White, and 15.4% were Hispanic. Significant age-obesity interactions were observed for all-cause and cardiovascular-specific mortality (P<0.01). Younger individuals had a higher hazard ratio (HR) for all-cause mortality per one SD increase in BMI (Age < 50, HR: 1.18, 95% CI: [1.06, 1.30]) and (Age 50-70, HR: 1.07 [1.00, 1.15]) compared with older individuals (Age > 70, HR: 0.98, 0.90, 1.06]), after adjusting for covariates including sex, race/ethnicity, education, income, health insurance, physical activity, and smoking. Similar patterns were observed for all obesity measures, all-cause and cardiovascular mortality. Being underweight had a greater impact on risk in younger individuals compared with older individuals.

Conclusions: Our findings indicate significant age-obesity interactions for all-cause and cardiovascular mortality. Younger individuals who were overweight or underweight faced a higher risk of mortality compared with older individuals.