Abstract 67: Obesity Paradox of Cardiovascular Mortality in Older Adults: National Health Interview Survey 1997-2018

Abstract

Background: The optimal body mass index (BMI) for cardiovascular disease (CVD) prevention in older adults remains uncertain. We aimed to evaluate the relationship between BMI and CVD mortality and identify the nadirs for CVD mortality in older (≥65 years) and younger (<65 years) individuals. Methods: We used data from the 1997 to 2018 National Health Interview Survey, linked to the National Death Index (NDI). We included adults aged 18 years and older with BMI and NDI follow-up data available. We used Cox regression to estimate hazard ratios (HRs) and 95% confidence intervals (CI) for the association between BMI and CVD mortality. Fully adjusted models were stratified by age and controlled for baseline age, sex, race, income, education, marital status, diabetes, cancer, general health, physical activity, smoking, and alcohol status. Results: Among 490,037 adults, the mean(±SD) age was 47(18) years; 55% were female. During a median follow-up period of 11 years, 19,194 CVD deaths occurred. The associations between BMI and CVD mortality were J-shaped in adults aged ≥ 65 years and < 65 years. The CVD mortality was minimized at a BMI of 26 kg/m 2 in adults aged ≥ 65 years and 22 kg/m 2 in those aged < 65 years. In adults aged ≥ 65 years, being overweight was associated with a lower risk of CVD mortality (HR 0.93, [95% CI, 0.89-0.96]); having level I obesity (0.90 [0.94-1.05]) and level II obesity (1.06 [0.97-1.16]) did not increase the risk of CVD mortality; and level III obesity was associated with increased risk of CVD mortality in comparison with individuals who had a normal BMI ( Figure ). In individuals aged < 65 years, being overweight, level I, II, and III obesity were associated with a progressively higher risk of CVD mortality. Conclusion: Overweight and level I obesity seem to be protective against CVD mortality in older adults. This obesity paradox suggests that the optimal BMI might be sensitive to age. Thus, weight management should be individualized.