Modification of Risk for All-cause and Cardiovascular Disease-related Mortality with Changes in the Body Mass Index in Older Individuals: A Population-based Cohort Study

Introduction: Existing evidence evaluating the impact of change in body mass index (BMI) on the risk of all-cause and cardiovascular disease (CVD)-related mortality in older people is limited and inconsistent. This population-based cohort study evaluated the association of changes in BMI over time with all-cause and CVD-related mortality in older adults. Methods: We recruited 55,351 adults aged over 65 years between 2006-2011 from Taipei Elderly Health Examination Program who underwent repeated annual health examinations at 3.2 year-intervals and were followed-up for mortality over 5.5 years. Cox proportional hazard and Fine-Gray sub-distribution hazard models with death from non-CVD causes as the competing risk were used to determine the impact of changes in BMI status on the risk of all-cause or CVD-related mortality, respectively. Results: Over 227,967 person-years of follow-up, 4,054 participants died, including 940 (23.2%) CVD-related deaths. After adjusting for other covariates, >10% decrease of BMI was significantly associated with a higher risk of all-cause (adjusted hazard ratio [AHR]= 1.93; 95% confidence interval [CI]: 1.74-2.13) and CVD-related mortality (AHR= 1.96; 95%CI: 1.60-2.40), compared with stable BMI. Sensitivity analysis showed that a >10% decrease in BMI was significantly associated with a high risk of all-cause and CVD-related mortality in participants with normal weight, underweight, overweight, or obesity at baseline. Discussion/Conclusion: Older adults with >10% decrease in BMI are at high risk of all-cause and CVD-related mortality. Our findings suggest that older individuals experiencing a substantial reduction in BMI should undergo a thorough evaluation to minimize the risks associated with mortality.