Modification of Risk for All-Cause and Cardiovascular Disease-Related Mortality With Changes in the Body Mass Index: A Prospective Cohort Study With 12 Years Follow Up

Objectives: The longitudinal impact of changes in body mass index (BMI) on the risk of all-cause and cardiovascular disease (CVD)-related mortality has not been extensively studied. We examined whether changes in BMI status over time are associated with risk of all-cause and CVD-related mortality. Methods: This longitudinal study recruited 90,258 adults between 2002-2008 from the Taiwan MJ cohort who underwent repeated BMI measurements at an interval of 3.3 years and were followed up for all-cause and CVD-related mortality over 12.1 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 1,094,606 person-years of follow-up, 2,084 participants died, including 391 (18.8%) CVD-related deaths. After adjusting for other covariates, >10% increase (adjusted hazard ratio aHR, 1.36; 95% confidence interval CI, 1.09-1.70) or >10% decrease of BMI (aHR, 1.86; 95% CI, 1.43-2.43) was significantly associated with higher risk of all-cause mortality, compared with stable BMI. Participants with obesity at baseline who had BMI increase of >10% during the follow-up period had a significantly higher risk of all-cause (aHR = 2.30; 95% CI:1.38-3.85) and CVD-related mortality (aHR = 3.44; 95% CI:1.33-8.89). Conclusions: A >10% increase in BMI in individuals with obesity was significantly associated with a higher risk of all-cause and CVD-related mortality. Our findings suggest that individuals with adiposity should adopt measures to reduce body weight to prevent premature mortality. Funding Sources: This study was supported by the Australian National Health and Medical Research Council Investigator Grant (APP1194510).