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.

BACKGROUND

The 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 and 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 was 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, the risks of all cause (adjusted hazard ratio [aHR], 1.86; 95% confidence interval [CI], 1.43-2.43) and CVD-related (aHR, 2.20; 95% CI, 1.24-3.93) mortalities were significantly higher in those with a BMI decrease of > 10% than in those 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 BMI decrease of > 10% was associated with a high risk of all-cause and CVD-related mortalities. Thus, those experiencing significant BMI decreases should undergo a comprehensive evaluation to mitigate mortality risks.