Effects of Initial Body Mass Index and Weight Change on All-Cause Mortality: A 10-Year Cohort Study in Korea

We evaluated the effects of baseline body mass index (BMI) and its changes over 4 years on all-cause mortality in Korean population. We analyzed 351 735 participants whose BMI was measured in both 2002/2003 and 2006/2007. Mortality was assessed until 2013. Multivariate hazard ratios for all-cause mortality were estimated. Underweight and severe obesity with BMI >30 kg/m² were significantly associated with higher mortality. Similarly, >5% decrease or >10% increase of BMI for 4 years was associated with the increased risk of death. Comparing the results between baseline BMI and BMI change, the BMI change showed more stable associations with mortality than the baseline BMI in subgroup analysis such as nonsmokers and healthy participants. This study suggests that BMI change could be a useful health indicator along with obesity level by BMI. In addition, maintaining a healthy weight is needed for longevity, but rapid weight change should be carefully monitored.