IJE Advance Access published online on September 17, 2009
International Journal of Epidemiology, doi:10.1093/ije/dyp282
Increases in body mass index over a 7-year period and risk of cause-specific mortality in Korean men
1Department of Family Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
2Department of Family Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
3Department of Epidemiology, School of Public Health and Institute of Health and Environment, Seoul National University, Seoul, Korea.
* Corresponding author. Department of Family Medicine, Asan Medical Center, University of Ulsan College of Medicine, 388-1, Poongnap-dong, Songpa-gu, Seoul 138-736, Korea. E-mail: hyesoon{at}amc.seoul.kr
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Abstract |
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Background The association between increased body mass index (BMI) and subsequent mortality remains unclear in Asians. This study investigated the associations between BMI increases and cause-specific mortality in middle-aged Korean men.
Methods We conducted a retrospective cohort study of 473 358 Korean men aged 30–64 years, who had undergone health examinations in both 1992 and 1998 and were followed up during 1998–2004. Cox proportional hazards for cause-specific 7-year mortality in relation to BMI changes after stratification of baseline BMI status were analysed.
Results Mortality from cardiovascular disease (CVD) was associated with BMI in both 1992 and 1998. Non-CVD mortality was inversely associated with BMI in both 1992 and 1998. We cross-classified participants into groups based on their baseline BMI levels and percent BMI changes during follow-up; men with the lowest BMI level at baseline (BMI in 1992 <21 kg/m2) and stable BMI during follow-up (percent change in BMI <5%) were included in the reference category. Compared with the reference group, CVD mortality was higher in initially obese men (BMI in 1992 
25 kg/m2) with any increase of BMI, and in initially lean men (BMI in 1992 <21 kg/m2) or initially overweight men (BMI in 1992 23–24.9 kg/m2) with BMI increases of 10%. BMI increases of 5.0–9.9% in men with baseline BMI <25 kg/m2 and stable BMI in men with baseline BMI 21 kg/m2 appeared to lower the risk for non-CVD or all-cause mortality, to below the levels seen in the reference group.
Conclusions Among middle-aged Korean men, obesity or severe weight gain was detrimental to CVD mortality. An increase in BMI appeared to have a predictive value for CVD mortality, especially when used in combination with baseline BMI level. In contrast, moderate weight gain in non-obese men seemed to protect against non-CVD and all-cause mortality.
Keywords Body mass index, body mass index increase, cardiovascular mortality, cause-specific mortality
Accepted 23 July 2009