Joo Young Lee1, Hyeon Chang Kim1, Changsoo Kim1, Keeho Park2, Song Vogue Ahn3, Dae Ryong Kang4, Kay-Tee Khaw5, Walter C Willett6, Il Suh1. 1. 1Department of Preventive Medicine,Yonsei University College of Medicine,50-1 Yonsei-ro,Seodaemun-gu,Seoul 120-752,Republic of Korea. 2. 2Cancer Policy Branch,National Cancer Center,Ilsan-ro,Ilsandong-gu,Gyeonggi-do,Republic of Korea. 3. 3Department of Preventive Medicine,Yonsei University Wonju College of Medicine,Gangwon-do,Republic of Korea. 4. 4Office of Biostatistics,Ajou University School of Medicine,Suwon,Republic of Korea. 5. 5Clinical Gerontology Unit,Addenbrookes' Hospital,University of Cambridge,Cambridge,UK. 6. 6Departments of Nutrition and Epidemiology,Harvard School of Public Health,Boston,MA,USA.
Abstract
OBJECTIVE: According to most prospective studies, being underweight (BMI<18·5 kg/m2) is associated with significantly higher mortality than being of normal weight, especially among smokers. We aimed to explore in a generally lean population whether being underweight is significantly associated with increased all-cause mortality. DESIGN: Prospective cohort study. SETTING: Korea Medical Insurance Corporation study with 14 years of follow-up. SUBJECTS: After excluding deaths within the first 5 years of follow-up (1993-1997) to minimize reverse causation and excluding participants without information about smoking and health status, 94 133 men and 48 496 women aged 35-59 years in 1990 were included. RESULTS: We documented 5411 (5·7 %) deaths in men and 762 (1·6 %) in women. Among never smokers, hazard ratios (HR) for underweight individuals were not significantly higher than those for normal-weight individuals (BMI=18·5-22·9 kg/m2): HR=0·87 (95 % CI 0·41, 1·84, P=0·72) for underweight men and HR=1·12 (95 % CI 0·76, 1·65, P=0·58) for underweight women. Among ex-smokers, HR=0·86 (95 % CI 0·38, 1·93, P=0·72) for underweight men and HR=3·77 (95 % CI 0·42, 32·29, P=0·24) for underweight women. Among current smokers, HR=1·60 (95 % CI 1·28, 2·01, P<0·001) for underweight men and HR=2·07 (95 % CI 0·43, 9·94, P=0·36) for underweight women. CONCLUSIONS: The present study does not support that being underweight per se is associated with increased all-cause mortality in Korean men and women.
OBJECTIVE: According to most prospective studies, being underweight (BMI<18·5 kg/m2) is associated with significantly higher mortality than being of normal weight, especially among smokers. We aimed to explore in a generally lean population whether being underweight is significantly associated with increased all-cause mortality. DESIGN: Prospective cohort study. SETTING: Korea Medical Insurance Corporation study with 14 years of follow-up. SUBJECTS: After excluding deaths within the first 5 years of follow-up (1993-1997) to minimize reverse causation and excluding participants without information about smoking and health status, 94 133 men and 48 496 women aged 35-59 years in 1990 were included. RESULTS: We documented 5411 (5·7 %) deaths in men and 762 (1·6 %) in women. Among never smokers, hazard ratios (HR) for underweight individuals were not significantly higher than those for normal-weight individuals (BMI=18·5-22·9 kg/m2): HR=0·87 (95 % CI 0·41, 1·84, P=0·72) for underweight men and HR=1·12 (95 % CI 0·76, 1·65, P=0·58) for underweight women. Among ex-smokers, HR=0·86 (95 % CI 0·38, 1·93, P=0·72) for underweight men and HR=3·77 (95 % CI 0·42, 32·29, P=0·24) for underweight women. Among current smokers, HR=1·60 (95 % CI 1·28, 2·01, P<0·001) for underweight men and HR=2·07 (95 % CI 0·43, 9·94, P=0·36) for underweight women. CONCLUSIONS: The present study does not support that being underweight per se is associated with increased all-cause mortality in Korean men and women.