Clinical Endocrinology

Higher mortality in metabolically obese normal-weight people than in metabolically healthy obese subjects in elderly Koreans

Authors


Correspondence: Nan Hee Kim, Division of Endocrinology and Metabolism, Department of Internal Medicine, Korea University Ansan Hospital, Gojan 1 dong, Danwon-gu, Ansan-si, Gyeonggi-do 425-707, Korea.Tel.: 82 31 412 6563; Fax:82 31 412 5659; E-mail: nhkendo@gmail.com

Abstract

Objective

The purpose of this study was to investigate the impact of body mass index (BMI) and the presence of metabolic syndrome (MetS) on all-cause and cardiovascular mortality in elderly Korean men and women, and especially to compare metabolically obese normal-weight (MONW) and metabolically healthy obese (MHO) subjects.

Patients and methods

A total of 2317 elderly people (over 60 years of age) were studied using follow-up data from the South-West Seoul (SWS) Study, a prospective cohort study. Mortality from all causes and cardiovascular disease (CVD) were evaluated according to the combination of the presence or absence of MetS and Asian-specific body mass index (BMI) criteria (BMI <23 kg/m2; normal weight, BMI 23–24·9 kg/m2; overweight, BMI ≥25 kg/m2; obesity).

Results

During a median follow-up of 10·3 years, 393 subjects died, including 126 from CVD. Among subjects with MetS, all-cause and CVD mortality were significantly higher in normal-weight subjects than overweight or obese individuals in Cox proportional-hazard models adjusted for confounding factors. Furthermore, among six groups with various MetS/BMI combinations, MONW individuals had the highest risk, whereas overweight subjects without MetS had the lowest risk of death from all causes and CVD [HR = 2·2 (95% CI = 1·4–3·4), HR = 3·0 (95% CI = 1·4–6·6) respectively]. Interestingly, all-cause mortality was significantly higher in MONW than MHO individuals.

Conclusions

In contrast to MHO subjects, elderly individuals with the MONW phenotype exhibited greater all-cause mortality during 10 years of follow-up.

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