Characteristics of metabolically obese, normal-weight women differ by menopause status: the Fourth Korea National Health and Nutrition Examination Survey

Objective: People with metabolically obese, normal-weight (MONW) phenotype, characterized by insulin resistance, are vulnerable to cardiovascular disease even though they are not physically obese. We assessed whether the characteristics of the MONW phenotype differed by menopause status in Korean women. Methods: A nationally representative sample of 1,736 Korean women aged 19 years or older (1,197 premenopausal women and 539 postmenopausal women), without diabetes, and with a body mass index of 18.5 to less than 25 kg/m(2) were randomly selected from the Fourth Korean National Health and Nutrition Examination Survey in 2008. MONW individuals were defined as those included in the highest quartile of a homeostatic model assessment of insulin resistance. Results: The prevalence of the MONW phenotype was highest (23.8%) in young women (<30 y) and decreased with age in premenopausal women. In postmenopausal women, there was a sharp increase in the prevalence of the MONW phenotype after the age of 60 years. After adjustment for covariates, including age, we found that young age, rural residence, high body mass index, high systolic blood pressure, low high-density lipoprotein cholesterol, high white blood cell count, and lack of regular exercise were significantly associated with the MONW phenotype in premenopausal women. However, for postmenopausal women, alanine aminotransferase was the only predictor that was independently associated with the MONW phenotype. Conclusions: The characteristics of the MONW phenotype seem to vary between premenopausal and postmenopausal women. This suggests that optimal clinical approaches to preventing cardiovascular disease in women with the MONW phenotype may differ according to menopause status.