Copyright @ 2009 The North American Menopause Society. Unauthorized reproduction of this article is prohibited. Menopause: The Journal of The North American Menopause Society Vol. 16, No. 5, pp. 998/1003 DOI: 10.1097/gme.0b013e3181a03807 * 2009 by The North American Menopause Society The relationship between reproductive factors and metabolic syndrome in Korean postmenopausal women: Korea National Health and Nutrition Survey 2005 Geum Joon Cho, MD, Hyun Tae Park, MD, PhD, Jung Ho Shin, MD, PhD, Tak Kim, MD, PhD, Jun Young Hur, MD, PhD, Young Tae Kim, MD, PhD, Kyu Wan Lee, MD, PhD, and Sun Haeng Kim, MD, PhD Abstract Objective: Postmenopausal women are known to have a higher prevalence of metabolic syndrome compared with premenopausal women. However, there are few studies that have investigated the effects of reproductive factors on metabolic syndrome in postmenopausal women. The objective of this study was to evaluate the association between reproductive factors and metabolic syndrome in postmenopausal women. Methods: A total of 892 postmenopausal women who participated in the 2005 Korean National Health and Nutrition Examination Survey were included. We determined an association between reproductive factors and metabolic syndrome. Results: Using a multivariate logistic regression analysis, it was found that age at first birth was negatively associated with metabolic syndrome. Having the first baby at a later age was associated with a decreased risk of having metabolic syndrome (odds ratio, 0.95; 95% CI, 0.90-0.99). However, other reproductive factors including age at menarche, age at menopause, parity, lifetime estrogen exposure, years since menopause, number of pregnancies, history of lactation, and oral contraceptives or hormone therapy use were not associated with metabolic syndrome. Conclusions: Among various reproductive factors, age at first birth was negatively associated with metabolic syndrome in Korean postmenopausal women. Key Words: Menopause Y Metabolic syndrome Y Reproductive factor. A woman’s reproductive factors are clearly related to chronic diseases including diabetes mellitus (DM), cardiovascular disease (CVD), and stroke. An earlier age at menarche has been associated with metabolic risk factors for CVD, 1 along with an increased risk for developing DM 2 and stroke. 3 In addition, an earlier age at menopause has been associated with an increased risk of CVD 4 and cardiovascular mortality. 5,6 Lifetime estrogen exposure has been inversely related with noncardioembolic ischemic stroke 3 and mortality due to CVD. 6 Moreover, lactation has been associated with a decreased incidence of DM 7 and hypertension. 8 Metabolic syndrome is a clustering of metabolic abnor- malities that collectively increase the risk for developing DM, CVD, stroke, and overall mortality. 9,10 Postmenopausal women have a higher prevalence of metabolic syndrome than premenopausal women. Postmeno- pause status was found to be an independent risk factor for metabolic syndrome. 11,12 However, there are few studies that have investigated the effects of reproductive factors on metabolic syndrome in postmenopausal women. The aim of this study was to evaluate the association between reproductive factors and metabolic syndrome in Korean postmenopausal women. METHODS Study population This study was based on data obtained from the Korean National Health and Nutrition Examination Survey among noninstitutionalized Korean civilians. This survey was con- ducted by the Korean Ministry of Health and Welfare in 2005. This survey was a nationwide representative study using a stratified, multistage probability sampling design for the selection of household units. The survey consisted of four components: the Health Interview Survey, the Health Behavior Survey, the Nutrition Survey, and the Health Exam- ination Survey. There were approximately 246,000 primary sampling units, each of which contained approximately 60 households. Two hundred sampling frames (12,000 house- holds) from the primary sampling units were randomly selected throughout South Korea. The survey was completed Received December 10, 2008; revised and accepted February 5, 2009. From the Department of Obstetrics and Gynecology, Korea University College of Medicine, Seoul, Korea. Financial disclosure/conflicts of interest: None reported. Address correspondence to: Sun Haeng Kim, MD, PhD, Department of Obstetrics and Gynecology, College of Medicine, Korea University, Medical Center, 126-1, 5-ga Anam-dong, Seongbuk-gu, 136-705, Seoul, Korea. E-mail: md.gjcho@gmail.com 998 Menopause, Vol. 16, No. 5, 2009