title: Z-score discordance and contributing factors in healthy premenopausal women with low bone mineral density: the Korean National Health and Nutrition Examination Survey 2008-9.
abstract: The premenopausal period is important for bone health and prevention of future fractures, but measuring bone mineral density (BMD) at only one site may not be sufficient to determine therapeutic strategies for low BMD in premenopausal women due to the presence of Z-score discordance. In this study, we investigated Z-score discordance in addition to contributing factors of idiopathic low BMD in healthy premenopausal Korean women. We studied 3003 premenopausal women aged 18-50 years, without secondary causes for low BMD and history of fragility fracture, who had participated in the Fourth Korean National Health and Nutrition Examination Surveys (2008-2009). Low body mass index (BMI), low vitamin D level, and low body muscle mass were associated with low BMD even in premenopausal women. Risk factors differed depending on the anatomic site. Low BMI and low vitamin D level were risk factors for low femoral neck BMD (FN-BMD), but not for low lumbar spine BMD (LS-BMD). Only total muscle mass had a slight effect on low LS-BMD. Z-score discordance was much higher than expected, in 75 and 73.8 % of the low LS-BMD and low FN-BMD groups, respectively. Our findings suggest the need to consider BMD discordance in premenopausal women and also to provide information on correctable factors affecting low BMD in younger populations. Long-term follow-up is needed to evaluate the possible effect of Z-score discordance on the prognosis of osteoporosis and subsequent fracture risk.
authors.affiliation: Division of Endocrinology and Metabolism, Department of Internal Medicine, National Health Insurance Service Ilsan Hospital, Goyang, Gyeonggi, South Korea.|Yonsei University Graduate School of Medicine, Seoul, South Korea.
authors.forename: Kyeong Hye
authors.initials: KH
authors.lastname: Park
authors.affiliation: Yonsei University Graduate School of Medicine, Seoul, South Korea.|Department of Internal Medicine, Yonsei University Wonju College of Medicine, Wonju, Gangwon, South Korea.
authors.forename: Jung Soo
authors.initials: JS
authors.lastname: Lim
authors.affiliation: Department of Internal Medicine, Seoul National University Bundang Hospital, Sungnam, Gyeonggi, South Korea.
authors.forename: Kyoung Min
authors.initials: KM
authors.lastname: Kim
authors.affiliation: Division of Endocrinology, Department of Internal Medicine, Yonsei University College of Medicine, 50 Yonsei-ro, Seodaemun-gu, Seoul, 120-752, South Korea.
authors.forename: Yumie
authors.initials: Y
authors.lastname: Rhee
authors.affiliation: Division of Endocrinology, Department of Internal Medicine, Yonsei University College of Medicine, 50 Yonsei-ro, Seodaemun-gu, Seoul, 120-752, South Korea. lsk@yuhs.ac.
authors.forename: Sung-Kil
authors.initials: SK
authors.lastname: Lim
mesh_terms: D000293:Adolescent; D000328:Adult; D015992:Body Mass Index; D015519:Bone Density; D005260:Female; D050723:Fractures, Bone / Q000453:epidemiology / Q000209:etiology / Q000378:metabolism*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009749:Nutrition Surveys; D010024:Osteoporosis / Q000150:complications / Q000453:epidemiology / Q000378:metabolism*; D017698:Postmenopause / Q000378:metabolism; D056910:Republic of Korea / Q000453:epidemiology; D012307:Risk Factors
keywords: Discordance; Low bone mineral density; Premenopausal women; Z-score