وضعیت تغذیه ای و اجتماعی اقتصادی ضعیف با پوکی استخوان در زنان کره ای پس از یائسگی ارتباط دارد: داده هایی از چهارمین نظر سنجی بررسی تغذیه و بهداشت ملی کره ۲۰۰۹ Poor Socioeconomic and Nutritional Status Are Associated with Osteoporosis in Korean Postmenopausal Women: Data from the Fourth Korea National Health and Nutrition Examination Survey (KNHANES) 2009

INTRODUCTION Osteoporosis is a significant public health problem in South Korea. According to the bone mineral density (BMD) data collected in the Fourth Korea National Health and Nutrition Examination Survey (KNHANES) 2009, about 39% and 8% of South Korean women and men aged 50 and over had osteoporosis, respectively [1]. These rates are almost four times higher than those in the U.S. population, at about 10% and 2%, respectively [2]. Also, the number of osteoporosis-related fractures significantly increased during the period of 2005–۲۰۰۸ in South Korea [3]. The residual lifetime probability of osteoporosis-related fractures at the age of 50 was 59.5% for women and 23.8% for men in South Korea in 2008 [3]. Given the rapidly growing older population, insufficient calcium intake, reduced physical activity, and increased sedentary behaviors in South Korea [1,4], it is projected that osteoporosis may become more prevalent in the near future. Several small studies have reported the characteristics of Korean women with osteoporosis [4,5]. However, very little has been reported about the characteristics of Korean women with osteoporosis using nationally representative data such as the KNHANES, which started assessing BMD in mid-2008 (KNHANES IV-2) [6]. One study using the KNHANES 2008–۲۰۰۹ reported that osteoporosis is highly prevalent (39.1%) in Korean premenopausal women, but is underdiagnosed (62.5%) and undertreated (76.5%) [7]. Osteoporosis was more prevalent among Korean women who were older and physically inactive and had lower body weight, poor calcium intake, and low educational levels; however, the awareness and treatment of osteoporosis in these women were similar to or lower than in women without osteoporosis [7]. A better understanding of the risk factors of osteoporosis in South Korean women is critical to developing effective interventions with the goal of promoting bone health and prevention of osteoporosis. The purpose of this study was to examine the risk factors associated with osteoporosis in a nationally representative sample of Korean postmenopausal women using the KNHANES 2009. The particular focus of this study was to explore various risk factors of osteoporosis identified in previous research, mostly conducted in Western countries, including poor dietary intake of key nutrients (e.g., calcium, vitamin D, protein, phosphorus, sodium, and vitamin K) [8,9], low physical activity [4,10], low body weight [4,5,10,11], insufficient estrogen exposure time in a woman’s life (e.g., later menarche, early menopause, and no history of estrogen replacement therapy) [4,12], and poor lifestyle characteristics (e.g., smoking) [10]. METHODS The data used for this study were from the KNHANES 2009. The KNHANES was designed to obtain nationally representative information on nutritional and health status in the South Korean population (aged 1 year), and was conducted by the Korea Centers for Disease and Control (KCDC) [6]. The study protocol of KNHANES was approved by the KCDC Institutional Review Board. The KNHANES 2009 is composed of three parts: Health Interview survey, Health Examination survey, and Nutrition survey. Both the Nutrition survey and the Health Interview survey were conducted by trained interviewers [6]. The Health Interview survey collected selfreported data on sociodemographic information; disease; health behaviors including smoking and drinking status; and the level, duration, and weekly frequency of physical activity. The Health Examination survey assessed anthropometry, blood and urine tests, and various health check-ups as well as measuring BMD [6]. The KNHANES 2009 data were collected from January to December 2009 [6]. A total of 10,533 people (4843 men and 5690 women) participated in the KNHANES 2009 [6]. Menopausal Status Menopausal status was determined based on the responses to the question, “Are you currently postmenopausal?” If a participant reported, “yes,” she was considered postmenopausal. Postmenopausal status was defined as not having had a period for 12 consecutive months. Osteoporosis Osteoporosis was determined based on the BMD measurement of the total femur, femoral neck, and spine with dualenergy X-ray absorptiometry (DEXA; Hologic Discovery, Hologic, Marlborough, MA, USA). Using the World Health Organization definition, osteoporosis was defined as a t-score of ¡۲٫۵ or below in at least 1 of the 3 sites [13]. Asian standard data were used as a reference [13]. Participants were divided into two groups: osteoporosis and nonosteoporosis (t-score is greater than 2.5 for all 3 sites).