Risk factors for bone mineral density at the calcaneus in 40–59 year-old male workers: A cross-sectional study in Korea

BACKGROUND: Few epidemiologic studies have attempted to investigate the prevalence and risk factors for osteopenia and osteoporosis in middle-aged Asian men. We performed this study to determine the prevalence and risk factors of osteopenia and osteoporosis in this population. METHODS: This cross-sectional study was conducted from March to July, 2004. The subjects were 2,073 males aged from 40 to 59 years in the KHNP (Korea Hydro & Nuclear Power) workplace-based cohort. Bone mineral density (BMD) was measured by peripheral, dual-energy, X-ray absorptiometry (DXA) at the calcaneus. Anthropometric and lifestyle factors were investigated using a standard, self-reported questionnaire. RESULTS: BMD was 0.60 ± 0.09 g/cm(2 )(mean ± standard deviation) and was negatively correlated with age (r = -0.18, P < 0.001), but positively correlated with waist-to-hip ratio (WHR; r = 0.15, P < 0.001), body fat (r = 0.10, P < 0.001), BMI (r = 0.35, P < 0.001), height (r = 0.26, P < 0.001), and weight (r = 0.43, P < 0.001). In multiple linear regression analysis, the independent determinants associated with BMD were increasing age (coefficient = -0.002, P < 0.001), physical activity (≤ 2/week vs. ≥ 3/week; coefficient = 0.017, P < 0.001), WHR (coefficient = -0.796, P < 0.001), body mass index (BMI; coefficient = 0.023, P < 0.001) and smoking status (never vs. ever; coefficient = -0.018, P < 0.001). CONCLUSION: We suggest that BMD of the calcaneus is correlated negatively with exposure to smoke and increased WHR, but positively with regular exercise and increased BMI.