FACTORS ASSOCIATED WITH BONE-MINERAL DENSITY IN MIDDLE-AGED MEN

This cross-sectional population-based study examined the association o f anthropometric and lifestyle risk factors with bone mineral density (BMD) in 218 white ambulatory men aged 50-64 from the Rancho Bernardo, California cohort. BMD was measured at the lumbar spine and hip using dual-energy X-ray absorptiometry and at the ultradistal wrist and mid shaft radius of the forearm using single-photon absorptiometry, Body m ass index (BMI) was significantly correlated with BMD at all four skel etal sites, Overall, 17.0% of men aged 55-64 were osteopenic (BMD grea ter than or equal to 2 SD below the distribution for ages 50-54) at on e skeletal site, 16.5% were osteopenic at two sites, and 13.6% were os teopenic at three or more sites, Men who reported regular exercise had significantly higher BMD levels at the spine and hip. Men meeting the recommended daily allowance (RDA) for calcium intake (greater than or equal to 800 g/day) had significantly higher BMD levels at the spine and wrist. Alcohol intake and smoking were associated,vith differences of borderline significance in BMD at the spine, In analyses adjusted for BMI, weight change, exercise, smoking, drinking, and calcium intak e, there was a significant independent age-related decline in BMD at t he hip (0.008 g/cm(2)/year; p = 0.001), at the wrist (0.004 g/cm(2); p < 0.01), at the forearm (0.006 g/cm(2); p < 0.01), but not at the spi ne (0.005 g/cm(2)), These data, although cross-sectional, strongly sug gest that age-related bone loss occurs in middle-aged men and that bot h physical activity and an adequate calcium intake are associated with better bone density.