[A population based study on factors related to bone mineral density in Wakayama Prefecture]

For evaluation of the community health program, 1543 inhabitants aged 40-79 years were recruited as cohort members in Miyama Village, Wakayama Prefecture. In this cohort, bone mineral density (BMD) of 400 subjects, 50 males and 50 females each randomly selected from each of four age strata, was measured at the lumbar spine and femur neck by dual energy X-ray absorptiometry. Information on exposure to possible risk factors was obtained from a self-administered questionnaire. The results were as follows; BMD at the lumbar spine and femur neck in women aged 70-79 who maintained an exercise habit (> or = one hour/week) was significantly higher than women with no exercise habit. The BMD at the femur neck in men aged 60-79 with alcohol drinking habit was significantly higher than those with no drinking habit. Significant correlation was not seen between milk intake or smoking and the BMD. BMD at the femur neck in women aged 60-69 with multiple child births (> or = 4) were significantly higher than those with fewer child births. The BMD in women aged 50-59 with earlier onset of menarche was higher than those with late menarche. Significant reduction in BMD of postmenopausal women was observed compared to premenopausal women analyzed after matching for age. The result of analysis of quantification method of the first type showed that age and menopause had a marked effect on BMD. Concerning lifestyles as other factors, a positive correlation was observed between BMD and drinking for men and exercise for women. These factors appear to be useful indicators of risk for osteoporosis.