Relationship between exercise and bone mineral density among over 5,000 women aged 40 years and above

An epidemiological survey was conducted to clarify the relationship between bone mineral density(BMD) and exercise at 14 health centers in Ibaraki Prefecture, Japan from September 1994 through March 1995. More than 5,000 women participated in this survey. Second metacarpal BMD was measured by CXD(Computed X-ray Densitometry) method. Information about past history of exercise was obtained by questionnaire. sigma GS/D < 2.3(sigma GS/D: a parameter of BMD) was used to estimate the suspicion of osteoporosis. Data on 5,124 women aged 40 years and above were analyzed. Subjects were categorized into two groups according to the presence(n = 1,687) or absence(n = 3,437) of past history of regular exercise. sigma GS/D values were significantly (p < or = 0.05) higher in women who have had regular exercise in the past than those of the non-exercise group except those aged over 70 years. Ball game, foot sports and gymnastics were the main exercises. When osteoporosis was suspected based on the measurements of bone mineral density, the odds ratio (exercise present/absent) was 0.27 (95% confidence limits: 0.08-0.94), 0.82 (0.65-1.04), 0.78 (0.61-0.99), and 1.25 (0.67-2.35) at 40-49, 50-59, 60-69, and over 70 years, respectively. The results of the present study suggest the beneficial influence of exercise on bone mineral density and its utility for preventing osteoporosis.