Bone mineral measurements among middle-aged and elderly Japanese residents in Hawaii

Cross-sectional data of bone mineral content measured at five skeletal sites (distal radius and ulna, proximal radius and ulna, and os calcis) with single photon absorptiometry were obtained from a population of Japanese-Americans living in Hawaii, comprising 1368 men (aged 61-81 years) and 1098 women (aged 43-80 years). Age-specific mean values of bone mineral content for all skeletal sites were much greater for men than for women and decreased steadily with advancing age in both sexes. The decrease in bone mineral content with age across a 15-year age range was two to four times (depending on skeletal site) greater for women than for men. In multiple regression analyses, age, weight, and postmenopausal estrogen use were potent determinants of bone mineral content for all skeletal sites. Weight was more strongly related to bone mineral content of the os calcis than age in both sexes. Height was significantly related only to the forearm bones. Strenuous exercise was significantly related to bone mineral content of the os calcis and the distal ulna only in men. When compared with US Caucasians of comparable sex and age, the Japanese in Hawaii have lower bone mineral content of the radius. This may partly be explained by the difference in body size. Significant correlations were found between bone mineral content of appendicular bones and radiographically determined vertebral osteoporosis.