Osteoporosis and Associated Bone Fractures in a Japanese Population

Along with the lengthening life span, maintaining good quality of life in the elderly is an important goal. We determined frequency and risk factors for osteoporosis and associated fractures among a Japanese cohort in Hiroshima and Nagasaki, known as the Adult Health Study (AHS). We found lower bone mass and a higher vertebral fracture prevalence among Japanese women, compared to women of Japanese descent living in Hawaii and American Caucasians. However, the incidence of vertebral fracture has decreased progressively among successive younger Japanese birth cohorts. These findings suggested that environmental factors probably play an important role on occurrence of osteoporosis and vertebral fracture. Age, sex, weight, menstrual history, and calcium intake were associated with bone mass and vertebral fracture prevalence. From the AHS cohort study, age, body mass index, age at menarche, and number of children, milk intake, alcohol intake, and prevalent vertebral fracture were related to the risk of hip fracture. Risk factors for falls, such as alcohol consumption, may be responsible for occurrence of hip fracture in addition to the risk factors related to bone mass. Elucidating risk factors related to bone mass, bone quality, and falls may lead to new strategies for preventing osteoporosis and associated fractures. J Epidemiol,1996 ; 6 : S225-S229.