CHANGING INCIDENCE AND RESIDUAL LIFETIME RISK OF COMMON OSTEOPOROSIS-RELATED FRACTURES

Changes in incidence and lifetime risk of fractures are of major importance in the epidemiology of osteoporosis. We focused on hip fractures in women and men and on radial and humeral fractures in women. The study subjects comprised 4500 women and men 20 years old or more with fractures. In women 1735 fractures of the distal radius, 747 fractures of the proximal humerus, 878 cervical and 635 trochanteric hip fractures were included. In men 273 cervical and 232 trochanteric hip fractures were included. The fractures were registered during the period 1976 to 1984 and changes in age-specific incidence were calculated (chi-squared test for linear trend; p-values less than 0.05 were considered significant). On the basis of life tables and population background data, the lifetime risk was estimated. The incidence of cervical hip fractures in women aged 60-89 years decreased significantly (p<0.05) during the observation period, while no significant decrease was found in the incidence of trochanteric fractures. No significant changes in incidence were observed in women with radial or humeral fractures, or in men with hip fractures. A woman 60 years old with a life expectancy of 81 years had an estimated residual lifetime risk of radial, humeral or hip fracture of 17%, 8% and 14% respectively. A man 60 years of age with a life expectancy of 77 years had an estimated risk of hip fracture of 6%. The residual lifetime risk of hip fracture for women surviving to the 25th percentile (88 years) was 32%, and in men (84 years) 15%. The causes of the observed decrease in age-specific incidence of cervical hip fractures in women are unknown, and prophylactic efforts to prevent hip fractures should continue to cover the healthy elderly women and men with expected longevity.