The menopause and the skeleton: key issues.

There is a persuasive rationale for the use of HRT at the time of the menopause, but there are a number of factors which limit its widespread application for osteoporosis. These relate partly to the long-term efficacy of HRT when given for a finite duration at the time of the menopause, and long-term prospective studies are warranted to address this issue. A further difficulty relates to the logic of targetting women at risk of osteoporosis at the time of the menopause when the benefits and risks of HRT are largely extraskeletal. Finally, the importance of the menopause to the problems of osteoporosis have probably been overemphasized and other factors are important in determining the geographical variation in hip fracture risk as well as the increase in age- and sex-specific incidence that has occurred in many countries. The causes for this are unknown, but are clearly not related to gonadal status since these phenomena are observed both in men and in women. A plausible hypothesis is the decrease in physical activity, but this remains an hypothesis. It will be important to determine the aetiology of these phenomena so that logical preventive strategies can be developed.