[Evaluation of the preventive role of estro-progestogens and non-hormonal therapies in postmenopausal osteoporosis].

Osteoporosis is a medical, social and economical problem for developed countries. Prevention remains the only realistic approach to reduce the burden related to this disorder. Primary prevention of osteoporosis is based on efforts to reach a maximal peak bone mass at the end of the growth period and, subsequently, at the time of menopause. No pharmacological intervention is considered at this stage. Biologically, hormone replacement therapy induces a correction of the biochemical changes observed in markers of bone remodeling at the time of the menopause. A systematic screening of asymptomatic postmenopausal women followed by the induction of hormonal replacement therapy in high risk subjects appears to be an interesting cost/benefit strategy in terms of reasonable attribution of health resources. Nasal administration of calcitonin fully prevents the trabecular bone loss observed during the first years of menopause. Notwithstanding, the exact dose of nasal calcitonin able to prevent bone loss remains to be fully elucidated. Bisphosphonates inhibit bone resorption. Tiludronate prevents trabecular postmenopausal bone loss. The use of selectif estrogen receptor modulators is based on a possible differential action of these molecules, at the level of the estrogenic receptors, depending of the tissue considered. Several direct inhibitors of osteoclastic resorption are also under development. Their main target is either to prevent the linkage of osteoclasts to the bone matrix or to prevent the acidification of bone matrix required to induce the resorption process.