Conclusions and Relevance This systematic review and meta- analysis did not show a significant beneficial or detrimental association of HT with muscle mass .
Importance Hormone therapy ( HT ) has been suggested for protection against age-related muscle weakness in women .
However , the potential for HT-associated health risks necessitates a better underst and ing of the direction and magnitude of the association between HT and health outcomes , such as lean body mass ( LBM ) .
Objective To determine whether HT was associated with reduced LBM loss compared with not receiving HT  among postmenopausal women aged 50 years and older .
Postmenopausal hormone replacement therapy prevents central distribution of body fat after menopause.
The reduction in cardiovascular risk induced by hormone replacement therapy is only partly explained by changes in serum lipids and lipoproteins . As body composition and body fat distribution in particular are independent predictors of cardiovascular disease , we investigated the effect of postmenopausal hormone therapy on body composition parameters directly measured . Sixty-two early postmenopausal women were followed up for 2 years in a prospect i ve , r and omized , placebo-controlled study . We found that combined estrogen-progestogen therapy prevented the increase in abdominal fat after menopause ( P less than .05 ) , and that this effect was independent of the effect on serum lipids and lipoproteins . The therapy reduced postmenopausal bone loss significantly ( P less than .001 ) , whereas it did not have a statistically significant influence on total body fat mass or total lean body mass . The findings of the present study suggest that some of the protective impact of postmenopausal hormone therapy on cardiovascular disease may be explained by the effect on body composition , in particular abdominal fat
Conclusions and Relevance This systematic review and meta- analysis did not show a significant beneficial or detrimental association of HT with muscle mass .
Importance Hormone therapy ( HT ) has been suggested for protection against age-related muscle weakness in women .
However , the potential for HT-associated health risks necessitates a better underst and ing of the direction and magnitude of the association between HT and health outcomes , such as lean body mass ( LBM ) .
Objective To determine whether HT was associated with reduced LBM loss compared with not receiving HT  among postmenopausal women aged 50 years and older .