Six months of hormone replacement therapy does not influence muscle strength in postmenopausal women

Postmenopausal hormone replacement therapy (HRT) has positive effects on fracture incidence before any effects on bone mineral density can be demonstrated. This has been attributed to increased muscle strength by HRT. This study was designed to evaluate the effect of 6 months of HRT on muscle strength in postmenopausal women.

Forty postmenopausal women, aged 60-78 were included in the study. They were randomly divided in two groups with 20 women in each group. One group received Menorest 50 microg/24 h (estradiol 4.3 mg) and Gestapuran 2.5 mg (medroxyprogesteron) daily and the other group received placebo treatment. The study was conducted as a double blinded, prospective and placebo controlled trial. Hand grip strength, isokinetic knee flexion and extention, and physical activity were measured before treatment, after 3 and 6 months. Physical activity was estimated using a classification system of physical activity. A JAMAR hydraulic hand dynamometer and a Cybex II dynamometer were used to evaluate muscle strength.

Hand grip strength in the right hand, increased significantly in both groups (HRT P<0.001 and placebo P<0.01) and in the left hand in the HRT group (P<0.01). However, there were no differences in muscle strength between the two groups. There was no significant change in isokinetic knee flexion or extension after 6 months in either of the groups. The estimated physical activity increased slightly in the placebo group, but there was no significant difference compared to the treatment group.

Our data suggest that 6 months of HRT does not influence muscle strength in postmenopausal women.