Maximal Muscle Strength of Elderly Women is not Influenced by Oestrogen Status

摘要

It has recently been reported that oestrogen replacement may preserve the ratio of muscle strength to cross-sectional area in the hand in addition to its beneficial effect on bone mass in postmenopausal women. Since muscle strength is associated with falls and fractures in elderly people, this additional effect of oestrogen replacement could be of considerable benefit to postmenopausal women. We therefore wished to determine whether this effect was also evident in larger muscle groups that are involved in ambulation, balance, and activities of daily living. We examined the relationship of oestrogen replacement therapy (ORT) to maximal dynamic muscle strength in 85 healthy women aged 65-82 years. Thirty-seven women were currently taking ORT and had been on stable doses for 2 to 43 years [17.8 (1.8); mean (SEM)], while 48 women had no previous exposure to postmenopausal oestrogen therapy. Dynamic muscle strength was determined for five standard lower-body exercises using isotonic equipment by the 1-RM method. Bone mineral density (BMD, g/cm~2) of the axial and appendicular skeleton as well as body composition was assessed by dual-energy X-ray absorptiometry. There was no difference between subjects according to ORT status for age, height, weight, lean body mass (LBM), fat mass, or percentage body fat. BMD of the spine (L2-4), mid-radius, and whole body was greater (p < 0.001) in individuals receiving ORT, with no significant difference at the femoral neck. No differences existed between groups for lower-body muscle strength. Normalizing muscle strength to body mass and LBM did not alter the result. Although individuals receiving ORT had enhanced bone mass compared with those not receiving ORT, there was no effect of oestrogen replacement on lower-body muscle strength.