MUSCULAR STRENGTH AND ESTROGEN REPLACEMENT THERAPY: CROSS-SECTIONAL AND LONGITUDINAL PERSPECTIVES

Abstract

1550 Results of studies on the efficacy of estrogen replacement therapy (ERT) to improve muscular strength are inconclusive. To determine the relationship of strength and ERT usage, post-menopausal women from the Baltimore Longitudinal Study of Aging (BLSA) were studied cross-sectionally between 1978-1985 (N=86) and 1992-1997 (N=83). Twenty-seven women were studied longitudinally for an average of 13.3 yrs (range 7.3 - 19.1 yrs). During the first test period, 17 women were pre-menopausal, 2 were peri-menopausal, and 8 were post-menopausal and all were post-menopausal during the second test. Upper body strength was measured during both time periods using different testing procedures. Because of these test differences, strength scores were converted to Z scores using 258 and 294 BLSA women (age 17-92 yrs) for the 1st and 2nd time periods respectively. In the cross-sectional analyses there were no significant differences in strength between those who had ever used ERT(users) and those who had never used ERT (non-users). The change in normalized strength between the first and second strength tests in the longitudinal analysis was significantly less in users than in nonusers of ERT (P < 0.05). All 8 nonusers of ERT declined in strength (7 by more than 1 SD), whereas, 10 out of 19 declined, 5 out of 19 increased, and 4 out of 19 maintained their strength in the ERT users. Therefore, ERT use appears to lessen the decline in muscular strength over time in some postmenopausal women.