Background: Muscle strength declines with advancing age; the causes of this are uncertain. In women, strength begins to decline around the time of menopause, suggesting that hormonal changes might influence strength. To determine the effect of postmenopausal estrogen use on muscle strength, neuromuscular function, and the risk of falling, we examined 9704 participants aged 65 years or more enrolled in the Study of Osteoporotic Fractures.
Methods: We measured hip abductor, triceps extensor, and hand-grip muscle strength, balance, gait speed, and self-reported functional disability. Falls during the first year of follow-up were determined from postcards that participants mailed every 4 months indicating whether they had fallen in the previous 4 months (> 99% complete follow-up).
Results: After adjusting for age, medications, medical history, and personal habits, current estrogen users did not differ in a clinically meaningful way from those who had never used estrogen on tests of hip abductor strength (mean difference, 0.15 kg; 95% confidence interval, -0.05 to 0.34 kg), triceps extensor strength (0.005 kg; -0.17 to 0.18 kg), or grip strength (0.30 kg; 0.00 to 0.59 kg). Gait speed, time to stand five times from a chair, balance, self-reported disability, and incidence of falls (odds ratio, 1.12; 95% confidence interval, 0.87 to 1.44) also did not differ between current users and never users. In addition, current users were similar to past users on all measures.
Conclusion: We found no evidence that postmenopausal estrogen use has beneficial effects on muscle strength or neuromuscular function or that it reduces the risk of falling.