Exercise-associated amenorrhea, low bone density, and estrogen replacement therapy

Background: Women with exercise-associated amenorrhea have a higher frequency of osteoporosis than eumenorrheic runners and sedentary women. The use of hormone replacement therapy was suggested many years ago to increase bone density in exercising women with amenorrhea and low bone density. Objective: To determine if hormone replacement therapy increased bone density in women with exercise-associated amenorrhea. Methods: We performed a retrospective clinical study comparing the changes in bone density in 8 women runners who took hormone replacement therapy with 5 who refused medication but who were followed up as controls over 24 to 30 months. Results: Vertebral and femoral neck bone density significantly increased by 8.0%+/-1.2% (+/-SEM) and 4.1%+/-0.3% (+/-SEM), respectively, in 8 women runners with amenorrhea taking 24 to 30 months of estrogen replacement therapy with progestational support. Control women not taking replacement therapy had nonsignificant decreases of less than 2.5% at each site. Conclusion: Hormone replacement therapy appears to increase bone density in amenorrheic runners.