Prevalence and determinants of estrogen replacement therapy in elderly women

To better understand which women use estrogen replacement therapy, we examined the prevalence and determinants of estrogen replacement therapy in 9704 nonblack women, age greater than or equal to 65 years, who participated in the multicenter prospective Study of Osteoporotic Fractures. We conclude that only a small proportion of elderly women in the United States use estrogen replacement therapy. Selection factors for use of estrogen are evident and may introduce bias in studies of estrogen and disease. In consideration of the distribution of these selection factors, estrogen users will tend to be at lower risk of coronary disease and possibly breast cancer but at greater risk for hip fractures.