Hormonal replacement therapy reduces forearm fracture incidence in recent postmenopausal women — results of the Danish Osteoporosis Prevention Study

Abstract Objectives: To study the fracture reducing potential of hormonal replacement therapy (HRT) in recent postmenopausal women in a primary preventive scenario. Methods: Prospective controlled comprehensive cohort trial: 2016 healthy women aged 45–58 years, from three to 24 months past last menstrual bleeding were recruited from a random sample of the background population. Mean age was 50.8±2.8 years, and the number of person years followed was 9335.3. There were two main study arms: a randomised arm (randomised to HRT; n =502, or not; n =504) and a non-randomised arm (on HRT; n =221, or not; n =789 by own choice). First line HRT was oral sequential oestradiol/norethisterone in women with intact uterus and oral continuous oestradiol in hysterectomised women. Results: After five years, a total of 156 fractures were sustained by 140 women. There were 51 forearm fractures in 51 women. By intention-to-treat analysis ( n =2016), overall fracture risk was borderline statistically significantly reduced (RR=0.73, 95% CI: 0.50–1.05), and forearm fracture risk was significantly reduced (RR=0.45, 95% CI: 0.22–0.90) with HRT. Restricting the analysis to women who had adhered to their initial allocation of either HRT ( n =395) or no HRT ( n =977) showed a significant reduction in both the overall fracture risk (RR=0.61, 95% CI: 0.39–0.97) and the risk of forearm fractures (RR=0.24, 95% CI: 0.09–0.69). Compliance with HRT was 65% after five years. Conclusions: It is possible to reduce the number of forearm fractures and possibly the total number of fractures in recent postmenopausal women by use of HRT as primary prevention.