Is there a reduced risk of breast cancer among women with hip fractures?

To test the hypothesis that osteoporosis, which results partly from long-term estrogen deficiency, is associated with a lowered risk of breast cancer, a population-based cohort study was performed in Amiens. To ascertain the incidence of breast cancer, 1300 women were followed through after a first hip fracture. Overall, 18 cases of cancer were observed cf. 21.8 expected (standardized incidence ratio (SIR): 0.82; 95% confidence interval (CI): 0.5-1.3). The results are consistent with previous studies which concluded that long-term estrogen deficiency is associated with a reduced risk of developing breast cancer.