REDUCED RISK OF BREAST AND ENDOMETRIAL CANCER AMONG WOMEN WITH HIP-FRACTURES (SWEDEN)

To test the hypothesis that osteoporosis, which results partly from lo ng-term estrogen deficiency, is associated with a lowered risk of brea st and endometrial cancer, a population-based cohort study was perform ed in Sweden. Some 18,000 women were followed through record-linkages after a first hip fracture, on average for almost six years, to ascert ain the incidence of breast and endometrial cancer. Expected numbers w ere derived from the general population. Overall, 253 cases of breast cancer were observed cf 300 expected (standardized incidence ratio [SI R] = 0.84; 95 percent confidence interval [CI] = 0.74-0.95). Forty-eig ht cases of endometrial cancer were found cf 55 expected (SIR = 0.87, CI = 0.54-1.16). There was no clearcut pattern of breast cancer risk b y age at diagnosis of hip fracture, follow-up time, or calendar period . Our results are consistent with the a priori hypothesis that long-te rm estrogen deficiency is associated with a reduced risk of developing breast cancer as well as endometrial cancer.