THE INFLUENCE OF MEDICAL CONDITIONS ASSOCIATED WITH HORMONES ON THE RISK OF BREAST-CANCER

Medical conditions related to hormonal abnormalities were investigated in a case-control study of breast cancer among women who attended a s creening centre. Information was obtained by telephone interview regar ding physician-diagnosed medical conditions such as thyroid or liver d iseases, diabetes, and hypertension, as well as hirsutism, acne, galac torrhoea, and reproductive, menstrual, and gynaecological factors. Res ults are presented for 354 cases and 747 controls. Women with fertilit y problems who never succeeded in becoming pregnant were at significan tly increased breast cancer risk (adjusted odds ratio [OR] = 3.5; 95% confidence interval [CI] : 1.1-10.9). An elevated cancer risk was also associated with having excess body hair (OR = 1.5; 95% CI : 1.0-2.3), or having excess body hair in addition to persistent adult acne (OR = 6.8; 95% CI : 1.7-27.1). Recurrent amenorrhoea (OR = 3.5; 95% CI : 1. 1-11.5), and a treated hyperthyroid condition (OR = 2.2; 95% CI: 1.1-4 .4) were significantly associated with risk. A non-significant elevati on of risk was present for endometrial hyperplasia (OR = 1.8; 95% CI : 0.8-4.0). There was a suggestion of an association between a history of galactorrhoea and breast cancer risk (OR = 2.0; 95% CI : 0.8-4.9) a mong premenopausal women. No associations were found with other medica l or gynaecological factors. The possibility that some of these findin gs are due to chance cannot be excluded because of the problem of mult iple comparisons.