Risk factors for endometrial hyperplasia: results from a case-control study.

We analyzed epidemiologic characteristics of women at risk for endometrial hyperplasia (EH), using data from a case-control study. One hundred twenty nine women aged 35-73 (median 51 years) with histologically confirmed complex endometrial hyperplasia without atypies identified at the University of Milan during the period 1990-99 were examined. Controls were 258 non hysterectomized women aged 36-74 (median 52 years), admitted to a network of hospitals covering the same area where cases had been identified for conditions other than gynecological, malignant, or hormone-related. Cases with EH were more educated than controls (OR > 12 years of education vs. < 7: 2.8, 95% CI 1.7-4.8), more frequently obese (OR 2.7, 95% CI 1.5-5.0) and diabetic (OR 2.4, 95% CI 0.8-6.9). Parous women (OR 1.8) and women reporting induced abortions (OR 1.6) showed an increased risk of EH, but the associations were not statistically significant. Compared to premenopausal women, the OR of EH was 0.2 (95% 0.1-0.5) for postmenopausal ones. Compared to women reporting menopause at age 50 or less, the OR of endometrial hyperplasia was 1.5 (95% CI 0.6-3.5) and 2.2 (95%CI 0.7-6.7), respectively, in women with menopause at age 50-52 and > or = 53. Considering postmenopausal women only the OR was 3.1 (95% CI 1.1-9.3) for use of hormonal replacement therapy (HRT). We conclude that this study indicates that high education, obesity, diabetes, and HRT use increase the risk of endometrial hyperplasia.