Endometrial carcinoma; ovarian dysfunction--a risk factor in young women.

From a referral area comprising one-fifth of the Swedish female population we investigated possible risk factors for endometrial cancer (EC) in different age groups. Seventy-seven women aged 31-45 with EC were collected retrospectively, and 99 women aged 46-65 were consecutively collected. Both groups were compared to referents randomly selected from a population based study from the city of Göteborg. The referents consisted of 1746 women aged 39-65 years. All cases were studied by hospital record and 82% of the women aged 31-45 years and 85% of those aged 46-65 years were studied by an extensive questionnaire. Among the referents 1409 (81%) were investigated by the above-mentioned questionnaire. Hirsutism, increased body mass index (BMI) and hypertension were significantly more common in both EC groups compared to referents. Nulliparity and infertility were significantly more common in the young EC group. Referents used combined oral contraceptives significantly more often than women developing EC. There was, however, no difference between the groups with respect to the duration of medication with combined oral contraceptives. There was a significant negative correlation between cigarette smoking and the development of EC. These findings indicate that untreated ovarian dysfunction like that present in polycystic ovarian disease (PCO) with unopposed estrogen action on the endometrium is associated with EC in younger women, and that smoking may protect against EC by an 'anti-estrogenic' effect.