EPIDEMIOLOGY OF ENDOMETRIOSIS IN A NORWEGIAN COUNTY

Objective. To estimate the prevalence and incidence of endometriosis i n Norwegian women aged 40 to 42, and to evaluate reproductive events a nd life-style as risk factors for endometriosis as well as to evaluate related health-problems. Material and methods. The study was performe d partly as a cross-sectional study to estimate occurrence of endometr iosis, partly as a case-control study to look for factors associated w ith endometriosis. The study group consisted of all female inhabitants - born 1950 to 1952 - living in the county of Sor-Trondelag. In conne ction with a cardiovascular screening program information about reprod uctive events and gynecological problems including endometriosis and i nfertility was obtained. Results. Totally 5 139 women were asked to pa rticipate, and a questionnaire was completed by 4 034 (78.5%). Endomet riosis was reported by 2.0% of the women. Life-time risk for endometri osis was estimated to 2.2%. The annual incidence of new cases of endom etriosis in this age group is less than 0.3%. There was a significant association between endometriosis and menarche before age 13, and freq uent menstrual periods. Nulliparity was more common in women with endo metriosis as were infertility problems and pelvic pain. No significant association was found between endometriosis and exercise, smoking, bo dy mass index and education. There was a high risk for women with endo metriosis having had cervical conization or gynecological laparotomies such as infertility surgery, operations on ovaries as well as hystere ctomies. Conclusion. In Sor-Trondelag county the prevalence of endomet riosis is 2.0% and the annual incidence is less than 0.3% for women in their early forties. A woman's life-time risk for endometriosis might be 2.2%. Early menarche, frequent menstruations, pelvic pain, inferti lity and nulliparity are associated with endometriosis.