High Risk Factors In Endometriosis A Case-Control Study

A reduction of incidence in pelvic inflammatory diseases has been achieved for years. Endometriosis is becoming one of the most important diseases in gynecological clinic. However, causes of the disease are still not clear. A clinical epidemiological case — control study was, therefore, carried out to explore the risk factors of endometriosis.Two hundred and three patients with pelvic endometriosis under 45 years of age were admitted to the Peking Union Medical College Hospital and the Beijing Obstetrical and Gynecological Hospital from 1987 through 1989. In over 90% of patients the diagnosis was pathologically proved, except 17 patients whose diagnoses were made by the aspiration of chocolate substance under laparoscpy. Two population controls, age matched ±1 year, were randomly selected for each patient from the same residential area, after careful pelvic examinations and ultrasono-graphies to rule out any detectable pelvic mass or nodules. A comprehensive questionaire for any possible risk factors to endometriosis was developed and by using this questionaire a face to face interview for each study subject was carried out by the trained interviewers. All interviews were tape recorded and checked by the authors. The epidemiologic data were imputed and calculated in a AST 386 computer. The continuous logistic regression for matched sets was used to obtain a maximum likelihood point and to control the potential confounding effects of selected variables. Relative risk (RR) substituted for odds ratio together with the 95% confidence intervals were estimated.The results were as following: 1) There was an increased risk for endometriosis in women with earlier menarche (≤ 12 years of age), longer menstrual periods (≥8 days ), and primary dysmenorrhea. A menstrual cycle length longer than 35 days seems to have protective effect. An increase of risk for endometriosis was also found in women who had physical exercise during menstrustion. 2) A decreased risk for endometriosis was found to be related to reproductive activity. the relative...