Comparative case-referent study of risk factors among hormone-related female cancers in Japan

To assess the impact of reproductive and anthropometric factors as a risk i ndicator for female cancers in hormone-related organs, i,e,, the breast, en dometrium and ovary, we conducted a comparative case-referent study using d ata from the Hospital-based Epidemiologic Research Program at Aichi Cancer Center (HERPACC), Japan. The case group consisted of 1,465, 133 and 99 wome n who had first been diagnosed as having breast, endometrial and ovarian ca ncer, respectively. The referents were 25,488 female first-visit outpatient s who had not previously been diagnosed with any type of cancer. The odds r atios (ORs) and their 95% confidence intervals (95%CI) were estimated using an unconditional logistic regression model. An inverse association with ex perience of delivery and a positive association with body mass index (BMI) and with change of BMI after 20 Sears of age, were observed consistently fo r all three cancer sites. We observed similar risk and protective factors f or breast and endometrial cancer, but the effect of reproduction and overwe ight condition (BMI greater than or equal to 25) were more prominent in end ometrial cancer. Although the present study failed to find site-specific ri sk factors for ovarian cancer, the results provided evidence that being ove rweight and/or weight gain in adult life is a common risk factor for all th ree cancer sites. The results obtained from this study suggested that avoid ance of weight gain may reduce the risk of female hormone-related cancers.