Reproductive and other factors and risk of epithelial ovarian cancer: An australian case‐control study

Abstract

Of the few factors known to be associated with epithelial ovarian cancer, the most consistently observed relate to women's reproductive function, although even here uncertainties remain. We have undertaken a case-control study involving personal interviews with over 1,600 women, the largest of its kind to date, to investigate further the associations between women's reproductive histories and other factors and the development of ovarian cancer. Cases were drawn from women diagnosed with epithelial ovarian cancer in 3 Australian states, Queensland, New South Wales and Victoria, between August 1990 and December 1993, and controls were drawn at random from the electoral roll, stratified by age and geographic region. Trained interviewers administered standard questionnaires to obtain detailed information about women's reproductive and contraceptive histories and other factors of interest, such as smoking and family history of ovarian or other cancer. Findings were based on data from 824 cases and 860 controls and confirmed the reduced risk of ovarian cancer associated with increasing parity and duration of use of the oral contraceptive pill (OCP), hysterectomy and tubal ligation. The strongest association of all was seen with use of the OCP for 10 years or more. An inverse association between ovarian cancer and age at first birth was observed, but this was not statistically significant. There were no associations between development of ovarian cancer and number of incomplete pregnancies, use of hormone replacement therapy or menstrual history. Among other factors considered, education after leaving school was negatively associated and high body mass index, family history of ovarian cancer, use of talc in the abdominal or perineal region and smoking were positively associated with occurrence of ovarian cancer.

Menstrual and reproductive factors in relation to ovarian cancer risk

“…Although one previous study suggested an association between heavier menstrual bleeding and increased risk (Purdie et al, 1995), we found no effect for the duration or the heaviness of menstrual bleeding. While our results suggest that cycle characteristics are unrelated to risk, such factors are poorly recalled (Bean et al, 1979;Harlow and Ephross, 1995), and errors of self-report may have attenuated underlying effects.…”

“…In this study, consistent with previous reports McGowan et al, 1988;Chen et al, 1992;Purdie et al, 1995), menstrual symptoms were largely unrelated to ovarian cancer risk. However, we found preliminary evidence of reduced risk associated with insomnia occurring in conjunction with the menstrual cycle, which to our knowledge has not been previously reported.…”

“…In this study, consistent with most previous studies (for example, Franceschi et al, 1991;Chen et al, 1992;Whittemore et al, 1992;Hankinson et al, 1995;Purdie et al, 1995;Salazar-Martinez, 1999), menarcheal age was unrelated to risk overall. However, our findings indicated that increasing age at menarche was associated with reduced risk among premenopausal women; similarly, at least two previous studies have found a stronger association between late menarcheal age and reduced risk among younger women (Parazzini et al, 1989;Whittemore, 1993).…”

“…In this study, late age at first birth was associated with reduced risk, although the effect was observed only in women who had used oral contraceptives and whose ovarian cancer was diagnosed before menopause. A few previous studies (Purdie et al, 1995), including the collaborative analysis of 12 population-based studies (Whittemore et al, 1992) also noted an inverse relationship between age at first birth and risk, but most found no association (for example, Risch et al, 1994), or an increased risk (for example, Negri et al, 1991). In contrast to previous studies (Risch et al, 1994;Salazar-Martinez et al, 1999), we also found a significant association between increasing age at last birth and reduced risk.…”

“…In this study, as in most previous studies (Cramer et al, Chen 1983;Purdie et al, 1995), ovarian cancer risk was not influenced by patterns or characteristics of the menstrual cycle. Although one previous study suggested an association between heavier menstrual bleeding and increased risk (Purdie et al, 1995), we found no effect for the duration or the heaviness of menstrual bleeding.…”