Ovarian cancer mortality among women aged 40-79 years in relation to reproductive factors and body mass index: latest evidence from the Japan Collaborative Cohort study

Objective: This study mainly aimed to investigate the association of ovarian cancer mortality with reproductive factors and body mass index among Japanese women aged 40-79 years. Methods: The source of the data was the Japan Collaborative Cohort (JACC) study which covered the period of 1988 to 2009. A representative sample of 64,185 women was used. Cox model was used to estimate the relative risk (RR) and 95% confidence interval (CI). Results: The total number of ovarian cancer deaths was 98, with a mortality rate of 9.30 per 100,000 person-years. Women with single marital status revealed significantly higher age-adjusted RR (RR, 4.11; 95% CI, 1.66 to 10.23; p=0.005) as compared to married women. The effect of single marital status was stronger among older women aged 50+ years (RR, 4.58; 95% CI, 1.65 to 12.72; p=0.003) than younger women. An elevated risk was found for both nulliparous and nullipregnant women. Similarly, an increased risk of ovarian cancer mortality was estimated among overweight among aged 50 years or less. Conclusion: Out of many factors only single marital status indicated a higher risk for ovarian cancer mortality. All other factors provided inconclusive results, which imply further epidemiological investigations.