Reproductive factors for ovarian cancer in southern Chinese women

open access

Objective To investigate the association between reproductive factors and the risk of ovarian cancer among southern Chinese women.

Methods A hospital-based case-control study was undertaken in Guangzhou, Guangdong Province, between 2006 and 2008. A structured questionnaire was used to obtain information on parity, oral contraceptive use and other reproductive factors in a sample of 500 incident ovarian cancer patients and 500 controls (mean age, 59 years). Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated using unconditional logistic regression models.

Results High parity was inversely associated with ovarian cancer, with an adjusted OR 0.43 (95% CI, 0.30 to 0.62) for women who had given birth to 3 or more children compared to women who had given no more than one birth. Ever use of oral contraceptives was also protective against ovarian cancer; adjusted OR 0.56 (95% CI, 0.40 to 0.78). No association was found for hormone replacement therapy, menopausal status, hysterectomy and family history of ovarian and/or breast cancer.

Conclusion High parity and oral contraceptive use are associated with a lower risk of ovarian cancer in southern Chinese women.

INTRODUCTION

Ovarian cancer ranks as the seventh most common cause of cancer mortality among women [1], accounting for 4.2% of cancer deaths [2]. It is the eighth most common cancer in women, with approximately 225,000 new cases reported worldwide in 2008 [1]. The incidence of ovarian cancer varies geographically. The age-standardised rate (per 100,000 females) is only 3.8 in China, relatively lower than developed countries such the USA (8.8) and Australia (7.7) [1]. The majority of ovarian malignancies are epithelial in origin [3] and are often diagnosed in the advanced stages of the disease due to the subtle and non-specific symptoms [4]. There is currently no effective screening method available for the detection of this disease [5], which has an overall five-year survival rate of approximately 45% [6]..........