Objective: To investigate the risk factors for benign serous and mucinous epithelial ovarian tumors.
Methods: Cases were women newly diagnosed with benign serous ovarian tumors (n=230) or benign mucinous tumors (n=133) between 2002 and 2005. Control women were selected at random from the general population (n=752). All participants completed a comprehensive reproductive and lifestyle questionnaire. Multivariable logistic regression was used to calculate odds ratios (ORs) and 95% confidence intervals (CIs) and to simultaneously adjust for potential confounding factors.
Results: Current smoking was associated with a three-fold increase in risk of benign mucinous tumors (OR 3.25, 95% CI 1.97-5.34), and there was a trend of increasing risk with increasing amount smoked (P<.001). Both recent obesity (OR 1.93, 95% CI 1.30-2.88) and obesity at age 20 (OR 4.38, 95% CI 1.88-10.20) were associated with increased risk of benign serous ovarian tumors, and having had a hysterectomy was also related to increased risk of serous (OR 2.75, 95% CI 1.90-3.96), but not mucinous tumors. Ever having had a term pregnancy was inversely associated with both tumor types (combined OR 0.65, 95% CI 0.43-0.97), although greater numbers of pregnancies did not decrease risk further. Use of hormonal contraceptives was unrelated to risk.
Conclusion: Our results suggest some differences in risk factors between benign serous and mucinous epithelial ovarian tumors and that risk factors for benign serous tumors differ from those well established for ovarian cancer. The results also suggest that there is potential for prevention of these common conditions through avoidance of smoking and obesity.
Level of evidence: II.