Sleep duration and the risk of epithelial ovarian cancer.

PURPOSE

Variations in sleep duration have been linked to biological mechanisms that may affect cancer risk. We investigated the association between sleep duration during adult life and the risk of epithelial ovarian cancer overall, and according to tumor behavior and invasive cancer type, in a population-based case-control study.

METHODS

Among 465 cases and 855 controls, sleep duration during life periods starting at age 20 years was assessed, with which average sleep during adult life was calculated. Unconditional multivariable logistic regression was used to estimate odds ratios (OR) and 95% confidence intervals (CI). Polytomous logistic regression was used to estimate associations by tumor behavior (invasive vs. borderline) and invasive cancer type (Type I vs. II).

RESULTS

Compared to an average sleep duration during adult life of the recommended 7-9 h/night, the ORs (95% CI) for ovarian cancer overall were 1.04 (0.74-1.46) and 1.78 (1.15-2.75) for < 7 and > 9 h/night, respectively. An increased risk with > 9 h/night was also observed for invasive and borderline tumors and among Type I and Type II invasive cancer types.

CONCLUSION

The results suggest that sleep durations longer than the recommended 7-9 h/night during adulthood may be associated with an increased ovarian cancer risk.