Intake of Coffee and Tea and Risk of Ovarian Cancer: A Prospective Cohort Study

Abstract:

There is some evidence from case-control studies that coffee consumption might be positively associated with ovarian cancer risk, whereas the epidemiologic evidence regarding tea consumption and ovarian cancer is inconsistent. To date, there have been few prospective studies of these associations. Therefore, we examined ovarian cancer risk in association with both coffee and tea intake in a prospective cohort study of 49,613 Canadian women enrolled in the National Breast Screening Study (NBSS) who completed a self-administered food frequency questionnaire between 1980 and 1985. Linkages to national mortality and cancer databases yielded data on deaths and cancer incidence, with follow-up ending between 1998 and 2000. Data from the food frequency questionnaire were used to estimate daily intake of coffee and tea. Cox proportional hazards models were used to estimate hazard ratios (HR) and 95% confidence intervals (CI) for the association between categories of coffee and tea intake and ovarian cancer risk. During a mean 16.4 years of follow-up, we observed 264 incident ovarian cancer cases. Tea intake was not associated with ovarian cancer risk in our study population. In contrast, a borderline positive association was observed among women who drank > 4 cups coffee/day compared to women who did not drink coffee (HR = 1.62, 95% CI = 0.95–2.75, P _trend = 0.06). Given the pervasive use of these beverages, the associations between coffee and tea consumption and ovarian cancer risk warrant investigation in further prospective studies.

Acknowledgments and Notes

Funded in part by the National Cancer Institute of Canada. We thank Statistics Canada, the provincial and territorial Registrars of Vital Statistics, and the Cancer Registry directors for their assistance in making the cancer incidence and mortality data available.

Notes

^‡ Numbers in parentheses represent the standard deviation.

^¥ Among parous women only.

^§ Multivariate models included age (time to event variable), smoking history (never, former, current), pack-years of smoking (never plus 4 non-zero categories), alcohol intake (any vs. none), education (> 12 yr vs. < = 12 yr), BMI in kg/m² (< 25, 25–29, > 30), parity (parous vs. nulliparous), participation in vigorous physical activity (any vs. none), menopausal status, oral contraceptive use (zero plus 3 non-zero categories), energy intake (continuous), lactose intake (continuous), study center, and randomization group.