Fat intake has been postulated to increase risk of ovarian cancer, but previous studies have reported inconsistent results.
The NIH-AARP Diet and Health Study, a large prospective cohort, assessed diet using a food frequency questionnaire at baseline in 1995-1996. During an average of 9 years of follow-up, 695 ovarian cancer cases were ascertained through the state cancer registry database. The relative risks (RRs) and 95% confidence interval (CI) were estimated using a Cox proportional hazard model.
Women in the highest vs the lowest quintile of total fat intake had a 28% increased risk of ovarian cancer (RR(Q5 vs Q1)=1.28, 95% CI: 1.01-1.63). Fat intake from animal sources (RR(Q5 vs Q1)=1.30; 95% CI: 1.02-1.66), but not from plant sources, was positively associated with ovarian cancer risk. Saturated and monounsaturated fat intakes were not related to risk of ovarian cancer, but polyunsaturated fat intake showed a weak positive association. The association between total fat intake and ovarian cancer was stronger in women who were nulliparous or never used oral contraceptives.
Fat intake, especially from animal sources, was related to an increased risk of ovarian cancer. The association may be modified by parity and oral contraceptive use, which warrants further investigation.