Dietary fat and fatty acid intake and epithelial ovarian cancer risk: evidence from epidemiological studies

The associations between dietary fat and fatty acid (FA) intakes and epithelial ovarian cancer (EOC) risk have been inconsistent in previous studies. We conducted a meta-analysis of epidemiological studies to evaluate these associations. We identified relevant studies by searching PubMed, EMBASE, and Web of Science databases. We used random-effects models to estimate summary relative risks (RRs) and 95% confidence intervals (CIs). Overall, the search yielded 20 studies (1 pooled analysis of 12 cohort studies, 5 cohorts, and 14 case-control studies). The summary RR for EOC for the highest versus lowest categories of total dietary fat intake was 1.12 (95% CI= 0.95-1.33; I-2 = 77.4%; n = 14). The RRs were not significant when fats were divided into plant-based fats (RR = 0.93, 95% CI = 0.77-1.13; n = 6), animal-based fats (RR = 1.15, 95% CI = 0.95-1.39; n = 8), dairy-based fats (RR = 1.02, 95% CI = 0.88-1.18; n = 3), saturated FAs (RR = 1.04, 95% CI = 0.93-1.17; n = 12), monounsaturated FAs (RR = 0.98, 95% CI = 0.84-1.13; n = 10), polyunsaturated FAs (RR = 0.96, 95% CI = 0.81-1.12; n = 10), and trans-unsaturated FAs (RR = 1.15, 95% CI = 0.98-1.36; n = 3). Similar non-significant results were also observed in most of the subgroup and sensitivity analyses. The findings of this meta-analysis suggest a lack of evidence for associations between dietary fat and FA intakes and EOC risk. Further analyses should be conducted to assess the associations with other types of fat, and the results should be stratified by tumor invasiveness and EOC histology.