Supplementary Table 3 shows the associations between folate intake (dietary, supplemental, total) and ovarian cancer by endometriosis status, and by histological subtype (endometrioid/clear cell cancers and high grade serous cancers).
Funding
Ovarian Cancer Research Fund (OCRF)
National Institutes of Health (NIH)
Canadian Institutes of Health Research (IRSC)
European Commission's Seventh Framework Programme
US National Cancer Institute GAME-ON Post-GWAS Initiative
Wellcome Trust (WT)
National Health and Medical Research Council (NHMRC)
U.S. Army Medical Research and Materiel Command
California Cancer Research Program
U.S. Department of Defense (DOD)
National Cancer Institute (NCI)
United States Department of Health and Human Services
Find out more...Rutgers Cancer Institute of New Jersey (CINJ)
Department Of Defense Congressionally Directed Medical Research Programs
ARTICLE ABSTRACT
Although folate intake has not been associated with an increased risk of ovarian cancer overall, studies of other cancer types have suggested that high folate intake may promote carcinogenesis in precancerous lesions. Women with endometriosis (a potential precancerous lesion) have an increased risk of developing ovarian cancer; however, whether high folate intake increases risk in this group is unknown.
We conducted a pooled analysis of six case–control studies from the Ovarian Cancer Association Consortium to investigate the association between folate intake and risk of ovarian cancer among women with and without self-reported endometriosis. We included 570 cases/558 controls with and 5,171/7,559 without endometriosis. We used logistic regression to estimate odds ratios (OR) and 95% confidence intervals for the association between folate intake (dietary, supplemental, and total) and ovarian cancer risk. Finally, we used Mendelian randomization (MR) to evaluate our results using genetic markers as a proxy for folate status.
Higher dietary folate intake was associated with an increased risk of ovarian cancer for women with endometriosis [OR, 1.37 (1.01–1.86)] but not for women without endometriosis. There was no association between supplemental folate intake and ovarian cancer risk for women with or without endometriosis. A similar pattern was seen using MR.
High dietary folate intake may be associated with an increased risk of ovarian cancer among women with endometriosis.
Women with endometriosis with high folate diets may be at increased risk of ovarian cancer. Further research is needed on the potential cancer-promoting effects of folate in this group.
