Evidence suggests that egg intake may be implicated in the aetiology of sex-hormone related cancers. However, dose-response relationships between egg intake and such cancers are unclear. Thus, we conducted dose-response meta-analyses to summarize the dose-response relationships between egg consumption and risks of breast, prostate, and gynecological cancers. PubMed and Embase were searched up to April, 2015 to identify relevant prospective observational studies. Summary relative risk (RR) and 95% confidence interval (CI) were estimated using a random-effects model. For breast cancer, linear dose-response meta-analysis found a non-significantly increased risk (RR for an increase of 5 eggs/week: 1.05, 95% CI 0.99, 1.11, 16,023 cases). Albeit evidence for non-linearity was not statistically significant (Pnon-linearity=0.50, 15,415 cases), consuming ≥ 5 eggs per week was associated with a statistically significantly increased risk compared to no egg consumption, with RR being 1.04 (95% CI 1.01, 1.07) at 5 eggs/week and 1.09 (95% CI 1.03, 1.15) at about 9 eggs/week. For other cancers investigated, the summary RR for an increase of five eggs consumed per week was 1.08 (95% CI 1.00, 1.17, 2,924 cases) for ovarian cancer and 1.47 (95% CI 1.01, 2.14, 609 cases) for fatal prostate cancer with evidence of small study effects (PEgger=0.04). No evidence of an association was found for total prostate cancer. While potential for publication bias and confounding temper our conclusion, high egg intake may be associated with a modestly elevated risk of breast cancer; a positive association of egg intake with ovarian and fatal prostate cancers cannot be ruled out.
CORE (COnnecting REpositories)
CORE (COnnecting REpositories)