Dairy consumption and risk of esophageal squamous cell carcinoma: A meta-analysis of observational studies.

AIM: Inconsistent results regarding the relations between consumption of dairy products and the risk of esophageal squamous cell carcinoma (ESCC) have been reported. In this report, we summarized the evidence by a meta-analysis of observational studies.

METHODS: Eligible studies published up to January 31, 2013 were retrieved via both computer searches and a manual review of references. Random-effects models were used to calculate the summary relative risk (SRR) based on high versus low and dose-response analysis.

RESULTS: A total of 19 studies with 4315 ESCC cases were included in this meta-analysis. Overall, there were no significant associations between intakes of total dairy products, milk, cheese and butter and ESCC for the highest versus lowest intake categories (total dairy products: SRR 1.03, 95% confidence interval [CI]: 0.60-1.77; milk: SRR 0.93, 95% CI: 0.74-1.16; cheese: SRR 0.84, 95% CI: 0.61-1.15; butter: SRR 1.77, 95% CI 0.85-3.75). A significant inverse association was found for yogurt consumption (SRR 0.73, 95% CI: 0.54-0.98). There was high heterogeneity among studies on total dairy products, milk and butter; however, little or no heterogeneity was observed among studies on cheese and yogurt.

CONCLUSION: No associations between consumption of milk, dairy products, butter or cheese and risk of ESCC were found, while yogurt consumption may have a protective effect. However, these associations may be subject to high levels of heterogeneity or confounding, and further efforts should be made to confirm these findings.