Dairy Consumption and Risk of Conventional and Serrated Precursors of Colorectal Cancer: A Systematic Review and Meta-Analysis of Observational Studies

Li-Lianagzi Guo; Yu-Ting Li; Jun Yao; Li-Sheng Wang; Wei-Wei Chen; Kai-Yin He; Lin Xiao; Shao-Hui Tang

doi:10.1155/2021/9948814

Dairy Consumption and Risk of Conventional and Serrated Precursors of Colorectal Cancer: A Systematic Review and Meta-Analysis of Observational Studies

J Oncol. 2021 May 25:2021:9948814. doi: 10.1155/2021/9948814. eCollection 2021.

Authors

Li-Lianagzi Guo^{1

2}, Yu-Ting Li¹, Jun Yao², Li-Sheng Wang², Wei-Wei Chen¹, Kai-Yin He¹, Lin Xiao¹, Shao-Hui Tang¹

Affiliations

¹ Department of Gastroenterology, The First Affiliated Hospital, Jinan University, Guangzhou, Guangdong 510632, China.
² Department of Gastroenterology, Shenzhen People's Hospital (The Second Clinical Medical College, Jinan University, The First Affiliated Hospital, Southern University of Science and Technology), Shenzhen, Guangdong 518020, China.

Abstract

Objective: The consumption of dairy is associated with decreased risk of colorectal cancer (CRC), but few studies have assessed the relationship between dairy consumption and precursors of CRC. Therefore, we performed the first meta-analysis to further evaluate this association.

Methods: PubMed, Embase, Scopus, and Web of Science databases were searched through July 2020 for observational studies. Study-specific risk estimates for the highest versus lowest category were pooled using the random-effects and fixed-effects model. The methodological quality of included studies was assessed using the ROBINS-I Scale.

Results: A total of 12 studies were included (3 cohort studies and 9 case-control studies). Compared with the lowest level consumption, fermented dairy products had a decreased risk of precursors of CRC in both cohort (RR = 0.92 95% CI: 0.87-0.97) and case-control studies (RR = 0.98 95% CI: 0.96-0.99). Total dairy (RR = 0.80 95% CI: 0.68-0.96) and cheese (RR = 0.96 95% CI: 0.93-0.99) consumption was inversely associated with the risk in case-control studies whereas yogurt consumption was inversely associated with the risk in cohort studies (RR = 0.91 95%CI: 0.86-0.96). No significant associations were found for consumption of total milk and non/low-fat milk. For dose-response analyses, evidence of linear association was found in total dairy and yogurt consumption. The risk decreased by 12% for an increment of 200 g/d total dairy consumption (RR = 0.88 95% CI: 0.81-0.95) and decreased by 8% for an increment of 50 g/d yogurt consumption (RR = 0.92 95% CI: 0.85-0.99).

Conclusions: Fermented dairy products, specifically yogurt and cheese, were significantly associated with decreased risk of conventional and serrated precursors of colorectal cancer.