A study on the relationship between cheese intake and caries occurrence based on Mendelian randomization method

Abstract

Objective: The study aims to investigate the causal relationship between cheese intake and caries occurrence by a two-sample Mendelian randomization method (TSMR).

Methods: Data from a genome-wide association study (GWAS) on cheese intake as an exposure factor were collected, and dental caries was the outcome variable, appropriate SNPs were selected as instrumental variables (IVs). The TSMR was analyzed by the inverse variance weighting (IVW) method, weighted median method, MR-Egger regression method, simple model and weighted model.

Results: We identified forty-four single-nucleotide polymorphisms (SNPs) in the gene encoding group-specific component (cheese) that were associated with cheese intake, and IVW was adopted. The IVW method supported a relationship between cheese intake and the risk of dental caries occurrence[OR,1.00(95 %CI,0.99-1.00), P = 0.039 < 0.05]. There was no horizontal pleiotropy between the IVs(b = -0.0037, P = 0.39), and the sensitivity analysis using the "leave-one-out" method was robust to causal effects.

Conclusion: The results of the TSMR analysis supported that an appropriate intake of cheese could reduce the occurrence of dental caries.

Keywords: Caries occurrence; Causality; Cheese intake; TSMR analysis.

Fig. 1

MR requires the following three assumptions to be satisfied.

Fig. 2

Data intersection of SNP exposure and outcome.

Fig. 3

The X- and Y-axis represent the effect of the SNP on exposure and outcome, respectively, and the slope <0 represents cheese intake as a favorable factor for dental caries.

Fig. 4

Each horizontal solid line represents a single SNP estimated by the Wald ratio method.

Fig. 5

The effect of each SNP on the Mendelian randomization analysis results were judged, and if there were outliers that needed to be removed and reanalyzed.

Fig. 6

A roughly symmetrical pattern of the points on either side of the IVW line.