Background and objectives

According to observational studies, dietary habits may influence the occurrence of multiple sclerosis (MS). There are, however, only a few Mendelian randomization (MR) studies on both.

Methods and study design

The objective of this two-sample MR study was to examine possible causal associations between the twenty-one dietary practices and MS. For this investigation, we employed MR analysis utilizing generally accessible statistics from genome-wide association studies (GWAS) to examine causal connections between dietary habits and MS susceptibility among persons of European descent. The IEU Open GWAS project (https://gwas.mrcieu.ac.uk/) provided these GWAS data. Pleiotropy and heterogeneity were investigated using the MR-Egger Intercept test and Cochran's Q test, respectively. MR-Egger, weighted median, inverse variance weighted (IVW), simple mode, and weighted mode were used to assess the causal relationship between 21 dietary habit levels and MS.

Results

After removing outliers, we found a significant association between genetically induced oily fish intake and MS risk (IVW, OR: 0.557; 95% CI: 0.351-0.884; p = 0.013). Extensive sensitivity analyses confirmed this result. Other dietary habits had no dis-cernible relationship with MS risk.

Conclusions

This MR analysis provides evidence of an association be-tween dietary patterns and the risk of developing MS. Notably, higher intake of oily fish was associated with a reduced risk of MS among individuals of European ancestry.