AUTHOR=Wang Haiyang , Wu Qinglin , Qu Pengda , Wang Shiqi , Du Shiyu , Peng Zhaorong , Tao Licheng , Wang Wuxia , Tang Xiaohu 

TITLE=Diet affects inflammatory arthritis: a Mendelian randomization study of 30 dietary patterns causally associated with inflammatory arthritis

JOURNAL=Frontiers in Nutrition

VOLUME=11

YEAR=2024

URL=https://www.frontiersin.org/journals/nutrition/articles/10.3389/fnut.2024.1426125

DOI=10.3389/fnut.2024.1426125

ISSN=2296-861X

ABSTRACT=<sec id="sec1"><title>Background</title><p>The causal associations between dietary intake and the risk and severity of Inflammatory Arthritis (IA) are currently unknown.</p></sec><sec id="sec2"><title>Objective</title><p>In this study, we aimed to investigate the causal relationship between nine dietary categories (30 types of diet) and IA using Mendelian randomization (MR).</p></sec><sec id="sec3"><title>Methods</title><p>We analyzed data from 30 diets and IA in a genome-wide association study (GWAS). Single nucleotide polymorphisms (SNPs) that could influence the results of MR analyses were screened out through the Mendelian Randomization Pleiotropy RESidual Sum and Outlier (MR-PRESSO) test. SNPs were analyzed through two-sample bidirectional MR using inverse variance weighting, MR-Egger regression, and weighted median method. The multiplicity and heterogeneity of SNPs were assessed using MR-Egger intercept term tests and Cochran’s <italic>Q</italic> tests. FDR correction was used to correct the <italic>p</italic>-values.</p></sec><sec id="sec4"><title>Results</title><p>IVW results showed that Beef intake [Odds ratio (OR) = 2.862; 95% confidence interval (CI), 1.360–6.021, <italic>p</italic> = 0.006, <italic>p_fdr</italic> &lt; 0.05] was positively associated with rheumatoid arthritis(RA); Dried fruit intake (OR = 0.522; 95% CI, 0.349–0.781, <italic>p</italic> = 0.002, <italic>p_fdr</italic> &lt; 0.05), and Iron intake (OR = 0.864; 95%CI, 0.777–0.960, <italic>p</italic> = 0.007, <italic>p_fd</italic>r &lt; 0.05) were negatively associated with RA, all of which were evidence of significance. Fresh fruit intake (OR = 2.528. 95% CI, 1.063–6.011, <italic>p</italic> = 0.036, <italic>p_fdr</italic> &gt; 0.05) was positively associated with psoriatic arthritis (PsA); Cheese intake (OR = 0.579; 95% CI, 0.367–0.914, <italic>p</italic> = 0.019, <italic>p_fdr</italic> &gt; 0.05) was negatively associated with PsA; both were suggestive evidence. Processed meat intake (OR = 0.238; 95% CI, 0.100–0.565, <italic>p</italic> = 0.001, <italic>p_fdr</italic> &lt; 0.05) was negatively associated with reactive arthritis (ReA), a protective factor, and significant evidence. All exposure data passed the heterogeneity check (Cochrane’s <italic>Q</italic> test <italic>p</italic> &gt; 0.05) and no directional pleiotropy was detected. Leave-one-out analyses demonstrated the robustness of the causal relationship in the positive results.</p></sec><sec id="sec5"><title>Conclusion</title><p>Our study presents genetic evidence supporting a causal relationship between diet and an increased risk of IA. It also identifies a causal relationship between various dietary modalities and different types of IA. These findings have significant implications for the prevention and management of IA through dietary modifications.</p></sec>