Association of a Novel Dietary Index Assessing Gut Microbiota Impact With Rheumatoid Arthritis: A Nationwide...

Growing research implicates the diet-microbiota-joint axis plays a key role in joint health. The Dietary Index for Gut Microbiota (DI-GM) is a novel metric evaluating dietary effects on microbial communities, yet its potential link to rheumatoid arthritis (RA) is unestablished. This study aimed to assess the relationship between DI-GM scores and RA. We conducted a cross-sectional analysis of 29,656 participants using data from the National Health and Nutrition Examination Survey (NHANES) 2007-2020. DI-GM scores were derived from 24-h dietary recalls, and RA status was defined by self-reported physician diagnosis. Weighted logistic regression was used to evaluate the association between DI-GM and RA prevalence. Among included participants (weighted mean age 44.01 years; 49.48% female), 7.16% reported RA. After comprehensive adjustment, a significant inverse correlation was observed: each unit increase in DI-GM score correlated with a 5.7% decrease in the odds of RA prevalence (odds ratio [OR] = 0.943; 95% confidence interval [CI]: 0.898-0.991). Individuals scoring DI-GM ≥ 7 exhibited a 27.2% lower odds of having RA compared to those scoring ≤ 4 (OR = 0.728, 95% CI: 0.576-0.920). Restricted cubic spline analysis indicated a linear dose-response relationship (p for nonlinear = 0.304). Furthermore, no significant subgroup interactions were detected (all p for interaction > 0.05). Our study found that higher DI-GM scores linearly associate with diminished RA prevalence among US adults, highlighting a potential link between diet-modulated gut microbiota and RA.