Association between the visceral adiposity index and rheumatoid arthritis: A cross-sectional study based on the NHANES 2007 to 2016

The visceral adiposity index (VAI), a measure of abdominal fat, has shown associations with various diseases. However, no study has investigated the relationship between VAI and rheumatoid arthritis (RA). This cross-sectional study aimed to examine the correlation between RA risk and VAI among US adults. Data from the National Health and Nutrition Examination Survey for the years 2007 to 2016 were downloaded. Participants were categorized into RA and non-RA groups based on arthritis questionnaire responses. VAI was classified both as continuous and in quartiles (Q1-4). All analyses incorporated National Health and Nutrition Examination Survey sampling weights, specifically the fasting subsample 2-year weights (WTSAF2YR), to account for the complex survey design and produce nationally representative estimates. The relationship between VAI and RA risk was assessed through weighted multivariable logistic regression analyses. In addition, a restricted cubic spline analysis assessed the relationship between VAI and RA risk. Subgroup analyses were conducted to investigate associations in specific subgroups. The same analyses were repeated after 1:1 propensity score matching in enrolled participants. A total of 8942 participants were included in the study. Weighted multivariable logistic regression analyses revealed that participants in the highest VAI quartile (Q4) had a 3% increased risk of RA (odds ratio = 1.03, 95% confidence interval = 1.01-1.05) compared with those in the lowest quartile (Q1). The restricted cubic spline curve indicated a nonlinear correlation between continuous VAI and RA risk. Subgroup analysis confirmed that VAI was associated with RA risk in different subgroups. After propensity score matching, only the Q2 VAI group showed a higher RA risk than the Q1 group, with a 7% increased risk (odds ratio = 1.07, 95% confidence interval = 1.01-1.15). Subgroup analysis revealed that the Q2 group had a high RA risk in populations with alcohol consumption, non-hypertension, and non-diabetes. Among US adults, higher VAI levels were associated with an increased risk of RA, particularly in populations with alcohol consumption and without hypertension or diabetes. These findings suggest an association rather than a causal relationship, highlighting the need for prospective studies to further elucidate this relationship.