Association between rheumatoid arthritis and serum vitamin C levels in Adults: Based on the National health and Nutrition Examination survey database

This study attempted to investigate relationship between rheumatoid arthritis and serum vitamin C levels using data from National Health and Nutrition Examination Survey (NHANES).The NHANES database aims to collect health, nutrition, biological, and behavioral data from a nationally representative sample of the population. This study utilizes NHANES data from three cycles: 2003–2004, 2005–2006, and 2017–2018, extracting data on the prevalence of rheumatoid arthritis and serum vitamin C levels. A generalized linear model is used to evaluate the association between the two.A total of 12,665 participants were included in the final analysis. Serum vitamin C levels were significantly higher in the non-rheumatoid arthritis group compared to the rheumatoid arthritis group (0.63 vs. 0.59, P = 0.042). Generalized linear model analysis showed that higher serum vitamin C levels were associated with a decreased risk of rheumatoid arthritis (OR = 0.62, 95 %CI: 0.40–0.98, P = 0.034). Stratified analysis revealed a significant interaction between non-hypertensive individuals and rheumatoid arthritis with serum vitamin C levels (P