INTRODUCTION: Ultraprocessed foods are typically high in fat, salt, sugar, and food additives, which may contribute to the development of arthritis. This study examined the association between ultraprocessed food intake and the presence of self-reported arthritis. METHODS: The 2002-2018 U.S. National Health and Nutrition Examination Survey data was used to analyze the association between ultraprocessed food intake and arthritis in 2025. Ultraprocessed foods were identified by applying Nova classifications to 24-hour dietary recall data and expressed as a percentage of daily total energy intake. The outcomes were self-reported physician's diagnosis of arthritis, osteoarthritis, and rheumatoid arthritis. Survey-weighted logistic regressions were conducted to analyze associations between ultraprocessed food intake and outcomes, controlling for age, gender, race/ethnicity, smoking status, health insurance status, and poverty-to-income ratio. RESULTS: UPFs contributed 55.2% of the daily total energy intake in the U.S. POPULATION: After adjusting for covariates, a positive association was found between daily total energy intake from ultraprocessed foods and self-reported arthritis (AOR associated with each 10-percentage point increase in intake: 1.04
95% CI=1.02, 1.06). For the second, third, and fourth quartiles of ultraprocessed food intake, the AOR of arthritis was 1.14 (95% CI=1.04, 1.25), 1.22 (95% CI=1.10, 1.35), and 1.27 (95% CI=1.14, 1.41), respectively (p for linear trend <
0.002). A positive association was also observed between ultraprocessed food intake and rheumatoid arthritis (AOR=1.05
95% CI=1.02, 1.09) but not for osteoarthritis. CONCLUSIONS: In this nationally representative sample of U.S. adults, higher consumption of ultraprocessed foods was associated with overall arthritis and rheumatoid arthritis.