Relationship between the atherogenic index of plasma and arthritis in American adults: Findings from the National Health and Nutrition Examination Survey 2005–2018

ObjectiveArthritis is an acute or chronic inflammatory joint disease characterized by pain and stiffness that typically worsen with aging. It is often accompanied with joint rigidity, cartilage degeneration, and pathological changes, such as monocyte infiltration, inflammation, synovial swelling, and mass formation. Osteoarthritis and rheumatoid arthritis are the two most common forms of arthritis worldwide. The atherogenic index of plasma, which reflects lipid metabolism, may influence arthritis progression. This study aimed to investigate the relationship between the atherogenic index of plasma and arthritis among adults in the United States.MethodsUsing the National Health and Nutrition Examination Survey data (2005-2018), 12,273 individuals (representing 74.2 million people) with complete data on the atherogenic index of plasma and arthritis assessments were analyzed. The atherogenic index of plasma was calculated using the following formula: log₁₀(triglycerides/high-density lipoprotein cholesterol). Weighted multivariable logistic regression, restricted cubic spline, and subgroup analyses were performed to evaluate the associations.ResultsHigher atherogenic index of plasma quartiles were correlated with increased arthritis prevalence (<i>p </i><<i> </i>0.05). After adjustments, the highest quartile showed a 45% higher arthritis risk (odds ratio = 1.45, 95% confidence interval: 1.20-1.74, <i>p </i><<i> </i>0.001) than the lowest quartile. Restricted cubic spline analysis confirmed a linear association between the atherogenic index of plasma and arthritis (<i>p </i><<i> </i>0.001). Subgroup analyses revealed significant interactions among age, sex, smoking status, educational level, and race (<i>p </i>=<i> </i>0.019).ConclusionThe atherogenic index of plasma was positively correlated with arthritis incidence, highlighting it as a potential biomarker for risk assessment and prevention. Clinicians should monitor elevated atherogenic index of plasma in high-risk populations. Prospective studies should be conducted to validate the causal role of the atherogenic index of plasma and explore its utility in arthritis prevention protocols.