Abstract
BACKGROUND: Depression and anxiety are significant global health concerns, with systemic inflammation playing a critical role in their pathophysiology. Recent studies have highlighted the C-reactive protein to lymphocyte ratio (CLR) as a potential biomarker of inflammation that may be associated with these mental health conditions. However, the relationship between CLR and depression and anxiety, especially within a diverse population, remains underexplored. METHODS: This study utilized data from the National Health and Nutrition Examination Survey (NHANES) (2015-2023) to examine the association between CLR and the prevalence of depression and anxiety. A total of 22,308 participants were included for depression analysis, and 16,138 participants were included for anxiety analysis. Depression was assessed using the PHQ-9, and anxiety was assessed through self-reported anxiety symptoms and medication use. CLR was calculated as the ratio of C-reactive protein to lymphocyte count, and logistic regression models were applied to analyze associations, adjusting for demographic and health-related variables. RESULTS: Higher CLR levels were significantly associated with increased odds of depression (OR: 1.49; 95% CI: 1.25-1.78) and anxiety (OR: 1.13; 95% CI: 1.02-1.26) after full adjustment for confounders. Non-linear relationships were observed, with specific inflection points for both depression (CLR = 0.96) and anxiety (CLR = 0.88), beyond which the risk of mental health disorders increased sharply. Subgroup analyses revealed that younger individuals and those without hypertension showed stronger associations between CLR and depression. CONCLUSION: Elevated CLR is associated with an increased risk of depression and anxiety, suggesting the potential role of systemic inflammation in influencing mental health outcomes. CLR may serve as a useful biomarker for identifying populations at higher risk, underscoring the need for further research into early intervention strategies and targeted approaches to address systemic inflammation in mental health care.