Abstract
BACKGROUND: The exact mechanisms underlying depression are not well understood. Chronic, low-grade inflammation is believed to play an important role in its development. The present study investigates the potential association between depressive symptoms and the neutrophil-to-lymphocyte ratio (NLR). METHODS: Seven data cycles of the National Health and Nutrition Examination Survey were extracted. Multivariable logistic regression and a generalized additive model were employed to determine the association. RESULTS: Thirty thousand eight hundred ninety-six subjects were analyzed. The results indicated that anhedonia and fatigue were significantly associated with NLR. Additionally, the generalized additive model results indicated a non-linear relationship between anhedonia, sleep disturbance and NLR. Subgroup analyses demonstrated that the correlation between anhedonia and NLR was significant in the above-60-year-old group (OR: 1.63, 95% CI: 1.14-2.33) and the male group (OR: 1.50, 95% CI: 1.07-2.10). Sleep disturbance was associated with NLR in the female group (OR: 1.36, 95% CI: 1.04-1.77). Fatigue was associated with NLR (OR: 1.30, 95% CI: 1.02-1.67) in the female group, as was the case in the non-Hispanic White group (OR: 1.32, 95% CI: 1.02-1.70). CONCLUSIONS: There were associations between NLR and specific symptoms, and these associations varied across demographic subgroups. There was a non-linear association between anhedonia, sleep disturbance and NLR. These findings could potentially contribute to the advancement of precision medicine within the field of mental health.