The longitudinal association between inflammation and incident depressive symptoms in men: The effects of hs-CRP are independent of abdominal obesity and metabolic disturbances

Abstract

<h4>Background</h4>This cohort study evaluates whether the association between low-grade inflammation and incident depressive symptoms is independent of abdominal obesity and metabolic disturbances.<h4>Methods</h4>A cohort of 1167 non-depressed men aged 35 to 80 years were followed up over 5 years to assess incident depressive symptoms measured by the Centre for Epidemiology Scale-Depression or Beck Depression Inventory-I. Venous tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6) and high sensitivity C-reactive protein (hsCRP) were quantified at baseline and 5years. Logistic regression determined whether hsCRP, IL-6 and TNF-α were associated with incident depressive symptoms independent of abdominal obesity and metabolic factors. Ancillary analysis utilizing depression z scores stratified participants by waist circumference ≥ 102 cm and ≥2 metabolic disturbances.<h4>Results</h4>Incident depressive symptoms occurred in 95 men at 5 years (8.14% of total). Clinically relevant depressive symptoms were associated with baseline hsCRP (adjusted OR=1.04; 95% CI 1.00-1.07, p=.03) and annualized ΔhsCRP (adjusted OR=1.04; 95% CI 1.01-1.08, p=.02). Ancillary analysis showed that the association between annualized ΔhsCRP and depression z score was only significant in men with waist circumference<102 cm (β=.19, p<.001) and ≤1 metabolic disturbance (β=.18, p<.001). None of the measured cytokines were significantly associated with depression.<h4>Conclusions</h4>hsCRP and annualized ΔhsCRP were positively associated with depressive symptoms in a cohort of men. Further investigation into the role of abdominal obesity and metabolic disturbances in the inflammation-depression hypothesis is warranted.