Abstract
Objective
Inflammation may play a role in the accelerated physical aging reported in schizophrenia though biomarker findings and associations with demographic and clinical factors are inconsistent.
Design
Cross-sectional, case-control design
Setting
Community-dwelling participants tested in an academic laboratory.
Participants
95 outpatients with schizophrenia (mean age ± SD: 48.1 ± 10.2 yrs) and 95 demographically-comparable healthy comparison subjects (HCs) (mean age ± SD: 48.1 ± 12.1 yrs)
Measurements
Sociodemographic and clinical data were collected, and plasma levels of tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and interferon-γ (IFN-γ) were assayed. We compared cytokine levels, examined demographic and clinical associations. and adjusted for relevant variables with linear models.
Results
Individuals with schizophrenia had higher levels of TNF-α and IL-6, but not IFN-γ, than HCs. Age was not related to cytokine levels, and age relationships did not differ between diagnostic groups. Women had higher levels of IL-6. TNF-α and IL-6 levels were significantly correlated with depressive symptoms, and adjustment for depression reduced the group effect for both. Within the HCs, TNF-α levels were associated with physical comorbidity and body mass index (BMI). IL-6 levels were significantly correlated with BMI, and within schizophrenia patients, with worse mental and physical well-being. Accounting for physical morbidity and mental well-being reduced group differences in TNF-α and IL-6 levels, respectively. Worse positive symptoms were associated with higher IL-6 levels.
Conclusions
Higher TNF-α and IL-6 levels in schizophrenia patients were associated with depression, physical comorbidity, and mental well-being. Further longitudinal studies are warranted to assess inflammation as a potential treatment target for a subgroup of schizophrenia.
Keywords:
TNF-α, IL-6, IFN-γ, schizophrenia, inflammation, cytokines
http://www.ajgponline.org/article/S1064-7481(16)30264-0/abstract