The inflammatory biomarker C-reactive protein (CRP) measures systemic inflammation and has been shown to be increased in patients with mood disorders such as depression. The objective of this study was to determine the association between self-reported mood disorders with CRP levels in a representative sample of the Canadian population using the Canadian Health Measures Survey (CHMS) data 2013-2014.
The CHMS is an ongoing national cross-sectional survey of Canadians about their general health. The current study used the data collected from Cycle 3 (2012/13) and was limited to adults aged 18 and older. Survey weights were assigned to adjust for non-response and non-random sample selection of the responding sample.
Data were analyzed from 5782 respondents (400 (6.9%) self-reported mood disorders and 5382 (93.1%) reported no mood disorders). The CRP level was significantly higher among those with mood disorders than among those without (3.22 (0.17) vs. 2.34 (0.04) mg/L, p = 0.003). Respondents with CRP levels > 10.00 mg/L had 2.69 greater odds of reporting a mood disorder compared with those with CRP levels ≤ 1.00 mg/L (p = 0.02). Higher proportions of respondents with mood disorders were older, had lower BMI, had secondary education, had weak sense of community, had higher proportion of asthma or arthritis, were current/past smokers, had daily consumption of 3+ drinks of alcohol, and used prescription drugs, cannabis/hashish, or other drugs compared with those without mood disorders (all p’s < 0.05).
This study supported the association of CRP and mood disorder, specifically in a representative sample of the Canadian population. Targeting inflammation in depression and mood disorder warrants further study.

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