The relationship of C-reactive protein to obesity-related depressive symptoms: A longitudinal study

Authors

  • Michael Daly

    Corresponding author
    1. Stirling Management School, University of Stirling, Stirling, FK9 4LA, United Kingdom
    • Health Services Research Unit, Health Sciences Building, University of Aberdeen, Foresterhill, Aberdeen, AB25 2ZD, United Kingdom
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  • Disclosure: The authors declare no conflict of interest.

  • Funding agencies: This research was supported by a European Commission co-funded Government of Ireland CARA Postdoctoral Mobility Fellowship.

Abstract

Objective:

Obesity has been shown to produce a state of systematic low-grade inflammation that may have detrimental neuropsychiatric effects.

Design and Methods:

Longitudinal associations between obesity, inflammation, and depressive symptoms amongst a cohort of older English adults over 4 years of follow-up were examined. Participants were 3,891 obese and nonobese people drawn from the English longitudinal study of ageing (ELSA) [aged 64.9 (SD = 8.8) years, 44.6% men]. Depressive symptoms were assessed at baseline and after 4 years of follow-up using the eight-item center for epidemiological studies—depression scale (CES-D).

Results:

Approximately 26.3% (N = 1,025) of the sample were categorized as obese at baseline. Obesity at baseline was associated with elevated levels of depressive symptoms at follow-up (P < 0.001), in analyses that adjusted for depression levels at baseline and sociodemographic and background variables including the prevalence of permanent illness/disability, alcohol consumption, sedentary behavior, and smoking. In addition, C-reactive protein (CRP) concentrations at baseline were independently associated with CES-D depression scores at follow-up (P = 0.008) in fully adjusted analyses. Subsequent mediation analyses revealed that CRP levels explained ∼20% of the obesity-related longitudinal change in depression scores.

Conclusion:

These data suggest that chronic inflammation may be a key determinant of depressive symptoms in obesity.

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