Psychol Med. 2013 Aug;43(8):1773-83. doi: 10.1017/S0033291712002437.
Epub 2012 Nov 14.
Association of C-reactive protein and interleukin-6 with new-onset
fatigue in the Whitehall II prospective cohort study.
Cho HJ1, Kivimäki M, Bower JE, Irwin MR.
1Cousins Center for Psychoneuroimmmunology, UCLA Semel Institute for
Neuroscience and Human Behavior, Los Angeles, CA, USA.
BACKGROUND: Although basic research on neuroimmune interactions
suggests that inflammatory processes may play a role in the
development of fatigue, population-based evidence on this association
is limited. This study examined whether plasma C-reactive protein
(CRP) and interleukin-6 (IL-6), biomarkers of systemic inflammation,
predict fatigue onset.
METHOD: The Whitehall II study is a large-scale cohort study conducted
in 20 civil service departments in London. Plasma CRP and IL-6 were
measured in 4847 non-fatigued participants at phase 3 (1991-1993, aged
39-63 years). Fatigue was assessed using the Vitality subscale of the
36-item Short Form Health Survey (SF-36) at phase 3 and phase 4
RESULTS: During a mean follow-up of 3.1 years, 957 new fatigue cases
(19.7%) were identified using the pre-established cut-off score of ≤
50 on the Vitality subscale. CRP values were dichotomized as low (<1.0
mg/l ) or high (≥ 1.0 mg/l) using the Centers for Disease
Control/American Heart Association recommendations. Similarly, IL-6
values were also dichotomized as low (<1.5 pg/ml) or high (≥ 1.5
pg/ml). After full adjustment for sociodemographic and biobehavioral
covariates, the odds ratios for new-onset fatigue were 1.28 [95%
confidence interval (CI) 1.09-1.49, p = 0.003] for high CRP and 1.24
(95% CI 1.06-1.45, p = 0.008) for high IL-6. Similar results were
found when CRP and IL-6 were treated as continuous variables.
CONCLUSIONS: Plasma CRP and IL-6 were prospectively associated with
new-onset fatigue, supporting the hypothesis that low-grade
inflammation has a role in the development of fatigue.
PMID: 23151405 [PubMed - indexed for MEDLINE] PMCID: PMC3819455
[Available on 2014/8/1]