C-reactive protein (CRP) is associated with chronic pain independently of biopsychosocial factors
One page on PainSci cites Farrell 2023: Inflamed, but not psychosocially
PainSci notes on Farrell 2023:
This new UK study has shown that chronic pain patients are inflamed, as measured by high C-reactive protein, the best known biomarker for systemic inflammation. That isn’t much of a news flash — chronic pain and inflammation? Who would have guessed?!
This is the cool part, and the reason I picked this one to write about today: the study showed that chronic pain patients aren’t just inflamed… they are inflamed even without any of the traditional psychosocial bogeymen. That is a surprise.
Farrell et al. went mining for data about hundreds of thousands of patients, identifying a strong link between pain and CRP compared to people without pain… and that link remained robust even when a great variety of other common correlates with pain were factored out: income, demographics, mental health, and so on. The authors reckon this means there is “a possible independent biological mechanism” for pain.
This is the opposite of what many experts would predict. Supposedly people get more inflamed precisely because of those influences: that is, we get unfit and unhealthy because of things like eating junk food, sitting all day, or getting really stressed trying to raise a kid alone. But this study shows that chronic pain patients are inflamed even without such things, which flies in the face of the (fashionable?) attempt to explain pain with a lot of psychosocial stuff — things that probably do matter, but these results strongly suggest there’s much more to the story, namely the “bio” in “biopsychosocial.” Relatively subtle pathology is probably the broad explanation for the inflammation in these chronic pain patients.
I do not think this is a surprise to the millions of people who felt like they had good, healthy lives right up until the pain started.
original abstract †Abstracts here may not perfectly match originals, for a variety of technical and practical reasons. Some abstacts are truncated for my purposes here, if they are particularly long-winded and unhelpful. I occasionally add clarifying notes. And I make some minor corrections.
Inflammation is linked with chronic pain but the extent to which this relationship is associated with biopsychosocial factors is not known. We investigated relationships between blood C-reactive protein (CRP) and regional chronic pain conditions adjusting for a large range and number of potential confounders. We performed cross-sectional analyses using the UK Biobank (N=415,567) comparing CRP in people reporting any of nine types of regional chronic pain with pain-free controls. Using logistic regression modelling, we explored relationships between CRP and the presence of chronic pain, with demographic, socioeconomic, psychological/lifestyle factors, and medical comorbidities as covariates. CRP was higher in chronic pain at any site compared with controls (Females: median [IQR] 1.60mg/L [2.74] vs 1.17mg/L [1.87], P<0.001; Males: 1.44mg/L [2.12] vs 1.15mg/L [1.65], P<0.001). In males, associations between CRP and all types of chronic pain were attenuated but remained significant after adjustment for biopsychosocial covariates (OR range 1.08 to 1.49, P≤0.001). For females, adjusted associations between CRP and pain remained significant for most chronic pain types (OR range 1.07 to 1.34, P<0.001) except for facial pain (OR 1.04, P=0.17) and headache (OR 1.02, P=0.07)-although these non-significant findings may reflect reduced sample size. The significant association between CRP and chronic pain after adjustment for key biopsychosocial confounders implicates an independent underlying biological mechanism of inflammation in chronic pain. The presence of yet unknown or unmeasured confounding factors cannot be ruled out. Our findings may inform better targeted treatments for chronic pain.
PERSPECTIVE: Using a large-scale dataset, this article investigates associations between chronic pain conditions and blood C-reactive protein (CRP), to evaluate the confounding effects of a range of biopsychosocial factors. CRP levels were higher in those with chronic pain vs controls after adjusting for confounders-suggesting a possible independent biological mechanism.
This page is part of the PainScience BIBLIOGRAPHY, which contains plain language summaries of thousands of scientific papers & others sources. It’s like a highly specialized blog. A few highlights:
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