A population-based study of inflammatory mechanisms and pain sensitivity.

Two recent studies suggest that experimental pain sensitivity is associated with low-grade systemic inflammation. However, only two biomarkers have been identified and the studies were conducted in adult individuals where confounding effects of comorbid diseases cannot be excluded. We therefore tested associations between pain sensitivity and 119 inflammation-related serum biomarkers in 827 healthy adolescents (15-19 years) in the population-based Tromsø Study: Fit Futures. The main outcome measure was cold-pressor pain tolerance (CPT), tested by placing the dominant hand in circulating cold (3°C) water for a maximum of 105s. Secondary outcomes were heat and pressure pain threshold and tolerance. Twelve proteins and six fatty acids were significantly associated with CPT after adjustment for possible confounding factors and correction for multiple comparisons. Of these, all fatty acids and 10 proteins were protective, i.e. higher biomarkers levels were associated with increased CPT, whereas two biomarkers were associated with lower tolerance. Taken together these biomarkers predicted completion of the tolerance test with a C-statistic of 0.65. Results for heat and pressure pain tolerance were remarkably similar, strengthening the generalizability of our findings. In this cohort of young healthy individuals, we found a relationship between inflammation-related biomarkers and pain tolerance and thresholds. Biomarkers with anti-inflammatory and analgesic effects predominated, suggesting that the development of prophylactic dietary or pharmaceutical treatments may be possible.