Chronic whiplash, pain and pain tolerance

Abstract

Abstract Aim Among individuals who experience whiplash accidents, around 20% develop chronic pain. We aimed to compare number of painful locations and pain intensity between individuals with chronic whiplash and individuals with other chronic pain, and to investigate whether differences could be explained by pain tolerance. Methods Employing data from the sixth wave of the Tromsø Study, individuals reporting whiplash were compared to individuals with other chronic pain. Number of pain locations was compared using Poisson regression, pain intensity using linear regression. Pain tolerance (cold-pressor test) was compared using cox regression; one model compared individuals with whiplash to those with other chronic pain, another model compared the two groups with chronic pain to pain-free controls. In order to investigate whether pain tolerance could account for differences in pain, the regression models were adjusted for time-till-failure in the cold-pressor test. Results Individuals with whiplash reported a higher number of painful locations (IRR = 5.23, 95%CI: 4.93–5.53 versus IRR = 3.57, 95%CI: 3.50–3.65) and higher pain intensity (mean: 7.80, 95%CI: 7.58–8.02 versus mean: 7.14, 95%CI: 7.08–7.21) than individuals with other chronic pain. Pain tolerance did not differ between these two groups, but compared to pain-free controls individuals in both groups had reduced pain tolerance. Conclusions Individuals with chronic whiplash had reduced pain tolerance compared to individuals without chronic pain, but not compared to individuals with other chronic pain. Reduced pain tolerance can account for some of the increased pain reported by individuals with chronic whiplash compared to controls but not compared to individuals with other chronic pain.