None of the authors have conflicts of interest relating to the contents of this manuscript.
Twin studies of pain
Article first published online: 13 AUG 2012
© 2012 John Wiley & Sons A/S
Volume 82, Issue 4, pages 331–340, October 2012
How to Cite
Twin studies of pain., , .
- Issue published online: 11 SEP 2012
- Article first published online: 13 AUG 2012
- Accepted manuscript online: 23 JUL 2012 12:27PM EST
- Manuscript Revised: 12 JUL 2012
- Manuscript Accepted: 12 JUL 2012
- Manuscript Received: 4 JUN 2012
- twin study
Twin studies provide a method for estimating the heritability of phenotypes and for examining genetic and environmental relationships between phenotypes. We conducted a systematic review of twin studies of pain, including both clinical and experimental pain phenotypes. Fifty-six papers were included, whereof 52 addressed clinical phenotypes. Of the most comprehensively studied phenotypes, available data indicates heritability around 50% for migraine, tension-type headache and chronic widespread pain, around 35% for back and neck pain, and around 25% for irritable bowel syndrome. However, differences in phenotype definitions make these results somewhat uncertain. All clinical studies relied on dichotomous outcomes and none used pain intensity as continuous phenotype. This is a major weakness of the reviewed studies and gives reason to question their validity with respect to pain mechanisms. Experimental pain studies indicate large differences in heritability across pain modalities. Whereas there is evidence for substantial common genetic risk across many clinical pain conditions, different experimental pain phenotypes appear to be associated with different genetic factors. Recommendations for future research include inclusion of pain intensity scaling and number of pain sites in phenotyping. Furthermore, studies examining the genetic relationships between pain phenotypes, in particular between clinical and experimental phenotypes, should be prioritized.