Heritability of Spinal Pain and Consequences of Spinal Pain: A Comprehensive Genetic Epidemiologic Analysis Using a Population-Based Sample of 15,328 Twins Ages 20-71 Years

Objective. To assess the relative contribution of genetic and environmental factors to different definitions of spinal pain and consequences of spinal pain. Methods. The Danish Twin Registry contains detailed survey information on spinal pain and its consequences in twins ages 20-71 years. A classic genetic epidemiologic analysis was performed in order to establish heritability for a number of phenotypes, including location of pain, radiation of pain in the extremities or chest, pain duration, and combinations of pain in >1 spinal area. Consequences included reduced physical activity, sick leave, care seeking, change of work, and disability pension. The analysis included a biometric analysis based on the effect of shared genetic and common environmental factors. Furthermore, a bivariate twin model was fitted to identify genetic and environmental correlations. Results. Altogether, data on 15,328 twin individuals (44% monozygotic and 56% dizygotic) from complete twin pairs were included. Genetic susceptibility explained similar to 38% of lumbar pain, 32% of thoracic pain, and 39% of neck pain. For patterns of pain, estimates were 7% for lumbar/thoracic, 24% for lumbar/cervical, 0% for thoracic/cervical, and 35% for pain in all 3 areas. Moderate to high genetic correlations indicated a common genetic basis for many spinal pain syndromes. In general, heritability was higher for women, and only a minor age effect was seen. Conclusion. Heritability estimates for pain in different spinal regions are quite similar and there is a moderate to high genetic correlation between the phenotypes. This may indicate a common genetic basis for a high proportion of spinal pain.