Genetic Influence on Osteoarthritis Versus Other Rheumatic Diseases

Abstract

AimTo compare the genetic contribution to osteoarthritis (OA) vs other rheumatic/musculoskeletal diseases (RMDs) in the same population, and 2) to explore the role for any shared genetics between OA and other RMDs.MethodsIn 59 970 Swedish twins aged 35 years or older, we estimated the heritability (the variance explained by genetic factors) to OA in peripheral joints, back and neck pain, shoulder pain (adhesive capsulitis, impingement syndrome, etc), rheumatoid arthritis (RA), spondyloarthritis and psoriatic arthritis (SpA/PSA), myalgia and osteoporosis diagnosed in specialist and inpatient care. We also studied how much of covariance between OA and each of the RMDs could be explained by genetics, by studying phenotypic correlations in bivariate classical twin models.ResultsAny‐site OA and hip OA (50% and 64%) were among the most heritable RMDs (as compared to 23% for fibromyalgia (lowest) and 63% for spondylarthritis (highest)). The highest phenotypic correlations were between OA (any joint site) and shoulder pain in the same individual (r=0.33, 95% CI=0.31‐0.35), of which 70% (52‐88) could be explained by shared genetics. The phenotypic correlation between OA and back/neck pain was r=0.25, with 25%‐75% explained by genetics. Phenotypic correlations between OA and each of the other RMDs were lower (r~0.1 to r~0.2) with inconclusive sources of variation.ConclusionOA has relatively large heritability as compared to other RMDs. The co‐existence of OA and shoulder pain, as well as back pain, was common and could often be explained by genetic factors. Findings imply similar etiologies of OA and several pain conditions.