Association Between Neck Pain and Osteoarthritis: A Bidirectional Mendelian Randomisation Study

BackgroundNeck pain is one of the most prevalent musculoskeletal complaints and has recently been recognized as a frequent comorbidity of osteoarthritis (OA). Whether this association reflects shared biological mechanisms or bidirectional influences remains unclear. ObjectivesTo investigate the bidirectional associations between genetic liability to neck pain and OA at three major joint sites (knee, hand, and hip) using Mendelian randomization (MR). MethodsA two-sample bidirectional MR study was conducted using summary-level data from large genome-wide association studies of neck pain (579,152 participants from the Million Veteran Program) and of knee, hand, and hip OA (up to 1.3 million participants from the international Osteoarthritis Consortium). The primary analysis was random-effects inverse-variance weighted (IVW). The additional analyses comprised of multiple pleiotropy-robust sensitivity methods (weighted median, mode-based estimators, MR-Egger, MR-PRESSO, MR-Lasso). ResultsGenetic liability to neck pain was positively associated with knee OA (IVW OR = 1.24, 95 % CI 1.10-1.41, p < 0.001) and showed a weaker, non-significant association with hand OA after correction for multiple testing (OR = 1.41, 95 % CI 1.03-1.95, p = 0.031). No association was observed with hip OA. In the reverse direction, genetic liability to knee (OR = 1.07, 95 % CI 1.03-1.11, p < 0.001) and hip OA (OR = 1.05, 95 % CI 1.02-1.07, p < 0.001) were associated with increased risk of neck pain, whereas hand OA showed no effect. Sensitivity analyses yielded consistent results with no evidence of directional pleiotropy. ConclusionsGenetic predisposition to neck pain was associated with a higher risk of knee OA, while genetic predisposition to knee and hip OA was associated with higher risk of neck pain. These bidirectional associations suggest overlapping biological pathways that warrant confirmation in independent studies.