Does Walking Have an Association with Osteoarthritis? A Two-Sample Mendelian Randomization Analysis

Jiankang Xu,1,2,* Longyao Zhang,1,2,* Ping Wang,1,2 Chao Zhang,1,2 Shuqing Ji3 1Orthopedics Department, The First Teaching Hospital of Tianjin University of Traditional Chinese Medicine, Tianjin, People’s Republic of China; 2Orthopedics Department, National Clinical Research Center for Chinese Medicine Acupuncture and Moxibustion, Tianjin, People’s Republic of China; 3Orthopedics Department, Tianjin Jizhou District Traditional Chinese Medicine Hospital, Tianjin, People’s Republic of China*These authors contributed equally to this workCorrespondence: Chao Zhang, Orthopedics Department, The First Teaching Hospital of Tianjin University of Traditional Chinese Medicine, Tianjin, People’s Republic of China, Email zhangchao2004.love@163.comObjective: Osteoarthritis (OA) is one of the major disabling human diseases. The related studies indicate a potential correlation between walking and OA. However, there is still a lack of evidence in genetics to support the correlation between walking and OA. Therefore, this study aimed to explore the relationship between walking and OA at the genetic level.Methods: The publicly available Genome Wide Association Study (GWAS) data were used, with inverse variance weighting (IVW, the random-effects model) as the main analysis method, whereas MR-Egger, Weighted median, Simple mode, and Weighted mode as the secondary analysis methods. In addition, Cochran’s Q test, pleiotropy test, and MR-Egger intercept test were conducted to examine the heterogeneity and pleiotropy of the outcome.Results: In the MR analysis, IVW results showed a negative correlation between types of physical activity in last 4 weeks: Walking for pleasure (not as a means of transport) and OA (KOA or HOA) (odds ratio (OR) = 0.3224, 95% confidence interval (CI): 0.1261 to 0.8243), and the difference was of statistical significance (P = 0.0181). Moreover, IVW results also revealed a negative correlation between types of physical activity in l