Hip osteoarthritis (OA) may increase the risk for overall stroke, ischemic stroke, and small vessel ischemic stroke, according to study results published in Osteoarthritis and Cartilage.
Researchers conducted a bidirectional, 2-sample Mendelian randomization (MR) study to determine the causal relationship between OA and stroke. Data on OA were collected from the published genome-wide association studies (GWAS). These data included OA at any site (n=77,052 cases, n=378,169 controls), knee OA (n=24,955 cases, n=378,169 controls), and hip OA (n=15,704 cases, n=378,169 controls).
Data on stroke were provided by the MEGASTROKE consortium for stroke (n=40,585 cases, n=406,111 controls), ischemic stroke (n=34,217 cases, n=406,111 controls), and intracerebral hemorrhage (n=1545 cases, n=1481 controls). The inverse variance weighted method was used to conduct the primary MR analysis. The researchers used MR-Egger regression, weighted median, MR pleiotropy residual sum and outlier, leave-one-out analysis, and Cochran Q statistic as needed.
A significant association was observed between hip OA and overall stroke (odds ratio [OR] 1.12 [95% CI, 1.06-1.20]; P =.0002), ischemic stroke (OR 1.13 [95% CI, 1.06-1.21]; P =.0003), and small-vessel ischemic stroke (OR 1.25 [95% CI, 1.10-1.42]; P =.0006). However, reverse MR analyses revealed no causal effects of stroke and subtypes on OA.
Limitations to the study included potential bias, a lack of investigation into the potential causal influence of ICH on OA, and the sole identification of a causal role of hip OA on risk for stroke.
The study authors concluded that the 2-sample MR analysis illuminated “a causal link between hip OA and stroke and stroke subtypes.” They noted that further studies are needed to “elucidate the underlying mechanisms of potential varied causal associations between site-specific OA and stroke subtypes.”