Causal relationship between ischemic stroke and its subtypes and frozen shoulder: a two-sample Mendelian...

Area of Science:

• Neuroscience
• Rheumatology
• Genetics

Background:

• Epidemiological studies suggest an association between ischemic stroke (IS) and frozen shoulder (FS).
• The causal relationship between IS and FS requires further investigation.
• Mendelian randomization is a robust method for exploring causal links between exposures and outcomes.

Purpose of the Study:

• To investigate the causal relationship between ischemic stroke (IS) and frozen shoulder (FS).
• To utilize a two-sample Mendelian randomization approach for robust causal inference.
• To examine potential causal links between IS subtypes and FS.

Main Methods:

• Employed a two-sample Mendelian randomization design using large-scale genome-wide association study data.
• Utilized inverse variance weighting (IVW) as the primary analysis method, supplemented by weighted median, MR-Egger, and other models.
• Assessed heterogeneity and pleiotropy using Cochran's Q-test, MR-Egger intercept, and MR-PRESSO, with leave-one-out analysis for result stability.

Main Results:

• The discovery stage indicated a causal association between IS and an increased risk of FS (OR=1.207, P=0.022).
• Replication analysis confirmed a significant causal link between lacunar stroke and FS (OR=1.252, P=0.0004).
• No significant causal relationships were found for other IS subtypes with FS; studies showed no significant pleiotropy or heterogeneity.

Conclusions:

• Confirmed a causal relationship between overall ischemic stroke and an elevated risk of frozen shoulder.
• Replication analysis supported the causal link, particularly with lacunar stroke as the exposure.
• Findings provide theoretical support for implementing shoulder care strategies in patients with ischemic stroke.