Rotator cuff injury and myocardial infarction: Findings of NHANES 2011 to 2018 and Mendelian randomization study

Rotator cuff injury (RCI) and myocardial infarction (MI) are prevalent conditions in clinical practice. Nevertheless, the causal relationship between the 2 remains poorly understood. This study aimed to explore the complex association between RCI and MI by integrating cross-sectional analysis with Mendelian randomization (MR) approaches. The cross-sectional study utilized data from the National Health and Nutrition Examination Survey spanning 2011 to 2018, which involved in 567,36 participants. It assessed the correlation between RCI and MI using Chi-square tests, T tests, and a multiple logistic regression model. Additionally, we conducted MR analysis to investigate the causal effects of RCI on MI. We employed inverse variance weighted (IVW), sensitivity analysis, heterogeneity testing, and other methods for MR. The RCI data was sourced from the FinnGen (n = 390,666), while the aggregated data on MI was obtained from genome-wide association studies statistics (n = 638,000). In this cross-sectional analysis, after adjusting for age, gender, race, smoking status, marital status, education level, and poverty income ratio, RCI remained an independent risk factor for MI [odds ratio (OR) 95% confidence interval (CI) = 1.68 (1.43-1.96), P < .001]. The subgroup analysis indicated that females aged over 60 exhibited a higher risk of MI associated with RCI compared to the overall population. The forward MR analysis included 79 single nucleotide polymorphisms (SNPs) linked to RCI. The results revealed a statistically significant causal relationship: individuals with genetic predisposition to RCI were at a higher risk of developing MI [IVW: OR = 1.09, 95% CI: 1.03-1.14, P < .001]. No heterogeneity (P > .05) or horizontal pleiotropy (P > .05) was detected, and the leave-one-out test did not identify any single SNP that unduly influenced the outcome. Conversely, the reverse MR analysis (which incorporated 78 MI-associated SNPs) did not provide strong evidence for a causal link in the opposite direction [IVW: OR = 0.98, 95% CI: 0.94-1.02, P = .39]. These findings suggest a directional causal relationship: RCI may increase the risk of MI, and vice versa, an association that is particularly pronounced in women over 60.