Genetically Predicted Cardiac Troponin I Concentrations and Risk of Stroke and Atrial Fibrillation

Objectives: Observational studies have shown that elevated circulating cardiac troponin I (cTnI) concentrations were linked to higher risk of stroke and atrial fibrillation, but the causality remains unclear. Therefore, we used mendelian randomization to assess the potential causal effects of cTnI concentrations on the risk of stroke, its subtypes and atrial fibrillation.

Materials and methods: The instrumental variables for circulating cTnI concentrations were selected from a genome-wide association study meta-analysis of 48,115 European individuals. We examined the associations of circulating cTnI concentrations with stroke, ischemic stroke, ischemic stroke subtypes (cardioembolic, large artery, small vessel stroke), intracerebral hemorrhage and atrial fibrillation.

Results: Genetically predicted elevated circulating cTnI concentrations were associated with higher risk of cardioembolic stroke (odds ratio [OR], 1.80; 95% confidence interval [CI], 1.20-2.68; P = 0.004), but not associated with large artery stroke, small vessel stroke, total stroke, ischemic stroke and intracerebral hemorrhage. Additionally, we also found that elevated cTnI concentrations were causally linked to higher risk of atrial fibrillation (OR, 1.30; 95% CI, 1.10-1.53; P = 0.003).

Conclusions: This study provides evidence that genetically predicted circulating cTnI concentrations are causally linked to higher risk of cardioembolic stroke and atrial fibrillation.