MVPA as the most influential factor for myocardial infarction through Bayesian Mendelian randomization among 11...

The causal associations between behavioral factors (BF) and myocardial infarction (MI), as well as the potential mediators and dose-response relationships, are incompletely clear. Therefore, this study aimed to evaluate the association of 11 BF with MI.

We used two-sample Mendelian randomization (2SMR) to investigate he associations between BF and MI and applied a two-sample multivariable MR approach based on Bayesian model averaging (MR-BMA) to prioritize the BF identified by 2SMR. For significant BF, we conducted extra conducted mediation analysis and restricted cubic spline (RCS) analysis to reveal potential mediating pathways and their dose-response relationships. Furthermore, we conducted replication analysis and meta-analysis to further support the results.

Among 11 BF, 2SMR identified 3 BF that were significantly associated with MI. Among them, MR-BMA identified moderate to vigorous intensity physical activity (MVPA) (Marginal inclusion probability (MIP) = 0.77) as the most influential factor. A potential mechanism underlying the MVPA-MI association was waist-hip ratio (WHR, 7.26%). RCS analysis further revealed that an MVPA of 1094-2043 MET minutes/week was associated with the lowest risk of MI. Finally, replication analysis and meta-analysis further supported the 3 BF and identified an extra association between tea intake and MI risk (Meta: OR = 0.991, P = .003).

Of the 11 BF, MVPA was the most influential factor independently associated with the reduced risk of MI, with WHR mediating this association. At least 39 minutes of MVPA per day is recommended to reduce the risk of MI. In addition, tea intake is a potential protective factor for MI that warrants further investigation. Key messages What is already known on this topic?  Previous studies have shown an association between behavioral factors and the risk of myocardial infarction (MI). However, the exact causal relationship, which behavioral factors is most influential for MI, and the potential dose-response relationship are incompletely clear. Mendelian randomization can provide genetic evidence of causal associations and reveal the underlying mechanisms. What this study adds?  This study provides novel genetic evidence that smoking initiation, leisure sedentary time, and moderate to vigorous intensity physical activity (MVPA) are associated with MI. MVPA is the most influential factor. Only MVPA is independently associated with MI, and waist-to-hip ratio mediated the association. In addition, we found that at least 39 minutes of MVPA per day resulted in the greatest reduction in MI. Finally, we also found a potential protective effect of tea drinking on MI. How this study might affect research, practice, or policy?  This study suggests that MVPA is independently associated with MI. In addition, this provides a basis for clinical exercise intervention. Finally, these results respond to the policy that "exercise is medicine", providing new insights into the advancement of that slogan.