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

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.