Association of Porphyromonas gingivalis with Acute Myocardial Infarction: A Systematic Review.

Background/Objectives: Periodontitis is a chronic oral infection in which Porphyromonas gingivalis (Pg) acts as a keystone pathogen capable of systemic dissemination and immune evasion. A possible association between Pg and acute myocardial infarction (AMI) has been proposed; this systematic review is, to our knowledge, among the first to evaluate this association through a pathogen-specific synthesis integrating both microbial and serological evidence. Methods: Five electronic databases (PubMed, Scopus, Embase, Web of Science, Cochrane Library) were searched from inception to February 2025, with a supplementary top-up search performed in July 2026 that identified no additional eligible studies. Observational studies assessing Pg presence or anti-Pg antibody levels in participants with and without AMI were eligible. Methodological quality was assessed using the Newcastle-Ottawa Scale (NOS). Findings were synthesised narratively due to substantial clinical and methodological heterogeneity. The protocol was registered in PROSPERO (CRD42025644043). Results: Twelve case-control studies (5147 participants; 2518 AMI cases, 2629 controls) were included. Six evaluated serum anti-Pg antibodies and six used direct microbial or molecular detection. Three studies in each category reported a significant Pg-AMI association; three in each category did not. NOS scores ranged from 6 to 9 (eight studies rated good quality; four fair quality). Heterogeneity in antigen selection, sampling site, immunoglobulin isotype, and confounder adjustment precluded meta-analysis. Conclusions: The available evidence suggests a possible but inconsistent association between Pg and AMI, insufficient to establish a causal relationship. Standardised detection protocols and prospective longitudinal studies with comprehensive confounder adjustment are needed. The detection of Pg in isolation is not currently validated for AMI risk stratification, and the available evidence does not establish a causal relationship between Pg and AMI.