Current status of premature myocardial infarction research in China: a systematic review and international comparative perspective.

Background and aims: Premature myocardial infarction (PMI) imposes a significant and growing public health burden in China, particularly affecting the nation's young and productive workforce. Despite accumulating localized evidence, a systematic, strategic assessment of the risk factor landscape and its alignment with global research standards is lacking. This study aims to map the evidence for PMI risk factors in China, diagnose systemic research gaps from an international comparative perspective, and propose actionable strategies for future research and prevention. Methods: We conducted a systematic review of Chinese and English databases (from inception to September 2025), identifying 317 eligible observational studies on PMI in China. To move beyond descriptive synthesis, we developed and applied a novel "Strength-Importance Matrix" scoring system. This tool quantitatively evaluates each risk factor based on two dimensions: (1) Evidence Strength (a weighted composite of study design, sample size, methodological rigor, and result consistency) and (2) Public Health/Clinical Importance (a weighted composite of guideline recommendation strength, estimated population attributable risk, and intervention feasibility). Results: Chinese PMI patients exhibit a distinctive premature atherosclerosis phenotype dominated by behavioral and metabolic factors. Smoking (prevalence >71% in patients <55 years) and hypertriglyceridemia are hallmark risks. The Strength-Importance Matrix categorized factors into four strategic quadrants: Quadrant I (High Evidence/High Importance): priority intervention targets (e.g., smoking, hypertriglyceridemia, family history, metabolic syndrome); Quadrant II (High Importance/Low Evidence): critical evidence gaps (e.g., psychological stress, overwork, sleep deprivation); Quadrants III (Low Evidence/Low Importance): exploratory factors; and Quadrant IV (High Evidence/Low Importance): routine management factors (e.g., hypertension, diabetes). Compared to international benchmarks (e.g., INTERHEART, PURE), systematic gaps were identified in: (1) Methodological rigor (over-reliance on retrospective designs, inconsistent "premature" definitions, underuse of population attributable risk percentage); (2) Depth of Exploration (fragmented investigation of psychosocial and environmental factors); and (3) Translation Efficiency (limited development of localized risk prediction tools and community interventions). Conclusions: Addressing PMI in China requires a dual strategy: immediate, intensive management of Quadrant I risk factors, and strategic investment to bridge critical gaps. Future efforts must focus on building a national prospective research platform, standardizing methodologies, deepening mechanistic research within a biopsychosocial framework, and strengthening the translation of evidence into precision prevention tools and policies. This shift is essential to mitigate the rising burden of PMI and contribute to global cardiovascular prevention science. Systematic Review Registration: The protocol for this systematic review was prospectively registered with PROSPERO (Registration ID: CRD420261344947).