The baseline characteristics of all qualified studies included in the meta-analysis.

P-B: population-based study; H-B: hospital-based study; CAD: coronary artery disease; MI: myocardial infarction; ACS: acute coronary syndrome; M(%): male(percent); F: female; HTN: hypertension; DM: diabetes mellitus; BMI: body mass index; a:early-onset coronary artery disease; b:late-onset coronary artery disease; c:data not available; d:single-vessel disease; e:multi-vessel disease; Age and BMI are expressed as mean ±SD (standard deviation) or median (5th and 95th percentiles).