Risk factors of premature coronary artery disease in Iran: A systematic review and meta-analysis

Background: The aim of this study was to determine the mean age at which coronary artery disease (CAD) hase decreased in recent years in Iran. This systematic review and meta-analysis compares the prevalence of different risk factors of premature CAD (PCAD) in patients vs healthy individuals.

Methods: Medline, Web of Science, Embase and Scientific Information Database were searched for studies about PCAD risk factors in Iran until 28 October 2017. Observational studies of Iranians, comparing risk factors between patients with PCAD and age- and sex-matched healthy subjects, were included. Fixed-effects and random-effects model were used for pooling data. Odds ratio (OR) with 95% CI and mean difference were used for effect size estimation among studies.

Results: Twelve studies were eligible for meta-analysis. Diabetes mellitus (OR: 2.4, 95% CI: 1.9-3.03; P = 0.0001, I² = 25.5%; P = 0.2), family history of CAD (OR: 2.09, 95% CI: 1.22-3.6; P = 0.007, I² = 86%; P = 0.0001), dyslipidaemia (OR: 2.05, 95% CI: 1.15-3.64; P = 0.01, I² = 54%; P = 0.08), smoking (OR: 1.65, 95% CI: 1.11-2.46; P = 0.01, I² = 77.2%; P = 0.000) and hypertension (OR: 1.35, 95% CI: 1.21 to-1.50; P < 0.001, I² = 31%, P = 0.1) associated with PCAD. Sensitivity analysis demonstrated that patients with PCAD had significantly lower levels of high-density lipoprotein (HDL) cholesterol and significantly higher levels of triglycerides compared to healthy subjects (MD: -2.56, 95% CI: -3.54 to -1.58, P < 0.001, I² = 42%, P = 0.01 and MD: 21.17, 95% CI: 14.73-27.62, P < 0.001, I² = 80.12%, P < 0.001, respectively). It should be noted that although high levels of heterogeneity in LDL and HDL values among the studies were observed, when dyslipidaemia was studied as a binary variable, no significant heterogeneity among studies was observed.

Conclusion: Diabetes mellitus, family history of CAD, dyslipidaemia, smoking, and hypertension were significantly and positively associated with CAD in young adults compared to healthy age- and sex-matched population in Iran.