Water Pipe Tobacco Smoking and Risk of Coronary Artery Disease: A Systematic Review and Meta-Analysis.

BACKGROUND: Waterpipe smoking has become a vitally important public health issue in the world with a false assumption that it has a less harmful effect. OBJECTIVE: The aim of this study was to systematically review the association between waterpipe tobacco smoking and the risk of coronary artery disease (CAD). METHODS: Up to September 25, 2018, we electronically searched the PubMed, Embase, and ISI Web of Science with no time restriction. We included observational studies and excluded conference abstracts, editorials, case reports, case series, and reviews. With the fixed model effect, we conducted a meta-analysis to evaluate the association between waterpipe smoking and coronary artery disease. Heterogeneity among studies was assessed by the I2 square test. Publication bias was assessed by Egger test. P<0.05 was set as significant level. RESULTS: Among 248 paper records identified through a database search, 52 full texts were eligible for full text assessment whereas 49 papers were excluded. Additionally, three studies were eligible for meta-analysis, which involved 58,960 adults with 1334 in the water pipe smoker group. Risk of CAD was increased in water pipe smokers compared to individuals who had never smoked water pipe but the result did not reach a statistical significance (OR=1.18, 95% CI: 0.98-1.38, p=0.06). We found that heavy water pipe smoking (40 to 50 sessions of waterpipe smoking/year) was associated with CAD compared to lower smokers defined as less than 40 to 50 water pipe/year (OR=2.001, 95% CI: 1.13-2.87). CONCLUSION: Heavy Water pipe smoking was associated with coronary artery disease based on clinical findings. It seems very crucial to increase public awareness on adverse effects of water pipe smoking and its cessation in clinical setting.

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.