Effect of Active and Passive Exposure to Cigarette Smoke on Lipid Profile of Children and Adolescents; A Systematic Review and Meta-Analysis

Background: The present systematic review and meta-analysis is designed in order to assess the association between passive and active smoking and lipid profile of children and adolescents. Materials and Methods:  An extensive search was done in databases of Medline, EMBASE, Web of Science, Scopus and CINAHL until October 2017. Two independent researchers screened articles and in the next step, full texts of probably relevant articles were read and summarized. At the end, results of mentioned studies were pooled and a standardized mean difference (SMD) with 95% confidence interval (95% CI) was reported. Results: Data from 17 studies (containing 41619 children and adolescents; age group between 4 and 18 years old; 51.72% boys) were entered. Comparing serum level of high density lipoprotein (HDL) in two groups of exposed and non-exposed to cigarette smoking showed that active exposure (SMD= -0.40, 95% CI: -0.59 to -0.21) and passive exposure to cigarette smoke (SMD= -0.18, 95% CI: -0.30 to -0.06) decreases the serum level of mentioned lipoprotein. Additionally, active exposure to cigarette smoke (SMD=0.16, 95% CI: 0.06 to 0.27) causes a modest increase in serum level of triglyceride. However, cigarette smoke exposure does not have any effect on the level of total cholesterol and low density lipoprotein (LDL). Conclusion: The present meta-analysis showed that exposure to cigarette smoke leads to a significant decrease in the level of HDL and triglyceride but, it does not have any effect of the level of total cholesterol and LDL in children and adolescents.