ABSTRACT
Objective The effect of electronic cigarettes (e-cigarettes) on smoking reduction,cessation and human health remains controversial,meanwhile,studies tocused on e-cigarettes are limited.We conducted this meta-analysis in purpose of helping figuring out the controversy.Methods PubMed, Medline,Embase,Cochrane library,CNKl and Wanfang Databases were searched for articles published up to May 2014.All studies discussing the relationship between e-cigarettes and smoking reduction,smoking cessation or human health were included.The fixed or random-eftect model was used to pool the relative risk(RR).Outcome 4 articles were included based on the inclusion and exclusion criteria,there were totally 7 002 subjects.Meta-analysis indicated that there was significant difference in e-cigarettes and smoking reduction,RR=1.88,95％ CI:1.07-3.32,P=0.09.The Meta-analysis showed that e-cigarettes were available in smoking cessation.RR=1.55,95％ CI:1.24-1.95,P=0.001.Conclusion Tiffs meta-analysis indicated that e-cigarettes were helpful in smoking cessation.Nonetheless,the articles included were too few to credibly support the outcome.Hence,more high-quality,randomized blind and large sample experiments are needed to verify the results.