Ambient temperature and cardiovascular mortality: A systematic review and metaanalysis

Introduction:Our study aims at identifying and quantifying the relationship between the cold and heat exposure, and the risk of cardiovascular mortality through a systematic review and meta-analysisMaterial and Methods:A systematic review and meta-analysis were conducted basing on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guideline. Peer-reviewed studies about the temperature and cardiovascular mortality were retrieved in the MEDLINE, Web of Science; and Scopus databases from January 2000 up to the end of 2015.The pooled effect sizes were calculated for the heat exposure and cold exposure separately. Also we tested the relationship between some variables with effect size of the risk of cardiovascular mortality by Meta regression. The explanatory variables were the year of study; average of temperature in each study; duration of study; number of lag days and the sample size of each study.Result:After screening the titles, abstracts and full texts; 26 articles were included in meta-analysis. The risk of cardiovascular mortality increased by 4% (RR, 1.041; 95% CI, 1.034 to 1.043) for the cold exposure, 1.3% (RR, 1.013; 95% CI, 1.012 to 1.015) for the heat exposure. In males it was at 4.1% increase (RR, 1.041; 95% CI, 1.036 to 1.047) and 1% increase (RR, 1.01; 95% CI, 1.009 to 1.013) for the cold exposure and heat exposure respectively. In the females it was at 4.1% increase (RR, 1.041; 95% CI, 1.036 to 1.047) and 1.4% increase (RR, 1.014; 95% CI, 1.019 to 1.017) for the cold exposure and heat exposure respectively. Conclusion:Our findings indicate that, the increase and decrease in ambient temperature had a relationship with the cardiovascular mortality. To prevent of the temperature- related mortality, persons with cardiovascular disease and the elderly should be targeted.