The effect of air pollution on cardiovascular diseases in the eastern mediterranean region: a systematic literature review

Objectives: To assess the risk of cardiovascular diseases associated with air pollution in Eastern Mediterranean Region (EMR) by summarizing the existing knowledge from previous studies in the region and to identify knowledge and research gaps to support further research efforts. Methods: Literature search between January 2000 and June 2016 using the combinations of keywords and hand search resulted in 366 articles published in the EMR. Of those, 13 studies met the inclusion/exclusion criteria. Results: Thirteen studies from few countries in EMR have examined the effect of air pollution on cardiovascular disease and met the inclusion criteria. Most of studies were conducted in Iran. The most common study designs were ecological time series and cross-sectional studies. The reviewed articles showed that air pollution has a significant association with cardiovascular morbidity, especially in high risk groups, but not with mortality. For the majority of reviewed studies, limitations do exist in all studies even well conducted ones. The limitations and shortcomings that arise from inappropriate study designs, poor assessment of exposure and outcomes, questionable sources of data, lack of standardized methods, poor adjustment of confounders, limited geographical area studies, small sample sizes, poor statistical modeling, and not testing for possible interactions between exposures. Conclusion: Air pollution has a significant association with cardiovascular morbidity, especially in high risk groups, but not with mortality in the reviewed studies. However, the limited number of studies in few EMR countries makes it difficult to construct evidence on the effect of air pollution on cardiovascular diseases in the region. The reviewed studies did not sufficiently represent the different geographic locations and compositions of the countries.