[Meta-analysis: cardiovascular effects in workers occupationally exposed to urban pollution].

BACKGROUND Many studies showed a connection between exposition to high levels of urban pollution (especially to particulate and traffic noise) and the onset of even deadly cardiovascular diseases. DESIGN Meta-analysis of case-control design. OBJECTIVES The aim of this study is to estimate the association between cardiovascular effects and occupational exposition to atmospheric pollution in urban environment. DATA SOURCES Biomedcentral, MEDLINE/ PubMed, MEDLINE/ National Library of Medicine (NLM), MEDLINE Plus, Nioshtic-2, Scopus, TOXNET/Toxline, unpublished studies known by the authors and acts of national and international conferences between 1988 and May 2010 included. There has not been any kind of language or typological restriction. CRITERIA OF ELEGIBILITY: The research on cardiovascular effects includes control cases of workers exposed to urban pollution, compared with non-exposed subjects. PARTICIPANTS AND INTERVENTIONS The selected studies present outdoor workers exposed to urban pollution (drivers and petrol pump attendants) and a control group of indoor workers (managers, university students and other selected subjects). STUDY APPRAISAL AND SYNTHESIS METHODS The evidences (independently token from two different authors) have been grouped in two classes, the first one formed by continuous variables (systolic blood pressure, diastolic blood pressure, heart rate, total cholesterol, HDL cholesterol, LDL cholesterol, triglycerides) and the second one by discontinuous variables (electrocardiographic abnormalities prevalence, hypertension prevalence, hypercholesterolemia prevalence). The studies related to both classes and presenting more than one variable for each class have been included and used, in order to elaborate the results. We calculated heterogeneity in each variable (ES calculation for continuous variables and OR calculation for discontinuous variables). RESULTS On 378 publications, we have selected and included 16 articles. The variables show statistically irrelevant differences between exposed group and control group, except regarding the triglycerides. LIMITATIONS The controlled studies are limited and characterized by a non-homogeneous evaluation of both expositional times of workers to urban pollution and of professional expositional values. CONCLUSIONS AND IMPLICATIONS OF KEY FINDINGS Considering the heterogeneity and the lack of studies, it is impossible at the moment to document effects on the cardiovascular system in workers exposed to urban pollution. The results of this meta-analysis only suggest the association of urban pollution with alteration of triglycerides blood levels (referring to just three studies). As reported in scientific literature on this subject, it is necessary to conduct a future professional investigation on this subject with more qualified and homogeneous studies.