The effect of occupational exposure to petrol on biochemical and hematological parameters: a review and meta-analysis

Continuous occupational exposure of fuel station workers to petrol and diesel vapors, which contain volatile organic compounds such as BTEXs, may adversely affect hematological parameters. This meta-analysis evaluated the impact of such exposures on blood indices. Online databases were systematically searched using relevant MeSH keywords. After removing duplicates, articles were screened, and quality was assessed using the Newcastle - Ottawa Scale. A random-effects model was applied to estimate standardized mean differences (SMD) in blood indices between exposed and unexposed groups. Sensitivity analysis, meta-regression, and Egger's test were used to assess study influence, exposure duration, and publication bias. Thirty-seven studies, with 2244 exposed and 2106 unexposed participants, were included. Pooled results showed significant decreases in red blood cell count (SMD = -1.03, 95% CI: -1.54 to -0.52), white blood cell count (SMD = -0.54, 95% CI: -0.94 to -0.15), hemoglobin (SMD = -0.82, 95% CI: -1.34 to -0.31), and mean corpuscular hemoglobin (SMD = -0.69, 95% CI: -1.14 to -0.23), while increases were observed in mean corpuscular hemoglobin concentration, hematocrit, platelets, lymphocytes, and neutrophils. Changes were more pronounced with longer exposure. Overall, exposure to fuel vapors was linked to reduced red blood cell indices and increased white blood cell indices, serving as potential early indicators of adverse health effects.