Workers exposed to low levels of benzene present in urban air: Assessment of peripheral blood count variations

Background: Few studies in the literature have examined the effects of benzene on blood cells. Aim: The aim of this study was to evaluate the possible correlation between the blood benzene levels and the blood cell counts. Materials and methods: From a population of 2658 workers, we studied a group of 215 subjects. Each worker underwent blood sampling for the assessment of the blood benzene levels and the blood cell counts. The Mann-Whitney U test for two-mode variables and the Kruskal-Wallis test for more-than two-mode variables were performed on all subjects. We estimated the Pearson correlation index between the variables in the total sample and the subgroups divided according to sex, the smoking habit, and job. After the main confounding factors were evaluated, multiple linear regression was performed on both the total sample and the subgroups. Results: A significant inverse correlation was found among the blood benzene levels and the white blood cells, lymphocytes, and neutrophils in traffic policemen, motorcyclists, and other outdoor workers. We did not find any significant correlation with any other parameters of blood cell count. Discussion and conclusions: Our results, which must be considered preliminary, indicate that increased blood benzene levels in outdoor workers lead to decreased counts of white blood cells, neutrophils, and lymphocytes, because of possible immune effects. These are worth investigating in the future by specific immune tests.