Influence of PAHs in ambient air on chromosomal aberrations in exposed subjects: international study - EXPAH

The aim of this study was to determine the influence of carcinogenic polycyclic aromatic hydrocarbons (c-PAHs) in complex mixtures in ambient air on DNA damage (chromosomal aberrations) in occupationally exposed subjects measured as percent of aberrant cells (% AB.C.). There were in total 203 exposed subjects and 150 respective controls in the whole project, allocated in three different European cities - Kosice (Slovakia), Prague (Czech Republic) and Sofia (Bulgaria). The studied population from Kosice (Slovakia) consisted of 106 subjects. From these 51 were exposed policemen and 55 were controls. The Czech population comprised 52 exposed policemen and 50 controls. In Bulgaria, there were two equally numerous exposed groups: 50 policemen and 50 professional bus drivers together with 45 controls. According to personal monitoring, policemen and bus drivers in the Bulgarian capital Sofia were exposed to the highest levels of c-PAHs amongst the exposed subject groups in the cities (45.3+/-25.9ng/m(3) in policemen resp. 36.1+/-31.6ng/m(3) in bus drivers in Sofia, 26.8+/-39.8ng/m(3) for policemen in Kosice and 11.9+/-11.2ng/m(3) for policemen in Prague), compared to the respective controls (24.9+/-17.7ng/m(3) for controls in Sofia, 7.9+/-3.8ng/m(3) for controls in Kosice and 6.2+/-3.6ng/m(3) for controls in Prague). We observed the following frequency of % AB.C. scored by conventional method: 2.60+/-2.64 in exposed policemen and 2.14+/-1.61 in controls in Kosice (p=n.s.); 2.33+/-1.53 in exposed policemen and 1.94+/-1.28 in controls in Prague (p=n.s.); 3.04+/-1.64 in exposed policemen, respectively, 3.60+/-1.63 in exposed bus drivers and 1.79+/-0.77 in the control group in Sofia (p<0.05, respectively, p<0.05). According to data from multiple regression analysis, and group comparison of smokers versus nonsmokers in Sofia also cigarette smoking (p=0.055) and the age (p=0.020) seem to play an important role within the aberrant cell formation in addition to the occupational c-PAHs exposure (p=0.000). Smoking status was the modifying factor for % AB.C. in Kosice (p=0.020) after multiple regression approach was employed. In summary, we can say that subjects occupationally exposed to higher levels of c-PAHs in ambient air in Sofia are at greater genotoxic risk compared to those working indoors.