SISTER-CHROMATID EXCHANGES AND HIGH-FREQUENCY CELLS IN MEN ENVIRONMENTALLY AND OCCUPATIONALLY EXPOSED TO AMBIENT AIR-POLLUTANTS - AN INTERGROUP COMPARISON WITH RESPECT TO SEASONAL-CHANGES AND SMOKING HABIT

Sister chromatid exchanges (SCE) and high-frequency cells (HFC) were m easured in peripheral blood lymphocytes from men environmentally and o ccupationally exposed to a mixture of ambient air pollutants. The envi ronmentally exposed individuals were inhabitants of the industrial reg ion of Upper Silesia; those occupationally exposed were Silesian coker y or steel plant workers, while the control group consisted of rural r egion residents. A total of 147 males were enrolled in the study. Bloo d samples were collected in winter (February) and summer (September) s easons. Three major areas were investigated during the study: exposure -based dose dependency, seasonal changes, and influence of smoking hab its on the SCE frequencies. The latter is frequently reported as a con founding factor in SCE analyses. In both winter and summer samples, st atistically significant increases of SCE were observed in the environm entally and occupationally exposed groups compared to the controls (p < 0.001). The difference between both exposed groups was also signific ant (p < 0.001). An intergroup comparison was based on ANOVA after adj ustment for smoking status. In all three groups of interest, a seasona l variation was found with higher levels in winter. However, in a part of the study in which each donor served as his own control, statistic al differences were only found within the exposed groups. Control regi on inhabitants did not have significantly higher frequencies of SCE in winter, compared to summer samples. The impact of two major confounde rs, age of the donor and smoking habit, was investigated by multiple r egression analysis. Smoking was a major factor influencing the level o f SCE. Nevertheless, the effect was seen in winter samples only, which suggests an additive response and adds new information to this known effect. (C) 1997 Elsevier Science B.V.