Cytogenetic study of workers exposed to chromium compounds

The frequency of sister chromatid exchanges (SCEs), high SCE frequency cell s (HFCs), and genetic polymorphism of genotypes glutathione S-transferase ( GST) M1 and T1 were analyzed in peripheral lymphocytes of 35 workers occupa tionally exposed to chromium (Cr) and 35 matched control group. Results sho wed that workers exposed to Cr showed 6.07 SCE/cell, as compared to 4.76 SC E/cell for the control group (p < 0.01). Smokers showed a statistically sig nificant higher frequency of SCE than non-smokers in both groups. The work duration of Cr workers was an important factor. Workers exposed for more th an 5 years showed a significantly higher level of SCEs (p < 0.05). Workers exposed to Cr for 5 or more years had higher HFC rates (51.4%) than those e xposed for less than 5 years (22.9%), with an odds ratio of 4.5 times than those exposed for less than 5 years. In HFC analysis, Cr workers who smoked showed a higher level of HFC (60%) than the control group (5.7%) and also had a higher odds ratio (60.4) compared with the control group. Among non-s mokers, the odds ratio was 9.0. Another objective of this study is to inves tigate the relationship between SCE and genetic polymorphisms of GST M1 and T1 in Cr workers. The results showed that the incidence of GSTM1 null geno type was 60% in the control group and 77.1% in Cr workers, and percentages of GSTT1 deletion were 42.9% and 62.9% in control and exposed individuals, respectively. There was a slightly increased frequency of SCE among Cr work ers with GSTM1 null genotype as opposed to non-null genotype individuals. A similar result was seen among the control group; however, there were no st atistically significant differences. In conclusion, the current study found the positive induction of SCE in workers who smoked or/and were exposed to Cr. However, different GST genotypes did not influence the level of cytoge netic damage between groups. Despite slight variation in numbers, they all appear to be not different. (C) 2000 Elsevier Science B.V. All rights reser ved.