Sister chromatid exchange frequency in asbestos workers.

In vitro cytogenetic studies of amosite, chrysotile, and crocidolite asbestos have shown that these fibers may induce chromosome abnormalities and an elevated sister chromatid exchange (SCE) rate in mammalian cells. Twenty-five asbestos insulators (6 with radiographic asbestosis) were compared to 14 controls frequency matched for age and were found to have a marginally increased SCE rate in circulating lymphocytes with increasing years of exposure (P= 0.057). There was a significant association between SCE rate and smoking (P=0.002) after controlling for years of asbestos exposure and age. Smoking asbestos insulators had the highest SCE rate. Sister chromatid exchanges in chromosomes of group A, i.e., the group with the longest chromosomes, were significantly associated with asbestos exposure and cigarette smoking, with an interaction between the two.