Sister chromatid exchanges and chromosome aberrations in rubber workers.

Sister chromatid exchanges and chromosomal aberrations were studied in peripheral blood lymphocytes of 55 rubber workers (from two different plants) and 35 controls mainly employed in office jobs. In both plants an increased frequency of SCEs (P less than 0.05 for plant A and P less than 0.01 for plant B) was detected in nonsmoking rubber workers as compared with nonsmoking referents. When the SCEs of worker groups belonging to the different job categories were compared with referents, the only groups showing statistically significant increases in SCEs were the smoking workers from the weighing and mixing departments of factory A and the nonsmoking weighers of factory B. A slight increase in the SCE frequencies was seen especially among smoking workers employed in the chemical mixing departments. The frequency of structural chromosome aberrations was not significantly increased in the occupational groups studied, the only exception being the small group of nonsmoking weighers in plant B. Among both the exposed workers and the controls, smokers had a higher mean SCE frequency than nonsmoking referents. This difference was significant between the exposed smokers and nonsmokers of plant A (P less than 0.01) and between smoking and nonsmoking controls for plant B (P less than 0.001). In addition, the chromosome aberration frequency of smoking controls of plant A was significantly higher (P less than 0.01 when gaps excluded and P less than 0.05 when gaps included) than that of nonsmoking referents. Also, smokers among controls for plant B had an increased frequency of aberrations in their cultured blood lymphocytes when compared with nonsmokers. This difference was significant (P less than 0.05) when gaps were excluded.