CHROMOSOME-ABERRATIONS IN WORKERS OF NUCLEAR-POWER-PLANTS

The frequencies of chromosome aberrations in 135 workers from nuclear- power plants were compared with those in 135 age-matched controls. A t otal of 135,000 cells was scored. The frequencies of dicentric chromos ome were 1.67 x 10(-3) in the exposed group and 0.49 x 10(-3) in the c ontrol group and those of chromosome-type deletion were 3.33 X 10(-3) and 1.10 x 10(-3), respectively. The frequencies of all types of chrom osome aberrations in the exposed subjects were higher than those in th e control group, but no significant trend of dose-dependent increase w as observed when only the exposed group were considered. Poisson regre ssion analysis, with both exposed and control included, showed that th ere was a significant association of chromosome aberration with radiat ion dose and the duration of work, but not with age, smoking habit and alcohol intake. It was also found that recent exposure to radiation, within the last 5 years, had contributed mure to the observed chromoso me aberration than earlier exposure.