To investigate whether there were separate and combined effects of occupati
onal exposure to tobacco dust and smoking on lymphocyte DNA damage, 148 wor
kers from a cigarette manufacturing factory (107 occupationally exposed to
tobacco dust from the production department and 41 unexposed controls who w
ere managerial workers) were included in the study. The Tail Moment (TM) of
Comet assay was used to measure DNA damage. The two groups had similar mea
n age, mean duration of work and smoking prevalence. The exposed workers ha
d a larger TM than that of the controls (mean +/- S.D.: 43.43 +/- 13.77 vs.
38.89 +/- 8.98, p < 0.05). Smokers had significantly larger TM than non-sm
okers (47.25 +/- 14.02 vs. 38.90 +/- 10.75, p < 0.001). Analysis of varianc
e after adjustment for age and gender showed that occupational exposure and
smoking had a significant and independent effect on Tail Moment(p = 0.025
and p = 0.002, respectively) and there was a significant positive two way i
nteraction between the two factors (p = 0.019). Age and gender had no signi
ficant effect on TM. The present study suggests that smoking and tobacco du
st exposure can induce lymphocyte DNA damage and there is a synergistic eff
ect of tobacco dust exposure and smoking on DNA damage. (C) 1999 Elsevier S
cience B.V. All rights reserved.