Aging and smoking increase the frequency of sister-chromatid exchanges (SCE) in man

The frequency of SCE was determined in lymphocytes of 88 healthy human subjects, not occupationally exposed to known genotoxic agents, who were uniformly distributed in several classes of age (from 16 to 70 years), including an equal number of smokers and non-smokers, and of males and females. Our results indicate that the frequency of SCE increases linearly with age and that smoking enhances the frequency of SCE independently of age and sex.