The effect of age and cell proliferation on the frequency of sister chromatid exchange in human lymphocytes cultured in vitro.

The impact of ageing on the frequencies of sister chromatid exchange of humans was determined in lymphocytes of 43 healthy male non-smokers. The frequencies of sister chromatid exchange in individuals under 70 years were the same, but were significantly lower than in men of 70 years and older. Since we did not see a difference in the frequencies of sister chromatid exchange between fast- and slow-cycling lymphocytes, this difference probably would still hold if the lymphocyte subpopulations of these people were all examined.