Effects of age, sex and diagnostic X-rays on chromosome damage.

The frequency of micronuclei assayed in lymphocytes obtained from 73 young adults increases significantly with the age, but not the sex, of the donor. The dose of medical X-rays absorbed by the lymphocytes in the 2 years before the examination has no significant effect on micronucleus frequency, provided the data are adjusted for age. However, a small significant increase in frequency is associated with X-ray examinations that involve the injection of contrast media into the blood.