DNA strand breaks in peripheral blood leucocytes of Polish blood donors

Knowledge about the basal level of DNA damage in leucocytes of healthy control populations is essential before estimation of the effects of exposure to external agents in biomonitoring studies. The aim of this study was to analyse the effects of some lifestyle factors on baseline DNA damage in leucocytes of humans. The material consisted of the peripheral blood from 276 healthy volunteer blood donors. In addition to the standard blood donation questionnaire, they were asked about age, gender, occupation, radiological history, smoking habit, alcohol consumption, medicine use and pet ownership. The results showed marked intra-individual variability. Significant differences in DNA damage levels were observed between individuals in different age and sex groups, between smokers and non-smokers and between samples taken in different seasons of the year, with the highest DNA damage in those obtained in the summer. Significantly higher levels of DNA damage were noted in leucocytes of donors older than 29 years, in men compared with women and in male smokers. Significantly higher DNA strand breaks were observed in heavy smokers. A non-significantly higher level of DNA damage was observed in individuals subjected to radiological investigation and in those drinking alcohol, whereas lower levels were observed in leucocytes of pet owners and in donors taking medicines. Pet ownership influences the level of DNA damage and there is an interaction between this effect and that of smoking. The smoker/pet owners showed almost half the level of DNA damage of smokers without pets. The current results confirmed high intra-individual variability between the levels of DNA damage of individuals. The significant factors that influence the DNA damage in leucocytes are age, sex and smoking habit, especially in men and in heavy smokers. The finding of reduced DNA damage in the leucocytes of pet owners suggests the tendency towards a beneficial effect of such company.