SISTER-CHROMATID EXCHANGE AND MICRONUCLEUS FREQUENCY IN HUMAN-LYMPHOCYTES OF 1,650 SUBJECTS IN AN ITALIAN POPULATION - II - CONTRIBUTION OFSEX, AGE, AND LIFE-STYLE

Sister chromatid exchange (SCE) and micronuclei (MN) analysis was carr ied out on 1,650 healthy individuals living in Pisa and in two nearby small cities, Cascina and Navacchio (Ca-Na). The effect of smoking on SCEs was linearly correlated with the number of cigarettes per day, an d an increase of 7.3% SCEs was detectable for as few cigarettes as 1-1 0/day. Ex-smokers showed intermediate mean values of SCEs (8.09 +/- 1. 88) in comparison with never smokers (7.54 +/- 1.61) and current smoke rs (8.45 +/- 1.94). Mean values of SCEs of ex-smokers decreased linear ly with time of smoking cessation, reaching the mean values of never s mokers within 8 years. The extent of SCE decrease was inversely propor tional to the number of cigarettes previously smoked. No interaction b etween smoking habits and coffee or alcohol drinking on SCEs was obser ved. A borderline (P = 0.053) increase in mean SCE values in coffee dr inkers (more than 3 cups/day) was found. The age effect on SCEs was re markable in Ca-Na, but not in Pisa donors. Job type was not associated with significant modification of mean values of SCEs. Multiple logist ic regression analysis revealed a statistically significant associatio n between the proportion of high frequency cells (HCF) outliers and co ffee consumption. Age and sex appeared to be by Far the most important variables associated with modifications in MN frequency, which increa sed by 0.04 parts per thousand and 0.02 parts per thousand per year in males and females, respectively. Children and young donors (age less than or equal to 40 years) showed lower MN frequency regardless of sex , whereas sex appeared to determine a significantly higher increase of MN only in females older than 40 years. In contrast, in males the MN rate by age tended to level off after the age of 30-50. MN frequencies of Pisa blue-and white-collar workers were statistically significantl y higher than in students (+0.71 and +0.55 parts per thousand, respect ively). Smoking did not determine any increase of MN frequency, A tota l lock of correlation (P = 0.913) between MN and SCEs was observed. (C ) 1998 Wiley-Liss, Inc.