Spontaneous micronucleus frequency and age: what are normal values

Micronucleus frequency in epidemiological studies of human exposure has bec ome a preferred biomarker. A generally recognized observation is that micro nucleus frequency increases with age. One requirement for comparison of dat a, which is being generated in many countries, is some common agreement abo ut what constitutes a typical or normal background frequency of micronuclei . This is also a requirement when examining any individual value, especiall y one which might be considered an outlier. A mean value for normal micronu cleus frequency with age is developed via the analysis of multiple studies, all of which employed large population bases and generally were conducted with the intent of determining population values. The result is presented h ere, with the understanding that it may over- or under-estimate the actual values in certain populations. (C) 1999 Elsevier Science B.V. All rights re served.