Bolognesi C, Abbondandolo A, Barale R, Casalone R, Dalprà L, De Ferrari M, Degrassi F, Forni A, Lamberti L, Lando C, Migliore L, Padovani P, Pasquini R, Puntoni R, Sbrana I, Stella M, Bonassi S
Unità di valutazione tossicologica, Centro per lo Studio dei Tumori di Origine Ambientale (CSTA), Istituto Nazionale per la Ricerca sul Cancro, Genoa, Italy.
Cancer Epidemiol Biomarkers Prev. 1997 Apr;6(4):249-56.
Intra- and interindividual variations of baseline frequencies of cytogenetic end points in lymphocytes of human populations have been reported by various authors. Personal characteristics seem to account for a significant proportion of this variability. Several studies investigating the role of age as a confounding factor in cytogenetic biomonitoring found an age-related increase of micronucleus (MN) frequency, whereas contradictory results were reported for chromosomal aberrations (CAs) and sister chromatid exchanges (SCEs). We have quantitatively evaluated the effect of age on SCE, CA, and MN through the analysis of a population sample that included data from several biomonitoring studies performed over the last few decades in 12 Italian laboratories. The large size of the data set, i.e., more than 2000 tests for each end point, allowed us to estimate the independent effect of age, taking into account other covariates, such as sex, smoking habits, occupational exposure, and inter- and intralaboratory variability. A greater frequency of the mean standardized values by increasing of age was observed for all of the end points. A leveling off was evident in the last age classes in the trend of MN frequencies. Frequency ratios (FRs), which express the increase of the cytogenetic damage with respect to the first age classes, i.e., 1-19 years, were estimated using Poisson regression analysis after adjustment for the potential confounding factors and confirmed the increasing trend by age class for all three end points. The most dramatic increase was observed for MN, with a FR that approaches the value of 2 at the age class 50-59 (FR, 1.97; 95% confidence interval, 1.43-2.71) and remains substantially unchanged thereafter. The trend of FRs for CA is more homogeneous, with a constant rise even in the older classes, whereas the frequency of SCE increases with age to a lesser extent, reaching a plateau in the age class 40-49 and the maximum value of FR in the age class over 70 (FR, 1.14; 95% confidence interval, 1.07-1.23). In conclusion, our results point to an age-related increase of the chromosome damage in lymphocytes and emphasize the need to take into account the potential confounding effect of this variable in the design of biomonitoring studies based on chromosome damage.
多位作者报告了人群淋巴细胞细胞遗传学终点基线频率的个体内和个体间差异。个人特征似乎在这种变异性中占很大比例。几项研究调查了年龄作为细胞遗传学生物监测中混杂因素的作用，发现微核（MN）频率随年龄增长而增加，而关于染色体畸变（CA）和姐妹染色单体交换（SCE）的结果则相互矛盾。我们通过分析一个人群样本，定量评估了年龄对SCE、CA和MN的影响，该样本包含了过去几十年在12个意大利实验室进行的多项生物监测研究的数据。数据集规模庞大，即每个终点超过2000次检测，这使我们能够在考虑其他协变量（如性别、吸烟习惯、职业暴露以及实验室间和实验室内变异性）的情况下，估计年龄的独立影响。所有终点均观察到随着年龄增加，平均标准化值的频率更高。MN频率趋势在最后几个年龄组中明显趋于平稳。频率比（FR）表示相对于第一个年龄组（即1 - 19岁）细胞遗传学损伤的增加，在对潜在混杂因素进行调整后，使用泊松回归分析进行估计，并证实了所有三个终点随年龄组的增加趋势。MN的增加最为显著，在50 - 59岁年龄组中FR接近2（FR，1.97；95%置信区间，1.43 - 2.71），此后基本保持不变。CA的FR趋势更为均匀，即使在较老的年龄组中也持续上升，而SCE的频率随年龄增加的幅度较小，在40 - 49岁年龄组达到平稳状态，在70岁以上年龄组达到FR的最大值（FR，1.14；95%置信区间，1.07 - 1.23）。总之，我们的结果表明淋巴细胞中的染色体损伤随年龄增加，强调在基于染色体损伤的生物监测研究设计中需要考虑该变量的潜在混杂效应。
