Agricultural exposures and DNA damage in PBMC of female farmers measured using the alkaline comet assay.

OBJECTIVE: Several studies investigated the link between agricultural occupational exposures and DNA damage, in an attempt to bring elements of biological plausibility to the increased cancer risk associated with them. However, only a few of these studies focused on females. METHODS: The comet assay was performed on PBMC (Peripheral Blood Mononuclear Cells) samples from 245 females working in open field farming and cattle raising, located in the Normandy area of France. Individual questionnaires on tasks performed were administered at the time of sampling to directly assess exposures. Environmental exposures were issued from a questionnaire assessing the farm productions. Linear regression analyses were done using the DNA damage scores. RESULTS: Regarding direct exposures, several tasks associated with exposure to potentially harmful chemicals were not associated with DNA damage, but a longer duration of use of herbicide on meadows (p = 0.05) or of cleaning and upkeep of agricultural equipment (p = 0.06) revealed higher DNA damage levels, although the number of exposed women was low. Several indirect and/or environmental exposures were associated with DNA damage in multivariate analyses: a larger surface of meadows (p = 0.006) or the presence of poultry (p = 0.03) was associated with less DNA damage, while the presence of swine (p = 0.01) was associated with higher DNA damage. Smokers and former smokers had less DNA damage than non-smokers (p = 0.0008 and p = 0.03). CONCLUSIONS: We report modified levels of DNA damage for those environmentally exposed to meadows, poultry and pig farming, underlining the need for a better knowledge of the potential health risks experienced by females in this setting.

Early-morning OFF and levodopa dose failures in patients with Parkinson's disease attending a routine clinical appointment using Time-to-ON Questionnaire.

BACKGROUND AND PURPOSE: In patients with Parkinson's disease (PD) with motor fluctuations, total daily OFF time is comprised of both end-of-dose time and the time taken to turn ON with medication. However, little is known about the impact of delays in ON time. METHODS: This was a single-visit pilot study of fluctuating patients with PD attending a routine appointment. During a single visit, adult patients with idiopathic PD who were treated with levodopa for at least 1 year completed a questionnaire evaluating the time waiting for ON and the symptoms experienced while waiting to turn ON. Patients then completed a 5-day home time-to-ON diary, where they documented how long it took to turn ON following their first morning dose of levodopa in 5-min increments. RESULTS: A total of 151 consecutive patients completed the study survey, of whom 97 (64.2%) experienced motor fluctuations. Of the patients experiencing motor fluctuations, 54 (56%) reported delays in ON time (latency >30 min) following their first morning dose of levodopa. Half (51%) reported that they had experienced delayed ON at least once in the previous week and 21% reported having delayed ON during all seven mornings of the previous week. In addition, 10% of patients reported having dose failures on four or more mornings during the previous week. The most common symptoms experienced while waiting for ON were slowness (94.8%), fatigue (87.6%), reduced dexterity (82.5%), problems in walking (66.0%) and problems with balance (59.8%). CONCLUSION: Early-morning OFF problems such as delays in time to ON and dose failures are common in levodopa-treated patients with PD.

The phenotype of migraine with unilateral cranial autonomic symptoms documents increased peripheral and central trigeminal sensitization. A case series of 757 patients.

BACKGROUND: Migraine with unilateral cranial autonomic symptoms (UAS) is a putative migraine endophenotype with convincing response to trigeminal-targeted treatments that still needs a thorough characterization. OBJECTIVE: The objective of this article is to carefully investigate the clinical phenotype of migraine with UAS in a large group of patients for more accurate migraine diagnoses, improved clinical management, and better outcome prediction. METHODS: We studied 757 consecutive episodic and chronic migraineurs in a tertiary headache clinic with face-to-face interviews, detailing in depth their lifestyle, sociodemographic and headache characteristics. RESULTS: Migraineurs with UAS (37.4%) differed from the general migraine population with respect to longer attack duration (OR = 2.47, p < 0.02, having >72-hour long attacks), more strictly unilateral (OR = 3.18, p < 0.001) and severe headache (OR = 1.72, p = 0.011), more frequent allodynia (OR = 3.03, p < 0.001) and photophobia (OR = 1.87, p = 0.019). CONCLUSIONS: Migraine patients with UAS are characterized not only by symptoms due to intense peripheral trigeminal activation but also to central sensitization. Our study broadens the knowledge on the clinical and phenotypic characteristics of migraine with UAS, suggests pathophysiological implications, and supports the need for future prospective clinical studies.

E-learning to improve the drug prescribing in the hospitalized elderly patients: the ELICADHE feasibility pilot study.

BACKGROUND: E-learning is an efficient and cost-effective educational method. AIMS: This study aimed at evaluating the feasibility of an educational e-learning intervention, focused on teaching geriatric pharmacology and notions of comprehensive geriatric assessment, to improve drug prescribing to hospitalized elderly patients. METHODS: Eight geriatric and internal medicine wards were randomized to intervention (e-learning educational program) or control. Clinicians of the two groups had to complete a specific per group e-learning program in 30 days. Then, ten patients (aged ≥75 years) had to be consecutively enrolled collecting clinical data at hospital admission, discharge, and 3 months later. The quality of prescription was evaluated comparing the prevalence of potentially inappropriate medications through Beer's criteria and of potential drug-drug interactions through a specific computerized database. RESULTS: The study feasibility was confirmed by the high percentage (90 %) of clinicians who completed the e-learning program, the recruitment, and follow-up of all planned patients. The intervention was well accepted by all participating clinicians who judged positively (a mean score of >3 points on a scale of 5 points: 0 = useless; 5 = most useful) the specific contents, the methodology applied, the clinical relevance and utility of e-learning contents and tools for the evaluation of the appropriateness of drug prescribing. CONCLUSIONS: The pilot study met all the requested goals. The main study is currently ongoing and is planned to finish on July 2015.

Biomonitoring of several toxic metal(loid)s in different biological matrices from environmentally and occupationally exposed populations from Panasqueira mine area, Portugal.

In the Panasqueira mine area of central Portugal, some environmental media show higher metal(loid) concentrations when compared with the local geochemical background and the values proposed in the literature for these environmental media. In order to evaluate the effect of the external contamination on selected indexes of internal dose, As, Cd, Cu, Cr, Fe, Hg, Mg, Mn, Mo, Ni, Pb, S, Se, Si, and Zn were quantified by inductively coupled plasma mass spectrometry and inductively coupled plasma optical emission spectrometry in blood, urine, hair and nail samples from individuals environmentally (N = 41) and occupationally exposed (N = 41). A matched control group (N = 40) was also studied, and data from the three groups were compared. Results obtained agreed with those reported by environmental studies performed in this area, pointing to populations living nearby and working in the mine being exposed to metal(loid)s originated from mining activities. Arsenic was the element with the highest increase in exposed populations. The concentration of other elements such as Cr, Mg, Mn, Mo, Ni, Pb, S, Se, and Zn was also increased, although at a lesser extent, specifically in the individuals environmentally exposed and in females. These findings confirm the need for competent authorities to act as soon as possible in this area and implement strategies aimed to protect exposed populations and the entire ecosystem.

Transcriptomic network analysis of micronuclei-related genes: a case study.

Mechanistically relevant information on responses of humans to xenobiotic exposure in relation to chemically induced biological effects, such as micronuclei (MN) formation can be obtained through large-scale transcriptomics studies. Network analysis may enhance the analysis and visualisation of such data. Therefore, this study aimed to develop a 'MN formation' network based on a priori knowledge, by using the pathway tool MetaCore. The gene network contained 27 genes and three gene complexes that are related to processes involved in MN formation, e.g. spindle assembly checkpoint, cell cycle checkpoint and aneuploidy. The MN-related gene network was tested against a transcriptomics case study associated with MN measurements. In this case study, transcriptomic data from children and adults differentially exposed to ambient air pollution in the Czech Republic were analysed and visualised on the network. Six genes from the network, i.e. BAX, DMNT1, PCNA, HIC1, p21 and CDC20, were retrieved. Based on these six genes and in combination with p53 and IL-6, a dedicated network was created. This dedicated network is possibly suited for the development of a reporter gene assay that could be used to screen populations complementary to the current MN test assay. In conclusion, we have shown that network analysis of transcriptomics data in relation to the formation of MN is possible and provides a novel mechanistic hypothesis by indicating which genes are regulated and influence others.

SV40 associated miRNAs are not detectable in mesotheliomas.

BACKGROUND: Simian virus-40 (SV40) is a DNA tumour virus that was introduced into the human population with contaminated poliovirus vaccine, and its role in mesothelioma is widely debated. PCR based testing has been called into question, as false positives can be because of cross-reactivity with related viruses, or to laboratory contamination. The Institute of Medicine has recommended the development of more sensitive and specific tests to resolve this controversy. METHODS: We have characterized highly sensitive RT-PCR based assays that are specific for SV40-encoded microRNAs (miRNAs), as an alternative to current testing methods. RESULTS: Using this sensitive and specific detection method, we were unable to identify SV40 miRNA expression in human malignant pleural mesothelioma (MM) samples. CONCLUSION: Our work indicates that SV40 miRNAs are not likely to contribute to mesothelioma tumourogenesis, but highlights the value of this approach when compared with the relatively unspecific current testing methods.

Gender-related differences in response to mutagens and carcinogens.

The incidences of many cancers can be very different in men and women. Besides differences in exposures to putative causative agents, it is plausible that both genetic and epigenetic effects play roles in these differences. In addition, gender-specific lifestyle and behavioural factors may modulate the effects of exposure to genotoxins. This commentary focuses on several aspects of gender-related differences in responses to mutagens and carcinogens, including sensitivity to chromosome damage, the contribution of genotypic variation and the role of DNA methylation. It is concluded that the reasons for gender differences in cancer susceptibility remain largely unknown in many cases, and the subject deserves more attention and study.

Micronuclei frequency in peripheral blood lymphocytes of cancer patients: a meta-analysis.

Micronuclei (MN) frequency is a biomarker of chromosomal damage, genome instability, and cancer risk that integrates acquired mutations and genetic susceptibility. To evaluate and summarize the evidence reporting association between cancer and MN formation, we performed a meta-analysis assessing the frequency of this biomarker in cancer patients. Findings from 37 publications were retrieved through an extensive search of the MedLine/PubMed database. Given the heterogeneity of the study design, all studies were re-classified into three groups: (i) baseline MN frequency of untreated cancer patients (25 studies), (ii) induced MN frequency in thyroid cancer patients undergoing radioiodine treatment (9 studies), and (iii) radiosensitivity of lymphocytes (12 studies) in untreated cancer patients. A meta-estimate of the frequency ratio (meta-FR) was computed in each group. A significant increase of MN frequency was found in untreated cancer patients (meta-FR=1.45; 95% Confidence Interval (95% CI): 1.28-1.64) and in thyroid cancer patients after radioiodine treatment (meta-FR=2.26; 95% CI: 1.90-2.68). The third meta-analysis showed a negative trend of meta-FR's when plotted vs. the dose used to study patients' radiosensitivity, possibly associated to a high rate of apoptosis. The results of this review substantiate the existing evidence about a role of MN in various steps of carcinogenesis. The relatively small numbers of papers suitable for the meta-analysis call for new and larger studies, possibly based on high-throughput techniques, to further understand the role of MN formation in the occurrence of genetic instability and cancer.

Genetic polymorphisms and micronucleus formation: a review of the literature.

The formation of micronuclei (MN) is extensively used in molecular epidemiology as a biomarker of chromosomal damage, genome instability, and eventually of cancer risk. The occurrence of MN represents an integrated response to chromosome-instability phenotypes and altered cellular viabilities caused by genetic defects and/or exogenous exposures to genotoxic agents. The present article reviews human population studies addressing the relationship between genetic polymorphisms and MN formation, and provides insight into how genetic variants could modulate the effect of environmental exposures to genotoxic agents, host factors (gender, age), lifestyle characteristics (smoking, alcohol, folate), and diseases (coronary artery disease, cancer). Seventy-two studies measuring MN frequency either in peripheral blood lymphocytes or exfoliated cells were retrieved after an extensive search of the MedLine/PubMed database. The effect of genetic polymorphisms on MN formation is complex, influenced to a different extent by several polymorphisms of proteins or enzymes involved in xenobiotic metabolism, DNA repair proteins, and folate-metabolism enzymes. This heterogeneity reflects the presence of multiple external and internal exposures, and the large number of chromosomal alterations eventually resulting in MN formation. Polymorphisms of EPHX, GSTT1, and GSTM1 are of special importance in modulating the frequency of chromosomal damage in individuals exposed to genotoxic agents and in unexposed populations. Variants of ALDH2 genes are consistently associated with MN formation induced by alcohol drinking. Carriers of BRCA1 and BRCA2 mutations (with or without breast cancer) show enhanced sensitivity to clastogens. Some evidence further suggests that DNA repair (XRCC1 and XRCC3) and folate-metabolism genes (MTHFR) also influence MN formation. As some of the findings are based on relatively small numbers of subjects, larger scale studies are required that include scoring of additional endpoints (e.g., MN in combination with fluorescent in situ hybridization, analysis of nucleoplasmic bridges and nuclear buds), and address gene-gene interactions.

Prevalence of post-partum thyroiditis in Liguria (Italy): an observational study.

BACKGROUND: Post-partum thyroiditis (PPT) is an autoimmune disorder occurring within the first year following delivery. A variable prevalence has been reported in different surveys. We prospectively evaluated PPT prevalence and outcome in a cohort of pregnant women living in a well-defined geographic area. AIM: A subset from a group of healthy women consecutively evaluated for thyroid function and thyroid autoimmunity during pregnancy, referring to the same obstetric unit, were followed up at 4-6 months and 1 yr after delivery. MATERIALS/SUBJECTS AND METHODS: Follow-up for PPT was performed in 258 pregnant women. Control data were obtained in a comparable group of healthy non-pregnant women. Free T3 (fT3), free T4 (fT4), TSH thyroglobulin/thyroid peroxidase autoantibodies (TgAb/TPOAb), and urinary iodine excretion were measured. RESULTS: Autoantibody positivity was observed in 9.3% of pregnant, similar to control women. Forty-three out of 59 autoantibody-positive women were followed up; 23 showed PPT at the first control, 18 had hypothyroidism at 1 yr (5 had not shown PPT at the first control). Among 215 out of 584 autoantibody-negative women followed up, 27 developed PPT (15 of them without thyroid autoantibodies); 16 developed thyroid autoantibodies without PPT. After 1 yr, 9 women had hypothyroidism: only 1 of them was autoantibody-negative at the former control. Urinary iodine was increased in several pregnant women. CONCLUSIONS: An overall PPT prevalence of about 18% may be estimated. PPT was also observed in autoantibody- negative women. Differences with other surveys may be related to both study protocol and characteristics of the population studied.

Exposure to genotoxic agents, host factors, and lifestyle influence the number of centromeric signals in micronuclei: a pooled re-analysis.

We pooled data from three biomonitoring studies using the cytokinesis-block micronucleus assay in peripheral blood lymphocytes in combination with fluorescence in situ hybridization. Centromere-positive micronuclei (C+MN) were classified in two groups: those containing one centromere (C1+MN) and those with two or more (Cx+MN). The three studies evaluated untreated cancer patients, welders, and pathologists/anatomists exposed to formaldehyde. The total number of subjects included in the pooled re-analysis was 113. A higher frequency of C+MN was observed in cancer patients and exposed workers, who showed significant differences from controls in all studies. C1+MN were particularly increased in the group of pathologists/anatomists, who showed a 3.29 times higher frequency than controls (95% CI: 2.04-5.30). A borderline increase in Cx+MN was observed in welders when compared to the corresponding control group (FR: 1.31; 95% CI: 0.99-1.74). An evident effect of gender was found, with significantly increased frequencies of all endpoints measuring aneuploidy in females (C+MN, C1+MN, and Cx+MN). Alcohol consumption had a significant effect on total MN frequency and particularly on C+MN and C1+MN. In conclusion, scoring the number of centromeric signals in the micronucleus assay provides additional information about the mechanism of action of various genotoxic agents, and the role of confounding factors may be more specifically accounted for. Indeed, C+MN could be efficiently used in biomonitoring studies as an independent biomarker of exposure and early biological effect. The use of centromeric signals allows the identification of two further endpoints, representing two alternative pathways of chromosome loss, i.e., impaired chromosome migration, leading to increased C1+MN frequency, and centrosome amplification, possibly leading to Cx+MN with two or more centromeric signals.

Induction cisplatin-gemcitabine-paclitaxel plus concurrent radiotherapy and gemcitabine in the multimodality treatment of unresectable stage IIIB non-small cell lung cancer.

BACKGROUND: To evaluate feasibility and safety of induction three-drugs combination chemotherapy and concurrent radio-chemotherapy in stage IIIB NSCLC. PATIENTS AND METHODS: Patients with stage IIIB NSCLC were treated with three courses of induction chemotherapy, cisplatin 50 mg/m(2), paclitaxel 125 mg/m(2) and gemcitabine 1000 mg/m(2) on days 1,8 of every 21 day cycle. Patients without distant progressive disease were then treated with radiotherapy and concurrent weekly gemcitabine (250 mg/m(2)). Toxicity and response of radio-chemotherapy treatment have been assessed. RESULTS: Between Jan 01 and Nov 02, 46 patients were enrolled. Grade 3+ hematological and non-hematological toxicity during the induction phase were 41.3% and 13.1%, respectively. In 38 patients a Clinical Response or Stable Disease was recorded and these patients underwent to concurrent radio-chemotherapy. Grade 3+ hematological and non-hematological toxicities were 8.2% in this group. Further response was observed in 66% of patients. Overall median survival time was 17.8 months, with a 3-year survival rates of 23%. CONCLUSION: Three-drugs induction chemotherapy and concurrent radio-chemotherapy with weekly gemcitabine in locally advanced stage IIIB NSCLC is feasible and safe.

Chromosomal aberrations and SCEs as biomarkers of cancer risk.

Previous studies have suggested that the frequency of chromosomal aberrations (CAs), but not of sister chromatid exchanges (SCEs), predicts cancer risk. We have further examined this relationship in European cohorts comprising altogether almost 22,000 subjects, in the framework of a European collaborative project (CancerRiskBiomarkers). The present paper gives an overview of some of the results of the project, especially as regards CAs and SCEs. The results confirm that a high level of CAs is associated with an increased risk of cancer and indicate that this association does not depend on the time between CA analysis and cancer detection, i.e., is obviously not explained by undetected cancer. The present evidence indicates that both chromatid-type and chromosome-type CAs predict cancer, even though some data suggest that chromosome-type CAs may have a more pronounced predictive value than chromatid-type CAs. CA frequency appears to predict cancers at various sites, although there seems to be a particular association with gastrointestinal cancers. SCE frequency does not appear to have cancer predictive value, at least partly due to uncontrollable technical variation. A number of genetic polymorphisms of xenobiotic metabolism, DNA repair, and folate metabolism affect the level of CAs and might collectively contribute to the cancer predictivity of CAs. Other factors that may influence the association between CAs and cancer include, e.g., exposure to genotoxic carcinogens and internal generation of genotoxic species. Although the association between CA level and cancer is seen at the group level, an association probably also exists for the individual, although it is not known if an individual approach could be feasible. However, group level evidence should be enough to support the use of CA analysis as a tool in screening programs and prevention policies in occupational and environmental health.

Chromosomal aberrations in lymphocytes predict human cancer: a report from the European Study Group on Cytogenetic Biomarkers and Health (ESCH).

Chromosomal aberrations (CAs), sister chromatid exchanges (SCEs), and micronuclei (MN) in peripheral blood lymphocytes have for decades been used as cytogenetic biomarkers to survey genotoxic risks in the work environment. The conceptual basis for this application has been the idea that increased cytogenetic damage reflects an enhanced cancer risk. Nordic and Italian cohorts have been established to evaluate this hypothesis, and analyses presented previously have shown a positive trend between CA frequency and increased cancer risk. We now report on a pooled analysis of updated data for 3541 subjects examined for CAs, 2703 for SCEs, and 1496 for MN. To standardize for interlaboratory variation, the results for the various cytogenetic end points were trichotomized on the basis of the absolute value distribution within each laboratory as "low" (1-33 percentile), "medium" (34-66 percentile), or "high" (67-100 percentile). In the Nordic cohort, there was an elevated standardized incidence ratio (SMR) for all cancer among subjects with high CA frequency [1.53; 95% confidence interval (CI), 1.13-2.05] but not for those with medium or low CA frequency. In the Italian cohort, a SMR in cancer of 2.01 (95% CI, 1.35-2.89) was obtained for those with a high CA frequency level, whereas the SMRs for those with medium or low did not noticeably differ from unity. Cox's proportional hazards models gave no evidence that the effect of CAs on total cancer incidence/mortality was modified by gender, age at test, or time since test. No association was seen between the SCEs or the MN frequencies and subsequent cancer incidence/mortality. The present study further supports our previous observation on the cancer predictivity of the CA biomarker, which seems to be independent of age at test, gender, and time since test. The risk patterns were similar within each national cohort. This result suggests that the frequency of CAs in peripheral blood lymphocytes is a relevant biomarker for cancer risk in humans, reflecting either early biological effects of genotoxic carcinogens or individual cancer susceptibility.

Chromosomal aberrations in lymphocytes predict human cancer independently of exposure to carcinogens. European Study Group on Cytogenetic Biomarkers and Health.

An increased risk of cancer in healthy individuals with high levels of chromosomal aberrations (CAs) in peripheral blood lymphocytes has been described in recent epidemiological studies. This association did not appear to be modified by sex, age, country, or time since CA test, whereas the role played by exposure to carcinogens is still uncertain because of the requisite information concerning occupation and lifestyle was lacking. We evaluated in the present study whether CAs predicted cancer because they were the result of past exposure to carcinogens or because they were an intermediate end point in the pathway leading to disease. A nested case-control study was performed on 93 incident cancer cases and 62 deceased cancer cases coming from two prospective cohort studies performed in Nordic countries (Denmark, Finland, Norway, and Sweden) and Italy. For each case, four controls matched by country, sex, year of birth, and year of CA test were randomly selected. Occupational exposure and smoking habit were assessed by a collaborative group of occupational hygienists. Logistic regression models indicated a statistically significant increase in risk for subjects with a high level of CAs compared to those with a low level in the Nordic cohort (odds ratio, 2.35; 95% confidence interval, 1.31-4.23) and in the Italian cohort (odds ratio, 2.66; 95% confidence interval, 1.26-5.62). These estimates were not affected by the inclusion of occupational exposure level and smoking habit in the regression model. The risk for high versus low levels of CAs was similar in subjects heavily exposed to carcinogens and in those who had never, to their knowledge, been exposed to any major carcinogenic agent during their lifetime, supporting the idea that chromosome damage itself is involved in the pathway to cancer. The results have important ramifications for the understanding of the role played by sporadic chromosome damage for the origin of neoplasia-associated CAs.

Incidence of type I diabetes in the Liguria Region, Italy. Results of a prospective study in a 0- to 14-year age-group.

OBJECTIVE: To assess updated incidence of insulin-dependent diabetes mellitus (IDDM) in 0- to 14-year-old children in Liguria, a northwest region of Italy. RESEARCH DESIGN AND METHODS: Incident cases were recorded prospectively from 1987 to 1991. Incidence rates (IRs) were directly standardized on the basis of the 1990 world population. The independent effect of age, sex, residence, and calendar year was estimated with a Poisson regression model. The degree of ascertainment was calculated in accordance with the capture/recapture method. RESULTS: During 5 full calendar years, 117 new cases of IDDM in children were diagnosed in Liguria. The standardized IR over the 5-year period was 11.72 cases.100,000(-1).year-1. The sex-specific IR among males and females was 11.45 and 12.01, respectively. The age-specific IR was higher in the 5-9 age-group. CONCLUSIONS: The IR of IDDM in Liguria is among the highest in southern Europe and approaches that of northern European countries. In particular, it is much higher than those reported in the surrounding Italian regions, except for Sardinia. Therefore, the geographical distribution of IDDM does not seem to reflect the simple north-south gradient reported in several previous studies.

Nucleosomal repeat length in active and inactive genes.

Nucleosomal repeat lengths of total chromatin, H4 histone and beta-DR genes have been measured in logarithmically growing HeLa cells. We have detected significant differences in nucleosomal spacing between inactive chromatin and chromatin regions actively engaged in transcription. These differences are also maintained in metaphase chromosomes at times when transcription ceases although a shortening in nucleosomal repeat length is observed in active and inactive chromatin. These observations support a model where DNA-core histone interactions are temporarily altered to allow selective remodelling of chromatin organization.

Influence of sex on cytogenetic end points: evidence from a large human sample and review of the literature.

The planning and evaluation of human cytogenetic studies should contemplate various confounders and effect modifiers, among these, sex and sex-related factors. The association between this variable and cytogenetic damage has been extensively studied, but conclusive evidence has thus far not been reached, especially for the most recent assays, such as the micronucleus test (MN). In the attempt to quantitatively estimate the sex effect on sister chromatid exchange (SCE), chromosomal aberration (CA), and MN in peripheral blood lymphocytes, we reanalyzed the original data sets of several biomonitoring studies performed over the last decades in 10 Italian laboratories. This approach yielded a very large database, namely 2140, 2495, and 2131 subjects screened for SCE, CA, and MN, respectively. Differences between sexes were expressed in terms of relative risk (RR) of females versus males, after adjustment for age, smoking habits, occupation exposure and inter- and intralaboratory variation. No difference between sexes was found for the frequency of SCE [RR = 1.01; 95% confidence interval (CI) = 0.99-1.03] and CA (RR = 1.00; 95% CI = 0.92-1.08) even if the CI of the RR for SCE includes the 3% excess in females frequently reported by the literature. Conversely, a 29% overall increase of the MN rate in females was observed in the whole data set (RR = 1.29; 95% CI = 1.20-1.38). Different trends by age of the MN rate are described in the two sexes, focusing on the peak observed in females in the menopausal period and on the subsequent decrease.

Age-related increase of baseline frequencies of sister chromatid exchanges, chromosome aberrations, and micronuclei in human lymphocytes.

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.