**3. Conclusion**

148 Biomarker

the X-chromosome. A possible explanation is the micronucleation of the X chromosome, which has been shown to occur in lymphocytes in females, both *in vitro* and *in vivo*, and that can be accounted for by the presence of two X chromosomes. This finding might explain the

Aging in humans appears to be associated with genomic instability. Cytogenetically, ageing is associated with a number of gross cellular changes, including altered size and morphology, genomic instability and changes in expression and proliferation (Bolognesi et al., 1999; Zietkiewicz et al., 2009). It has been shown that a higher MN frequency is directly associated with decreased efficiency of DNA repair and increased genome instability (Kirsch-Volders et al., 2006; Orsière et al., 2006). The data has shown a significant increase of MN in lymphocytes in the exposed group. This can be explained in light of genomic instability, understood as an increased amount of mutations and/or chromosomal aberrations that cytogenetically translate into a greater frequency of changes in chromosome number and/or structure and in the formation of micronuclei (Zietkiewicz et al., 2009). The involvement of micronucleation in age-related chromosome loss has been supported by several studies showing that the rate of MN formation increases with age, especially in women (Catalán et al., 1998). This study provides evidence that age and gender interact to determine the frequency of MN in the lymphocytes of exposed subjects. The higher incidence of MN in both genders is more manifest in older age groups and the effect of gender becomes more pronounced as age increases. Several reports link this observation to

Tobacco smoke has been epidemiologically associated to a higher risk of cancer development, especially in the oral cavity, larynx, and lungs, as these are places of direct contact with the carcinogenic tobacco's compounds. In this study, smoking habits did not influence the frequency of the genotoxicity biomarkers; moreover, the frequencies of MN in buccal cells were unexpectedly higher in exposed non-smokers than in exposed smokers, though the difference was not statistically significant. In most reports, the results about the effect of tobacco upon the frequency of MN in human lymphocytes were negative as in many instances smokers had lower MN frequencies than non-smokers (Bonassi et al., 2003). In the current study, the analysis of the interaction between FA exposure and smoking habits indicates that exposure is preponderant in determining the frequency of biomarkers. Nevertheless, the effect of smoking upon biomarkers remains controversial. Some studies reported an increased frequency of MN in lymphocytes, NPB, and NBUD as a consequence of the tobacco-specific nitrosamine 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK). Still in this study no associations were observed between tobacco and nuclear abnormalities

As for alcohol consumption, it did not appear to influence the frequency of genotoxicity biomarkers in study, to the exception of MN in lymphocytes in controls (Mann-Whitney, p=0.011), with drinkers having higher means. Alcohol is definitely a recognized genotoxic agent, being cited as able to potentiate the development of carcinogenic lesions (Ramirez & Saldanha, 2002). In our study, drinkers in the control group had higher mean frequencies of all biomarkers than non-drinkers, but the differences were only significant for MN in lymphocytes. Stich and Rosin (1983) study of alcoholic individuals, reported absence of significant differences concerning MN frequencies in buccal cells. That is important to corroborate our result, because of the lack of "heavy drinkers" in our study. The same study

preferential micronucleation of the inactive X (Catalán et al., 1998, 2000a, 2000b).

an elevated loss of X chromosomes (Battershill et al., 2008).

(El-Zein et al., 2006, 2008).

Another important application of biological monitoring, besides exposure assessment, is the use of biomarkers, at either individual or group level, for the correct interpretation of doubtful clinical tests. These are usually performed as part of occupational health surveillance program when exposure assessment data are unavailable or are deemed unreliable. Health surveillance is the periodical assessment of the workers' health status by clinical, biochemical, imaging or instrumental testing to detect any clinically relevant, occupation-dependent change of the single worker's health. Biomarkers are usually more specific and sensitive than most clinical tests and may be more effective, therefore, for assessing a causal relationship between health impairment and chemical exposure when a change is first detected in exposed workers (Manno et al., 2010).

Experience in biological monitoring gained in the occupational setting has often been applied to assess (the effects of) human exposure to chemicals in the general environment. The use of biological fluids/tissues for the assessment of human exposure, effect or susceptibility to chemicals in the workplace represents, together with the underlying data (e.g. personal exposure and biological monitoring measurements, media-specific residue measurements, product use and time-activity information), a critical component of the occupational risk assessment process, a rapidly advancing science (Manno et al., 2010).

Au et al. (1998), advise to put more emphasis on monitoring populations which are known to be exposed to hazardous environmental contaminant and on providing reliable health risk evaluation. The information can also be used to support regulations on protection of the environment.
