**6. Confounding factors in studies with the comet assay in buccal cells**

A systematic and adequately powered investigation of key variables such as age, gender, genotype, season, diet, oral hygiene and dental health, life-style, smoking, alcohol, and other recreational drugs needs to be performed to identify the variables that have to be controlled [7].



Assessment of DNA Damage by Comet Assay in Buccal Epithelial Cells: Problems, Achievement, Perspectives http://dx.doi.org/10.5772/62760 105







Assessment of DNA Damage by Comet Assay in Buccal Epithelial Cells: Problems, Achievement, Perspectives http://dx.doi.org/10.5772/62760 111






None of demographic or lifestyle factors tested as possible confounding factors (age, gender, dietary habits, pH of saliva, alcohol, smoking habits, drug intake, and others have exhibited significant influence on values of comet assay parameters in buccal cells [55,56,64,66,67,76,82, 83,85]. On contrary, Pal et al. [62] in their evaluation of various confounding factors like age, tenure of tobacco habit, and tea habit showed significant associations with DNA damage. In the same line, Sudha et al. [80] showed that the combined exposure to cigarette smoke and Cr(VI) increased basal DNA damage in buccal epithelial cells of welders. How et al. [81] characterized potential risk factors that influence levels of DNA damage from exposure to mixtures of organophosphates, among all, age, smoking habit, smoking duration, number of cigarettes (per day); and secondhand smokers highlighted the significant differences between subjects and within groups. Martín-Cameán et al. [57] observed that DNA damage in buccal cells induced for orthodontic appliances was higher in women, and Jayakumar and Sasikala [78] found a synergistic effect of the habit of cigarette smoking among the jewellery workers.
