## 3 Results
\begin{tabular}{l c c c c c c c c} \hline \hline \multirow{2}{*}{**DNA Damage Markers**} & \multicolumn{3}{c}{**EXPOSED WORKERS**} & \multicolumn{3}{c}{**CONTROLS**} \\ \cline{2-9}  & **N.** & \
\begin{tabular}{c} **Mean \(\pm\)** \\ SD \\ \end{tabular} & **Median** & **Range** & **N.** &
To assess the dependency of the single biomarkers of spontaneous and BLM-induced DNA damage on the independent variables, namely occupational exposure, sex, age, BMI, cigarette smoking, alcohol consumption, and the presence of allelic variants for each of the genetic polymorphisms studied, linear stepwise regression was performed. The results demonstrated a positive dependency of the frequency of spontaneous chromosomal breaks on occupational exposure, and a dependency of the frequency of BLM-induced MN negative on occupational exposure and positive on the consumption of alcohol and on the null _GSTM1_ genotype (Table 8).  
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**DNA Damage** & **Polymorphism** & \multicolumn{3}{c}{**Exposed**} & \multicolumn{3}{c}{**Controls**} \\ \cline{3-8}
**Markers** & **XRCCI** & **N** & **Median** & **Range** & **N** & **Median** & **Range** \\ \hline Total chromosome & wild-type & 11 & 3.0 & 1.0–6.0 & 13 & 2.0 & 1.0–7.0 \\ \cline{2-8} aberrations (\%) & one or more allelic & 29 & 2.0 & 0.0–6.0 & 26 & 1.0 & 0.0–6.0 \\ \hline Chromatid breaks (\%) & wild-type & 11 & 2.0 & 1.0–3.0 & 13 & 2.0 & 0.0–6.0 \\ \cline{2-8} Chromosomal breaks & one or more allelic & 29 & 2.0 & 0.0–6.0 & 26 & 1.0 & 0.0–6.0 \\ \cline{2-8} Chromatid breaks (\%) & one or more allelic & 29 & 2.0 & 0.0–4.0 & 13 & 0.0 & 0.0–2.0 \\ \cline{2-8} Micronucle/1000 BN (\%) & wild-type & 11 & 11.0 & 3.0–22.0 & 13 & 12.0 & 5.0–42.0 \\ \cline{2-8} Micronucle/1000 BN (\%) & one or more allelic & 29 & 16.0 & 6.0–45.0 & 26 & 13.0 & 4.0–32.0 \\ \hline TI (\%) & wild-type & 11 & 3.5 & 0.9–4.3 & 13 & 3.1 & 0.9–4.0 \\ \cline{2-8}  & one or more allelic & 29 & 3.3 & 0.9–4.9 & 27 & 3.4 & 1.2–4.7 \\ \hline TI Fpg (\%) & wild-type & 11 & 3.3 & 1.2–4.9 & 13 & 3.1 & 0.8–4.8 \\ \cline{2-8}  & one or more allelic & 29 & 3.2 & 1.1–5.0 & 27 & 3.3 & 1.2–4.8 \\ \hline TI Endo III (\%) & wild-type & 11 & 2.8 & 1.9–4.4 & 13 & 2.8 & 1.3–4.4 \\ \cline{2-8}  & one or more allelic & 29 & 3.1 & 1.1–4.6 & 27 & 3.1 & 0.9–5.5 \\ \hline Wild-type vs. one or more allelic & & & & & & \\ - null & & & & & & \\ \hline \hline \end{tabular}
\end{table}
Table 7: DNA damage markers in exposed and controls divided based on the combination of genetic polymorphisms Arg194 Trp, Arg280 His, and Arg399 Gln of _XRCC1_.  
\begin{table}
\begin{tabular}{l c c c c} \hline \hline
**Independent Variable** & \multicolumn{2}{c}{**Spontaneous Chromosome Breaks**} & \multicolumn{2}{c}{**BLM-Induced Micronuclei**} \\ \cline{2-5}  & **Frequency (\%)** & **Frequency (MN/1000 BN)** \\ \cline{2-5}  & **Beta** & \(\mathbf{p}\) & **Beta** & \(\mathbf{p}\) \\ \hline Exposure groups (ref. control) & & & & \\ \hline - exposed workers & 0.28 & 0.012 & \(-\)0.23 & 0.033 \\ \hline Alcohol consumption (g/week) & - & ns & 0.25 & 0.001 \\ \hline _GSTM1_ (ref. wild-type) & & & & \\ - null & - & ns & 0.22 & 0.001 \\ \hline \hline Model & \(F\) & \(p\) & \(R^{2}\) & \(F\) & \(p\) & \(R^{2}\) \\ \cline{2-5}  & 6.55 & 0.012 & 0.07 & 5.85 & 0.001 & 0.16 \\ \hline \hline \end{tabular}
\begin{tabular}{c c c c c c} \hline \hline \multicolumn{5}{c}{Other independent variables not found to be significant: age, sex, BMI, cigarette smoking habit, presence of allelic} \\ \multicolumn{5}{c}{variants for the genetic polymorphisms of the enzymes _XRCC1_, _XRCC3_, _XPD_, _BLHX_, _GSTTI_; ns = not significant. \\ \end{tabular} } \\ \hline \hline \end{tabular} 
\end{table}
Table 8: Linear stepwise regression to study the dependency of the variables frequency of spontaneous chromosome breaks and frequency of BLM-induced micronucleeli on the independent variables’ occupational exposure, consumption of alcohol, and _GSTM1_ polymorphism.