# Urinary Levels of Free 2,5-Hexanedione in Italian Subjects Non-Occupationally Exposed to n-Hexane
## 3 Results  
The study population aged 39.6 \(\pm\) 12.8 years (range: 17-67 years), was composed of 52 males (52.5%) and 47 females (47.5%). The percentage of smokers was 34.3%, 41% of whom were females and 59% males. Moreover, almost 75% of the subjects lived in urban areas, 54% of which lived in areas characterized by medium intensity of vehicular traffic and 20% in high traffic density areas. Regarding weight, 65.7% of subjects were normal weight (BMI \(<\) 25 kg/m\({}^{2}\)), 23.2% were overweight (25 \(<\) BMI \(<\) 30 kg/m\({}^{2}\)) and 11.1% were obese (BMI \(>\) 30 kg/m\({}^{2}\)). The characteristics of subjects were comparable to those of the Italian population in the same range of age [35]. The levels of free 2,5-HD in the 99 samples were in the range of \(<\)12.0-154.9 \(\upmu\)g/L and had a non-normal distribution (Shapiro-Wilk test). A total of 39.4% of data (39 subjects) were below the quantification limit of 12 \(\upmu\)g/L (Figure 2). Table 2 reports the description in terms of percentiles, geometric mean, arithmetic mean and variability of data considered in totality as well as stratified by gender, class of age, smoking habit, residence and traffic intensity, BMI, expressed in \(\upmu\)g/L. Table 2: Urinary levels of free 2,5-HD in all samples and differentiated by gender, class of age, smoking habit, area of residence, traffic intensity and BMI. \begin{table} \begin{tabular}{c c c c c c c c c} \hline  & \begin{tabular}{c} **Sample** \\ **Size** \\ \end{tabular} & \
\begin{tabular}{c} **Geometric Mean \(\pm\)** \\ **GSD (ug/L)** \\ \end{tabular} &
\begin{tabular}{c} **Mean** \\ **(ug/L)** \\ \end{tabular} & \multicolumn{4}{c}{**Selected Percentile (ug/L)**} \\ \hline  & & & & 5 th & 25 th & 50 th & 75 th & 95 th \\
**Total** & 99 & 19.1 \(\pm\) 28 & 31.4 & \(<\)12.0 & \(<\)12.0 & 20.3 & 54.3 & 77.9 \\ \hline
**Gender** & & & & & & & & \\ Males & 52 & 17.9 \(\pm\) 27 & 31.8 & \(<\)12.0 & \(<\)12.0 & 20.6 & 58.2 & 85.5 \\ Females & 47 & 18.1 \(\pm\) 3.0 & 31.0 & \(<\)12.0 & \(<\)12.0 & 20.3 & 52.2 & 72.2 \\ \hline
**Age** & & & & & & & & \\ \(<\)30 years & 24 & 19.8 \(\pm\) 27 & 30.3 & \(<\)12.0 & \(<\)12.0 & 21.5 & 49.4 & 79.7 \\ \(>\)30-5 years & 54 & 19.8 \(\pm\) 2.9 & 32.1 & \(<\)12.0 & \(<\)12.0 & 23.9 & 53.1 & 74.2 \\ \(>\)50 years & 21 & 17.0 \(\pm\) 3.1 & 30.9 & \(<\)12.0 & \(<\)12.0 & 14.3 & 65.0 & 77.4 \\ \hline
**Smoking habit** & & & & & & & & \\ No & 65 & 17.1 \(\pm\) 27 & 27.0 & \(<\)12.0 & \(<\)12.0 & 15.9 & 47.4 & 69.0 \\ Smokers & 34 & 23.8 \(\pm\) 3.1 & 39.9 & \(<\)12.0 & \(<\)12.0 & 33.0 & 59.9 & 97.4 \\ \(<\)5 cigarettes/day & 15 & 24.9 \(\pm\) 27 & 35.5 & \(<\)12.0 & \(<\)12.0 & 37.9 & 57.9 & 66.2 \\ \(>\)10 cigarettes/day & 8 & 16.3 \(\pm\) 3.1 & 27.5 & \(<\)12.0 & \(<\)12.0 & 14.4 & 42.4 & 71.7 \\ 11-20 cigarettes/day & 11 & 25.9 \(\pm\) 3.8 & 54.9 & \(<\)12.0 & \(<\)12.0 & 57.9 & 84.6 & 128.0 \\ \hline
**Residence** & & & & & & & & \\ Industrial & 1 & - & - & \(<\)12.0 & & - & & \\ Urban & 74 & 17.7 \(\pm\) 2.9 & 29.9 & \(<\)12.0 & \(<\)12.0 & 16.7 & 52.4 & 75.9 \\ Rural & 24 & 25.7 \(\pm\) 2.7 & 37.3 & \(<\)12.0 & \(<\)12.0 & 31.4 & 58.5 & 81.0 \\ \hline
**Traffic intensity** & & & & & & & & \\ Low & 34 & 26.3 \(\pm\) 2.8 & 39.9 & \(<\)12.0 & \(<\)12.0 & 36.4 \({}^{*}\) & 60.5 & 89.3 \\ Medium & 48 & 15.6 \(\pm\) 2.8 & 27.1 & \(<\)12.0 & \(<\)12.0 & 13.3 & 40.3 & 76.6 \\ High & 17 & 17.9 \(\pm\) 2.6 & 26.9 & \(<\)12.0 & \(<\)12.0 & 15.9 & 47.4 & 68.4 \\ \hline
**BMI** & & & & & & & & \\ \(<\)25 kg/m\({}^{2}\) & 65 & 16.9 \(\pm\) 2.8 & 27.8 & \(<\)12.0 & \(<\)12.0 & 16.0 \({}^{b}\) & 47.0 & 68.3 \\ \(>\)30 kg/m\({}^{2}\) & 23 & 27.6 \(\pm\) 2.9 & 41.9 & \(<\)12.0 & \(<\)12.0 & 39.4 & 85.0 & 93.6 \\ \(>\)30 kg/m\({}^{2}\) & 11 & 18.4 \(\pm\) 2.9 & 31.3 & \(<\)12.0 & \(<\)12.0 & 15.9 & 44.3 & 90.7 \\ \hline \end{tabular}   
* *The 5 th-95 th percentile range of data was \(<\)12.0-77.9 \(\upmu\)g/L. No differences were found in relation to the gender or class of age, although the 2,5-HD excretion was lower in the subjects over 50 years old (see geometric mean or median).