# Phthalates Exposure and Occupational Symptoms among Slovakian Hairdressing Apprentices
## 3 Results and Discussion
We detected higher FEV1% of PV (\(p\leq 0.001\)) and VC (\(p\leq 0.001\)) in control group of our previous study [12] in comparison with hairdressing apprentices from the current study, and FVC% of PV (\(p\leq 0.05\)), FEV1(\(p\leq 0.001\)), and VC (\(p\leq 0.001\)) in comparison with hairdressing apprentices from our previous study [12]. Our findings on FFT, (except PEF), are in accordance with results from cohort composed from Parisian hairdressing apprentices [50]. However, compared to other hairdressing occupational studies [47; 49; 58] we detected higher values of pulmonary functions. These differences, however, may have been influenced by age and length of exposure, as in the current study we examined apprentices and not adult hairdressers. From all probands (n = 74) only 64 (86.49%) provided a first-morning-void urine sample. Analyses detected MEHHP, MEP, and MnBP in all urine samples, followed by MEOHP (98.4%) and MEHP (89.16%). The frequency distribution of the concentration of urinary phthalate metabolites was positively skewed. Urinary concentration of phthalate monoesters confirmed occupational exposure to phthalates shown in Table 6.  
The highest ratio level from DEHP metabolites scored MEHHP (57.24%), followed by MEOHP (31.29%) and MEHP (11.46%). The mean excretion-ratios of MEHP to MEHHP and MEHP to MEOHP were 1:5 and 1:2.7, respectively. Basically, the excretion pattern of primary and secondary DEHP metabolites was in accordance with that observed in hairdressing apprentices previously [12]; however, currently we observed higher concentration of all phthalate metabolites (medians and 95 percentile, ng/mL), except 95 percentile of MEHHP and \(\sum\)DEHP in comparison to our previous data. Concentrations of MEHHP (\(p\leq 0.005\)), MEOHP (\(p\leq 0.005\)), and \(\sum\)DEHP (\(p\leq 0.05\)) were higher in the current study compared to urine samples of hairdressing apprentices from Slovakia [12]. Those finding suggest potential higher exposure to parental diesters in this specific type of work environment. The present median concentration of MEP compares well with US data on nail salon workers (22-58 years), although we scored higher with MEHHP and MEOHP but lower with MEHP [59]. However, in children exposed to vinyl flooring at home, median and 95 percentile of MEP concentration reached higher values than in our study. \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline  & **Mean** & **SD** & **Min** & \multicolumn{4}{c}{**Percentiles**} & \multirow{2}{*}{**Max**} \\ \cline{4-4} \cline{6-7}  & & & **5 th** & **50 th** & & **95 th** & \\ \hline MEP & 330 & 837 & 2.21 & 24 & 108 & 884 & 5761.47 \\ MnBP & 130 & 98 & 12.04 & 24 & 109 & 338 & 482.33 \\ MEHP & 7.5 & 9.3 & 0.81 & \(\leq\)LOD & 4.2 & 30 & 48.42 \\ MEHHP & 38 & 33 & 5.4 & 7 & 27 & 97 & 173.47 \\ MEOHP & 20 & 18 & 0.3 & 2.09 & 14 & 52 & 86.61 \\ \(\sum\)DEHP & 65 & 57 & 6.5 & 11 & 45 & 158 & 267.78 \\ \hline \hline \end{tabular} MEP—monoethyl phthalate, MnBP—mono-n-butyl phthalate, MEHP—mono(2-ethylhexyl) phthalate, MEHHP—mono(2-ethyl-5-hydroxyhexyl) phthalate, MEOHP—mono(2-ethyl-5-oxohexyl) phthalate, \(\sum\)DEHP = sum of MEHP, MEHHP, MEOHP, LOD—Limit of detection.  
\end{table} 
Table 6: Descriptive statistics of concentrations of phthalate metabolites (ng/mL) in study group (n = 74). We also observed a decrease of FVC% of PV vs. MEOHP (r = \(-\)0.26; \(p\) = 0.054) and \(\sum\)DEHP (r = \(-\)0.28, \(p\) = 0.037) and of VC% of PV vs. MEHHP (r = \(-\)0.33, \(p\) = 0.014), MEOHP (r = \(-\)0.35, \(p\) = 0.008) and \(\sum\)DEHP (r = \(-\)0.35, \(p\) = 0.008) in females (Table 7). In males (n = 8) we observed negative associations between MnBP and waist circumference (r = \(-\)0.74, \(p\) \(\leq\) 0.05), hip circumference (r = \(-\)0.86, \(p\) \(\leq\) 0.05), and WHtR (r = \(-\)0.74, \(p\) \(\leq\) 0.05) and between MEP and FVC% of PV (r = \(-\)0.88, \(p\) \(\leq\) 0.05). In contrast, we observed a positive association between the concentration of MEHP and MVV% of PV (r = 0.74, \(p\) \(\leq\) 0.05).