## 3 Results and Discussion
### Choice of Place to Live
\begin{table}
\begin{tabular}{c c c c c} \hline \hline \multirow{2}{*}{**Residence Time**} & \multicolumn{2}{c}{**Serzedelo**} & \multicolumn{2}{c}{**Abacão (São Tome)**} \\ \cline{2-5}  & **Yes** & **No** & **Yes** & **No** & **Did not Answer** \\ \hline Less than 1 year & 0.0 & 2.0 & 0.0 & 1.0 & 0.0 \\ From 1 to 2 years & 3.0 & 0.0 & 0.0 & 1.0 & 0.0 \\ From 3 to 10 years & 3.0 & 5.0 & 3.0 & 6.0 & 0.0 \\ From 11 to 20 years & 6.0 & 8.0 & 8.0 & 10.0 & 1.0 \\ From 21 to 30 years & 0.0 & 0.0 & 0.0 & 0.0 & 0.0 \\ From 31 to 40 years & 12.0 & 4.0 & 10.0 & 5.0 & 0.0 \\ More than 40 years & 9.0 & 1.0 & 4.0 & 0.0 & 0.0 \\ Since he/she was born & 28.0 & 13.0 & 23.0 & 27.0 & 0.0 \\ Did not answer & 3.0 & 3.0 & 1.0 & 0.0 & 0.0 \\ Total & 64.0 & 36.0 & 49.0 & 50.0 & 1.0 \\ \hline \hline \end{tabular}
\end{table} 
Table 11: Proportion between residence time and health problems in Serzedelo. \begin{table}
\begin{tabular}{c c c c} \hline \hline \multirow{2}{*}{**Analyzed Areas**} & **Yes (\%)** & **No (\%)** & **Total (\%)** \\ \hline Serzedelo & 64.0 & 36.0 & 100.0 \\ Abacão (São Tome) & 49.0 & 51.0 & 100.0 \\ \hline \hline \end{tabular}
\end{table} 
Table 9: Interviewees who have a health problem in Serzedelo and Abacão (São Tome). The percentage of those interviewed who had a health problem was higher for the village of Serzedelo, especially cardiovascular diseases--32.0% in the case of the \"exposed\" group and 19.0% in the case of the \"unexposed\" group. In both groups, the largest segment of the population surveyed presented a health problem that affects the heart and blood vessels (cardiovascular diseases), namely, hypertension and cardiac arrhythmia, besides mental illnesses, depressive episodes and anxiety (Table 12). These results follow other investigations, such as the one conducted in the 1990s in Poland, with 30 individuals disturbed by noise [51; 52]. The 30 individuals were compared to an equal number of people, living in the same apartment block, but without the presence of low frequency noise. This study showed a greater number of sleep disorders and depression among exposed individuals. However, the author clarifies that the results can be confounded by the differences between the populations studied. The high percentages for cardiovascular diseases, depression and sleep disorders may be caused by exposure to low-frequency noise. The population of the village of the \"exposed\" group may suffer more from influence due to exposure to the noise emitted by high voltage power poles and power lines (added to that emitted by sources other than the study source, such as traffic road noise), rather than the presence of the electromagnetic field emitted by these infrastructures. Concerning the association between distance to the highway and the presence of health problems, there is no clear pattern in the spatial distribution of disease in the villages of the \"exposed\" (Figure 5) and the \"unexposed\" (Figure 6) groups. We also find it complex to establish a spatial distribution pattern of the diseases in Serzedelo due to the presence of power poles and power lines in more than 80% of the territory (Figure 7). There is no statistically significant correlation between residing near the source (power poles and power lines) and the presence of health problems in Serzedelo (chi-square = 6.94 for 7; \(p\)-value > 0.05--Table 13). \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Distance from Source (m)** & **Yes** & **No** & **Total** \\ \hline
50–99 & 18 & 8 & 26 \\
100–149 & 13 & 9 & 22 \\
150–199 & 14 & 7 & 21 \\
200–249 & 7 & 5 & 12 \\
250–299 & 2 & 0 & 2 \\
300–349 & 0 & 1 & 1 \\
350–399 & 4 & 0 & 4 \\ \(\geq\)400 & 6 & 6 & 12 \\ Total & 64 & 36 & 100 \\ \hline \hline \end{tabular}
\end{table} 
Table 13: Percentage of interviewees who have a health problem regarding distance from the source (power poles and power lines) in Serzedelo.