Excerpt: RESULTS AND DISCUSSION
The data obtained for use in this study were collected between February 1st and May 31st, 2013. In total there were 412 surveys returned; 16 of these survey respondents did not provide their home address. Therefore, 396 surveys were included in the analysis.
The relationship between ln(distance) (as a continuous variable) and mean Pittsburgh Sleep Quality Index (PSQI) was found to be statistically significant (P=0.0096) when controlling for age, gender and county. This relationship shows that as the distance increases (move further away from a wind turbine), PSQI decreases (i.e. sleep improves) in a logarithmic relationship. Multivariate analysis involved assessing distance
to the nearest wind turbine as both distance and ln(distance). In all cases, ln(distance) resulted in improved model fit. The relationship between vertigo and ln(distance) was statistically significant (P<0.001) when controlling for age, gender, and county. The relationship between tinnitus and ln(distance) approached statistical significance (P=0.0755). Both vertigo and tinnitus were worse among participants living closer to wind turbines.
Spearman‟s rank correlation coefficients (rs) between PSQI, vertigo and tinnitus are shown below. All relationships were found to be positive and statistically significant. The strongest correlation was seen between the variables „tinnitus‟ and „vertigo‟ (rs=0.2).
In conclusion, relationships were found between ln(distance) and PSQI, ln(distance) and self-reported vertigo and ln(distance) and self-reported tinnitus. Study findings suggest that future research should focus on the effects of wind turbine noise on sleep disturbance and symptoms of inner ear problems.
Counties and projects in the study include:
* Bruce (Enbridge project);
* Chatham-Kent (Raleigh);
* Dufferin (Melancthon);
* Elgin ( Erie Shores );
* Essex (Comber):
* Frontenac ( Wolfe Island );
* Huron (Kingsbridge); and
* Norfolk (Frogmore/Cultus/ClearCreek).