Those who move away not part of turbine study

Dr. Hazel Lynn says an important segment of the population has been left out of a Health Canada study into the impact of industrial wind turbines on peoples' health.

The Health Canada study, released Thursday, found no link between wind turbine noise and negative health effects in people. But Lynn, the medical officer of health for Grey-Bruce who has done a review of such studies, said some of the best survey findings are from the people who have moved away because they simply couldn't live near turbines.

"These folks are still living there so obviously they are not in that 10% of people who actually abandoned their homes," Lynn said of those who participated in the study.

"Although the wind folks would pooh-pooh those people (who have moved away) as being especially difficult, I think they are especially sensitive and if you are living in a place where you are afraid to go to sleep at night then you are going to move. Obviously this study didn't pick up any of those folks."

The study by Health Canada of more than 1,200 households living near industrial wind turbines concluded there was no evidence to support a link between exposure to wind turbine noise and adverse ill effects including dizziness and migraines, chronic illnesses such as heart disease and high blood pressure and decreased quality of sleep.

The study did find there was a relationship between wind turbine noise and annoyance towards several features associated with turbines including noise, vibration, shadow flicker and the warning lights on top of them.

More than 400 properties approached for the study were deemed not valid dwellings. David Michaud, a research scientist at Health Canada and principal investigator in the study, said they were deemed not valid for various reasons.

"(Statistics Canada) would visit an address and find out in some cases it could have been a church or could have been an industry, it could have been a vacant home and it could have been a home that is being constructed, so those are considered to be out-of-scope homes because they are not valid addresses for the purpose of this study," said Michaud.

"If somebody has potentially left their homes because of wind turbines, we would have no way of knowing that in a study like this."

Health Canada partnered with Statistics Canada for the study, which was launched in 2012 and cost $2.1 million. It included three parts - a questionnaire done by participants; a collection of physical health measures that assessed stress levels using hair cortisol, blood pressure, resting heart rate and measures of sleep quality; and more than 4,000 hours of wind turbine noise measurements conducted by Health Canada.

All potential homes within approximately 600 metres of a wind turbine in 12 study areas in southwestern Ontario and six in Prince Edward Island were selected to participate, as were a random selection of homes between 600 metres and 10 kilometres.

One person between the age of 18 and 79 years of age from each household was randomly selected to participate.

Lynn called the study results preliminary and questioned many of the conclusions.

"I would like to see the study design, I would like to see what kind of actual statistical significance their study population would have," said Lynn.

"There is lots of stuff I need to know before I can say this is a well-done study and we can be confident in what it says as a conclusion."

Lynn said the Health Canada study will not be the last on the subject and that it will take much more work before the true impact of wind turbines on peoples' health will be known.

"It is going to take years and years as it did with any environmental exposures and illness to actually prove it or not prove it," Lynn said. "You don't know until the studies are done properly and you can get enough of them."

In 2013, Lynn and epidemiological researcher Dr. Ian Arra released a review of studies from around the world on wind turbines and people's health. They found "reasonable evidence that an association exists between wind turbines and distress in humans."

Lynn said the measurement used in her review was distance from wind turbines, not noise level, which was used in the Health Canada study, although some of the studies she and Arra looked at made conclusions based on noise levels.

Lynn said the Health Canada study defined annoyance as very or extremely annoyed, which she said is not a definition. In her review they used the term "distress."

One area Lynn had expressed particular interest in was infrasound exposure, adding she would like to see more work on the effects of the very low frequency sound emitted by turbines.

The Health Canada study found infrasound from the turbines could sometimes be measured up to 10 kilometres away, but was in many cases "below background infrasound levels."

"The levels of infrasound measured near the base of the turbine were around the threshold of audibility that has been reported for about 1% of people that have the most sensitive hearing," according to the study findings.

Health Canada intends to further analyze the infrasound data and release results throughout 2015.

"We are still looking at the data set and doing some more analysis with respect to the acoustic information that was collected," said Michaud. "Our ongoing work wouldn't change what we posted (Thursday)."