The amount of the stress hormone cortisol found in people's hair could help scientists understand the potential health impacts that may arise from exposure to low-frequency noise and vibrations from wind turbines.
Starting in May, the federal government plans to study the hair of up to 1,200 people who live near wind turbines. The results could tell scientists if wind turbines are linked to health problems, such as chronic stress.
"The objective of the contract is to analyse hair cortisol concentrations from hair samples collected during the community noise and health study," says a contract notice posted Friday.
"The hair cortisol concentrations will be added to the data file for this survey and analysed in relationship to other measures of health and respondent demographics.
"Specifically, the hair cortisol results will be used to assess if there is a relationship between levels of systemic stress and distance from wind turbines."
The adrenal glands produce the hormone cortisol. Stress — either psychological or physical — causes cortisol levels to spike. In small doses, that's not so bad. A brief jolt of cortisol sends a quick burst of energy through the body, heightens memory and numbs sensitivity to pain.
Prolonged exposure to high levels of cortisol, however, can lead to health problems.
Statistics Canada and Health Canada are collaborating on a study to measure people's health in up to a dozen communities located within 10 kilometres of wind turbines.
Besides hair cortisol, scientists will also measure people's blood pressure, heart rates and sleep patterns.
David Michaud of Health Canada, who is leading the study, said his team will go door-to-door to ask people for hair samples.
Each centimetre of hair gives a one-month average of cortisol levels, he said. His team will ask people to provide a single, three-centimetre sample, giving researchers the average levels of cortisol for a 90-day period.
Michaud stressed the study will not definitely link wind turbines to health effects.
"We cannot say that, no matter what the cortisol value looks like, that it's being caused by the wind turbine noise," he said.
"What we can say is that when we look at the average values in people that live, say, in the higher areas versus the lower areas, there is or there is not an association in terms of the concentrations.
"So we can draw a line through those averages and apply statistical modelling and see whether or not the association is there. But at this point, it's only an association. You haven't established causality."
The contract notice says the work will take place between May and November.
The research is needed because scientists don't know a great deal about the potential health effects of wind turbines. Some people who live near the turbines complain of sleep disorders, headaches, depression, anxiety and even blood pressure changes.
The wind energy industry, on the other hand, insists turbines are a safe, clean source of power.
The government wants to be sure they're safe, too, given the industry's ambitions to supply 20 per cent of Canada's electricity by 2025.
Wind turbines now supply 2.3 per cent of the country's electricity, according to Health Canada.
No one from the Canadian Wind Energy Association, which represents the industry, was available for an interview.
In an emailed statement, the association said it has started its own review of the government's study.
"Based on our initial review, it appears that while some modifications have been made to the study design, many elements of the fundamental approach proposed have not changed," the statement quotes Robert Hornung, the group's president, as saying.
"CanWEA will be taking more time to review the revised Health Canada study design in more detail before coming to any formal conclusions on its ability to contribute to a greater scientific understanding of these issues."
The University of Western Ontario has been picked to do the study, worth $88,140. No one from the university was immediately available to comment.