Monday August 3 2009
There is no conclusive evidence that wind turbines affect health
“Living too close to wind turbines can cause heart disease, tinnitus, vertigo, panic attacks, migraines and sleep deprivation,” The Independent on Sunday reported. The newspaper said that research to be published later this year by an American doctor has identified a new health risk: “wind turbine syndrome”.
The story is based on the work of Dr Nina Pierpont, a New York paediatrician who is publishing a book based on her own case series study, discussions and theories. The study looked at 10 families living near wind turbines, the results of which were used to define a set of symptoms that can be used in future studies.
No firm conclusions can be drawn from this study as the design was weak and included only 38 people. Participants were asked about their symptoms before they were exposed to wind turbines to provide a control for their symptoms after exposure. This was not a sufficient control as many of the participants were reportedly already convinced that wind turbines caused their symptoms and were actively trying to move out of their homes or had already moved. Further study is needed.
Where did the story come from?
The story is based on the work of Dr Nina Pierpont, a New York paediatrician who is publishing a book based on her own case series study, discussions and theories of wind turbine syndrome. This appraisal is based on a draft of the book available through Dr Pierpont’s website.
What kind of scientific study was this?
The book is based around a case series study carried out by Dr Pierpont, which involved 10 families reporting symptoms they associated with living near a wind farm. The author says that the study’s purpose was to “establish a case definition” for the set of symptoms that people experience while living near wind turbine installations.
The researcher interviewed 23 people from 10 families by telephone, some of whom gave information on the symptoms of other family members, resulting in a total of 38 participants to include in analysis. It is not clear how these families were selected or what countries they come from. Dr Pierpont says that she collected information about the symptoms of everyone in the family to “further create comparison groups” and to investigate if certain aspects of medical history “pre-exposure” to wind turbines could predict particular symptoms that were experienced during exposure.
The 38 family members ranged in age from less than one to 75 years and lived within a range of 305m to 1.5km from wind turbines that had been erected since 2004. They were asked for the details of any symptoms they experienced before the turbines were erected, symptoms experienced while living near the operational turbines, and symptoms experienced after they had moved home or while they spent prolonged periods away from their homes.
Dr Pierpont’s book discusses the results of these interviews using a narrative approach, interspersing the findings with a discussion of the potential impact of wind turbines on the environment and the human body. The publication is divided into two sections, one for clinicians and one for non-clinicians. The “family tables” present the results of the interviews in the interviewees’ own words.
What were the results of the study?
Many participants had pre-existing comorbidities at baseline (before wind turbines were erected near their homes), including:
- Seven people with a history of mental disorders.
- Eight people with pre-existing migraine disorder.
- Eight people with permanent hearing problems.
- Six people with continuous tinnitus.
- Twelve people who had previously been exposed to significant noise, such as through work in industrial or construction settings.
- Eighteen people who were motion sensitive.
- Seven people who remembered a history of a single concussion.
[There may be some overlap in the individuals in these groups].
The author then discusses the symptoms the participants reported during their period of exposure to wind turbines. These core symptoms had to be “common and widely described by study participants”, “closely linked…to turbine exposure” and “amenable to diagnosis by medical history”.
- Sleep disturbance reported by 32 people (including trouble getting to sleep, prolonged awakening, night terrors).
- Headache reported by 19 subjects as having increased in frequency, duration or severity since living near wind farms. These headaches were significantly associated with a pre-existing migraine disorder.
- Tinnitus and ear sensations reported by 14 subjects as new or worse than baseline. This symptom was linked with previous noise exposure, baseline tinnitus and baseline hearing loss.
- Balance problems during exposure to wind turbines reported by 16 subjects.
- Internal quivering, vibration or pulsation sometimes in association with other symptoms including agitation, anxiety, nausea and irritability. The author calls this condition visceral vibratory vestibular disturbance (VVVD). There was no link between VVVD and previous panic disorder or panic episodes.
- Concentration and memory problems reported by 20 people (all of whom were aged over 34 years) and some unexpected declines in school performance reported in children.
- Significant irritability and anger reported in 28 people.
- Fatigue and motivation problems in 21 people.
The author then discusses the appearance of other problems in some people including prolonged respiratory infections, exacerbations of pre-existing heart arrhythmias in two people, increased blood pressure in two people, gastrointestinal problems, pain, glucose instability in one person and worsening tinnitus in one person.
These symptoms are used to define "wind turbine syndrome".
What interpretations did the researchers draw from these results?
Dr Pierpont says that the core symptoms of wind turbine syndrome are sleep disturbance, headache, tinnitus, other ear and hearing sensations, balance and equilibrium disturbances, anxiety, nausea, irritability, energy loss, motivation loss, memory and concentration disturbances, and visceral vibratory vestibular disturbance.
The author advises a minimum distance for wind farms from properties, recommending at least 2km between wind turbines and residences on normal terrain and 3.2km in mountainous terrain.
While the author suggests that the report “documents a consistent and often debilitating complex of symptoms experienced by adults and children while living near large industrial wind turbines”, she also adds that “further research is needed to prove causes and physiological mechanisms, establish prevalence and to explore effects in special populations, including children”.
What does the NHS Knowledge Service make of this study?
This study provides no conclusive evidence that wind turbines have an effect on health or are causing the set of symptoms described here as "wind turbine syndrome". The study design was weak, the study was small and there was no comparison group.
Asking this particular group about their symptoms prior to their exposure to wind turbines was not a sufficient control measure. Many of the participants were reportedly already convinced that wind turbines were to blame for their symptoms and were actively trying to move out of their homes or had already moved.
It is also impossible to know how frequent these symptoms are in people who live near wind turbines compared to those who don’t. There is also no information on how the group was selected in the first place and some uncertainty as to which countries these people come from.
However, it is physically and biologically plausible that low frequency noise generated by wind turbines can affect people, and the author puts forward several possible theories regarding this.
The author acknowledges some of the study’s weaknesses and states that the next step would be an epidemiological study. One possibility would be to compare "wind turbine syndrome" like symptoms in people who live near wind turbines with those who don’t. This would show how common these symptoms are in the different groups.