Wind Turbines and Adverse Health Effects

To the Editor: Regarding adverse health effects (AHEs) in the environs of industrial wind turbines (IWTs), McCunney et al1 respond by stating that “the epidemiological and experimental literature provides no convincing or consistent evidence that wind turbine noise is associated with any well-defined disease outcome.” Similarly in 2014, the National Health and Medical Research Council (NHMRC) in Australia concluded that “there is no reliable or consistent evidence that wind farms directly cause adverse health effects in humans.”2 Nevertheless, the CEO of the NHMRC also stated that “the existing body of evidence relating to wind farms and health remains small and mostly of poor quality and further high quality research is needed” and “NHMRC previously recommended that relevant authorities take a precautionary approach in the regulation of wind farms.”3 McCunney et al seem to have affirmed the all-too-common tendency to misinterpret the lack of evidence for causation as proof of the absence of direct AHEs. A classic example of this phenomenon is London physician Dr John Snow's conclusion about a cholera episode of 1854 in Soho, with his spatial epidemiological study suggesting a particular water well polluted by feces, and Snow's suggestion to remove a water pump handle as a precautionary action. We now know Snow's conclusion was accurate (Koch in Germany determined the bacterial cause of cholera in 1883), but the Royal College of Physicians and London Board of Health had considered Snow's thesis and rejected it as “untenable” and biologically implausible. Snow's story illustrates many of the key features surrounding the precautionary principle, namely, conflicting expert advice, the strength of scientific advice needed to justify action, the long time lag between observing compelling associations and understanding their mechanism of action, and the pros and cons of action versus inaction.4 Another systematic review by Danish clinicians5 in 2014 investigated health effects related to wind turbine noise exposure. The evidence presented in the systematic review relied on case–series reports and cross-sectional studies, and suggested an association between wind turbine noise, annoyance and stress, and sleep disturbance (summarized in Tables 1 and 2 of the article). Some government agencies and IWT proponents contend that AHEs are conjecture or negligible or “mere” annoyance. A significant issue here concerns the term “annoyance.” It is apparent that in Canada, the United States, the UK, and Australia, industry literature reviews, and/or some governmental reviews have interpreted the word “annoyance” to mean a minor inconvenience,6 acknowledging that although this “annoyance” may occur, and although it may be unpleasant, it is not an AHE. McCunney et al do cite sources indicating that noise annoyance indoors and outdoors is correlated with A–weighted sound pressure levels, that sleep disturbance is related to annoyance and increasing sound pressure levels, and that the amplitude modulation of wind turbine noise has a statistically significant effect on subjects’ perception of noise annoyance. Nevertheless, their review seems to be preoccupied with personality factors, “global psychogenic health worries and nocebo reactions as [with] other modern technologies,” and nonacoustical factors associated with annoyance such as visual effects and economic benefits for those hosting wind turbines. Yet some of the same authors acknowledge wind turbine noise as causing annoyance, stress, and sleep disturbance7(p. 4–10) and also state that “the similarity between the symptoms of noise annoyance and those of ‘wind turbine syndrome’ indicates that this ‘diagnosis’ is not a pathophysiological effect, but is an example of the well-known stress effects of exposure to noise, as displayed by a small proportion of the population.” In contrast, Shepherd et al8 state that in contemporary medicine, annoyance exists as a precise technical term describing a mental state characterized by distress and aversion, which if maintained, can lead to a deterioration of health and well-being. Noise-induced annoyance is acknowledged to be an AHE by the World Health Organization and bodies such as Health Canada,9 and chronic severe noise annoyance should be classified as a serious health risk. Likewise, the US Environmental Protection Agency states that noise induced “… ‘annoyance’ can have major consequences, primarily to one's overall health.”10 Although McCunney et al emphasize factors such as visual impact on annoyance, Shepherd et al8 stress the inherent complexity of individual reactions to any noise source. Thus, the higher proportion of noise-sensitive individuals in rural areas with low background noise levels is associated with higher annoyance rates. Shepherd et al outline a model showing how wind turbine noise can lead to primary health effects of annoyance and sleep disturbance, and on to secondary health effects involving reductions in quality of life and general well-being, and stress-related disease emerging from chronic annoyance and sleep disturbance. The multiplicity of relationships represented in the model underlines why it is difficult with current study designs to determine with certainty the association between turbine noise exposure and health-related outcomes. Focusing on “direct” causal links alone is unwarranted. Such a focus limits the discussion to a small slice of the potential health effects of wind turbines, with “indirect” pathways also being relevant to the symptoms experienced by exposed people. The issue is whether health practitioners, planners, and policymakers accept having to prove causality before responding. There are many conditions (multiple sclerosis, migraine, cancer) and many drugs on the market for which causality has yet to be demonstrated, but treatment and preventive strategies are deployed. Frequently wind turbine proponents invoke the nocebo response as McCunney et al do. Academics such as Simon Chapman at the University of Sydney and Keith Petrie at the University of Auckland subscribe to the mass hysteria ideas promoted by controversial British psychiatrist Simon Wessely. Such assessments primarily implicate people's fears and anxieties about new technologies to explain noise complaints and sleeping difficulties that appear in conjunction with wind farm developments. The nocebo effect has been used by wind energy proponents as a way of invalidating claims about AHEs. What is problematic about the use of psychogenic theory is that all manner of technology (eg, IWTs, mobile phones, and mobile phone towers) can be declared benign, when more detailed knowledge of the areas in question suggests the opposite. For example, Chapman11 casts current concerns about electromagnetic fields as being merely a form of “technophobic” anxiety about modern technology. Nevertheless, there is now reinforced scientific evidence of risk from chronic exposure to low–intensity electromagnetic fields and to wireless technologies, with World Health Organization/International Agency for Research on Cancer classifying radiofrequency electromagnetic fields as possibly carcinogenic to humans (Group 2B) in 2011.12 Using the “nocebo” concept as an explanation for the chronic sleep disorders from nighttime arousals related to noise from wind turbines is irresponsible when more plausible and likely pathophysiological pathways cannot be excluded. The NHMRC in Australia noted that all the studies identified in its 2014 systematic review used self–reported measures of health outcomes to determine whether there was any association with exposure to wind turbine emissions. Given the claimed lack of objective health measurements (validated self-reported questionnaires are in fact “objective” measures and are widely deployed in research) in these studies, the NHMRC considers that field studies are needed that objectively measure physiological and biochemical characteristics (including sleep) along with an individual's self–reported physical and psychological status (including annoyance). Such measures should be compared with objectively recorded noise from wind turbines measured inside and outside residences.2 Likewise, the Danish systematic review5 argues that future studies should use objective measures of health such as sleep monitoring and stress hormones in combination with more subjective measurements as in questionnaires to determine annoyance from wind turbine noise. There seems to be considerable inertia and reluctance on the part of proponents to conduct independent epidemiological clinical studies of this kind, even after wind turbine noise has been recognized as a problem for communities. Schmidt and Klokker's review5 summarizes larger cross-sectional studies on annoyance and wind turbine noise (two in Sweden, one in the Netherlands, one in Poland, and one in Japan), demonstrating a dose--response effect and a significant relationship between A-weighted sound exposure and annoyance. The meta-analysis showed that noise from wind turbines was perceived as more annoying than noise from road traffic, airports, and trains at similar values. In addition, a dose--response relationship was found between self-reported sleep disturbance and A-weighted noise exposure in three of four of the larger studies from Sweden, the Netherlands, and Poland, and disturbed sleep was found to be higher among exposed subjects than among unexposed subjects in three studies from Japan, the United States, and New Zealand. Although those working with or funded by the wind energy industry claim to be “independent scientific professionals” whose “views and research are not influenced by these contractual obligations,”13 previous research has demonstrated that study results may be influenced by funding sources and other conflicts of interest. Findings and conclusions are more likely to favor the industry's product than is the case with research funded by nonindustry sources.14 McCunney et al acknowledge funding for their review from the Canadian Wind Energy Association, and also acknowledge the authors’ roles in providing testimony favorable to the wind industry in environmental tribunal hearings in Canada and the United States. Despite the findings about industry-sponsored research quoted above, the authors claim that bias has been eliminated in interpreting the literature. At a more pragmatic level, a legal hearing in 2011 in Ontario, Canada, heard evidence from teams of experts arguing for and against claims of AHEs from wind turbines (those arguing against harm included Drs McCunney and Colby, coauthors of the article we are responding to, and those asserting harm included Dr McMurtry,15 coauthor of the current letter). The Environmental Review Tribunal16(p.207) concluded: “This case has successfully shown that the debate should not be simplified to one about whether wind turbines can cause harm to humans. The evidence presented to the tribunal demonstrates that they can, if facilities are placed too close to residents.” In addition, McCunney at al suggest that the rate of complaints around wind farms is relatively low, and that generally only a small proportion of people report some degree of annoyance with wind turbines. The systematic review by Schimdt and Klokker5 points to a less comforting picture, with some studies even reporting a majority of households being annoyed. As a general statement, they report 10% to 45% of the population being annoyed if the sound exposure is above 40 dB(A), but less than 10% of the population annoyed if the sound exposure is less than 35 dB(A). Another conclusion by McCunney et al is that the components of wind turbine sound, including infrasound and low-frequency sound, have not been shown to present unique health risks to people living near wind turbines. Rather, they refer to studies of other noise sources, where noise levels have been considerably higher than those associated with wind turbines. In contrast, we consider that a more sophisticated analysis of noise has been provided by Large and Stigwood,17 suggesting that the focus on decibel levels and frequency parameters ignores crucial elements of noise character and noise context. Comparisons between wind turbine noise and a fridge for example are misleading, because the noise from a fridge is relatively constant with limited variation, whereas wind farm noise is often highly changeable and variable, without predictability or regularity. Logically, transportation noise cannot reasonably be compared with wind farm noise, with the latter already having been shown to be more annoying.18 The Large and Stigwood analysis helps to explain why many wind farms found to be compliant with noise limits still generate significant complaints. Methodological issues have also been raised by a recent acoustic survey of Waterloo Wind Farm in South Australia conducted by researchers at the University of Adelaide,19 one of whom (Dr Hansen) has been working in the acoustics and vibration field for more than 40 years. The results and conclusions of this survey are in marked contrast with the results and conclusions of the acoustic monitoring study of the same wind farm done by the South Australian Environmental Protection Authority. The University of Adelaide study concluded: “… the results show that there is a low frequency noise problem associated with the Waterloo wind farm. Therefore, it is extremely important that further investigation is carried out at this wind farm in order to determine the source of the low frequency noise and to develop mitigation technologies. In addition, further research is necessary to establish the long-term effects of low frequency noise and infrasound on the residents at Waterloo. This research should include health monitoring and sleep studies with simultaneous noise and vibration measurements.” Significantly, 30 years ago, Kelley et al20 demonstrated a direct causal relationship between downwind IWT's production of infrasound and low frequency noise and AHEs such as sleep disturbance and psychological distress. The newer upwind IWTs have never been exonerated from having similar effects. Modern IWTs do produce infrasound and low-frequency noise. The counterclaims by the proponents of IWTs and their paid experts lack credibility. At minimum, proponents should agree with those who are concerned about AHEs that definitive research to settle the matter is urgently required. The continuing absence of such support calls the integrity of proponents’ claims into question.

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