This week the national Health and Medical Research Council (NHMRC) released a report that looked at the health effects of wind farms. The take home conclusion, presented with the press release, was that
there is no reliable or consistent evidence that wind farms directly cause adverse health effects in humans.
This message was repeated in headlines such as ABC’s environmental reporter Jake Sturmer (No reliable link between wind farms and health problems, National Health and Medical Research Council says) and Simon Chapman at the Conversation (Study finds no evidence wind turbines make you sick – again). The commmentary invoked verbal eye-rolls usually reserved for creationists.
However, if you read the report it becomes clear that these headlines are misleading. The failure to find “reliable” “consistent” evidence is actually because the NHMRC did not trust the research. This is understandable. They could only find seven studies that were sufficiently rigorous to even include in the review, and even those studies, the authors viewed with a jaundiced eye. But even in those seven studies there were some findings that wind farms could be detrimental to health.
Quality of life.
The NHMRC authors found that of the research that has been done, there seems to be a detrimental effect on quality of life. Here they are talking about it on page 15:
Three studies assessed quality of life and proximity to wind farms. Only one of them attempted to mask the purpose of the study from participants and used a formally validated questionnaire. 11 This study found an association between distance from wind turbines and overall quality of life. Two other studies used author-formulated questions and did not mask the purpose of the study. In one of these studies, the majority of people reported that their quality of life had altered since living near a wind turbine, regardless of how close they lived to the turbine. 13 The other study reported that more residents living close to a turbine wanted to move away than residents living further from a turbine.
Yep, they found three whole studies into quality of life. Count em! All three found basically the same thing: quality of life was reduced due to proximity to wind farms. There was also evidence that people who live near wind farms want to move away from the wind farms. Quality of Life is a hair’s breadth away from depression: this is indirect evidence of health effects.
The association of wind farm noise with self-reported sleep quality was assessed in all seven studies. Six studies reported poorer sleep (mostly disturbed sleep and poor sleep quality) among people exposed to higher estimated levels of wind farm noise 8-10 or living closer to wind farms.
There is a pile of evidence the size of Mount Everest that there’s a link between poor sleep and poor health outcomes. The authors are playing hard-to-get by not acknowledging this as evidence of an effect on health.
They found some evidence that people reported that nearby wind turbines “annoyed” them. That’s not as damning as sleep disruption or lost quality of life, but it was enough for the ABC to erroneously sew them together in the following sentence, which at least has the advantage of parsimony: “However, the study by the NHMRC – Australia’s peak medical and scientific research body – did link wind farms to a level of annoyance that can cause sleeplessness.”
“No studies were identified that assessed the health effects of shadow flicker from wind turbines.”
Let’s read that sentence from page 16 again. “No studies”. The authors describe this elsewhere in the report as “insufficient evidence”. Yeah, you could call it that.
They were highly critical of these studies as being small and poorly designed.
In all these studies, the participants self-reported their health and health-related outcomes; none of the outcomes were objectively measured (e.g. by using a test performed by a doctor or scientist). (p6)
The number of participants in most of the studies was modest. (p6)
In many of the studies, the purpose of the research was not masked (i.e. hidden) from participants. Where the studies did attempt to hide the intent of the study from participants, this may not have been effective. (p7)
All of the health and health-related outcomes recorded in the included studies were self-reported. (p7).
We should applaud the authors’ stringent inclusion rules for methodologically robust research. I was concerned that they had overdone it somewhat (it’s hard to know as details in the report was scarce). For example they excluded any study that didn’t use comparison groups (ie people near a wind farm and people further away). It’s not clear if, for example correlational studies were allowed, or studies that compared a group to known population parameters. Neither of these use “groups” in the sense of medical trials. Epidemiological standards would be a better fit to this problem than a model more closely linked to medical trials. But regardless, let’s not quibble too much: throwing out poorly designed research is a good thing to do. better to conclude “no evidence’ than draw the wrong conclusion.
More research needed
Given the lack of methodological rigor, combined with some evidence of negative health effects, wouldn’t the best thing to do be to call for more research? It would. And full credit to the authors, that’s what they did. They detailed the sort of “further investigation” that is needed in the conclusions of the report, and in the press release, the CEO of NHMRC, Warwick Anderson, is quoted as saying: “Given that the quality of the existing evidence is poor, further research of the highest standard is warranted.”
But somehow, the headline “NHMRC calls for more research into the health effects of wind farms” is not very ABC friendly.
For that matter, I can’t see this (accurate headline) being too popular at ABC or the Conversation: “Science shows that wind farms disrupt sleep.”
Both of these headlines would have been completely accurate.
Simon Chapman at The Conversation noted cynically that this review brings the number of reviews of the health effects of wind farms to 20. That’s almost three times as many reviews as actual studies.
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