We are aware of the current divide in the scientific assessment of the potential health
effects of wind turbine installations. Therefore, a transparent, scientific, and open
debate is necessary, and it is our duty as editors and reviewers to take such a critique
seriously.
There were six major points of critique expressed by Shepherd [1] regarding the paper
of Mroczek et al. [2] in this journal. The editors received another comment; however,
the person did not want to have the comment published. This comment is, however, covered
by Shepherd’s comments.
We reassessed the paper [2] and the critique [1] and came to the following conclusions.
1. Duplicate Publication
The authors of this general critique are not fully satisfied. They responded quite
correctly; the current article is a more “in-depth analysis” of the data [3].
In addition, the major conclusion in the abstract is slightly different from the older
2012 paper [4], “Within all scales, the quality of life was assessed highest by residents
of areas located closest to wind farms, and the lowest by those living more than 1500
m from wind farms” was changed to a more differentiated description: “The lowest overall
QoL and general health scores were noted among residents of places where windfarm
developments were either at the stage of planning or under construction”.
However, this conclusion is selectively taken as a message, and, given the wide variety
of the additional—partly contradictory—results from the new analysis, a more modest
conclusion would have been more appropriate.
2. Conflicts of Interest
There is no doubt that the first author would have been obliged by a variety of international
ethic rules to report about her husband’s (Jaroslaw Mroczek) involvement as the Polish
Wind Energy Association (PWEA) President in the Polish windfarm community, and as
a member of the Top Management team in the EPA Sp. z o.o. around the time the study
was conducted. Jaroslaw Mroczek is currently (time of publication in 2015) President
of the EPA Sp. z o.o.
It is a requirement to disclose such relationships—especially in cases where no direct
money from the windfarm community was involved in the project.
The International Committee of Medical Journal Editors (ICMJE) Form for Disclosure
of Potential Conflicts of Interest states clearly in Section 5 [5]: “Are there other
relationships or activities that readers could perceive to have influenced, or that
give the appearance of potentially influencing, what you wrote in the submitted work?”
3. Scientific Critique on Methods: Presentation of SF-36 Summary Scores
Shepherd [1]:
Omission Three: The means for the SF-36 Scale were not reported for the groups of
interest. This makes it very difficult to determine whether the differences between
the groups (i.e., effect sizes) were substantial or not. This is important when one
has large sample sizes such as those reported in the Mroczek et al. study (n = 1277),
as very small and clinically insignificant differences may in fact reach statistical
significance. In fact, the means reported in their Table Four (p. 6074) are totally
irrelevant to their research objectives ...
Shepherd is right on this point. In order to judge the obtained results—instead of
presenting the overall means—the relevant tables should show the means by the respective
group (e.g., by distance to wind farm, by respondents who did not accept the development,
by wind-farm development in the planning stage, etc.)
Furthermore, as “Age is the sociodemographic factor that had the greatest effect on
QoL in the multiple regression model”, stratification by age would have been important
(note also the wide age range of this study).
Furthermore, general and specific reservations against the use of summary scores of
the SF-36 exist in the literature (e.g., Simon et al. 1998 [6], Wilson et al. 2000
[7], and Hawthorne et al. 2007 [8]).
In response to such reservations, Ware & Kosinski (2001) [9] responded: “we again
repeat our 7-year-old recommendation that results based on summary measures should
be thoroughly compared with the SF-36 profile before drawing conclusions”.
Another point made by Shepherd merits further investigation: “while the authors laud
the ‘availability of normative data’ (p. 6070), they do not compare their data to
these”.
In their response, the authors replied: “As normative we regarded data which come
from international studies” and quote the User Manual for the SF-36v2 Health Survey.
Under Point 7 (below), there are several reasons mentioned that suggest that the survey
population may depart strongly from typical populations and that a comparison with
data from international studies may not be appropriate (especially with those from
the USA).
Therefore, the point made by Shepherd has good rationale, as these substantial differences
in the health status of the surveyed population in the Mroczek et al. study (which
are not discussed in the paper) would have suggested following the approach Shepherd
indicated. Moreover, Hawthorne et al. (2007) [8] mentioned that the used population
norms are important to account for local factors and avoid wrong conclusions.
4. Scientific Critique on Included Literature
According to Shepherd [1], Omission One: “In support of their statement that ‘No scientific
evidence has been found so far in favor of the influence of turbines (in particular,
of their noise) on health’ (p. 6067) the authors cite two reviews“ [10,11]. Shepherd
regarded these two reviews [10,11] as “out-dated and widely derided” and “also limited”
and asks why “[a] more recent and more competently undertaken review from the University
of Oxford” [12] has not been included.
The response by Mroczek et al. [3] was not correct: “We are familiar with the article
of Onakpoya et al. [of] 2015, but it concerns the influence of noise on sleep disorders,
which was not a subject of our study”.
In fact, the review included studies on annoyance and visual impact on health and
quality of life and followed the STROBE guidelines [13] for the assessment of study
quality.
In addition, it should be mentioned that the summary paper on the annoyance response
to wind turbine noise curves from four surveys by Janssen et al. [14] is clearly missing
and in contrast to the “no scientific evidence statement”.
5. Other Missing Points: A Clear Discussion of the Limitations of This Study
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No noise assessment at all was provided.
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No continuous distance measure was used in the analyses—in spite of the fact that
the study was a door to door survey, where addresses were known.
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The study was of cross-sectional design—but the interpretation was done in terms of
“development stage“ (as if of longitudinal design).
6. Other Scientific Remarks
6.1. Statistical Issue
The regression model presented in Table 5 [2] used a wide variety of “independent”
variables (diseases, symptoms, risky behaviours, etc.), which are known to have high
inter-correlations and may be prone to collinearity. However, there was no mention
of how this potential problem was treated.
6.2. Scientific Critique on Statements in the Results Section
Irritation (OR = 1.49), anxiety (OR = 0.66), anger (OR = 0.87), and nervousness (OR
= 0.80) occurred more frequently in respondents who lived closer to the development
than in those living about 2 km from such development. People living close to wind-farm
construction sites feel nervous (W = 32.56, p = 0.0001) and angry (W = 46.01, p =
0.0001).
[2]
The content of these two sentences is not scientifically sound: First, from the single
point estimate of the odds ratios, the statistical significance of this estimate cannot
be judged without including confidence intervals.
Second, the signs of the odds ratios are on both sides of 1; however, the interpretation,
given in the paper, is the same: it “occurred more frequently in respondents”. This
is obviously a wrong conclusion.
Third, these results are in strong conflict with the SF-36 results in the discussion
and conclusions.
6.3. Scientific Critique on Statements in the Discussion and Conclusions
There were several statements in this paper that were not unequivocally founded by
the obtained results. “The available results imply that wind turbines, when located
at a proper distance, do not exert any negative effects on human health” [2].
“The presence of wind farms near residential areas has no negative influence on the
QoL of residents” [2]. This statement is an inappropriate generalization of the study
results to the universe.
The cross-sectional design prohibits such a conclusion—especially when the study population
may be quite different and the acoustic features of this windfarm are not at all characterized
in this study.
Furthermore, the discrepancy in the results of the SF-36 scores and the symptom analysis
should have led the authors to be very cautious in deriving any conclusions beyond
this study with this highly differing study population (see Point 7). See COPE guidelines
[15]—12.1. Errors, inaccurate or misleading statements must be corrected promptly
and with due prominence—for reference.
7. What Is Different in This Study from Others (and Should Have Been Discussed)
7.1. Sociodemographic Factors
A few socio-demographic features are unusual in the sample and should have been sensibly
discussed in comparison with other studies—as these factors strongly influence the
morbidity prevalence of the sample.
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High unemployment proportion.
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Low proportion of higher education (thus adjustment for education is not working).
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Age range up to 94 (women) and 85 (men).
7.2. Health Related Factors
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A very high proportion of people with diseases was described in this study; afflictions
included hypertension (26.62%, 340), rheumatism (14.17%, 181), coronary heart disease
(12.84%, 164), and diabetes (11.82%, 151). e.g., Fabian et al. in 2005 [16] reported
the local prevalence of diabetes in Szczecin (Poland) as 3.56% in age 3–95 years (mean
65.4 ± 13.6 years)
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From international data bases you get the following picture:
The prevalence of diabetes in the study is even higher than expected. The OECD (2013)
[17] estimated the prevalence of diabetes for Poland at 9.2%.
Prevalence of hypertension is within the higher range in Europe.
Coronary heart disease (CHD) prevalence is higher than that in other parts of Europe,
except for the eastern countries
Overall, there is a higher burden of illness in this survey sample compared with other
studies of this kind.
7.3. Proportion of Survey Residents Who May Profit from the Windfarm Installation
Different from other studies, a high proportion of survey residents may profit economically
from windfarm installations in this study:
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residents who derived real economic benefits by leasing their land (8.65%; n = 110)
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residents who expected to be able to lease their land at the planning stage (21.78%;
n = 277)
A comparison with a similar question from Table 3 in the study of Bakker et al. in
2012 [18] showed that the proportion of residents who may profit somehow from the
windfarm installation was only 99/685 = 14.4% in the sample of Bakker et al.
8. Other Concerns
Incomplete Compliance with Reviewers Suggestions
Reviewer No. 2 Irritation vs. Annoyance
“For consistency with the referenced literature, the term irritation should be replaced
with the term annoyance throughout the paper”.
Answer by Mroczek [2]: “Changed as suggested”—Editorial comment: There is still irritation
in the text and no explanation was given in the paper why annoyance was not used.
“Where results seem to be contradictory there should also be a discussion about why
this might be”.—Editorial comment: suggestion not considered.
Reviewer No. 3
“There is a need for discussion of study limitations”.
Editorial comment: suggestion not considered.
9. Conclusions
The close involvement of the first author’s husband with the wind turbine industry
was not mentioned at the time of submission.
The authors did not follow important advice from the reviewers on central issues (e.g.,
irritation vs. annoyance, discussion of limitations, and discrepant results).
There are also scientific concerns with the presentation of the SF-36 data.
The conclusions drawn were not appropriate based on the inherent limitations and other
peculiarities (see Point 7) of the study population.
Note from the editor: This editorial was provided by the Academic Editors in response
to the reply provided by Mroczek and co-workers. This is only a part of an extensive
discussion. The entire discussion will be also published.