Systematic review and meta-analysis of wind turbine noise effects on sleep using validated objective and subjective sleep assessments 

Abstract:
Little is known about the potential impacts of wind turbine noise (WTN) on sleep. Previous research is limited to cross-sectional studies reporting anecdotal impacts on sleep using inconsistent sleep metrics. This meta-analysis sought to comprehensively review studies evaluating the impact of WTN using widely accepted and validated objective and subjective sleep assessments. Search terms included: “wind farm noise”, “wind turbine noise”, “wind turbine sound”, “wind turbine noise exposure” AND “sleep”. Only original articles published in English published after the year 2000 and reporting sleep outcomes in the presence of WTN using polysomnography, actigraphy or psychometrically validated sleep questionnaires were included. Uniform outcomes of the retrieved studies were meta-analysed to examine WTN effects on objective and subjective sleep outcomes. Nine studies were eligible for review and five studies were meta-analysed. Meta-analyses (Hedges’ g; 95% confidence interval [CI]) revealed no significant differences in objective sleep onset latency (0.03, 95% CI −0.34 to 0.41), total sleep time (−0.05, 95% CI −0.77 to 0.67), sleep efficiency (−0.25, 95% CI −0.71 to 0.22) or wake after sleep onset (1.25, 95% CI −2.00 to 4.50) in the presence versus absence of WTN (all p > .05). Subjective sleep estimates were not meta-analysed because measurement outcomes were not sufficiently uniform for comparisons between studies. This systematic review and meta-analysis suggests that WTN does not significantly impact key indicators of objective sleep. Cautious interpretation remains warranted given variable measurement methodologies, WTN interventions, limited sample sizes, and cross-sectional study designs, where cause- and-effect relationships are uncertain. Well-controlled experimental studies using ecologically valid WTN, objective and psychometrically validated sleep assessments are needed to provide conclusive evidence regarding WTN impacts on sleep.

Statement of significance:
Studies investigating the impact of wind turbine noise (WTN) on objectively measured sleep outcomes are scarce. Previous reviews and meta-analyses are limited to cross-sectional studies based largely on anecdotal impacts on sleep and reporting indirect and inconsistent sleep metrics. Without the use of objective and standardised questionnaires, only limited conclusions can be drawn. To date, several experimental studies have examined the i pact of WTN on sleep using polysomnography, actigraphy and psychometrically validated questionnaires, calling for an updated review. The present review and meta-analysis show that key indicators of objective sleep outcomes do not appear to be impacted by WTN, whereas psychometrically validated subjective sleep outcomes showed more inconsistent findings.

Branko Zajamšek, Tessa Liebich, Leon Lack, Nicole Lovato, Peter Catcheside, Kristy Hansen, Gorica Micic
Adelaide Institute for Sleep Health: A Flinders Centre of Research Excellence, College of Medicine and Public Health, Flinders University, Bedford Park; College of Education, Psychology and Social Work, Flinders University, Adelaide; College of Science and Engineering, Flinders University, Adelaide, SA, Australia

Journal of Sleep Research. Published on line November 12, 2020. doi: 10.1111/jsr.13228

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