The influence of wind turbine visibility on the health of local residents: a systematic review.

PURPOSE: The health effects of visible wind turbine features on residents were investigated. Further, it was examined, if visual annoyance has an influence on residents' health, and if wind turbine visibility impacts residents' health independently of or in combination with acoustical aspects.

METHODS: Medical databases, Google Scholar, public health institutions, and reference lists were searched systematically (PROSPERO registry number: CRD42016041737). Two independent reviewers screened titles/abstract and full texts, extracted data, and critically appraised the methodology of included studies. Study findings were analyzed qualitatively and quantitatively.

RESULTS: Seventeen studies from 19 publications of varying methodological quality were included (two cohort studies, fifteen cross-sectional studies). The pooled prevalence of high annoyance due to altered views and shadow flicker was 6% each. The results of other health effects were inconsistent, with some indications showing that direct wind turbine visibility increases sleep disturbance. Annoyance by direct visibility, shadow flicker, and blinking lights was significantly associated with an increased risk for sleep disorders. One study indicated reactions to visual wind turbine features may be influenced by acoustical exposures.

CONCLUSIONS: In interpreting the results, the differing methodological quality of the included studies needs to be considered. Direct and indirect wind turbine visibility may affect residents' health, and reactions may differ in combination with noise. Further, annoyance by wind turbine visibility may interact as mediator between visual exposures and the health of local residents. To confirm the results, more high-quality research is needed.