BackgroundWind turbine noise exposure and suspected health-related effects thereof have attracted substantial attention. Various symptoms such as sleep-related problems, headache, tinnitus and vertigo have been described by subjects suspected of having been exposed to wind turbine noise.ObjectiveThis review was conducted systematically with the purpose of identifying any reported associations between wind turbine noise exposure and suspected health-related effects.Data SourcesA search of the scientific literature concerning the health-related effects of wind turbine noise was conducted on PubMed, Web of Science, Google Scholar and various other Internet sources.Study Eligibility CriteriaAll studies investigating suspected health-related outcomes associated with wind turbine noise exposure were included.ResultsWind turbines emit noise, including low-frequency noise, which decreases incrementally with increases in distance from the wind turbines. Likewise, evidence of a dose-response relationship between wind turbine noise linked to noise annoyance, sleep disturbance and possibly even psychological distress was present in the literature. Currently, there is no further existing statistically-significant evidence indicating any association between wind turbine noise exposure and tinnitus, hearing loss, vertigo or headache.LimitationsSelection bias and information bias of differing magnitudes were found to be present in all current studies investigating wind turbine noise exposure and adverse health effects. Only articles published in English, German or Scandinavian languages were reviewed.ConclusionsExposure to wind turbines does seem to increase the risk of annoyance and self-reported sleep disturbance in a dose-response relationship. There appears, though, to be a tolerable level of around LAeq of 35 dB. Of the many other claimed health effects of wind turbine noise exposure reported in the literature, however, no conclusive evidence could be found. Future studies should focus on investigations aimed at objectively demonstrating whether or not measureable health-related outcomes can be proven to fluctuate depending on exposure to wind turbines.

ObjectivesTo systematically review studies of the epidemiology of tinnitus and hyperacusis in children and young people, in order to determine the methodological differences implicated in the variability of prevalence estimates and the influence of population characteristics on childhood tinnitus and hyperacusis.Data sourcesArticles were retrieved from PubMed, EMBASE and Scopus databases and from the relevant reference lists using the methods described in the study protocol, which has previously been published. Reporting Items for Systematic Review (PRISMA) guidelines were followed.Eligibility criteriaStudies addressing childhood prevalence, for example, children and young people aged 5–19 years.Data selection2 reviewers independently assessed the studies for eligibility, extracted data and assessed study consistency. Owing to the heterogeneity in the methodologies among the reported studies, only narrative synthesis of the results was carried out.ResultsHaving identified 1032 publications, 131 articles were selected and 25 articles met the inclusion criteria and had sufficient methodological consistency to be included. Prevalence estimates of tinnitus range from 4.7% to 46% in the general paediatric population and among children with normal hearing, and from 23.5% to 62.2% of population of children with hearing loss. Reported prevalence ranged from 6% to 41.9% when children with hearing loss and normal hearing were both included. The prevalence of hyperacusis varied from 3.2% to 17.1%.ConclusionsData on prevalence vary considerably according to the study design, study population and the research question posed. The age range of children studied was varied and a marked degree of variation between definitions (tinnitus, hyperacusis) and measures (severity, perception, annoyance) was observed. The lack of consistency among studies indicates the necessity of examining the epidemiology of tinnitus and hyperacusis in children and adolescents with a set of standardised criteria.Trial registration numberCRD42014013456.

Objective To investigate the association between long term residential exposure to road traffic and railway noise and risk of incident dementia. Design Nationwide prospective register based cohort study. Setting Denmark. Participants 1 938 994 adults aged ≥60 years living in Denmark between 1 January 2004 and 31 December 2017. Main outcome measures Incident cases of all cause dementia and dementia subtypes (Alzheimer’s disease, vascular dementia, and Parkinson’s disease related dementia), identified from national hospital and prescription registries. Results The study population included 103 500 participants with incident dementia, and of those, 31 219 received a diagnosis of Alzheimer’s disease, 8664 of vascular dementia, and 2192 of Parkinson’s disease related dementia. Using Cox regression models, 10 year mean exposure to road traffic and railway noise at the most (L den max) and least (L den min) exposed façades of buildings were associated with a higher risk of all cause dementia. These associations showed a general pattern of higher hazard ratios with higher noise exposure, but with a levelling off or even small declines in risk at higher noise levels. In subtype analyses, both road traffic noise and railway noise were associated with a higher risk of Alzheimer’s disease, with hazard ratios of 1.16 (95% confidence interval 1.11 to 1.22) for road L den max ≥65 dB compared with <45 dB, 1.27 (1.22 to 1.34) for road L den min ≥55 dB compared with <40 dB, 1.16 (1.10 to 1.23) for railway L den max ≥60 dB compared with <40 dB, and 1.24 (1.17 to 1.30) for railway L den min ≥50 dB compared with <40 dB. Road traffic, but not railway, noise was associated with an increased risk of vascular dementia. Results indicated associations between road traffic L den min and Parkinson’s disease related dementia. Conclusions This nationwide cohort study found transportation noise to be associated with a higher risk of all cause dementia and dementia subtypes, especially Alzheimer’s disease.