Basner, Dr Mathias et al. Auditory and Non-auditory Effects of Noise on Health

REVIEW October 30, 2013

Unit for Experimental Psychiatry, Division of Sleep and Chronobiology, Department of Psychiatry, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA

Mathias Basner, Wolfgang Babisch, Adrian Davis, Mark Brink, Charlotte Clark, Sabine Janssen, Stephen Stansfeld

Noise is pervasive in everyday life and can cause both auditory and non-auditory health effects. Noise-induced hearing loss remains highly prevalent in occupational settings, and is increasingly caused by social noise exposure (eg, through personal music players). Our understanding of molecular mechanisms involved in noise-induced hair- cell and nerve damage has substantially increased, and preventive and therapeutic drugs will probably become available within 10 years. Evidence of the non-auditory effects of environmental noise exposure on public health is growing. Observational and experimental studies have shown that noise exposure leads to annoyance, disturbs sleep and causes daytime sleepiness, affects patient outcomes and staff performance in hospitals, increases the occurrence of hypertension and cardiovascular disease, and impairs cognitive performance in schoolchildren. In this Review, we stress the importance of adequate noise prevention and mitigation strategies for public health.

Introduction

Evolution has programmed human beings to be aware of sounds as possible sources of danger. Noise, defined as unwanted sound, is a pollutant whose effects on health have been neglected, despite the ability to precisely measure or calculate exposure from peak levels or energy averaged over time (panel 1, figure 1). Although people tend to habituate to noise exposure, degree of habituation differs for individuals and is rarely complete. If exposure to noise is chronic and exceeds certain levels, then negative health outcomes can be seen. Health effects were first recognised in occupational settings, such as weaving mills, where high levels of noise were associated with noise-induced hearing loss.

Occupational noise is the most frequently studied type of noise exposure. Research focus has broadened to social noise (eg, heard in bars or through personal music players) and environmental noise (eg, noise from road, rail, and air traffic, and industrial construction). These noise exposures have been linked to a range of non-auditory health effects including annoyance, sleep disturbance, cardiovascular disease, and impairment of cognitive performance in children.

The health effects of noise from entertainment venues and from neighbours are elusive, but nevertheless, cause many complaints to local authorities. The meaning attributed to sounds might affect our response to them—eg, the response to aircraft noise might differ between an airport employee and a resident who fears long-term health consequences due to the noise exposure. Noise is pervasive in urban environments and the availability of quiet places is decreasing. In the European Union, about 56 million people (54%) living in areas with more than 250 000 inhabitants are exposed to road traffic noise of more than average LDEN 55 dB per year, which is thought to be risky to health. Thus, understanding of occupational and environmental noise is important for public health. In this Review, we summarise knowledge and research related to noise expo- sure and both auditory and non-auditory health effects.

Subjects covered in this section:

Auditory Health Effects

Noise-induced hearing loss
Occupational noise-induced hearing loss
Social noise exposure
Noise-induced hearing loss and age
Scientific advances and therapeutic strategies
Diagnosis of noise-induced hearing loss

Non-auditory Health Effects

Introduction

The most investigated non-auditory health endpoints for noise exposure are perceived disturbance and annoyance, cognitive impairment (mainly in children), sleep disturbance, and cardiovascular health. WHO estimated that in high-income western European countries (population about 340 million people), at least 1 million healthy life- years (disability-adjusted life-years) are lost every year because of environmental noise (figure 2).

Subjects covered in this section

Annoyance
Cardiovascular disease
Cognitive performance
Sleep disturbance (see below)
Hospital noise

Sleep Disturbance

Sleep disturbance is thought to be the most deleterious non-auditory effect of environmental noise exposure (figure 2), because undisturbed sleep of a sufficient length is needed for daytime alertness and performance, quality of life, and health.5,14 Human beings perceive, evaluate, and react to environmental sounds, even while asleep.64

Maximum sound pressure levels as low as LAmax33 dB can induce physiological reactions during sleep including autonomic, motor, and cortical arousals (eg, tachycardia, body movements, and awakenings).5,65 Whether noise will induce arousals depends not only on the number of noise events and their acoustical properties,2 but also on situational moderators (such as momentary sleep stage66) and individual noise susceptibility.64 

Elderly people, children, shift-workers, and people with a pre-existing (sleep) disorder are thought of as at-risk groups for noise- induced sleep disturbance.5 Repeated noise-induced arousals interfere with sleep quality through changes in sleep structure, which include delayed sleep onset and early awakenings, reduced deep (slow-wave) and rapid eye movement sleep, and an increase in time spent awake and in superficial sleep stages.2,66 However, these effects are not specific for noise,67 and generally less severe than those in clinical sleep disorders such as obstructive sleep apnoea.68 Short-term effects of noise-induced sleep disturbance include impaired mood, subjectively and objectively increased daytime sleepiness, and impaired cognitive performance.69,70 Results of epidemiological studies indicate that nocturnal noise exposure might be more relevant for the creation of long-term health out- comes such as cardiovascular disease than is daytime noise exposure,71 probably because of repeated autonomic arousals that have been shown to habituate to a much lesser degree to noise than other—eg, cortical—arousals.2 In 2009, WHO published the Night Noise Guidelines for Europe, an expert consensus mapping four noise exposure groups to negative health outcomes ranging from no substantial biological effects to increased risk of cardiovascular disease (panel 2).72 WHO regards average nocturnal noise levels of less than LAeq,outside 55 dB to be an interim goal and 40 dB a long-term goal for the prevention of noise-induced health effects.

Published Online October 30, 2013 http://dx.doi.org/10.1016/ S0140-6736(13)61613-X

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