Abstract
Assess the effect of non-pharmaceutical interventions at work on noise exposure or occupational hearing loss compared to no or alternative interventions. Pubmed, Embase, Web of Science, OSHupdate, Cochrane Central and Cumulative Index to Nursing and Allied Health Literature (CINAHL) were searched. Randomized Controlled Trials (RCT), Controlled Before-After studies (CBA) and Interrupted Time-Series studies (ITS) evaluating engineering controls, administrative controls, personal hearing protection devices, and hearing surveillance were included. Case studies of engineering controls were collected. Cochrane methods for systematic reviews, including meta-analysis, were followed. 29 studies were included. Stricter legislation can reduce noise levels by 4.5 dB(A) (very low-quality evidence). Engineering controls can immediately reduce noise (107 cases). Eleven RCTs and CBA studies (3725 participants) were evaluated through Hearing Protection Devices (HPDs). Training of earplug insertion reduces noise exposure at short term follow-up (moderate quality evidence). Earmuffs might perform better than earplugs in high noise levels but worse in low noise levels (very low-quality evidence). HPDs might reduce hearing loss at very long-term follow-up (very low-quality evidence). Seventeen studies (84028 participants) evaluated hearing loss prevention programs. Better use of HPDs might reduce hearing loss but other components not (very low-quality evidence). Hearing loss prevention and interventions modestly reduce noise exposure and hearing loss. Better quality studies and better implementation of noise control measures and HPDs is needed.
Highlights
Worldwide millions of workers are exposed to noise levels that increase their risk of hearing disorders[1]
Confounding opposes the direction of the effect; aFinal grading of quality of evidence, between brackets domain that led to down/upgrading the quality; Caption: N = number of; Interrupted Time-Series studies (ITS) = interrupted timeseries analysis; Randomized Controlled Trials (RCT) = randomized controlled trial; Controlled Before-After studies (CBA) = controlled before after study; na= not applicable; 1 study = only one study available and impossible to assess consistency or publication bias
One CBA study found no reduction of the rate of hearing loss (MD -0.82 dB per year for a hearing loss prevention programs (HLPPs) that provided regular personal noise exposure information compared to a program that did not provide such information (Table 8)
Summary
Worldwide millions of workers are exposed to noise levels that increase their risk of hearing disorders[1]. A systematic review of studies that evaluated interventions to reduce occupational exposure to noise or to decrease occupationally induced hearing loss is warranted. To assess the effectiveness of non-pharmaceutical interventions for preventing occupational noise exposure or occupational hearing loss compared to no or alternative interventions. This is an abridged version of the second update of a Cochrane Review originally published in 2009 based on the methods originally described in the review protocol[3]. Systematic searches were conducted combining search words for the occupational setting, exposure, interventions, and effects on noise or hearing loss. Ratings are interpreted as: 1) high-quality evidence is unlikely to change, moderate-quality evidence; 2) further research is likely to have an impact and may change estimates, low-quality evidence; 3) further research is very likely to have an important impact, and very low-quality evidence provides very uncertain effects estimates
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