Background: This is an update of a Cochrane Review first published in The Cochrane Library in Issue 2, 2006 and previously updated in 2009.Noise-induced hearing loss can be prevented by eliminating or lowering noise exposure levels. Where the source of the noise cannot be eliminated, workers have to rely on hearing protection equipment. Several trials have been conducted to study the effectiveness of interventions to influence the wearing of hearing protection.
Objectives: To evaluate the effectiveness of interventions to enhance the wearing of hearing protection among persons regularly exposed to high noise levels.
Search methods: We searched the Cochrane Ear, Nose and Throat Disorders Group Trials Register; the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2011, Issue 1); PubMed; EMBASE; CINAHL; Web of Science; BIOSIS Previews; Cambridge Scientific Abstracts; ICTRP and additional sources for published and unpublished trials. The date of the most recent search was 8 April 2011.
Selection criteria: We included studies if they had a randomised design, if they were among noise exposed (> 80 dB(A)) persons, if they included an intervention to promote the wearing of hearing protection (compared to another intervention or no intervention), and if the outcome measured was the amount of use of hearing protection or a proxy measure thereof.
Data collection and analysis: Two authors selected relevant trials, assessed risk of bias and extracted data.
Main results: Seven studies, involving 4670 participants, were included.A computer-based intervention lasting 30 minutes, tailored to the risk of an individual worker, was not found to be more effective than a video providing general information among workers, around 80% of whom already used hearing protection.A four-year school-based hearing loss prevention programme found that the intervention group was twice as likely to wear some kind of hearing protection as the control group that received a baseline hearing test and two additional tests at years two and three.We conducted two meta-analyses for the comparisons 'tailored strategy (the use of communication or other types of interventions that are specific to an individual or a group and aim to change behaviour) versus non-tailored strategy' and 'tailored strategy versus a commercial video on the use of hearing protection' to look at mean percentage use of hearing protective devices (HPDs), that showed improvement in the mean use of HPDs for the tailored group. A meta-analysis of the comparison 'mixed interventions' (classroom instruction, distribution of HPDs, mailings, noise level assessments and audiometric testing) versus control (audiometric testing alone) also showed improvement in self reported use of HPDs when shooting firearms.Tailored education showed an improvement in HPD use of 8.3% versus targeted education (6.1%).
Authors' conclusions: The evidence found in this review shows that some interventions improve the mean use of hearing protection devices compared to non-intervention. Future trials should have standard outcomes and interventions to allow the combining of results in meta-analysis.