There is very low-quality evidence that implementation of stricter legislation can reduce noise levels in workplaces. Controlled studies of other engineering control interventions in the field have not been conducted. There is moderate-quality evidence that training of proper insertion of earplugs significantly reduces noise exposure at short-term follow-up but long-term follow-up is still needed.There is very low-quality evidence that the better use of hearing protection devices as part of HLPPs reduces the risk of hearing loss, whereas for other programme components of HLPPs we did not find such an effect. The absence of conclusive evidence should not be interpreted as evidence of lack of effectiveness. Rather, it means that further research is very likely to have an important impact.

There is low quality evidence that legislation can reduce noise levels in workplaces.The effectiveness of hearing protection devices depends on their proper use. There is contradictory evidence that HLPPs are effective in the long-term. Even though case studies show that substantial reductions can be achieved, there is no evidence that this is realised in practice. Better implementation and reinforcement is needed.Better evaluations of technical interventions and long-term effects are needed. Audiometric and noise measurement data are potentially valuable for such studies.

Objective To assess the effectiveness of interventions for preventing occupational noise exposure or hearing loss compared to no intervention or alternative interventions. Design We searched biomedical databases up to 25 January 2012 for randomized controlled trials (RCT), controlled before-after studies and interrupted time-series of hearing loss prevention among workers exposed to noise. Study sample We included 19 studies with 82 794 participants evaluating effects of hearing loss prevention programs (HLPP). The overall quality of studies was low to very low, as rated using the GRADE approach. Results One study of stricter legislation showed a favorable effect on noise levels. Three studies, of which two RCTs, did not find an effect of a HLPP. Four studies showed that better use of hearing protection devices in HLPPs decreased the risk of hearing loss. In four other studies, workers in a HLPP still had a 0.5 dB greater hearing loss at 4 kHz (95% CI – 0.5 to 1.7) than non-exposed workers. In two similar studies there was a substantial risk of hearing loss in spite of a HLPP. Conclusions Stricter enforcement of legislation and better implementation of HLPPs can reduce noise levels in workplaces. Better evaluations of technical interventions and long-term effects are needed.

There is low quality evidence that implementation of stricter legislation can reduce noise levels in workplaces. Even though case studies show that substantial reductions in noise levels in the workplace can be achieved, there are no controlled studies of the effectiveness of such measures. The effectiveness of hearing protection devices depends on training and their proper use. There is very low quality evidence that the better use of hearing protection devices as part of HLPPs reduces the risk of hearing loss, whereas for other programme components of HLPPs we did not find such an effect. Better implementation and reinforcement of HLPPs is needed. Better evaluations of technical interventions and long-term effects are needed.

Purpose Assess the effect of non-pharmaceutical interventions at work on noise exposure or occupational hearing loss compared to no or alternative interventions. Research strategies Pubmed, Embase, Web of Science, OSHupdate, Cochrane Central and Cumulative Index to Nursing and Allied Health Literature (CINAHL) were searched. Selection criteria 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. Data analysis Cochrane methods for systematic reviews, including meta-analysis, were followed. Results 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). Conclusion 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.