Interventions for preventing NIHL · Interventions for preventing NIHL a Cochrane Systematic Review Jos Verbeek, Erik Kateman, Thais Morata, ... Verbeek NHCA 2013.ppt [Compatibility

Interventions for preventing NIHLa Cochrane Systematic Review

Jos Verbeek, Erik Kateman, Thais Morata, Wouter Dreschler, Christina Mischke

© Finnish Institute of Occupational Health – www.ttl.fi

Can / do we prevent NIHL?

• Technically Yes:

• immediate effects of saw blades measured by IFA, Germany

• With noise-reduced saw blades, high sound level reductions can be achieved:

• Up to approx. 6 dB(A) with the saw idling• Up to approx. 6 dB(A) when sawing aluminium• Up to approx. 7 dB(A) when sawing wood panels• Up to approx. 11 dB(A) when sawing plastic profiles• Up to approx. 12 dB(A) when sawing hardwood

edge-banding

25.2.2013 1Esittäjän nimi 1


Can / do we prevent NIHL?

• Implementation of technical measures ???

25.2.2013 2Esittäjän nimi


Cochrane Review

• Objective:

• To assess the effectiveness of non-pharmaceutical interventions for preventing occupational noise exposure and occupational hearing loss compared to no or alternative interventions

• Set out in 2006, first published in 2009, updated in 2012



Cochrane Colaboration

• International network dedicated to reviewing the effects of health care interventions.

• Well elaborated methods for systematic reviews published in electronic journal named Cochrane Library

• Named after Archie Cochrane, British epidemiologist

• OSH review group specialised in OSH interventions since 2004

22.2.2013 4Jos Verbeek


What to prevent?

• Noise Exposure• Immediate noise attenuation

• TTS, MIRE, REAT• long-term (years)

• dB(A)

• Occupational NIHL:• Less loss / decrease over time

• All NIHL measures considered equivalent• Change at 4 kHz (last minus first measurement)• Standard Threshold Shift (STS)

• any definition / frequency / ear(s)



What kind of interventions?

• Engineering and administrative controls

• Technical noise reduction measures

• Hearing Protection Devices

• Hearing Loss Prevention Programmes (HLPP)



What kind of evidence?

• Evaluation studies that control for changes over time

• Randomised Controlled Trials

• Controlled Before After Study

• incl control group without exposure

• Interrupted Time Series



Results of review

• 25 included studies

• Design:3 RCTs, 1 quasi-RCT, 19 CBAs, 2 ITSs

• Interventions:2 Noise-reduction, 8 hearing protection, 15 HLPP

• Outcomes:• long-term

2 dB(A), 8 STS, 9 mean hearing loss, • short-term

2 TTS, 2 REAT, 2 MIRE



Risk of bias / quality



Results noise reduction

• Noise reduction measures• 1 study (Joy 2007) effect of regulation

• Uncontrolled case studies• Noise measurements very unreliable or quality

unreported.



Results Hearing Protection

• Hearing Protection immediate effects

• all HP reduced noise levels

• additional effect of noise cancellation

• For ear plugs instruction crucial • (Park 1991)



Results HLPP long term

• HLPP versus minor alternative (audiometry)(4)

• Berg 2009: no effect after 3 /16 year follow-up on STS

• Rabinowitz 2011: ± effect of noise exp monitoring on HL

• Seixas 2011: no effect of noise exp monitoring on noise

• Seixas 2011: no effect of info on noise levels

• HLPP well implemented versus less well (5)

• RR = 0.4 (95% CI 0.23 to 0.69) for STS • (Adera 1993/2000, Brink 2002, Simpson 1994)

• similar in Heyer 2011

22.2.2013 12Jos Verbeek


Results HLPP vs No Exposure> 5 year follow-up


Study or SubgroupPell 1973Gosztonyi 1975Hager 1982Lee-Feldstein 1993

Total (95% CI)Heterogeneity: Tau² = 0.00; Chi² = 2.53, df = 3 (P = 0.47); I² = 0%Test for overall effect: Z = 0.97 (P = 0.33)

Std. Mean Difference0.020.15-0.1

0.2913

SE0.058673

0.16840.31630.1858

Total3997127

111

608

Total1173

7116

363

1623

Weight79.6%9.7%2.7%7.9%

100.0%

IV, Random, 95% CI0.02 [-0.09, 0.13]0.15 [-0.18, 0.48]

-0.10 [-0.72, 0.52]0.29 [-0.07, 0.66]

0.05 [-0.05, 0.15]

Year1973197519821993

HLP Program Non-exposed Std. Mean Difference Std. Mean DifferenceIV, Random, 95% CI

-0.5 -0.25 0 0.25 0.5Favours HLPP Favours Non-exposed

Study or SubgroupPell 1973Gosztonyi 1975Hager 1982Lee-Feldstein 1993

Total (95% CI)Heterogeneity: Tau² = 0.00; Chi² = 1.17, df = 2 (P = 0.56); I² = 0%Test for overall effect: Z = 1.48 (P = 0.14)

Std. Mean Difference0.020.15-0.1

0.2913

SE0.058673

0.16840.31630.1858

Total3997127

111

209

Total1173

7116

363

450

Weight0.0%

47.5%13.5%39.0%

100.0%

IV, Random, 95% CI0.02 [-0.09, 0.13]0.15 [-0.18, 0.48]

-0.10 [-0.72, 0.52]0.29 [-0.07, 0.66]

0.17 [-0.06, 0.40]

Year1973197519821993

HLP Program Non-exposed Std. Mean Difference Std. Mean DifferenceIV, Random, 95% CI

-0.5 -0.25 0 0.25 0.5Favours HLPP Favours Non-exposed

Plus Muhr 2006 and Davies 2008


Conclusions

• Low quality evidence

• use of HP devices probably prevents NIHL

• unclear which components of HLPP effective

• compared to non-exposed, HLPP do not prevent NIHL well enough (still > 85 dB(A) rísk of NIHL)

• Practice• better implementation needed (noise reduction)

• Research• RCTs possible; need to test specific HLPP components


© Finnish Institute of Occupational Health – www.ttl.fi 25.2.2013 15Esittäjän nimi

Thank You!

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Interventions for preventing NIHL · Interventions for preventing NIHL a Cochrane Systematic Review Jos Verbeek, Erik Kateman, Thais Morata, ... Verbeek NHCA 2013.ppt [Compatibility