Old Topics – New Insights

Noise Exposure – What's New?

Hugh W Davies, PhD, CIH

School of Environmental Health

Noise – a very old topic…

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Who is exposed?Occupationally

o One of the most ubiquitous of occupational hazards– No routine surveillance– Loss of data

o Recent study in US by Tak, et al (2009)– Self-reported exposure (NHANES)– 22 million exposed

o Rule of 1/10th’s– ~ 2.2 million in Canada– ~ 200, 000 in BC

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Who is exposed?Environmentally

o Transportation noise major source of chronic exposure– Road traffic: noise 2 million > 65 dBA– Aircraft noise: 50,000 > 65 dBA

• Health Canada

o 7.9% very or extremely annoyed by noise– 40-50% of those, transport noise major factor– Less than 20% “not at all” bother by road traffic

• Michaud, 2008

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“Non-auditory” effects of Noise

– Annoyance– Sleep Disturbance– Hypertension– Ischemic Heart Disease– Learning problems– Accidents– Immune system– Effects on the fetus– Other psychiatric disorders

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Noise, stress,and CVD

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Experimental Evidence

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Don’t you just habituate?

o Response rapidly extinguished with repetition in lab– However, response elicited by superimposing a new

tone– Response more resilient if source unpredictable,

variable

o Noise-disturbed sleepo Awakenings subside, but heart rate increase does

not extinguish (Greifan et al, 2008)

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Epidemiological evidence: The Sawmill Cohort Study

o 27,000 male sawmill workers in 14 BC Millso Employed 1950 – 1998, > 1 yearo Linked to vital stats, hospital discharge and

MSPo Retrospective noise exposure assessment

– N=1900 measurements

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Noise & Hypertension

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Sbihi, et al., Occup Environ Med 2008;65:643–646

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Noise & Hypertension

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Sbihi, et al., Occup Environ Med 2008;65:643–646

Sawmill Cohort: Noise and AMI

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Davies et al., 2005, Epidemiology, 16:25-32

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Sawmill Cohort: Noise and AMI

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Davies et al., 2005, Epidemiology, 16:25-32

Hypertension in US Workers

o NHANES 1999-2004– 6307 participants– Self-reported noise exposure

o Outcomes– Self-report physician-diagnosed cardiovascular disease– Blood pressure monitoring/blood biochemistry

o Results• 2-3 fold risk for angina, AMI, all types of CHD, isolated

diastolic hypertension• Higher risk in workers under 50 years

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Gan, WQ, et al, In press, OEM, 2010

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Our hearing is a choice and dainty sense,And hard to mend, yet soon it may be marred……….

…… things that breed it most offense,Blows, fall and noise ……

The Medical Poem of Salerno, 1608

Burden of NIHL

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Do hearing conservation programs work?

o Weaknesses in most aspects of HCP’s

o Yet no broad-based evaluation of HCP’s

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UBC HCP Evaluation Study

o Examined 316,000 audiograms from 1979-96– Outcome: 10 dB STS (2,3 & 4 KHz) from baseline– Main indicator variables: participation in HCP, HPD– Co-variates: noise exposure, age, medical Hx, non-

occupational exposures

o Finding– 42,282 S’s; 5919 STS– RR for HCP = 0.5

• 0.7 – HPD• 0.7 – HCP participation

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Davies et al, Am J Ind Med (51):923

UBC Barriers to Noise Controls study

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o Exposure to noise expected, acceptedo Over reliance on HPDo Poor knowledge of engineered noise controlso Engineered noise controls considered

impracticableo Low risk perception for noiseo Poor knowledge of regulationso Individual responsibility overemphasizedo Communication issueso Noise given low priority

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‘The noise and clatter which makes conversation almost impossible on many streets of New York at the present time will be done away with, for horseless vehicles of all kinds are always noiseless or nearly so.’ Sci Am, 1890’s

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Traffic noise and CVD

OEMAC Conference, Saskatoon, 2010 22Babisch, 2008

Noise, air pollution & CHD

o Vancouver study analyses in progress – BAQSo All adults 45-85,

– N=450,000

o 4-year follow upo LUR air pollution exposure datao Co-variates

– Age, gender– SES (from census)– Co-morbidity

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BAQS – Road Proximity Study, CHD

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Gan, Tamburic, Davies et al, Epidemiology 2010;21: 642–649)

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UBC Vancouver Noise MappingUBC Vancouver Noise Mapping

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PM2.5 NO BC

Leq, 24 0.14 0.39 0.44

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Future Studies – Early Child Development

o Social and environmental factors influence of early child development– Collaboration with Human Early Learning Partnership

• Early Development Indictor (EDI)• Sociodemographic covariates

– BAQS birth cohort• All kids born 1999-2002• Maternal exposure• Childhood exposure• Perinatal health• Infant health

– Opportunity for life-course study of these early exposures

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To summarize…

o Noise remains one of our most ubiquitous occupational health hazards

o Claims – incidence? – remain higho Lack of will to reduce exposureo Limited data on effectiveness of hearing

conservation programso Noise has important “non-auditory” health

effects, including cardiovascular disease

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Acknowledgments

o Paul Demers, Murray Hodgson, Kay Teschke, Jean Shoveller, Mike Brauer

o Hind Sbihi, Musarrat Nahid, Amber Louie, Kim McLeod

o Sarah Chiarello, Kathleen McLean

o Christine Harrison, Heather Gillis

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Questions?

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