Noise & Cardiovascular Disease

Old Topics – New Insights

Noise Exposure – What's New? Hugh W Davies, PhD, CIH

School of Environmental Health

Noise – a very old topic…

OEMAC Conference, Saskatoon, 2010

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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 OEMAC Conference, Saskatoon, 2010

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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 sleep o Awakenings subside, but heart rate increase does not extinguish (Greifan et al, 2008)

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Epidemiological evidence: The Sawmill Cohort Study

o o o o

27,000 male sawmill workers in 14 BC Mills Employed 1950 – 1998, > 1 year Linked to vital stats, hospital discharge and MSP Retrospective noise exposure assessment – N=1900 measurements

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Noise & Hypertension

Sbihi, et al., Occup Environ Med 2008;65:643–646 OEMAC Conference, Saskatoon, 2010

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Noise & Hypertension

Sbihi, et al., Occup Environ Med 2008;65:643–646 OEMAC Conference, Saskatoon, 2010

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Sawmill Cohort: Noise and AMI

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

OEMAC Conference, Saskatoon, 2010

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Sawmill Cohort: Noise and AMI

Davies et al., 2005, Epidemiology, 16:25-32 OEMAC Conference, Saskatoon, 2010

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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 Gan, WQ, et al, In press, OEM, 2010 OEMAC Conference, Saskatoon, 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 OEMAC Conference, Saskatoon, 2010

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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, nonoccupational exposures

o Finding – 42,282 S’s; 5919 STS – RR for HCP = 0.5 • 0.7 – HPD • 0.7 – HCP participation Davies et al, Am J Ind Med (51):923 OEMAC Conference, Saskatoon, 2010

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UBC Barriers to Noise Controls study o o o o o o o o o

Exposure to noise expected, accepted Over reliance on HPD Poor knowledge of engineered noise controls Engineered noise controls considered impracticable Low risk perception for noise Poor knowledge of regulations Individual responsibility overemphasized Communication issues Noise given low priority OEMAC Conference, Saskatoon, 2010

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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

Babisch, 2008

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Noise, air pollution & CHD o Vancouver study analyses in progress – BAQS o All adults 45-85, – N=450,000

o 4-year follow up o LUR air pollution exposure data o Co-variates – Age, gender – SES (from census) – Co-morbidity

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BAQS – Road Proximity Study, CHD

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

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UBC Vancouver Noise Mapping

Leq, 24

PM2.5

NO

BC

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 OEMAC Conference, Saskatoon, 2010

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To summarize…

o Noise remains one of our most ubiquitous occupational health hazards o Claims – incidence? – remain high o Lack of will to reduce exposure o Limited data on effectiveness of hearing conservation programs o 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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