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 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
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Noise & Hypertension
Sbihi, et al., Occup Environ Med 2008;65:643–646
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Sawmill Cohort: Noise
and AMI
Davies et al., 2005, Epidemiology, 16:25-32
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Sawmill Cohort: Noise and AMI
Davies et al., 2005, Epidemiology, 16:25-32
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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
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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
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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
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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
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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
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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)
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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
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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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