Pollution, lungs and vascular disease

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Pollution, lungs and vascular disease

• Jon Ayres
• Institute of Occupational Environmental
  Medicine
• University of Birmingham
• j.g.ayres_at_bham.ac.uk

RCPSG Triennial Conference 6th November 2008
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Outdoors and indoors
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Exposure to air pollution
HEALTH EFFECT
CONTROL
EXPOSURE Time, person, place
EMISSIONS
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Controlling outdoor air pollution

• Exposure driven event
• London smog, 1952

HEALTH EFFECT
CONTROL
EXPOSURE Time, person, place
EMISSIONS
Clean Air Act, 1956
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Air pollution and health

• Pollutants
• Particles
• vehicles, power stations, industry, agriculture,
  surface dust, sea spray
• Measured as PM10/2.5 etc or BS
• Nitrogen dioxide
• vehicles
• Sulphur dioxide
• power stations, vehicles
• Ozone
• sunlight on vehicle emissions
• Carbon monoxide
• vehicles

• Impacts
• Short term (i.e. day to day)
• deaths
• hospital admissions
• symptoms/QoL
• work/school loss
• Long term
• chronic mortality
• initiation/ worsening of chronic disease QoL
• Latent
• cancer

• Lung disease
• Heart disease
• Effects on fetus and neonate
• Cancer
• CNS disease

lead, carcinogens etc
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Time-series estimates (up to 2006) Respiratory
mortality and PM10 (n47)
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Time-series estimates (up to 2006) Respiratory
mortality and PM10 (n47)
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Time-series estimates (up to 2006)Daily
cardiovascular mortality and PM10 (n177)
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Long-term exposures

• Longitudinal studies best
• 6 Cities study
• ACS study
• NL study
• Numbers of deaths, life expectancy or life lost?
• Measures of lesser severity?
• Reduced lung growth
• Respiratory symptoms
• Increased disease prevalence (e.g. COPD, IHD)

Dockery et al NEJM 19933291753
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Coefficients for quantification of effects of
long-term exposures

• change in death rates per 10µg/m3 change in
  annual average PM2.5
• All-cause mortality
• Best estimate 6 (2-11)
• Cardio-pulmonary mortality
• Best estimate 9 (3-16)
• Lung cancer mortality
• Best estimate 8 (1-16)

COMEAP 2008
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(Some) issues

• Heterogeneity of response
• Even allowing for confounders
• Why cardiovascular effects?
• Why are there such immediate effects when higher
  particle exposures (cigarette smoke, biomass
  exposure) do not apparently have such an effect?
• What mechanisms might be in play?
• How much does this cost?
• and are interventions cost-effective?

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Particle size, shape and content
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The inflammatory hypothesis

• Ultrafine particles cause alveolar inflammation
• This leads to mediator release
• This, in turn, in susceptible individuals,
  exacerbates respiratory illness and promotes
  blood coagulability

Seaton et al Lancet 1995345176-8
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Particle size matters
Neutrophils in rat BAL 24h after instillation of
1mg latex particles of various sizes
but consider content e.g. metals, free radicals
Donaldson, 2003
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Effects of diesel exhaust on ST-segment change
and fibrinolytic activity (t-PA) in IHD
Mills et al NEJM 20073571075-82
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Effects on HRV of carbon and SO2 exposure in
patients with severe coronary artery disease
BUT - No significant changes from baseline in
any indices of HRV following exposure to air,
carbon or SO2 in patients with IHD
Routledge et al. Heart 200692220-7.
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Particles, IHD and COPD
INHALED PARTICLE LOAD
AIRWAYS
LOWER

• Oedema
• Mucus
• Spasm

Worsening airflow obstruction
Worsening cellular function
Inc. HYPOXIA inc. CO2
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Particles, IHD and COPD
INHALED PARTICLE LOAD
AIRWAYS
LOWER
UPPER

• ANS effects
• Arrhythmia

• Oedema
• Mucus
• Spasm

Worsening airflow obstruction
LV decompensation
Worsening cellular function
Inc. HYPOXIA inc. CO2
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Particles, IHD and COPD
INHALED PARTICLE LOAD
AIRWAYS
ALVEOLI
LOWER
UPPER
Pro-thrombotic effects Endothelial activation

• Local
• Oedema
• wall
• airspace

• ANS effects
• Arrhythmia

• Oedema
• Mucus
• Spasm

Coronary circulation
Worsening airflow obstruction
LV decompensation
Worsening cellular function
Inc. HYPOXIA inc. CO2
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• Exposure to particles generated outdoors is
  associated with cardio-pulmonary disease indices
• So how does this feed into responses to indoor
  exposures to particles?

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(No Transcript)
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ETS exposure reduction following the Scottish
smoking ban
Semple et al Ann Occup Hyg 200751571-80

• Two months after ban
• PM2.5 levels fell from around 250 mg/m3 to around
  20 mg/m3
• an average fall of 86
• Levels reduced in all 53 post-legislation visits
• Personal exposures down by 86
• PM2.5 salivary cotinine

US EPA ambient AQS for PM2.5 gt65 µg/m3
unhealthy gt250 µg/m3 hazardous
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Health improvements in bar-workers one year
post-ban
Ayres et al OEM 2008 (in press)
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Symptom improvements one year post-ban

• Baseline 1 year p
• All subjects
• Any respiratory Sx 69 57 0.02
• Any sensory Sx 75 64 0.02
• Non-smokers
• Phlegm 32 14 0.011
• Eye irritation 44 18 0.001
• Smokers
• Wheeze 48 31 0.006
• Shortness of breath 42 29 0.038
• Eye irritation 35 25 0.02

Ayres et al OEM 2008 (in press)
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Reduction in admissions from acute coronary
syndrome post ban
Overall reduction ACS admissions 17
Pell et al NEJM 2008359482-91
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ETS exposure

• Is side-stream smoke more toxic than we thought?
• Likely that particle content as important as
  particle size (perhaps more)

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Indoor air pollution in the developing world

• Use of biomass
• 3 bn of the worlds population exposed
• 5th in burden of disease standings
• Causes
• Chronic bronchitis/COPD
• ALRI in children
• Lung cancer (coal smoke)
• Cataract

Wood, crop residues, animal dung, coal plus
much else..
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Exposures PM2.5 20 hour means
United Kingdom oudoor PM2.5 5-20 µg/m3
US EPA AQI hazardous 250µg/m3
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Respiratory morbidity

• COPD
• 19.9 rural, 10.9 urban
• In LLNS
• COPD
• 8.5 rural, 6.3 urban
• Wheeze ever
• 18.9 rural, 7.0 urban
• Morning cough
• 3.4 rural, 4 urban
• Morning phlegm
• 2.4 rural, 10.1 urban

• Cardiovascular morbidity
• Blood pressure higher in urban
• dwellers
• Exertional chest pain more in
• rural dwellers

Kurmi et al. ATS, Toronto, 2008
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Biomass intervening with stoves

• Xuanwei county, PRC
• Subjects
• 20 453 born into houses with unvented coal stoves
• 16 606 subsequently changed to stoves with
  chimneys
• Used smoky coal

Chapman et al BMJ 20053311050-2
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Impact of stoves on COPD Chapman et al BMJ
20053311050-2

• Those with chimneys had less COPD
• OR 0.58 (0.49 0.70)
• Improvements appeared around ten years after
  installation

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Exposure to outdoor air pollution
HEALTH EFFECT
CONTROL
EXPOSURE Time, person, place
EMISSIONS
Cardio-respiratory mortality morbidity
AQ standards
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Exposure to outdoor air pollution
HEALTH EFFECT
CONTROL
EXPOSURE Time, person, place
EMISSIONS
Cardio-respiratory mortality morbidity
AQ standards
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Exposure to indoor air pollution
Cardio-respiratory mortality morbidity
Legislation for public areas
HEALTH EFFECT
CONTROL
EXPOSURE Time, person, place
EMISSIONS
COPD, ALRI ? CVS disease
Advice for local control
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Stone crushing site
But its much more difficult than
this.. Especially when it comes to complex
exposures