Study of lung cancer due to airborne lead in the us
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Study of lung cancer due to airborne lead in the US. Lead is a heavy metal found in the air Historically lead came motor vehicles. After phase out of leaded gasoline, a major source is now lead smelters People are exposed to lead by breathing, and it accumulates in the blood

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Study of lung cancer due to airborne lead in the us
Study of lung cancer due to airborne lead in the US

  • Lead is a heavy metal found in the air

  • Historically lead came motor vehicles. After phase out of leaded gasoline, a major source is now lead smelters

  • People are exposed to lead by breathing, and it accumulates in the blood

  • Health impacts are particularly a concern for children, and they include: damaged organs, nervous system, lower IQ, etc

  • Question: What is the health impact of airborne lead on lung cancer?


Some standards and statistics
Some standards and statistics

  • National Standard for airborne lead

    • Quarterly average < 1.5 mg/m3

  • OSHA standard for blood lead

    • Concentration in blood < 25mg/100ml

  • National health statistics for lung cancer

    • 1999 lung cancer incidence rate = 55 (per 100,000)

    • 1999 lung cancer incidence = 150,000


Model based health impact assessment
Model-based health impact assessment

f(PbA) E[PbA]

of lung cancer due to exposure to lead

Spatiotemporal monitoring

BME spatiotemporal mapping

Exposure assessment, PbA(s,t)

Stochastic Toxicokinetics modelling

Log PbB=a+b log PbA

Dose assessment, PbB(s,t)

Epidemiological research /biostatistics

D= dt PbB(t)

SIR=1+(1/ h -1)(1-exp-3D/Ds)

H=(SIR-1)h

Health effect assessment, H(s,t)

Demographics, population p(s,t)

L=Hp

Population impact assessment, L(s,t)

Uncertainty evaluation


Exposure to airborne lead in the us
Exposure to airborne lead in the US

BME median estimate of airborne lead concentration (mg/m3)


Toxicokinetic lead model
Toxicokinetic lead model

Log(PbB)=1.9652+0.2356 log PbA (Lai et al., JIAOEH, 1997)


Dose of lead in the blood
Dose of lead in the blood

due to exposure to airborne lead

BME median estimate of blood lead concentration (mg/100ml)


Dose of lead in the blood1
Dose of lead in the blood

due to exposure to airborne lead

BME 16% quantile of blood lead concentration (mg/100ml)

We expect people had at least this amount in the blood with only a 16% chance of being wrong


Epidemiology study for lung cancer
Epidemiology study for lung cancer

Cumulative lead dose in relation to Standardized Incidence Rate (SIR) of lung cancer (Lundstrom et al., SJWEH, 1997)


Dose health response model
Dose / Health response model

Proposed model of health effect:

D= dt PbB(t)

SIR=1+(1/ h -1)(1-exp-3D/Ds)

H=(SIR-1)h

  • D = cumulated dose

  • = expected lung cancer incidence rate

  • Ds = saturation (lethal) dose


Lung cancer incidence rate
Lung cancer incidence rate

due to exposure to airborne lead

BME median estimate of lung cancer incidence rate (per 100,000) due to exposure to airborne lead from 1984 till year t)


Lung cancer incidence density
Lung cancer incidence density

due to exposure to airborne lead

BME median estimate of lung cancer incidence density (per sqmi) due to exposure to airborne lead from 1984 till year t)



Dose of lead in the blood2
Dose of lead in the blood

due to exposure to airborne lead


Lung cancer incidence rate1
Lung cancer incidence rate

due to exposure to airborne lead


Total incidence of lung cancer
Total incidence of lung cancer

due to exposure to airborne lead


Toxicokinetic sensitivity analysis
Toxicokinetic sensitivity analysis

Lead model 2: Log(PbB)=a’+0. 6 log PbA


Toxicokinetic sensitivity analysis1
Toxicokinetic sensitivity analysis

Total incidence of lung cancer due to exposure to airborne lead using toxicokinetic models 1 and 2


Conclusion for airborne lead study
Conclusion for airborne lead study

  • Model-based exposure mapping and health impact assessment provides a framework to assess the impact of airborne lead pollution on lung cancer in the US

  • The framework allows for an uncertainty evaluation

  • The analysis estimates a total incidence of 32,500+/-2,000 cases of lung cancer due to exposure from 1984 to 2000.

  • A sensitivity analysis shows that extrapolation of toxicokinetic models to low dose is a critical

  • Future work should consider stochastic toxicokinetic modelling


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