Arsenic and Nonmelanoma Skin Cancer in Slovakia

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Arsenic and Nonmelanoma Skin Cancer in Slovakia

• Beate Pesch
• Environmental Health Research Institute, Germany

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Part of the EU-funded Project EXPASCAN
Exposure to Arsenic and Cancer in Central
Eastern Europe

• www.icconsultants.co.uk/EXPASCAN.html

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PARTNERS Imperial College IC Consultants,
London, UK State Health Institutes, Prievidza,
Bankska Bystrica, SK Institute of Hygiene and
Epidemiology, Prague, CZ Environmental Health
Research Institute, Duesseldorf, D University of
Cluj, RO
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Objective

• Estimation of the risk of environmental arsenic
  exposure from power plant emissions for
  non-melanoma skin cancer (NMSC)

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Estimation of the risk of environmental arsenic
exposure

• Choose study design(s)
• Assess exposure
• Estimate risk
• Discuss confounders

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Arsenic and arsenic compounds

• Environmental Health Criteria (EHC) 2nd
  edition, 224 2001
• WHO, Geneva
• www.inchem.org

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Estimate by Distance to the Power Plant

• Environmental As exposure
• NMSC incidence
• Associate As exposure with NMSC risk control
  for covariates

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ENO Power Plant (Slovakia)
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Environmental Arsenic Exposure

• Historical As exposure
• Air pollution modelling
• (Colvile et al. 2001)
• Current As exposure
• Measurement of As in soil, house dust
• (Keegan et al. 2002)

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Arsenic Emissions (tons/year) of the ENO Power
Plant, Slovakia
200
As t/a
100
0
1953
1960
1970
1980
1990
1999
Year
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Arsenic (mg/g) in soil 1999 by distance from the
plant Distance N Median Min Max lt 5 km
40 41 14 134 5-10 km 102 23 9
139 gt10 km 68 20 10 53
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Cancer Incidence Analysis

• Prievidza district versus Slovakia
• Within Prievidza district by distance to the
  plant

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Comparative Incidence Figures (CIF) Prievidza
district versus Slovakia 1975-84

• All malignancies 1.1
  
• NMSC 1.6
• Lung cancer 1.0
• Bladder cancer 0.9

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CIF by Distance to the Power Plantcutoff 7.5
km 1977-1991

• Basal cell carcinoma 1.6Squamous cell ca.
  1.6
• Lung cancer 1.0
• Bladder cancer 1.1

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SIR NMSC (1996-1999)by Distance to the Plant

• lt5km 5-10 km gt10km
• Reference
• District 1.2 1.1 0.8
• 0.9- 1.6 1.0-1.3 0.6-0.9
• Slovakia 1.6 1.5 1.0
• 1.2- 2.2 1.3-1.7 0.9-1.3

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Population-based Case-Control Study

• 264 NMSC cases (1996-99)response rate 80
• 286 population controls
• response rate 72
• Matching by sex, age

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Statistical Power

• ? 5 one-sided
• ? 20 (power 80)
• controls exposed to As10
• N cases 264
• N controls 286
• RR to be detected gt 1.9

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NMSC Risk Estimation

• Logistic regression
• conditional on age, genderOdds Ratio (OR),
  95 CI
• Potential confounders occupational As exposure
• smoking

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Occupational As exposure (Job-Exposure Matrix)
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Cigarette Smoking
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Skin Type UV Exposure
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Fresh Vegetables Fruits
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Exposure Assessment and Risk Estimationfor
Environmental Arsenic

• Dietary habits
• Residential history

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Arsenic Exposurefrom Dietary Habits

• AsNut1 S w(f ) I(f) 25 food items f
  w(f) food frequencies I(f) annual As
  intake
• AsNut2 AsNut1 s if self-support s 2,
  else 1

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Arsenic Exposure with Dietary Habits
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As Exposurefrom Residential Data

• AsRes1 S E(t) w(d(t),t)
• for all places of residenceE(t) annual
  emissionw(d(t),t) immission weight

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Correction of spatial selection bias for
distance-related variables AsRes

• (1) Random re-sampling of controls SAS
  Surveyselect
• (2) Bootstrap method OR, 95 CI for
  R800 re-sampled groups

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Arsenic Exposure with Residential Data
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Environmental Arsenic Exposure NMSC Risk

• Elevated NMSC incidence in the vicinity of the
  plant.
• As exposure from dietary and residential data are
  associated with excess risk.
• Residual confounding can not be excluded.