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Arsenic and Nonmelanoma Skin Cancer in Slovakia. Beate Pesch Environmental Health Research Institute, Germany. Part of the EU-funded Project EXPASCAN ‚Exposure to Arsenic and Cancer in Central & Eastern Europe‘. www.icconsultants.co.uk/ EXPASCAN.html. PARTNERS
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Arsenic and Nonmelanoma Skin Cancer in Slovakia Beate Pesch Environmental Health Research Institute, Germany
Part of the EU-funded Project EXPASCAN‚Exposure to Arsenic and Cancer in Central & Eastern Europe‘ www.icconsultants.co.uk/EXPASCAN.html
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
Objective Estimation of the risk of environmental arsenic exposure from power plant emissions for non-melanoma skin cancer (NMSC)
Estimation of the risk of environmental arsenic exposure • Choose study design(s) • Assess exposure • Estimate risk • Discuss confounders
Arsenic and arsenic compounds Environmental Health Criteria (EHC) 2nd edition, 224; 2001 WHO, Geneva www.inchem.org
Estimate by Distance to the Power Plant • Environmental As exposure • NMSC incidence Associate As exposure with NMSC risk& control for covariates
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)
Arsenic Emissions (tons/year) of the ENO Power Plant, Slovakia 200 As t/a 100 0 1953 1960 1970 1980 1990 1999 Year
Arsenic (mg/g) in soil 1999 by distance from the plant Distance N Median Min Max < 5 km 40 41 14 134 5-10 km 102 23 9 139 >10 km 68 20 10 53
Cancer Incidence Analysis • Prievidza district versus Slovakia • Within Prievidza district by distance to the plant
Comparative Incidence Figures (CIF) Prievidza district versusSlovakia 1975-84 All malignancies 1.1 NMSC 1.6 Lung cancer 1.0 Bladder cancer 0.9
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
SIR NMSC (1996-1999)by Distance to the Plant <5km5-10 km >10km Reference District 1.21.1 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
Population-based Case-Control Study • 264 NMSC cases (1996-99)response rate 80% • 286 population controls response rate 72% Matching by sex, age
Statistical Power • = 5% one-sided • = 20% (power 80%) • controls exposed to As=10% • N cases = 264 • N controls = 286 • RR to be detected >= 1.9
NMSC Risk Estimation • Logistic regression conditional on age, gender:Odds Ratio (OR), 95% CI • Potential confounders: occupational As exposure smoking
Exposure Assessment and Risk Estimationfor Environmental Arsenic • Dietary habits • Residential history
Arsenic Exposurefrom Dietary Habits • AsNut1 = Σ 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
As Exposurefrom Residential Data AsRes1 = Σ E(t)* w(d(t),t) for all places of residence:E(t) annual emissionw(d(t),t) immission weight
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 R=800 re-sampled groups
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.