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 nonmelanoma skin cancer (NMSC)
Estimation of the risk of environmental arsenic exposure n Choose study design(s) n Assess exposure n Estimate risk n Discuss confounders
Arsenic and arsenic compounds Environmental Health Criteria (EHC) 2 nd edition, 224; 2001 WHO, Geneva www. inchem. org
Estimate by Distance to the Power Plant n Environmental As exposure n NMSC incidence Associate As exposure with NMSC risk & control for covariates
ENO Power Plant (Slovakia)
Environmental Arsenic Exposure n Historical As exposure Air pollution modelling (Colvile et al. 2001) n Current As exposure Measurement of As in soil, house dust (Keegan et al. 2002)
Arsenic Emissions (tons/year) of the ENO Power Plant, Slovakia As t/a 200 100 0 1953 1960 1970 1980 Year 1990 1999
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 20 10 53 68
Cancer Incidence Analysis n Prievidza Slovakia n Within district versus Prievidza district by distance to the plant
Comparative Incidence Figures (CIF) Prievidza district versus Slovakia 1975 -84 All malignancies NMSC Lung cancer Bladder cancer 1. 1 1. 6 1. 0 0. 9
CIF by Distance to the Power Plant cutoff 7. 5 km 1977 -1991 Basal cell carcinoma Squamous cell ca. Lung cancer Bladder cancer 1. 6 1. 0 1. 1
SIR NMSC (1996 -1999) by Distance to the Plant <5 km 5 -10 km >10 km 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
Population-based Case-Control Study n 264 NMSC cases (1996 -99) response rate 80% n 286 population controls response rate 72% Matching by sex, age
Statistical Power n = 5% one-sided n = 20% (power 80%) n controls exposed to As=10% n N cases = 264 n N controls = 286 n RR to be detected >= 1. 9
NMSC Risk Estimation n Logistic regression conditional on age, gender: Odds Ratio (OR), 95% CI n Potential confounders: occupational As exposure smoking
Occupational As exposure (Job-Exposure Matrix)
Cigarette Smoking
Skin Type & UV Exposure
Fresh Vegetables & Fruits
Exposure Assessment and Risk Estimation for Environmental Arsenic n Dietary habits n Residential history
Arsenic Exposure from Dietary Habits n As. Nut 1 = Σ w(f )* I(f) 25 food items f: w(f) food frequencies I(f) annual As intake n As. Nut 2 = As. Nut 1 * s if self-support s= 2, else 1
Arsenic Exposure with Dietary Habits
As Exposure from Residential Data As. Res 1 = Σ E(t)* w(d(t), t) for all places of residence: E(t) annual emission w(d(t), t) immission weight
Correction of spatial selection bias for distancerelated variables As. Res n (1) Random re-sampling of controls SAS Surveyselect n (2) Bootstrap method OR, 95% CI for R=800 re-sampled groups
Arsenic Exposure with Residential Data
Environmental Arsenic Exposure & NMSC Risk n Elevated NMSC incidence in the vicinity of the plant. n As exposure from dietary and residential data are associated with excess risk. n Residual confounding can not be excluded.
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