Estimating serum polychlorinated biphenyl levels in highly exposed workers: an empirical model.
A regression model estimating high-homolog polychlorinated biphenyl (PCB) serum concentration on the basis of job exposure categorizations was developed. The model assumes first-order kinetics with a half-life determined empirically and uses variables that incorporate both intensity and duration of exposure over a 30-yr period. In order to compare the efficiency of these regression-based exposure estimates relative to often-used epidemiological parameters, models with dichotomized, ordinal, and continuous exposure surrogates were also investigated. Among the alternative exposure categorizations the most straightforward measure, ever versus never direct, was a particularly poor predictor of serum PCB level (r2 = .01). Nearly all of the candidate exposure measures we tried predicted serum levels poorly. The best of these after the fact was with total months employed in direct-exposure jobs (r2 = .43). None of the logical deductive models approached the predictability of the empirical model developed here (r2 = .69).
Taylor
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PR
Cancer Prevention Studies Branch, National Cancer Institute, Bethesda, Maryland 20892.
Reilly
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AA
Stelma
J M
JM
Lawrence
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CE
D000328:Adult; D000368:Aged; D000395:Air Pollutants, Occupational / Q000032:analysis*; D001724:Birth Weight; D015331:Cohort Studies; D004581:Electronics; D005260:Female; D005865:Gestational Age; D006801:Humans; D016018:Least-Squares Analysis; D008297:Male; D008875:Middle Aged; D016273:Occupational Exposure; D011078:Polychlorinated Biphenyls / Q000097:blood*; D011247:Pregnancy; D011256:Pregnancy Outcome; D012044:Regression Analysis
D000395:Air Pollutants, Occupational; D011078:Polychlorinated Biphenyls