Characterization of exposure in epidemiological studies on air pollution from biodegradable wastes: Misclassification and comparison of exposure assessment strategies.
The assignment of exposure is one of the main challenges faced by environmental epidemiologists. However, misclassification of exposures has not been explored in population epidemiological studies on air pollution from biodegradable wastes. The objective of this study was to investigate the use of different approaches for assessing exposure to air pollution from biodegradable wastes by analyzing (1) the misclassification of exposure that is committed by using these surrogates, (2) the existence of differential misclassification (3) the effects that misclassification may have on health effect estimates and the interpretation of epidemiological results, and (4) the ability of the exposure measures to predict health outcomes using 10-fold cross validation. Four different exposure assessment approaches were studied: ammonia concentrations at the residence (Metric I), distance to the closest source (Metric II), number of sources within certain distances from the residence (Metric IIIa,b) and location in a specific region (Metric IV). Exposure-response models based on Metric I provided the highest predictive ability (72.3%) and goodness-of-fit, followed by IV, III and II. When compared to Metric I, Metric IV yielded the best results for exposure misclassification analysis and interpretation of health effect estimates, followed by Metric IIIb, IIIa and II. The study showed that modelled NH3concentrations provide more accurate estimations of true exposure than distances-based surrogates, and that distance-based surrogates (especially those based on distance to the closest point source) are imprecise methods to identify exposed populations, although they may be useful for initial studies.
The Mærsk Mc-Kinney Møller Institute, Faculty of Engineering, University of Southern Denmark, Odense, Denmark.
Manuella Lech
ML
Cantuaria
Bouvé College of Health Sciences, Northeastern University, Boston, MA, USA.
Helen
H
Suh
Department of Environmental Science, Aarhus University, Roskilde, Denmark.
Per
P
Løfstrøm
The Mærsk Mc-Kinney Møller Institute, Faculty of Engineering, University of Southern Denmark, Odense, Denmark. Electronic address: vbv@mmmi.sdu.dk.
Victoria
V
Blanes-Vidal
D000328:Adult; D000393:Air Pollutants / Q000032:analysis*; D000397:Air Pollution / Q000032:analysis*; D000641:Ammonia / Q000032:analysis*; D003718:Denmark; D004781:Environmental Exposure / Q000032:analysis*; D016021:Epidemiologic Studies; D005260:Female; D006798:Housing; D006801:Humans; D008019:Life Style; D008297:Male; D008875:Middle Aged; D008962:Models, Theoretical; D009812:Odorants; D011795:Surveys and Questionnaires; D014866:Waste Products
D000393:Air Pollutants; D014866:Waste Products; D000641:Ammonia
Air pollution; Animal waste; Exposure misclassification; Predictive models; Rural population