Document Detail


Impact of pesticide exposure misclassification on estimates of relative risks in the Agricultural Health Study.
MedLine Citation:
PMID:  21257983     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
BACKGROUND: The Agricultural Health Study (AHS) is a prospective study of licensed pesticide applicators and their spouses in Iowa and North Carolina. We evaluate the impact of occupational pesticide exposure misclassification on relative risks using data from the cohort and the AHS Pesticide Exposure Study (AHS/PES).
METHODS: We assessed the impact of exposure misclassification on relative risks using the range of correlation coefficients observed between measured post-application urinary levels of 2,4-dichlorophenoxyacetic acid (2,4-D) and a chlorpyrifos metabolite and exposure estimates based on an algorithm from 83 AHS pesticide applications.
RESULTS: Correlations between urinary levels of 2,4-D and a chlorpyrifos metabolite and algorithm estimated intensity scores were about 0.4 for 2,4-D (n=64), 0.8 for liquid chlorpyrifos (n=4) and 0.6 for granular chlorpyrifos (n=12). Correlations of urinary levels with kilograms of active ingredient used, duration of application, or number of acres treated were lower and ranged from -0.36 to 0.19. These findings indicate that a priori expert-derived algorithm scores were more closely related to measured urinary levels than individual exposure determinants evaluated here. Estimates of potential bias in relative risks based on the correlations from the AHS/PES indicate that non-differential misclassification of exposure using the algorithm would bias estimates towards the null, but less than that from individual exposure determinants.
CONCLUSIONS: Although correlations between algorithm scores and urinary levels were quite good (ie, correlations between 0.4 and 0.8), exposure misclassification would still bias relative risk estimates in the AHS towards the null and diminish study power.
Authors:
Aaron Blair; Kent Thomas; Joseph Coble; Dale P Sandler; Cynthia J Hines; Charles F Lynch; Charles Knott; Mark P Purdue; Shelia Hoar Zahm; Michael C R Alavanja; Mustafa Dosemeci; Freya Kamel; Jane A Hoppin; Laura Beane Freeman; Jay H Lubin
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Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Intramural; Research Support, U.S. Gov't, Non-P.H.S.; Research Support, U.S. Gov't, P.H.S.     Date:  2011-01-21
Journal Detail:
Title:  Occupational and environmental medicine     Volume:  68     ISSN:  1470-7926     ISO Abbreviation:  Occup Environ Med     Publication Date:  2011 Jul 
Date Detail:
Created Date:  2011-06-07     Completed Date:  2011-08-12     Revised Date:  2014-11-09    
Medline Journal Info:
Nlm Unique ID:  9422759     Medline TA:  Occup Environ Med     Country:  England    
Other Details:
Languages:  eng     Pagination:  537-41     Citation Subset:  IM    
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MeSH Terms
Descriptor/Qualifier:
2,4-Dichlorophenoxyacetic Acid / urine
Agriculture / statistics & numerical data*
Algorithms
Biological Markers / urine
Environmental Monitoring / methods
Humans
Occupational Exposure / adverse effects,  analysis*,  statistics & numerical data
Pesticides / toxicity*
Prospective Studies
Pyridones / urine
Risk Assessment / methods
Grant Support
ID/Acronym/Agency:
P30 CA086862/CA/NCI NIH HHS; Z01-ES049030-1/ES/NIEHS NIH HHS; Z01CP010119/CP/NCI NIH HHS; ZIA CP010119-17/CP/NCI NIH HHS
Chemical
Reg. No./Substance:
0/Biological Markers; 0/Pesticides; 0/Pyridones; 2577AQ9262/2,4-Dichlorophenoxyacetic Acid; 6515-38-4/3,5,6-trichloro-2-pyridinol
Comments/Corrections

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