Imputation method for lifetime exposure assessment in air pollution epidemiologic studies

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  • Beyea, Jan
    • Other Affiliation: Consulting in the Public Interest (CIPI), Lambertville, NJ
  • Stellman, Steven D
    • Other Affiliation: Department of Epidemiology, Mailman School of Public Health, Columbia University, New York, NY, USA
  • Teitelbaum, Susan
    • Other Affiliation: Department of Preventive Medicine, Mount Sinai School of Medicine, New York, NY, USA
  • Mordukhovich, Irina
    • Other Affiliation: Department of Epidemiology, Raleigh, North Carolina, USA
  • Gammon, Marilie D
    • Other Affiliation: Department of Epidemiology, Raleigh, North Carolina, USA
Abstract
  • Abstract Background Environmental epidemiology, when focused on the life course of exposure to a specific pollutant, requires historical exposure estimates that are difficult to obtain for the full time period due to gaps in the historical record, especially in earlier years. We show that these gaps can be filled by applying multiple imputation methods to a formal risk equation that incorporates lifetime exposure. We also address challenges that arise, including choice of imputation method, potential bias in regression coefficients, and uncertainty in age-at-exposure sensitivities. Methods During time periods when parameters needed in the risk equation are missing for an individual, the parameters are filled by an imputation model using group level information or interpolation. A random component is added to match the variance found in the estimates for study subjects not needing imputation. The process is repeated to obtain multiple data sets, whose regressions against health data can be combined statistically to develop confidence limits using Rubin’s rules to account for the uncertainty introduced by the imputations. To test for possible recall bias between cases and controls, which can occur when historical residence location is obtained by interview, and which can lead to misclassification of imputed exposure by disease status, we introduce an “incompleteness index,” equal to the percentage of dose imputed (PDI) for a subject. “Effective doses” can be computed using different functional dependencies of relative risk on age of exposure, allowing intercomparison of different risk models. To illustrate our approach, we quantify lifetime exposure (dose) from traffic air pollution in an established case–control study on Long Island, New York, where considerable in-migration occurred over a period of many decades. Results The major result is the described approach to imputation. The illustrative example revealed potential recall bias, suggesting that regressions against health data should be done as a function of PDI to check for consistency of results. The 1% of study subjects who lived for long durations near heavily trafficked intersections, had very high cumulative exposures. Thus, imputation methods must be designed to reproduce non-standard distributions. Conclusions Our approach meets a number of methodological challenges to extending historical exposure reconstruction over a lifetime and shows promise for environmental epidemiology. Application to assessment of breast cancer risks will be reported in a subsequent manuscript.
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Resource type
  • Article
Rights statement
  • In Copyright
Rights holder
  • Jan Beyea et al.; licensee BioMed Central Ltd.
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Journal title
  • Environmental Health
Journal volume
  • 12
Journal issue
  • 1
Page start
  • 62
Language
  • English
Is the article or chapter peer-reviewed?
  • Yes
ISSN
  • 1476-069X
Bibliographic citation
  • Environmental Health. 2013 Aug 07;12(1):62
Publisher
  • BioMed Central Ltd
Access right
  • Open Access
Date uploaded
  • August 21, 2013

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file details Figure S1-2. 2019-05-06 Public Download
file details Details about imputation of the transfer function, 2019-05-06 Public Download
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