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Effects of systematic exposure assessment errors in partially ecologic case-control studies.

Björk, Jonas LU and Strömberg, Ulf LU (2002) In International Journal of Epidemiology 31(1). p.154-160
Abstract
BACKGROUND: In ecologic studies, group-level rather than individual-level exposure data are used. When using group-level exposure data, established by sufficiently large samples of individual exposure assessments, the bias of the effect estimate due to sampling errors or random assessment errors at the individual-level is generally negligible. In contrast, systematic assessment errors may produce more pronounced errors in the group-level exposure measures, leading to bias in ecologic analyses. METHODS: We focus on effects of systematic exposure assessment errors in partially ecologic case-control studies. Individual-level information on disease status, group membership, and covariates is obtained from registries, whereas the exposure is a... (More)
BACKGROUND: In ecologic studies, group-level rather than individual-level exposure data are used. When using group-level exposure data, established by sufficiently large samples of individual exposure assessments, the bias of the effect estimate due to sampling errors or random assessment errors at the individual-level is generally negligible. In contrast, systematic assessment errors may produce more pronounced errors in the group-level exposure measures, leading to bias in ecologic analyses. METHODS: We focus on effects of systematic exposure assessment errors in partially ecologic case-control studies. Individual-level information on disease status, group membership, and covariates is obtained from registries, whereas the exposure is a group-level measure obtained from an established exposure database. Effects on bias and coverage of 95% CI in various error situations are investigated under the linear risk model, using both simulated and empirical ecologic data on exposures that are binary at the individual level. RESULTS: Our simulations suggest that the bias produced by systematic exposure assessment errors under the linear risk model is generally approximately equal to the ratio of the slope bias and the intercept bias in ordinary linear regression with measurement errors in the independent variable. Consequently, bias in either direction can occur. Exposure assessment errors that systematically distort the group-level exposure measures have more pronounced effects on bias and coverage than errors producing random fluctuations of the group-level measures, which imply bias towards the null. CONCLUSIONS: The results indicate the need for careful consideration of potential effects of systematic distortions of the group-level exposure measures when constructing and applying group-level exposure databases, such as probabilistic job exposure matrices. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Occupational Exposure, Bias (Epidemiology), Case-Control Studies, Confidence Intervals, Linear Models, Human, Odds Ratio, Sensitivity and Specificity
in
International Journal of Epidemiology
volume
31
issue
1
pages
154 - 160
publisher
Oxford University Press
external identifiers
  • wos:000174993500032
  • pmid:11914312
  • scopus:0036009572
ISSN
1464-3685
language
English
LU publication?
yes
id
e2c9d2b1-f574-462d-9826-84d64c024732 (old id 107185)
alternative location
http://ije.oxfordjournals.org/cgi/content/full/31/1/154
date added to LUP
2007-07-11 15:43:56
date last changed
2017-09-24 03:33:48
@article{e2c9d2b1-f574-462d-9826-84d64c024732,
  abstract     = {BACKGROUND: In ecologic studies, group-level rather than individual-level exposure data are used. When using group-level exposure data, established by sufficiently large samples of individual exposure assessments, the bias of the effect estimate due to sampling errors or random assessment errors at the individual-level is generally negligible. In contrast, systematic assessment errors may produce more pronounced errors in the group-level exposure measures, leading to bias in ecologic analyses. METHODS: We focus on effects of systematic exposure assessment errors in partially ecologic case-control studies. Individual-level information on disease status, group membership, and covariates is obtained from registries, whereas the exposure is a group-level measure obtained from an established exposure database. Effects on bias and coverage of 95% CI in various error situations are investigated under the linear risk model, using both simulated and empirical ecologic data on exposures that are binary at the individual level. RESULTS: Our simulations suggest that the bias produced by systematic exposure assessment errors under the linear risk model is generally approximately equal to the ratio of the slope bias and the intercept bias in ordinary linear regression with measurement errors in the independent variable. Consequently, bias in either direction can occur. Exposure assessment errors that systematically distort the group-level exposure measures have more pronounced effects on bias and coverage than errors producing random fluctuations of the group-level measures, which imply bias towards the null. CONCLUSIONS: The results indicate the need for careful consideration of potential effects of systematic distortions of the group-level exposure measures when constructing and applying group-level exposure databases, such as probabilistic job exposure matrices.},
  author       = {Björk, Jonas and Strömberg, Ulf},
  issn         = {1464-3685},
  keyword      = {Occupational Exposure,Bias (Epidemiology),Case-Control Studies,Confidence Intervals,Linear Models,Human,Odds Ratio,Sensitivity and Specificity},
  language     = {eng},
  number       = {1},
  pages        = {154--160},
  publisher    = {Oxford University Press},
  series       = {International Journal of Epidemiology},
  title        = {Effects of systematic exposure assessment errors in partially ecologic case-control studies.},
  volume       = {31},
  year         = {2002},
}