Misclassification rates for current smokers misclassified as nonsmokers.
OBJECTIVE
This paper provides misclassification rates for current cigarette smokers who report themselves as nonsmokers. Such rates are important in determining smoker misclassification bias in the estimation of relative risks in passive smoking studies.


METHODS
True smoking status, either occasional or regular, was determined for individual current smokers in 3 existing studies of nonsmokers by inspecting the cotinine levels of body fluids. The new data, combined with an approximately equal amount in the 1992 Environmental Protection Agency (EPA) report on passive smoking and lung cancer, yielded misclassification rates that not only had lower standard errors but also were stratified by sex and US minority majority status.


RESULTS
The misclassification rates for the important category of female smokers misclassified as never smokers were, respectively, 0.8%, 6.0%, 2.8%, and 15.3% for majority regular, majority occasional, US minority regular, and US minority occasional smokers. Misclassification rates for males were mostly somewhat higher.


CONCLUSIONS
The new information supports EPA's conclusion that smoker misclassification bias is small. Also, investigators are advised to pay attention to minority/majority status of cohorts when correcting for smoker misclassification bias.
Impact Assessment, Inc, California Department of Health Services, Environmental Health Investigations Branch, Emeryville, USA.
A J
AJ
Wells
P B
PB
English
S F
SF
Posner
L E
LE
Wagenknecht
E J
EJ
Perez-Stable
D015982:Bias; D015415:Biomarkers; D003367:Cotinine / Q000097:blood / Q000378:metabolism* / Q000493:pharmacokinetics / Q000652:urine; D003951:Diagnostic Errors; D005260:Female; D006801:Humans; D008297:Male; D012907:Smoking / Q000378:metabolism; D014028:Tobacco Smoke Pollution; D014481:United States
D015415:Biomarkers; D014028:Tobacco Smoke Pollution; D003367:Cotinine