Misclassification rates for current smokers misclassified as nonsmokers

Area of Science:

• Environmental Health
• Epidemiology
• Toxicology

Background:

• Accurate assessment of smoking status is critical in epidemiological studies, especially those investigating passive smoking and lung cancer.
• Smoker misclassification bias can significantly impact the estimation of relative risks in such studies.

Purpose of the Study:

• To determine misclassification rates of current cigarette smokers who self-report as nonsmokers.
• To provide data that can help correct for smoker misclassification bias in passive smoking research.

Main Methods:

• Utilized cotinine levels in body fluids to verify true smoking status (occasional or regular) in current smokers from three existing studies.
• Integrated new data with existing data from the 1992 Environmental Protection Agency (EPA) report on passive smoking.
• Stratified misclassification rates by sex and US minority/majority status.

Main Results:

• Reported specific misclassification rates for female smokers misclassified as never smokers across different categories (majority/minority, regular/occasional).
• Rates for females were 0.8% (majority regular), 6.0% (majority occasional), 2.8% (US minority regular), and 15.3% (US minority occasional).
• Observed generally higher misclassification rates for males compared to females.

Conclusions:

• Supported the EPA's conclusion that smoker misclassification bias is generally small.
• Recommended that researchers consider the minority/majority status of study cohorts when adjusting for smoker misclassification bias.