Use of objective measurement in the validation of self-reported smoking in children aged 10 and 11 years: saliva thiocyanate.

This study of objective measurement of smoking behaviour reports the findings from a sample of 421 children aged 10 and 11 years from Sheffield. Saliva thiocyanate determination did not provide a satisfactory objective method of validating the self-reported smoking of children in this age group. There was a trend (non-significant) for non-smoking children from homes in which a close relative smoked to have higher concentrations of saliva thiocyanate than non-smokers from "non-smoking" homes. Prior knowledge that a scientific test predicting smoking behaviour would be taken after completion of a questionnaire on smoking increased the self-reportage of experimental smoking.