PARENTAL REPORTING OF CHILDRENS COUGHING IS BIASED

Assessment of cough in the clinical setting as well as in community-ba sed studies of respiratory epidemiology has relied on self-reports. To examine the accuracy and potential for systematic bias in reported co ugh during a field study, questionnaires administered to parents about their childrens' coughing were compared to overnight cough recordings performed in 145 homes in the community of Wallaceburg, Canada. Perce ntage agreement between reported and recorded coughing was low, with k appa statistics ranging from 0.02-0.10. Compared to non-smoking parent s, smokers under-reported their childrens' coughing (p = 0.01). The as sociation found between parental smoking and recorded coughing was bia sed towards the null when reported coughing was substituted for record ed coughing: the odds ratio between parental smoking and recorded coug hing was 3.1 (95% CI: 1.1-8.8) whereas for reported coughing it was 0. 6 (95% CI: 0.2-1.7), the difference in the odds ratios being significa nt atp = 0.03. When carrying out field surveys, consideration should b e given to measuring cough in a subsample of the population in order t o estimate the degree of bias inherent in the questionnaire-based resu lts.