Background: Self-reported tobacco use among young people can underestimate the actual prevalence of tobacco use. Biochemical validation of self-reports is particularly recommended for intervention studies where cessation outcomes are to be measured. Literature on biochemical validation of self-reports of multiple forms of tobacco use in India is sparse, particularly among young people.
Methods: The study was conducted during the baseline household survey of a community-based tobacco prevention and cessation intervention trial for youth (10-19 years old) residing in slum communities in Delhi, India in 2009. Salivary cotinine measurement on 1,224 samples showed that youth were under-reporting use of chewing and smoking tobacco.
Results: Self-reports had a low sensitivity (36.3%) and a positive predictive value of 72.6%. No statistically significant difference in under-reporting was found between youth in the control and intervention conditions of the trial, which will be taken into consideration in assessing intervention outcomes at a later time point.
Conclusion: Biochemical validation of self-reported tobacco use should be considered during prevention and cessation studies among youth living in low-income settings in developing countries like India. Impact: The future results of biochemical validation from Project ACTIVITY (Advancing Cessation of Tobacco In Vulnerable Indian Tobacco consuming Youth) will be useful to design validation studies in resource-poor settings.