Psychometric qualities of the Brazilian versions of the Fagerström Test for Nicotine Dependence and the Heaviness of Smoking Index

Abstract

Introduction: This study examined the psychometric properties of the Brazilian versions of the Fagerström Test for Nicotine Dependence (FTND) and the Heaviness of Smoking Index (HSI).

Methods: The test-retest reliability of the FTND was assessed in a sample of 61 smoking university students, with a 15-day interval between assessments. The interrater reliability was examined in 30 smoking patients of a psychosocial care center for alcohol and drug users (PCC-AD). The reliability coefficient was estimated by the kappa and intraclass correlation coefficients. The predictive validity, internal consistency, and factor structure of the FTND and the HSI were evaluated by factor analysis in 271 smokers treated at an emergency unit and at the PCC-AD. The gold standard was the nicotine dependence criteria of DSM-IV, as assessed by the Structured Clinical Interview for DSM-IV.

Results: The FTND showed high reliability, with correlation coefficients of .92 for test-retest reliability and .99 for interrater reliability. Both the FTND and the HSI presented high levels of sensitivity and specificity. The internal consistency evaluation yielded a Cronbach's alpha coefficient of .83 for the FTND and of .56 for the HSI. An exploratory factor analysis found 2 factors in the FTND, which were validated by a confirmatory factor analysis.

Discussion: The results obtained in this study confirm the validity and reliability of the Brazilian versions of the FTND and the HSI.