Psychometric Properties of the Fagerström Test for Nicotine Dependence in a Sample of Mexican Smokers.

INTRODUCTION: The Fagerström Test for Nicotine Dependence (FTND) is a widely used six-item questionnaire, often used as a measure of physical dependence on nicotine, although evidence of its validity in Spanish-language studies is scarce.

AIM: The aim of this study was to assess the psychometric properties of FTND in Spanish speakers.

METHOD: We recruited 136 regular adult smokers to answer the FTND. We assessed the internal consistency of the FTND with a Cronbach's alpha and convergent and divergent validity with the Pearson product-moment coefficient between variables of external criteria, both measure and nonmeasure related; the FTND items, and the total score. We performed a binary logistic regression model to determine predictive validity of the questionnaire, using the FTND total scores as an independent variable and cessation as the outcome. We performed a confirmatory factor analysis to assess the robustness of a single-factor model.

RESULTS: The internal consistency had a lower coefficient than current standards. The FTND was unable to predict cessation at any assessed time point. The FTND total score showed significant correlation with exhaled carbon monoxide, urinary cotinine, and self-report of cigarettes smoked per day. However, Items 5 (smoke in the first hours) and 6 (smoke if ill) failed to obtain a significant correlation with biological biomarkers.

DISCUSSION: Although the FTND showed an adequate construct validity, the results suggest that its convergent and predictive validity is limited; therefore, it might not be suitable for the Mexican population. More studies in other populations are needed to establish the generalizability of these findings.