The Brazilian Validation of a Health Literacy Instrument: The Newest Vital Sign

Objectives: This study aimed to perform the cross-cultural adaptation and validation of the Newest Vital Sign for Brazilian Portuguese.
Methods: Two hundred and fifty adults responded to the adapted version of the Newest Vital Sign, the Brazilian version of the Rapid Estimate of Adult Literacy in Dentistry (BREALD-30), ten questions of the National Functional Literacy Index (NFLI), and a questionnaire about demographic and oral health-related aspects. Statistical analysis determined the internal consistency, stability, difficulty of items, and convergent/discriminant/predictive validities of the NVS. P < 0.05 was considered significant.
Results: The NVS displayed a good 41 internal consistency (Cronbach’s alpha=0.79) and a fair stability (ICC=0.57; 0.39-0.70 95% CI). Seventy-two percent of participants answered the easier question (#5) correctly, whereas only 28.4% were successful in responding the most difficult question (#1). The convergent validity of the NVS was demonstrated by its significant correlation with the BREALD-30 (Rs=0.601, P<0.001) and NFLI (Rs=0.544, P<0.001). The observation of higher NVS scores among health professionals, white and more educated people confirmed the discriminant validity of the instrument. Moreover, health literacy was a significant predictor of self-reported oral health and reason for dental utilization.
Conclusions: The NVS demonstrated adequate psychometric properties to be applied in Brazilian oral health epidemiological surveys.