Brief instruments for measuring nutrition literacy - the Nutrition Health Literacy Scale and the Self-Perceived Food Literacy Scale Short Form.

BACKGROUND: A healthy diet is a critical factor in maintaining long-term health. In addition to a health-promoting food environment, the nutrition health literacy (NHL) and food literacy (FL) of the population are important in this context. This paper describes the development and validation of two short instruments to measure the nutrition literacy of the population, used in the Austrian Nutrition Literacy Survey 2021. METHODS: An instrument to measure NHL (Nutrition Health Literacy Scale; NHLS) has been adapted and further developed. To measure FL, the Self-perceived Food Literacy Scale by Poelman et al. has been modified and shortened (SPFL-SF). Validation of the instruments was based on data from a web survey conducted in Austria in 2021 with almost 3,000 participants aged 18 years and older. Exploratory and confirmatory factor analyses were performed to assess the factorial validity/dimensionality of the instruments. Additionally, internal consistency was assessed using Cronbach's alpha, ordinal alpha, and McDonald's omega. RESULTS: Both instruments demonstrate excellent data-model fit. The NHLS also shows excellent internal consistency (α = 0.91), while the SPFL-SF displays a sufficient internal consistency for all (α between 0.70 and 0.89) but one sub-dimension (resisting temptation α = 0.61). Furthermore, the distribution of the items indicates that the measures are understandable and suitable, as evidenced by the absence of missing values in the sample. In addition, the items of both instruments differ in their level of difficulty or agreement. CONCLUSIONS: The NHLS and SPFL-SF are reliable and valid instruments for measuring NHL and FL in the general adult population. The brief instruments measuring the different aspects of nutrition literacy can be easily used in nutritional or evaluation studies. Further work is required to investigate other aspects of validity.

Associations between digital health literacy and health system navigating abilities among Norwegian adolescents: validating the HLS19-DIGI scale using Rasch modeling.

BACKGROUND: Despite increasing global attention to health literacy and adolescents' digital health information seeking, no unidimensional instruments measuring digital health literacy (DHL) in adolescents have reportedly been validated using Rasch modeling. Moreover, the evidence of adolescents' abilities to navigate the health system (NAV-HL) in light of their DHL proficiency is still scarce. Therefore, our study aims to evaluate the psychometric properties of a DHL instrument (HLS19-DIGI scale) in order to investigate DHL in adolescents and young adults aged 16-25 and associations with abilities to navigate the health system. METHODS: A population-based cross-sectional survey among 890 Norwegian adolescents was conducted during April-October 2020 using computer-assisted telephone interviewing. Rasch modeling, independent samples t-test, chi-square test, and binary regression models were used to analyze the data. RESULTS: The HLS19-DIGI scale was sufficiently unidimensional, whereas no differential item functioning or disordered response categories were observed. However, relatively poor targeting was revealed indicating too many easy items for the target population. Yet, a high proportion (54%) of low DHL proficiency in adolescents was observed, as well as DHL was positively associated with the abilities to navigate the health system. CONCLUSIONS: The HLS19-DIGI scale is considered a sufficiently unidimensional and valid instrument for measuring DHL in adolescents, which may be a useful tool for health authorities, public health workers, and health service providers. While DHL affects adolescents' abilities to navigate the health system, future research should measure and examine their ability to utilize digital health services, separately.