Measurement of availability and accessibility of food among youth: a systematic review of methodological studies.

BACKGROUND: Comprehensive and psychometrically tested measures of availability and accessibility of food are needed in order to explore availability and accessibility as determinants and predictors of dietary behaviors. The main aim of this systematic review was to update the evidence regarding the psychometric properties of measures of food availability and accessibility among youth. A secondary objective was to assess how availability and accessibility were conceptualized in the included studies. METHODS: A systematic literature search was conducted using Medline, Embase, PsycINFO and Web of Science. Methodological studies published between January 2010 and March 2016 and reporting on at least one psychometric property of a measure of availability and/or accessibility of food among youth were included. Two reviewers independently extracted data and assessed study quality. Existing criteria were used to interpret reliability and validity parameters. RESULTS: A total of 20 studies were included. While 16 studies included measures of food availability, three included measures of both availability and accessibility; one study included a measure of accessibility only. Different conceptualizations of availability and accessibility were used across the studies. The measures aimed at assessing availability and/or accessibility in the home environment (n = 11), the school (n = 4), stores (n = 3), childcare/early care and education services (n = 2) and restaurants (n = 1). Most studies followed systematic steps in the development of the measures. The most common psychometrics tested for these measures were test-retest reliability and criterion validity. The majority of the measures had satisfactory evidence of reliability and/or validity. None of the included studies assessed the responsiveness of the measures. CONCLUSIONS: The review identified several measures of food availability or accessibility among youth with satisfactory evidence of reliability and/or validity. Findings indicate a need for more studies including measures of accessibility and addressing its conceptualization. More testing of some of the identified measures in different population groups is also warranted, as is the development of more measures of food availability and accessibility in the broader environment such as the neighborhood food environment.