[Psychometric properties of the diet-related quality of life (DRQOL) scale and its short version among older adults].

Abstract

Objectives　The purpose of this study was to examine the psychometric properties of the diet-related quality of life (DRQOL) scale among older adults. Specifically, the study was conducted to confirm the scale's factor structure and construct a short version of the scale. Further, the scale's internal consistency and gender- and age-based differences as well as the validity of the DRQOL scale and its short version were examined.Methods　We surveyed a random sample of community-dwelling older Japanese adults (aged 60-84 years; N=1,200; response rate: 70.8%) and used the data of 780 participants (367 men and 413 women). We used the DRQOL scale, comprising 18 items that were measured using a five-point Likert-type scale. Additionally, we assessed subjective well-being, diet satisfaction, appetite, meal restriction, mastication, number of meals with others, frequency of using ready-made and instant food, information gathering regarding food, and dietary variety scores as external criterion variables; socioeconomic status and health habits were used to describe basic participant characteristics.Results　Confirmatory factor analysis revealed a replication of the four-factor structure of the measure ("pleasure from a meal," "eating satisfaction," "circumstances of meal," and "diet diversity"). A short version of the measure comprising 8 items was developed. The DRQOL scale, its subscales, and its short version had high Cronbach's alpha coefficients as indicators of reliability (0.94; 0.86, 0.89, 0.77, and 0.72; and 0.90, respectively). There were significant sex differences in the scores of all constructs, and no significant age-based differences. The DRQOL scale scores had weak-to-moderate correlations with the external criterion variables mentioned above.Conclusion　Overall, this study confirmed the psychometric properties of the DRQOL scale, including factor structure, reliability, gender and age differences, and its validity among older adults using data from the general population in Japan. In addition, a short version of the DRQOL scale was developed. Future studies should examine the factors associated with the DRQOL. The predictive validity of the scale, with health outcomes as external criteria, should be examined to test its usefulness for epidemiological surveys among older adults in community settings.