Objectives: To examine the reliability and validity of the simplified Japanese version of the WHO-Five Well-Being Index (S-WHO-5-J), which reduces the original 6-point scale to a 4-point scale.
Methods: Subjects were selected from 4,439 community-dwelling elderly living in Tokyo. Their mean age +/- SD was 74.2 +/- 6.6 years, and 2,475 (55.8%) were female. We mailed a questionnaire to all potential subjects, and collected 3,068 (69.1%). We analyzed the data from 1,356 questionnaires that had no missing values for the following items: S-WHO-5-J, Geriatric Depression Scale short version (GDS-15), age, gender, persons living together, need of care, subjective rating of health, physical pain, subjective memory impairment, activities of daily living (TMIG Index of Competence), social support, housebound, and subjective feeling of economic affluence. The mean age +/- SD of the sample was 73.2 +/- 5.9 years, and the proportion of females was 51.1%. An additional analysis compared the number of missing values between a simplified version and an original version using the data of 2,034 subjects from another study.
Results: A factor analysis identified only one factor and showed high correlation coefficients between total score and items (0.79-0.87) and between all items (0.52-0.82) and a high Cronbach's alpha (0.889). The S-WHO-5-J was correlated to the GDS-15, to the item on mental health and to factors that affected mental health, physical health (subjective rating of health, physical pain, illness), physical function (walking, falling, nutritional status, oral health care), memory impairment, activities of daily living, and social function (housebound, interaction with others, social support). Additional analysis showed that there were fewer missing values for the S-WHO-5-J than for the WHO-5-J.
Conclusion: The S-WHO-5-J is a reliable, valid, and convenient measure of mental health for large samples of community-dwelling elderly persons.