Development and evaluation of a questionnaire for measuring suboptimal health status in urban Chinese.

BACKGROUND: Suboptimal health status (SHS) is characterized by ambiguous health complaints, general weakness, and lack of vitality, and has become a new public health challenge in China. It is believed to be a subclinical, reversible stage of chronic disease. Studies of intervention and prognosis for SHS are expected to become increasingly important. Consequently, a reliable and valid instrument to assess SHS is essential. We developed and evaluated a questionnaire for measuring SHS in urban Chinese. METHODS: Focus group discussions and a literature review provided the basis for the development of the questionnaire. Questionnaire validity and reliability were evaluated in a small pilot study and in a larger cross-sectional study of 3000 individuals. Analyses included tests for reliability and internal consistency, exploratory and confirmatory factor analysis, and tests for discriminative ability and convergent validity. RESULTS: The final questionnaire included 25 items on SHS (SHSQ-25), and encompassed 5 subscales: fatigue, the cardiovascular system, the digestive tract, the immune system, and mental status. Overall, 2799 of 3000 participants completed the questionnaire (93.3%). Test-retest reliability coefficients of individual items ranged from 0.89 to 0.98. Item-subscale correlations ranged from 0.51 to 0.72, and Cronbach's alpha was 0.70 or higher for all subscales. Factor analysis established 5 distinct domains, as conceptualized in our model. One-way ANOVA showed statistically significant differences in scale scores between 3 occupation groups; these included total scores and subscores (P<0.01). The correlation between the SHS scores and experienced stress was statistically significant (r=0.57, P<0.001). CONCLUSIONS: The SHSQ-25 is a reliable and valid instrument for measuring sub-health status in urban Chinese.

[Development of an indicator system for recognizing the sub-health status and study on the related reliability and validity].

OBJECTIVE: To establish a subjective indicator system for the evaluation of sub-health status and study on its reliability and validity. METHODS: Based on the basic features of general malice and losing ability of workforce, the indicator system for sub-health status evaluation was developed according to the chronic stress on human body' s main systems. The items were adjusted according to the experience from experts and the results of the pilot study. Indices as Chronbach's alpha, IIC and ICC were used to evaluate the reliability of the questionnaire. Factor analysis and ANOVA were used to evaluate the construct validity and discriminative ability of the questionnaire. RESULTS: The formal sub-health survey questionnaire would include five domains and 25 questions in total. The whole questionnaire's Chronbach's alpha coefficient was 0.92. Cronbach's alpha of the four domains, including cardiovascular, digestive tract, immunity and mental health were no less than 0.7 while IIC ranging from 0.51 to 0.72 and ICC ranging from 0.89 to 0.98. The five extracted common factors which contributed 62.35% to the total variation were basically consistent with the five dimensions. ANOVA showed significant differences among different groups (P<0.05). CONCLUSION: The questionnaire appeared reliable and valid for measurement of sub-health status.