Structural stability and reliability of the Swedish occupational fatigue inventory among Chinese VDT workers

The aim of the present study was to test the structural stability and reliability of the Swedish occupational fatigue inventory (SOFI) for use in a group of Chinese visual display terminal (VDT) workers. A qualified translator was recruited to translate the Chinese version of the SOFI (SOFI-C). The content validity was established with 12 bilingual practitioners and seven professional experts. The translated SOFI was administered to 104 sedentary workers on two occasions with an interval of 60 min. Most of them were female (80.8%) and they had a mean age of 34.5 years. Fifty-one percent of them reported using a VDT for 4h or more at work. Exploratory factor analysis revealed a five-factor solution, which was comparable to the original latent factors. Cronbach's alpha for the five-factor scales was between 0.88 and 0.95. The test-retest reliability was satisfactory with intra-class correlations ranging from 0.69 to 0.83. The workers who used a VDT for 4h or more had significantly higher SOFI scores than those who used one for less than 4 h (p = 0.007 - 0.046). The results indicated that the SOFI-C was valid and reliable for measuring fatigue among Chinese sedentary workers. The satisfactory structural stability suggested that cultural influences on the construct of fatigue were not strong. Its characteristics of discrimination of the sedentary workers who had high VDT exposure suggested that the SOFI-C would be a useful instrument for prevention and intervention programs designed for work-related injuries in the workplace.