Fatigue in the general population: A translation and test of the psychometric properties of the Norwegian version of the fatigue severity scale

OBJECTIVE: A study was undertaken to test the psychometric properties of the Fatigue Severity Scale (FSS), and to explore the relationship between fatigue and sociodemographic variables in the general population. METHOD: A national representative sample of 1893 respondents was randomly selected from a pool of 4,000 Norwegians aged 19-81 years. A mailed questionnaire that included the FSS was used to measure fatigue severity. RESULTS: The FSS showed satisfactory internal consistency (Cronbach's alpha 0.88). The prevalence of high fatigue (FSS score > = 5) was 23.1% in the total sample. More women (26.2%) than men (19.8%) experienced high fatigue (p = 0.004). Respondents with chronic illness (more than six months) reported a higher mean (M = 4.69, SD = 1.35) than the rest of the sample (M = 3.67, SD = 1.17) (p<0.001). An inverse correlation was found between fatigue and level of formal education (r = 0.20, p<0.001). CONCLUSION: The psychometric properties of the Norwegian version of FSS were satisfactory. To avoid over-diagnosing people for high level of fatigue, the threshold for high fatigue probably should be 5 on the FSS scale instead of 4 as had been suggested originally, but further validation of the cut-off point is needed.