Fatigue in the General Population

BACKGROUND: Fatigue symptoms are often found in cancer patients. One test to assess fatigue is the Multidimensional Fatigue Inventory (MFI-20). It has been successfully applied to specific groups of cancer patients. However, until now population-based norm values are missing. METHODS: We conducted an investigation on a representative sample of the adult German population, which comprised 2,037 subjects aged 14-92 years. RESULTS: The reliability of the 5 MFI-20 subscales (general fatigue, physical fatigue, reduced activity, reduced motivation, and mental fatigue) is satisfying. The correlations between MFI-20 subscales and the fatigue scale of the quality-of-life questionnaire EORTC indicate convergent validity. As an important result we found that all subscales of the MFI-20 showed a clear and nearly linear dependency on age with higher fatigue values for older subjects (p < 0.0001). Females as compared with males are characterized by higher mean values in all MFI-20 subscales (p < 0.001). CONCLUSIONS: The results show that it is necessary to take into account age and sex when different groups of cancer patients have to be compared.