Fatigue varies by social class in African Americans but not Caucasian Americans.

Socioeconomic status explains many ethnic disparities in health; however, mechanisms are hard to identify. Fatigue-a frequent complaint in patients and normals-is associated with poorer quality of life. We wondered if ethnicity and social class interact to explain fatigue. A total of 40 African Americans (AAs) and 64 Caucasian Americans (CAs) completed short forms of the Profile of Mood States (POMS-SF) and Multidimensional Fatigue Symptom Inventory (MFSI-SF). Participants were divided into high-middle and low social class groups (as per Hollingshead, 1958a). After controlling for gender, body mass index, depressive symptoms, and response bias, ethnicity and social class interacted for POMS-SF fatigue. AAs in the high-middle classes reported more fatigue than AAs in the low classes and CAs in the high-middle classes. Fatigue did not differ by class for CAs nor by ethnicity in the lower classes. Similar findings emerged for MFSI-SF general fatigue. Social class is important for understanding fatigue in AAs but not CAs.