The causal role of fatigue in the stress-perceived health relationship: a MetroNet study

We conducted a cross-sectional survey of 4 primary care MetroNet centers in metropolitan Detroit. Our objective was to describe the causal role of fatigue in the relationship among stress, stress resiliency, and perceived health in primary care. Fatigue is a public health problem that has been linked to stress and poor health. The causal role of fatigue between stress and perceived health is unknown.

Four hundred surveys were distributed to adult patients in 4 primary care centers in metropolitan Detroit between 2006 and 2007. Internal consistency reliabilities and principal factor analyses were calculated for the key psychological scales. Perceived health is the primary outcome. Path models were used to study the relationship among stress, fatigue, and perceived health. We also modeled the impact of select stress resiliency factors including sleep, recovery, and social support.

Of the 400 distributed surveys, 315 (78.7%) had a response rate of 70% or more and were included in the analysis. Respondents were predominantly middle aged (median age, 43 years); female (58.7%); and African American (52.0%). The majority worked full time (56.5%); did not have a college degree (77.7%); and were not married (55.2%). Fatigue was reported by 59% of respondents, 42.7% of which was unexplained. The path model supported the causal role of fatigue between stress and perceived health. The positive effects of sleep, recovery, and social support on fatigue, stress, and perceived health were validated.

Fatigue was common in this metropolitan primary care environment and completely mediated the relationship between stress and poor perceived health. Therefore, stress, when significant enough to cause fatigue, may lead to poor health.