Cortisol, Health, and Coping in Patients with Nonspecific Low Back Pain.

Subjective health complaints (SHC), including nonspecific low back pain (LBP) as the most common single complaint, are the main reasons for long-term sick leave in many western countries. These complaints are often attributed to "stress". Cortisol has frequently been considered a biomarker reflecting sustained physiological HPA-axis activity, and is characterized by a high cortisol awakening response (CAR) and low evening values. The aim of the study was to investigate whether LBP patients had a normal characteristic cortisol profile, and whether possible deviations were related to coping and health. 305 patients on long-term sick leave for LBP participated in the study, and saliva cortisol profiles were compared to a reference population consisting of Danish workers. Cortisol was measured upon awakening, after 30 min, and in the evening. Additionally, patients answered questionnaires about SHC, fatigue, pain, coping, and social support. The patients showed a seemingly normal cortisol profile. However, CAR was larger among patients compared to the reference population. Patients with low cortisol reactivity had more SHC, pain, and fatigue, and those with higher evening cortisol reported higher scores on coping. The results are discussed in terms of theory, practical considerations, and possible mechanisms for the association between cortisol, health, and coping.