Disease related pain and cortisol levels in women with osteoarthritis?
When people suffer from a breakdown of joint cartilage and underlying bone, they are said to be affected from osteoarthritis. The main highlights of the study were to establish: 1) Osteoarthritis (OA) related pain associated with diurnal cortisol pattern and cortisol level (2) diurnal pattern of cortisol varies with severity of OA pain and (3) association between OA pain and cortisol is mediated by daily experience variables (DEV).
To serve this purpose, a community-based study of changes in regional and widespread pain among women with OA was employed. It included 31 patients who completed daily diaries and collected three saliva samples daily for 7 days. The severity of OA-related pain was analysed by validated Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain subscale. For evaluating associations between OA pain and diurnal cortisol levels and slopes, controlling for body mass index (BMI), medication use, time and day; multilevel regression analyses were used. The mediation analyses inspected DEV as potential mediators of the association between OA pain and cortisol.
The outcomes revealed that the mean age was 57 years and average BMI was 31 kg/m2. The mean WOMAC pain subscale score was 8.8. Both WOMAC pain scores and cortisol were high throughout the day. The approximate association of WOMAC with cortisol [β 0.083(0.02, 0.15) P = 0.009] constitute a ∼9% increase in cortisol for every unit increase in WOMAC pain score. Women with WOMAC pain scores ≥9 had higher cortisol levels than those with scores <9. At the day to day level the scrutiny of DEV disclosed no significant mediated associations between these relationships.
Therefore, in women with OA, disease-related pain is positively associated with cortisol production, with special reference to greater pain severity. Although future studies should explore biologic mediating variables between OA pain and cortisol.