The demand control model and circadian saliva cortisol variations in a Swedish population based sample (The PART study).

BACKGROUND: Previous studies of the relationship between job strain and blood or saliva cortisol levels have been small and based on selected occupational groups. Our aim was to examine the association between job strain and saliva cortisol levels in a population-based study in which a number of potential confounders could be adjusted for. METHODS: The material derives from a population-based study in Stockholm on mental health and its potential determinants. Two data collections were performed three years apart with more than 8500 subjects responding to a questionnaire in both waves. In this paper our analyses are based on 529 individuals who held a job, participated in both waves as well as in an interview linked to the second wave. They gave saliva samples at awakening, half an hour later, at lunchtime and before going to bed on a weekday in close connection with the interview. Job control and job demands were assessed from the questionnaire in the second wave. Mixed models were used to analyse the association between the demand control model and saliva cortisol. RESULTS: Women in low strain jobs (high control and low demands) had significantly lower cortisol levels half an hour after awakening than women in high strain (low control and high demands), active (high control and high demands) or passive jobs (low control and low demands). There were no significant differences between the groups during other parts of the day and furthermore there was no difference between the job strain, active and passive groups. For men, no differences were found between demand control groups. CONCLUSION: This population-based study, on a relatively large sample, weakly support the hypothesis that the demand control model is associated with saliva cortisol concentrations.

Salivary cortisol, a biological marker of stress, is positively associated with 24-hour systolic blood pressure in patients with acute ischaemic stroke.

BACKGROUND/AIM: The cause of elevated blood pressure (BP) in acute stroke is unknown. Stress is often suggested as a main contributing factor. We aimed to investigate the relationship between BP and stress in patients with acute stroke. METHODS: 58 patients with clinical symptoms of stroke were recruited prospectively after exclusion of haemorrhage by CT scan within 14 h and 15 min (mean) after symptom onset (range 2 h and 45 min-23 h and 40 min). The mean age of the patients was 66 years (range 39-86 years), and the mean National Institute of Health Stroke Scale score was 7 (range 1-26). BP and pulse rate were recorded by non-invasive automatic monitoring hourly for 24 h. Stress was evaluated by testing the level of salivary cortisol. Four samples of saliva were obtained at inclusion, on the evening of the inclusion day (20.00-22.00 h), on the morning of the next day (7.00-9.00 h) and on the afternoon of the inclusion day/next day (15.00-17.00 h) within 24 h after inclusion in the study. Logarithmic transformation was done for cortisol levels. RESULTS: The 24-hour mean cortisol level (geometric mean 13.6 nmol/l) was related to 24-hour mean systolic BP [SBP; r = 0.36, p = 0.01, multivariate p = 0.02], mean night-time (22.00-6.00 h) SBP (r = 0.43, p = 0.001, multivariate p < 0.005) and mean night-time diastolic BP (r = 0.31, p = 0.02, multivariate p = 0.02). Cortisol levels at inclusion (r = 0.31, p = 0.02, multivariate p = 0.05 for 24-hour SBP) and in the evening were also statistically significantly related to the above BP variables. The morning cortisol (r = 0.28, p = 0.04, multivariate p = 0.04) was related to night-time SBP. CONCLUSIONS: Salivary cortisol was positively correlated with 24-hour SBP and night-time BP, suggesting that stress is a contributing factor for high BP in acute stroke.