Salivary cortisol levels and work-related stress among emergency department nurses

The objective of this study was to assess and compare the self-perceived work-related stress of emergency department (ED) and general ward (GW) nurses and to assess the relationship between self-perceived stress and salivary cortisol levels in these groups of nurses. Seventy-three female ED (n = 23) and GW (n = 50) nurses from a general hospital completed a self-administered questionnaire. A modified mental health professional stress scale (PSS) was used to measure self-perceived work-related stress. Salivary samples were collected at the start and end of morning shiftwork. An enzyme-linked immunosorbent assay method was used to determine the salivary cortisol concentration (nmol/L). ED nurses perceived that nursing was more stressful (mean, 1.58; 95% confidence interval [CI], 1.35 to 1.81) than did GW nurses (mean, 1.30; 95% CI, 1.18 to 1.40). On the PSS subscales, scores of organizational structure and process, lack of resources, and conflict with other professionals were higher in ED nurses (all P < 0.01). The morning cortisol was significantly lower in ED (geometric mean, 9.10; 95% CI, 6.62 to 12.42 nmol/L) than in GW (geometric mean, 15.45; 95% CI, 11.86 to 20.14 nmol/L) nurses. Log morning salivary cortisol was negatively correlated with PSS (r = -0.255), scores of organizational structure and process, and conflict with other professionals (all P < 0.05). The difference between morning and afternoon cortisol concentration in ED nurses (geometric mean, 6.35; 95% CI 4.14 to 9.93 nmol/L) was lower than in GW nurses (geometric mean, 12.42; 95% CI, 9.38 to 16.28 nmol/L). The log value of the difference correlated marginally with PSS (r = -0.21, P = 0.07) and significantly with scores of organizational structure and process, lack of resources, and conflict with other professionals (all P < 0.05). There was no difference between the two groups in afternoon salivary cortisol level. ED nurses perceived more stress compared with GW nurses. Morning salivary cortisol concentration is better correlated with PSS compared with the morning-afternoon salivary cortisol difference. The result raises the possibility of using a single morning salivary cortisol sample to reflect self-perceived stress.