Salivary cortisol waking response is higher in healthy girls than boys

  • MD, PhD Walter Osika, Stress Research Institute, Stockholm university, Sweden
  • PhD Yun Chen, Clinical Physiology, Sahlgrenska University Hospital, Sweden
  • MD, PhD Peter Friberg, Clinical Physiology, Sahlgrenska University Hospital, Sweden
  • MD, PhD Frida Dangardt, Clinical Physiology, Sahlgrenska University Hospital, Sweden
  • PhD Scott Montgomery, Department of Medicine, Karolinska University Hospital, Clinical Epidemiology Unit, Sweden

Objective: Childhood living conditions and exposures can influence health throughout life. Salivary cortisol, particularly the cortisol waking response (CWR) indicates hypothalamic-pituitary-adrenocortical system activity, also considered a stress marker. We hypothesised that CWR is higher in girls, reflecting increased level of stress.

Methods: Saliva samples were collected in 207 healthy school children (10ą1.5 meanąsd, 101 girls) on an ordinary school day by chewing a cotton swab immediately on waking up and 15 minutes later. The difference between these two values defined CWR. Psychological wellbeing was measured using 8 items, used by the Swedish National Board of Health and Welfare: Had difficulty in concentrating, had difficulty in sleeping, suffered from headaches, suffered from stomach aches, felt tense, had little appetite, felt sad, and felt dizzy. The response categories were: never, seldom, sometimes, often, and always. The answers were summed to create a total score. Linear regression was used to investigate associations with CWR and psychological wellbeing score, with adjustment for age and sex.

Results: Girls had a higher CWR compared with boys indicated by a regression coefficient (95% CI) of 0.181 (0.057, 0.304; P=0.004). A higher psychological wellbeing score was negatively associated with CWR: -0.018 (-0.032, -0.005; p=0.007). On average, girls reported more symptoms in the wellbeing score.

Conclusions: Low psychological wellbeing in children was associated with a less pronounced CWR, possibly due to chronic arousal. Girls either experience more symptoms or are more likely to report them. The higher CWR among girls compared with boys may reflect developmental differences.