Associations between depressive mood, health behaviour, and diurnal cortisol slopes among women with breast cancer — ASN Events
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  3. Associations between depressive mood, health behaviour, and diurnal cortisol slopes among women with breast cancer

Associations between depressive mood, health behaviour, and diurnal cortisol slopes among women with breast cancer (#503)

Rie Tamagawa 1 2 , Michael Speca 1 2 , Janine Giese-Davis 1 2 , Richard Doll 3 , Joanne Stephen 3 , Linda E Carlson 1 2
  1. Psychosocial resources, Alberta Health Services, Tom Baker Cancer Centre, Calgary, AB, Canada
  2. University of Calgary, Calgary, AB, Canada
  3. BC Cancer Agency, Vancouver, BC, Canada

Background: Chronic experience of depressive mood has been associated with aberrant diurnal cortisol rhythms, which is one of the risk factors for early mortality among individuals with cancer. In contrast, some health behaviour, specifically, regular exercise has been shown to improve mood, and attenuate cortisol levels at certain times of a day. However, little is known about how these psychological and behavioural factors are associated with diurnal cortisol rhythms, which are especially disease-relevant for cancer patients.

Objectives: This study examined the relationships between depressive mood, health behaviour, and diurnal cortisol rhythms.

Methods: A total of 277 breast cancer patients were recruited from tertiary cancer clinics in Calgary and Vancouver. Participants were asked to complete questionnaires assessing health behaviour including quality of sleep and diet, daily duration of exercise, and depressive mood, and to collect a saliva sample at awakening, noon, 5pm and bedtime for three consecutive days, which were used to calculate diurnal cortisol slopes. Hierarchical multiple regression analyses were conducted to examine the relative importance of psychological and behavioural factors in their association with the cortisol slopes.

Results: A longer duration of daily exercise was associated with steep, healthier cortisol slopes. Unexpectedly, greater cancer severity was also associated with steep cortisol slopes. Depressive mood was more strongly associated with diurnal cortisol slopes over and above the medical and behavioural factors. High levels of depressive mood were associated with aberrant diurnal cortisol rhythms. Greater daily exercise contributed to higher morning cortisol levels, while greater depressive mood contributed to lower bedtime cortisol levels.

 Conclusions: Psychological morbidity relative to the behavioural and medical factors was more strongly associated with physiological regulation of cortisol. Promoting regular exercise and alleviating depressive mood may be important to restore physiological regulation, particularly for individuals with high levels of depressive mood and a difficulty engaging in exercise.