The Effects of Acute Psychosocial Stress on HPA-Axis and SAM-Axis Function in Men with Type 2 Diabetes Mellitus
Open Access
- Author:
- Walter, Kimberly Nicole
- Graduate Program:
- Biobehavioral Health
- Degree:
- Doctor of Philosophy
- Document Type:
- Dissertation
- Date of Defense:
- December 19, 2013
- Committee Members:
- Laura Klein, Dissertation Advisor/Co-Advisor
Laura Klein, Committee Chair/Co-Chair
David Manuel Almeida, Committee Member
Elizabeth Susman, Committee Member
Sheila Grace West, Committee Member - Keywords:
- Type 2 diabetes mellitus
Acute psychosocial stress
Stress physiology - Abstract:
- Type 2 diabetes mellitus is one of the most common and costly chronic diseases in the United States and the world (Whiting et al., 2011). Scientists estimate that by 2050 one in three Americans will have type 2 DM (Boyle et al., 2010). Although type 2 DM related mortality has declined in recent years, it remains a major public health concern (Whiting et al., 2011). The exact etiology of type 2 DM is not known, but scientists have identified multiple genetic and environmental factors (e.g., obesity, diet, socioeconomic status, physical inactivity) that likely contribute to the pathogenesis and pathophysiology of the disease (Codario, 2011). In recent years, scientists have started to investigate the role of psychological factors, such as psychosocial stress, in the pathophysiology of type 2 DM (Nathan et al., 2009). Data from observational studies provide suggestive evidence that psychosocial stress is a factor affecting type 2 DM onset and progression (e.g., Mommersteeg et al., 2012; Pouwer et al., 2010; Toshihiro et al., 2008). However, the stress physiological mechanisms involved in the relationship are unclear, and there is a paucity of research examining stress physiological processes in individuals with type 2 DM. The primary aim of this dissertation was to determine if men with type 2 DM who do not have major disease-related complications have dysregulated stress systems by examining the effects of acute psychosocial stress exposure on HPA-axis and SAM-axis function. A secondary aim of this dissertation was to investigate if allostatic load, a measure of chronic stress exposure, influences stress physiological processes in men with type 2 DM. This dissertation study used a mixed between- and within subjects-design to examine the effects of type 2 DM and acute psychosocial stress (Trier Social Stress Test) on stress physiology in a sample of 34 men (20 healthy, 14 type 2 DM) between the ages of 25 and 65. Primary dependent measures included biomarkers of the HPA-axis (salivary cortisol, salivary DHEA-S) and SAM-axis (salivary alpha-amylase), as well as allostatic load parameters (cardiovascular, metabolic, neuroendocrine, anthropometric, immune measures). Results revealed that men with type 2 DM displayed significantly higher total allostatic load levels and significantly lower DHEA-S levels compared to healthy men. Furthermore, men with type 2 DM were able to mount both HPA- and SAM-axis responses to the acute stressor that was comparable to the healthy participants. Overall, the findings suggest that men with type 2 DM without major disease-related complications are able to physiologically respond to acute psychosocial stressors, in spite of having increased total allostatic load and decreased DHEA-S levels.