Author	R. Hackett
Author	A. Steptoe
Author	M. Hamer
Abstract	Type II diabetes increases the risk of cardiovascular disease. Evidence suggests that psychosocial stress is involved in both conditions but the biological pathways involved are poorly understood. This PhD investigated the role of psychosocial wellbeing and stress-related biological processes in diabetes. Studies 1 and 2 used acute laboratory stress testing to assess biological stress responses in people with diabetes. Studies 3 and 4 used data from a large population dataset to assess associations between cortisol and diabetes. Study 1 tested the notion that people with diabetes experience stress-related disturbances across multiple biological systems, coupled with heightened life stress. A comparison of laboratory stress responses in people with diabetes and matched controls was conducted. The results suggested that people with diabetes have dysregulated biological responses to stress and increased exposure to life stress. Study 2 assessed whether hostility (a psychosocial factor) exaggerated the pattern of disturbances in stress responsivity seen in Study 1, looking at the diabetes group alone. The findings suggest that high hostile individuals with diabetes have heightened inflammatory stress responses and blunted cortisol stress responses in comparison to low hostile individuals. Studies 3 and 4 assessed neuroendocrine disturbances in diabetes using Whitehall II study data. Study 3 assessed whether daily cortisol output differs between people with and without diabetes cross-sectionally. The findings suggested that people with diabetes have a flatter slope in cortisol output combined with heightened evening cortisol concentrations. 4 Following on from this Study 4 used a prospective approach to assess whether components of daily cortisol output are linked to future diabetes in an initially healthy sample. The results suggested that raised evening cortisol levels are predictive of new onset diabetes over a 9 year follow-up period. In combination, these studies contribute to the literature linked diabetes with poor psychosocial wellbeing and stress-related alterations in biological processes.