Stress, cortisol and central obesity in middle aged adults

Introduction: Obesity is associated with various psychological and physiological disturbances. Of interest is the relationship between central obesity and psychological stress. Central obesity is characterised by increased adipose tissue, often associated with glucocorticoid excess, specifically, the stress hormone cortisol. Consequently, a disturbed cortisol basal diurnal rhythm and impaired responses to psychological stress in middle aged adults with central obesity may be observed. Method: In study one, basal diurnal cortisol profiles were examined (n=147; mean = 46.21 ± 7.18 years) in a sample of high and low waist-hip ratio (WHR) males and females. Profiles were explored in terms of the area under the curve (AUC) of the cortisol-awakening response and diurnal decline. In study two, cortisol responses to a psychological stressor versus no-stress control (n=66; mean = 46 ± 7.17 years) in a sample of high and low WHR individuals were explored. Results: Blunted cortisol profiles, characterised by a reduced AUC, were observed in the majority (78%) of a middle-aged sample and were associated with significantly greater WHR. Further, blunted cortisol profiles were associated with a less favourable metabolic profile. When exposed to a psychological stressor, high WHR individuals, specifically males, tended to secrete greater cortisol. Conclusion: The findings suggest that central obesity is associated with altered cortisol responsivity. This highlights the vulnerability of high WHR individuals to stress related illness and disease. Further research, however, is required to elucidate whether stress exposure increases the propensity for central obesity or whether central obesity elevates stress responsivity