Central adiposity and cortisol responses to waking in middle-aged men and women.
OBJECTIVE
Central obesity is associated with disturbances of hypothalamic-pituitary-adrenocortical (HPA) axis function. We investigated whether central adiposity indexed by waist/hip ratio is related to cortisol responses to waking and other measures of salivary cortisol over the working day.


METHODS
In total, 89 men and 83 women aged 47-59 y recruited from the British civil service. All were members of the Whitehall II epidemiological cohort.


METHODS
Saliva samples were collected on waking, 30 min later, and then at 2-h intervals from 0800-0830 to 2200-2230. A strict procedure for excluding individuals who did not adhere to the sampling schedule was applied.


RESULTS
Waist/hip ratio in men was positively correlated with the cortisol response to waking (30 min-waking value) after adjusting for age, socioeconomic position, smoking status, alcohol consumption, time of waking, and cortisol level on waking (r=0.29, P=0.009). The cortisol response to waking was negatively related to high-density lipoprotein (HDL) cholesterol (r=-0.25) and positively with total/HDL cholesterol ratio (r=0.25). Associations between the decline in cortisol over the day and waist/hip ratio, HDL cholesterol and total/HDL cholesterol ratios were also significant. No associations were significant in women, and body mass index was unrelated to cortisol.


CONCLUSIONS
The cortisol response to waking is a dynamic indicator of HPA function that has previously been related to chronic psychological stress. These results confirm a recent Swedish study, and indicate that cortisol responses to waking may be indicative of neuroendocrine disturbance in central obesity.
Steptoe
A
A
Department of Epidemiology and Public Health, University College London, London, UK. a.steptoe@ucl.ac.uk
Kunz-Ebrecht
S R
SR
Brydon
L
L
Wardle
J
J
D000273:Adipose Tissue / Q000473:pathology*; D001824:Body Constitution; D002784:Cholesterol / Q000097:blood; D008076:Cholesterol, HDL / Q000097:blood; D002940:Circadian Rhythm; D005260:Female; D006801:Humans; D006854:Hydrocortisone / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000097:blood / Q000378:metabolism* / Q000473:pathology; D012463:Saliva / Q000378:metabolism; D012737:Sex Factors; D014851:Wakefulness
D008076:Cholesterol, HDL; D002784:Cholesterol; D006854:Hydrocortisone