Diurnal salivary cortisol is associated with body mass index and waist circumference: The multiethnic study of atherosclerosis

Abstract

Objective: Neuroendocrine abnormalities, such as activation of the hypothalamic-pituitary-adrenal (HPA) axis, are associated with obesity; however, few large-scale population-based studies have examined HPA axis and markers of obesity. We examined the cross-sectional association of the cortisol awakening response (CAR) and diurnal salivary cortisol curve with obesity. Design and Methods: The Multiethnic Study of Atherosclerosis Stress Study includes 1,002 White, Hispanic, and Black men and women (mean age 65 6 9.8 years) who collected up to 18 salivary cortisol samples over 3 days. Cortisol profiles were modeled using regression spline models that incorporated random parameters for subject-specific effects. Cortisol curve measures included awakening cortisol, CAR (awakening to 30-min postawakening), early decline (30 min to 2-h postawakening), late decline (2-h postawakening to bedtime), and the corresponding areas under the curve (AUC). Body mass index (BMI) and waist circumference (WC) were used to estimate adiposity. Results: For the entire cohort, both BMI and WC were negatively correlated with awakening cortisol (P < 0.05), AUC during awakening rise, and early decline and positively correlated to the early decline slope (P < 0.05) after adjustments for age, race/ethnicity, gender, diabetes status, socioeconomic status, bblockers, steroids, hormone replacement therapy, and smoking status. No heterogeneities of effects were observed by gender, age, and race/ethnicity. Conclusions: Higher BMI and WC are associated with neuroendocrine dysregulation, which is present in a large population sample, and only partially explained by other covariates.

Hypothalamic-pituitary-adrenal axis dysregulation and cortisol activity in obesity: A systematic review

“…As such, it is thus far unclear whether a consistent relationship exists between cortisol slope and either type of obesity. It does appear, however, that flatter, less sharply declining slopes are generally related to BMI and WHR, a finding supported by the strongest studies reviewed here (Champaneri et al, 2013;Steptoe et al, 2004). Both of these studies incorporate multiple sampling time points, which allows for a more precise slope measurement.…”

“…Of note, this is the only study reviewed here that uses a longitudinal design which revealed that body size at baseline was positively associated with increases in cortisol concentrations seven years later without any increased BMI. Finally, one study found no relationship between BMI and total output, as measured by AUC (Champaneri et al, 2013).…”

“…For example, one study of middle-aged men found that morning cortisol concentrations were inversely related to WHR (Ljung et al, 1996). Another study in a large sample (n = 1002) of men and women found that BMI and waist circumference were negatively correlated with CAR (Champaneri et al, 2013). In a female sample, obese women showed a more blunted CAR than non-obese women (Ranjit et al, 2005).…”

“…We suspect that this blunted CAR is the more reliable perturbation. For example, one of the strongest studies in terms of methodology (Champaneri et al, 2013), which conducted multi-point diurnal saliva sampling across three days in a large sample of men and women, evidences this negative relationship between obesity and CAR. Finally, considering that all but one reviewed study (Ursache et al, 2012), measured CAR as the difference between waking cortisol and thirty minutes postwaking, we recommend that future research incorporate smaller time intervals (e.g., 15 min), especially given that different trends at the 15-min interval level can have a marked impact on the resulting CAR calculation (Fekedulegn et al 2007).…”

“…There are only 5 studies reviewed here that examined either whole slope or proxies of diurnal slope and general or abdominal obesity. One study of a large sample of men and women found that BMI was negatively correlated with the early decline (the decline in cortisol observed after the initial CAR, 30 min to 2 h post awakening) and thus positively correlated with the slope of the early decline (Champaneri et al, 2013). This indicates a failure to fully recover from the initial CAR, which suggests sustained increased cortisol concentrations throughout the day.…”