Antecedent longitudinal changes in body mass index are associated with diurnal cortisol curve features: The multi-ethnic study of atherosclerosis

Abstract

Context: Prior studies have shown a cross-sectional association between body mass index (BMI) and salivary diurnal cortisol profile features (cortisol features); however, to our knowledge prior population-based studies have not examined the longitudinal association of body-mass index (BMI) with cortisol features.

Objective: To examine the association of (1) prior annual BMI percent change over 7years with cortisol features, (2) baseline cortisol features with subsequent change in BMI over 6years and (3) the association of change in cortisol features with change in BMI over 6years.

Design: Longitudinal study.

Setting: Multi-Ethnic Study of Atherosclerosis (MESA) Stress I & II Studies (2004-2006 & 2010-2012).

Participants: 1685 ethnically diverse men and women attended either MESA Stress exam (mean age 65±10years at MESA Stress I; mean age 69±9years at MESA Stress II).

Outcome measures: Log-transformed cortisol features including wake-up cortisol, cortisol awakening response, early decline slope (30min to 2h post-awakening), late decline slope (2h post-awakening to bedtime), bedtime, and total area under the curve (AUC) cortisol.

Results: Over 7years, following multivariable adjustment, (1) a 1% higher prior annual BMI % increase was associated with a 2.9% (95% CI: -5.0%, -0.8%) and 3.0% (95% CI: -4.7%, -1.4%) lower current wake-up and total AUC cortisol, respectively; (2) there was no significant association between baseline cortisol features and subsequent change in BMI and (3) among participants with BMI≥30kg/m², flattening of the late decline slope was associated with increases in BMI (every 1-unit increase late decline slope were associated with a 12.9% increase (95%CI: -1%, 26.8%) in BMI, respectively).

Conclusions: We found a significant association between prior annual BMI % change and cortisol features, but no significant association between baseline cortisol features and subsequent change in BMI. In participants with obesity increases in BMI were associated with less pronounced declined. Collectively, our results suggest that greater adiposity may lead to a blunted diurnal cortisol profile.

Keywords: Body mass index; Cortisol; Hypothalamic–Pituitary–Adrenal axis; Obesity; Waist circumference.

Figure 1

Diurnal Cortisol Profile: Summary of diurnal cortisol features. Key: A. Wake-up cortisol (Time 0) B. Cortisol awakening response (0 minutes to 30 minutes) C. Early decline slope cortisol (30 minutes to 2 hours) D. Late decline slope cortisol (2 hours to bedtime) E. Bedtime cortisol F. Total area under the curve (0 minutes to bedtime) cortisol

Figure 2

Associations of 7 years of prior percent change in waist circumference with cortisol features Key: A. Wake-up cortisol (Time 0) B. Cortisol awakening response (0 minutes to 30 minutes) C. Early decline slope cortisol (30 minutes to 2 hours) D. Late decline slope cortisol (2 hours to bedtime) E. Bedtime cortisol F. Total area under the curve (0 minutes to bedtime) cortisol Red Line - Reference Diurnal Cortisol Profile Yellow Line – Change in diurnal cortisol profile per 1% higher prior annual waist circumference change (significant features denoted by yellow dashed arrow) Fully adjusted for cortisol feature at stress exam as outcome variables and include waist circumference prior annual percent change and MESA Stress study indicator as covariates, waist circumference at MESA Exam 1, demographic variables (Age, Race, Sex) and Socioeconomic Status (gross family annual income) at stress exam when cortisol feature was measured, diabetes, depression symptoms (Center for Epidemiologic Studies Depression), medications (beta-blocker, hormone replacement therapy, aspirin), and health behaviors (current smoking status, physical activity) at stress exam when cortisol feature was measured.

Figure 3

Associations of baseline cortisol features with subsequent changes in waist circumference over 6 years. Key: A. Wake-up cortisol (Time 0) B. Cortisol awakening response (0 minutes to 30 minutes) C. Early decline slope cortisol (30 minutes to 2 hours) D. Late decline slope cortisol (2 hours to bedtime) E. Bedtime cortisol F. Total AUC (0 minutes to bedtime) cortisol Red Line – Reference Diurnal Cortisol Profile Yellow Line – Change in diurnal cortisol profile per 1% higher prior annual waist circumference change (significant features denoted by yellow dashed arrow) Adjusted for waist circumference at stress exam as outcome variables and includes time (years since MESA Stress I) and the interaction term of baseline cortisol feature with time, the interaction terms of baseline demographic variables (Age, Race, Sex, Socioeconomic Status (gross family annual income)) with time and the interaction terms of baseline diabetes, depression symptom (Center for Epidemiologic Studies Depression), medications (beta-blocker, hormone replacement therapy, aspirin), and health behavior (current smoking status and physical activity) with time.

Figure 4A

Associations of within person percent changes in body mass index with a 1-unit within person increase in the late decline slope over 6 years stratified by baseline World Health Organization body mass index category. Fully Adjusted for body mass index (log-transformed) at MESA Stress Exam as outcome variables and included time (years since MESA Stress I) and the time varying cortisol curve feature, the interaction terms for baseline demographic variables (age, race, sex) with time and the time-varying measures of self-reported annual gross family income, time-varying diabetes status, depression symptoms (Center for Epidemiologic Studies Depression), medication use (beta-blocker, hormone replacement therapy, aspirin), and health behaviors (current smoking status and physical activity). # p=0.05

Figure 4B

Associations of within person percent changes in waist circumference with a 1-unit within person increase in the late decline slope over 6 years stratified by baseline World Health Organization body mass index category Fully Adjusted for waist circumference (log-transformed) at MESA Stress Exam as outcome variables and included time (years since MESA Stress I) and the time varying cortisol curve feature, the interaction terms for baseline demographic variables (age, race, sex) with time and the time-varying measures of self-reported annual gross family income, time-varying diabetes status, depression symptoms (Center for Epidemiologic Studies Depression), medication use (beta-blocker, hormone replacement therapy, aspirin), and health behaviors (current smoking status and physical activity).