Diurnal dynamic range as index of dysregulation of system dynamics. A cortisol examplar using data from the Study of Midlife in the United States. (August 2022)

• Record Type: Journal Article
• Authors: Karlamangla, Arun S.; Almeida, David M.; Lachman, Margie E.; Merkin, Sharon Stein; Thomas, Duncan; Seeman, Teresa E.
• Is Part Of: Psychoneuroendocrinology. Volume 142(2022)
• Publication Date: 2022-08
• Subjects: AUC Area under the curve (used here for area under the log-cortisol curve over 16 h, start from time of waking) -- MIDUS Midlife in the United States -- NSDE National Study of Daily Experiences; Cortisol diurnal peak and nadir -- Allostatic load -- HPA axis dysregulation -- Cortisol area under the curve -- Cognitive decline -- All-cause mortality; Psychoneuroendocrinology -- Periodicals; Endocrinology -- Periodicals; Neurology -- Periodicals; Psychiatry -- Periodicals; Neuropsychoendocrinologie -- Périodiques; 616.8
• DOI: 10.1016/j.psyneuen.2022.105804
• Languages: English
• ISSNs: 0306-4530

Abstract

Abstract: We discuss the importance of including measures of dysregulated system dynamics in the operationalization of allostatic load. The concept of allostatic load, as originally proposed by McEwen and Stellar, included dysregulation not only in the resting state of physiological systems, but also in system dynamics. We describe previous work on cortisol diurnal dynamic range (peak to nadir spread) as an index of the health of the hypothalamic-pituitary-adrenal axis, with compression of dynamic range being a marker of dysregulation. In particular, we review the evidence for a) diurnal dynamic range compression in people from disadvantaged backgrounds, b) cross-sectional association of cortisol diurnal dynamic range compression with dysregulation in other systems' resting states, and c) cross-sectional association of cortisol diurnal dynamic range compression with lower scores on cognitive testing. Then, we present new data from the Study of Midlife in the United States (MIDUS) on longitudinal associations of cortisol dynamic range compression with subsequent cognitive decline and all-cause mortality. Briefly, each standard deviation decrement in cortisol diurnal dynamic range is associated with adjusted mortality hazard ratio of 1.35 (95% confidence interval: 1.19, 1.54). Among those who scored at median or lower in executive functioning at baseline and survive, each standard deviation decrement in cortisol dynamic range is associated with 1% greater decline in executive functioning over a decade (95% confidence interval: 0.4%, 2.0%). We conclude that including measures of system dynamics like diurnal dynamic range in the next generation of allostatic load measurement will likely advance understanding of the cumulative physiological burden of chronic stress and life experiences, and improve the prediction of future health consequences. Highlights: Cortisol diurnal peak to nadir dispersion is compressed in individuals who have experienced life adversities. Smaller cortisol diurnal dynamic range is associated with faster decline in executive functioning in some. Smaller cortisol diurnal dynamic range is strongly associated with increased all-cause mortality rate. Diurnal dynamic range measures need to be included in future generations of allostatic load score.