Stability and predictors of change in salivary cortisol measures over six years: MESA

Abstract

Summary A major challenge in characterizing features of the daily cortisol curve is variability in features over time. Few studies have examined the stability of daily features of the cortisol curve over long periods or the predictors of long term changes. Repeated salivary cortisol measures on 580 adults from the MESA Stress study were used to examine the stability of various features of the daily cortisol curve (wakeup value, the cortisol awakening response (CAR), the early and late decline slope and the area under the curve (AUC)), over short periods (several days) and long periods (approximately 6-years) and to investigate the association of demographic factors with the changes. Intraclass correlation coefficients (ICCs) were used to estimate the short and long term stability. Piecewise linear mixed models were used to assess factors associated with changes in features over time. For most features, short term stability (ICCs: 0.17–0.74) was higher than long term stability (ICCs: 0.05–0.42), and long term stability was highest when several days were averaged for each time point. The decline over the day showed the highest long term stability: when several days for each wave were averaged the stability of the daily decline slope across 6 years was similar (or higher) than the stability across short periods. AUC had high stability over short periods (ICCs: 0.65–0.74) but much lower stability across long periods (ICC: 0.05). All features of daily cortisol curve investigated changed significantly over the approximately 6 year follow-up period. The wakeup cortisol became higher; the CAR became smaller; both the early and late decline became flatter; and the AUC became larger. Hispanics experienced significantly larger increases in the wakeup value; and African-Americans and Hispanics showed less flattening over time of the early decline slope than Non-Hispanic Whites. Our findings have implications for characterization of features in studies linking cortisol to health outcomes. The presence of variability over time suggests opportunities for future investigation of the predictors of changes over time as well as the links between these changes and health outcomes.

Association of Sleep Duration and Quality With Alterations in the Hypothalamic-Pituitary Adrenocortical Axis: The Multi-Ethnic Study of Atherosclerosis (MESA)

“…The use of 2 consecutive days is therefore an advantage over single-day studies. In MESA, long-term stability over 6 years is moderate (intraclass correlation 0.25 for the early decline and 0.42 for the late decline) (38). Variability in both sleep and cortisol over time may have attenuated the estimates of the true associations.…”

Daily family stress and HPA axis functioning during adolescence: The moderating role of sleep

“…In particular, studies have found low short-term stability in CAR and the diurnal slope and these HPA parameters are sensitive to situational factors that can result in their day-to-day fluctuations (Ross et al, 2014; Stalder et al, 2016; Wang et al, 2014). Evidence suggests better short-term stability for total daily cortisol output (Rotenberg et al, 2012; Wang et al, 2014). Suggestions on the number of sampling days have varied and depend on the specific HPA parameter.…”

Acute and Chronic Effects of Tantric Yoga Practice on Distress Index

“…These results corroborate the data in the literature showing that despite use of different psychological instruments, practicing yoga had mental beneficial effects. 10 These feelings may related to an increase in the cortisol levels in the morning and a decrease in the cortisol levels before sleep.…”