Developmental origins of flatter cortisol rhythms: socioeconomic status and adult cortisol activity.

OBJECTIVE: Low socioeconomic status (SES) is associated with increased psychosocial stress among low-income persons, which could contribute to differences in activity of the HPA axis (assessed by diurnal cortisol profiles). The current article investigates associations of SES from different developmental stages with cortisol profiles. METHODS: Using data from a large, socioeconomically diverse birth cohort (N = 1,490) in Cebu, Philippines, the current study compares the relative and joint contributions of SES from five developmental periods, between the prenatal/birth period and early adulthood, to adult cortisol, and examines the effects of chronic exposure to low SES. RESULTS: Chronically low SES from infancy through early adulthood predicts the highest bedtime cortisol levels, lowest cortisol awakening responses (CARs), lowest total cortisol levels across the day (area under curve or AUC), and the flattest cortisol rhythms between wake up and bedtime, a profile associated with poorer health. Results indicate that cumulative economic strain (between the prenatal period and early adulthood) predicts flatter cortisol rhythms more consistently than SES from any particular period. CONCLUSION: Interventions focusing on the psychosocial stressors associated with economic deprivation during any period from infancy to adulthood may be helpful, but targeting interventions across multiple periods may have the greatest impact. Interventions aimed at improving economic conditions between infancy and early adulthood may have implications for long-term changes in HPA axis functioning.

Associations of neighborhood characteristics with sleep timing and quality: the Multi-Ethnic Study Of Atherosclerosis.

STUDY OBJECTIVES: To investigate the associations of specific neighborhood features (disorder, safety, social cohesion, physical environment, and socioeconomic status) with sleep duration and quality. DESIGN: Cross-sectional. One wave of a population-based study (Multi-Ethnic Study of Atherosclerosis). SETTING: Community-dwelling participants in New York, NY and Los Angeles, CA. PARTICIPANTS: There were 1,406 participants (636 males, 770 females). INTERVENTIONS: NA. MEASUREMENTS AND RESULTS: Sleep was assessed using reported hours of sleep, the Epworth Sleepiness Scale, and insomnia symptoms. Neighborhood characteristics were assessed via questionnaires administered to neighbors of study participants and were aggregated to the neighborhood (census tract) level using empirical Bayes estimation. An adverse social environment (characterized by high disorder, and low safety and social cohesion) was associated with shorter sleep duration after adjustment for the physical environment, neighborhood and individual-level socioeconomic status (SES), and other short sleep risk factors (mean difference per standard deviation increase in summary social environment scale 0.24 h 95% confidence interval 0.08, 0.43). Adverse neighborhood social and physical environments, and neighborhood SES were associated with greater sleepiness, but associations with physical environments were no longer statistically significant after adjustment for sociodemographic characteristics. Neighborhood SES was a weaker and less consistent predictor of specific measures of neighborhood social and physical environments. Neighborhood characteristics were not associated with insomnia. CONCLUSIONS: Shortened sleep related to adverse social environments represents one potential pathway through which neighborhoods may influence health.

Racial/ethnic differences in cortisol diurnal rhythms in a community sample of adolescents.

PURPOSE: To identify potential physiological pathways to racial disparities in health outcomes, this study uses cortisol data collected from a community sample of 255 adolescents to examine whether there are racial/ethnic differences in cortisol slopes and levels across the waking day in naturalistic settings. METHODS: This study uses salivary cortisol data (sampled five times per day over 3 days) to examine racial/ethnic differences in diurnal cortisol rhythms, while covarying the presence of major depressive disorder and chronic and episodic life stress (assessed by structured interviews), momentary negative emotion (reported in diaries completed with cortisol samples), and socioeconomic status, sleep, and health variables (assessed by questionnaire) previously found to be associated with cortisol levels. RESULTS: African-American and Hispanic youth were found to have flatter cortisol slopes across the waking day than their Caucasian counterparts. Differences are due to higher bedtime cortisol levels among Hispanics and to both lower wakeup and higher bedtime levels among African-Americans. Although higher levels of negative emotion were associated with flatter diurnal rhythms, the socioenvironmental factors examined failed to explain the observed racial/ethnic differences in diurnal cortisol rhythms. CONCLUSIONS: Significantly flatter diurnal cortisol slopes were found among African American and Hispanic adolescents, a pattern which has been related to negative health consequences. Further research is needed to examine how early these differences emerge and to identify their developmental origins. Although genetic contributions are possible, greater prenatal stress exposure, low birth weight, adverse early childhood experiences, experiences with racism or discrimination, and lifetime history of chronic stress are all reasonable psychosocial hypotheses to pursue.