Stress Reactivity as a Contributor to Racial and Socioeconomic Disparities: Rationale and Baseline Results From the Richmond Stress and Sugar Study

Abstract

Objective There are pronounced racial and socioeconomic disparities in type 2 diabetes. Although “stress” as a general phenomenon is hypothesized to contribute to these disparities, few studies have objective measures of stress reactivity in diverse samples to test hypotheses about purported mechanisms. This study describes the rationale and baseline characteristics of a cohort designed to address the question: how does stress contribute to disparities in diabetes risk? Methods The Richmond Stress and Sugar Study recruited 125 adults at elevated risk of type 2 diabetes using a two-by-two sampling frame wherein non-Hispanic whites and African Americans (AAs) were each recruited from neighborhoods of higher and lower socioeconomic status (SES). Stress reactivity was assessed using the Trier Social Stress Test (TSST) and salivary cortisol. Analyses of variance and multilevel modeling were used to examine how stress reactivity varied both within and across race and neighborhood SES. Results The mean (SD) age was 57.4 (7.3) years, 49% were female, 54% were AA or another racial/ethnic minority, and mean hemoglobin A1c level was in the prediabetes range (5.8%; range, 5.50%–5.93%). Living in a lower-SES neighborhood was associated with 16% (95% confidence interval [CI] = −0.04 to 34) higher pre-TSST cortisol, 8.4% (95% CI = −14 to −3) shallower increase in response to the TSST, and 1% (95% CI = 0.3 to 1.7) steeper decline post-TSST than living in the higher neighborhood SES. Post-TSST cortisol decline was 3% greater among AA compared with non-Hispanic whites. Race-by-SES interaction terms were generally small and nonsignificant. Conclusions SES is associated with stress reactivity among adults at high risk of diabetes.

Psychosocial Stress and Hypothalamic-Pituitary-Adrenal Axis Stress Reactivity: Variations by Race and Socioeconomic Status Among Adults at Risk of Diabetes

“…Samples were stored at −20°C and processed in 27 batches using Enzyme Immuno-Assay (Salimetrics LLC). Intra-assay coefficient of variation was 4.07%, which was within the manufacturer-reported range (20).…”

“…Participants’ addresses were geocoded using geographic information system and linked to the 2010 Census to index area-level (hereafter neighborhood ) SES. Details of constructing the composite measure are described elsewhere (20). Briefly, a composite census tract measure was created using information on median household income, ownership, and value of housing units.…”

“…Briefly, a composite census tract measure was created using information on median household income, ownership, and value of housing units. The neighborhoods were assigned as “high” and “low” SES based on the top and bottom tertiles of the composite SES index, respectively (20). Race/ethnicity (coded as “NHW” and “NHB”) was self-reported.…”

Self-Regulatory Coping Behaviors and Stress Reactivity: Exploring the Environmental Affordance Model of Health Disparities

“…Eight salivary cortisol samples were taken to characterize the HPA-axis response: two pre-stress taken 15 minutes apart, and six post-stress, beginning immediately after the task, and thereafter every 15 minutes. Details of how the TSST was implemented in RSASS have been described previously (Mezuk et al, 2020). Briefly, the TSST began at 5:00 pm for all participants after resting quietly for approximately 30 minutes.…”

“…Sample. Details of the study design and inclusion/exclusion criteria of the RSASS are described elsewhere (Mezuk et al, 2020). Briefly, targeted recruitment of adults aged 40-70 who were at elevated risk of T2D was facilitated using geocoded healthcare records.…”