Change in quality of life over eight years in a nationally representative sample of US adults with heart disease and type 2 diabetes:minority race and toxic stress as keysocial determinants

Background
Toxic stress (TS), minority race and their interaction are evaluated as determinants of change in quality of life (QOL) over 8 years follow-up in a nationally representative sample of United States (US) adults (≥50 years old) with heart disease (HD) and/or type-2 diabetes (T2DM) diagnosed by 2006 as part of the Health and Retirement Study (HRS).

Methods
Recent and life-course stress plus experiences of lifetime discrimination were measured every 2 years using the stressful life experiences questionnaire. QOL was assessed by participant self-rated health (SRH) and operationally defined as improved, unchanged or declined in current year versus two years prior. Repeated measures multinomial logistic regressionusing generalized estimating equations (GEEs) was implemented to estimate race-, TS and their interaction- related odds of worse SRH from2006–2014. Odds ratios (OR) and 95% confidence intervals (CIs) were calculated with adjustment for time, age, sex and socio-economic status.

Results
Three thousand nine hundred four adults with HD/T2DM, mean age 71.1 ± 9.3 years old, 80.9, 14.7 and 4.4% that respectively self-identified as Caucasian, African-American and Other race, were included. Over the eight-year follow-up, the odds of worse SRH for African-American and Other race were respectively 1.46 (95% CI: 1.25–1.70) and 1.43 (95% CI, 1.10–1.86) times higher relative to Caucasians. Relative to older Americans that reported ≥2 lifetime discrimination events, the odds of poor SRH was respectively 33% (OR = 0.67, 95%CI: 0.50–0.89) and 17% (OR = 0.83, 95%CI: 0.59–1.17) lower for those that reported none vs one lifetime discrimination experience. Furthermore, the relationship of life-course stress to SRH decline over 8 years varied by race (time*stress*race, p = 0.1173). Specifically, increasing life-course stress predicted worse QOL among Caucasians (p = 0.0063) and among African-American (p = 0.0820) but not among Other race (p = 0.9943).

Conclusion
Toxic stress and minority race are social determinants of deterioration in QOL among older Americans with chronic diseases (HD/T2DM). The types and prevalence of toxic stressors varied by race/ethnicity. Policy interventions to address root causes of TS while targeted at proximate drivers of TS by race/ethnicity represent a viable strategy for mitigating racial disparities in overall wellbeing and improving QOL in all aging Americans regardless of race.