Understanding the relationship between perceived discrimination, allostatic load, and all-cause mortality in US older adults: A mediation analysis.

OBJECTIVE: To understand the relationship between perceived discrimination, allostatic load, and all-cause mortality; and to determine whether allostatic load is a mediator in the relationship between perceived discrimination and all-cause mortality among an older adult US population. METHODS: Data from the Health and Retirement Study (2006-2012) was analyzed. Cox proportional hazard models were used to investigate the relationship between all-cause mortality and perceived discrimination, and all-cause mortality and allostatic load. Linear regression models were used to investigate the relationship between perceived discrimination and allostatic load. A mediation model with perceived discrimination and allostatic loads as independent variables was used to determine the association with all-cause mortality. RESULTS: There were 5062 adults over the age of 50 included in the analysis. The relationship between perceived discrimination and allostatic load was statistically significant (b:0.14, [95%CI 0.10,0.19]; p < 0.001). The relationship between perceived discrimination and all-cause mortality was statistically significant (HR: 1.12, [95%CI 1.03,1.22]; p = 0.01). The relationship between allostatic load and all-cause mortality was statistically significant (HR: 1.11, [95%CI 1.08,1.13]; p < 0.001). The mediation model resulted in a decrease in hazard ratio and loss of statistical significance for perceived discrimination (HR: 1.09, [95%CI 0.98,1.21]; p = 0.13) when allostatic load (HR: 1.17, [95%CI 1.10,1.24]; p < 0.001) was added to the Cox regression model, indicating full mediation. CONCLUSIONS: Allostatic load fully mediates the relationship between perceived discrimination and all-cause mortality. Understanding the role of allostatic load in this relationship provides an additional implication for screening and indications for tighter control of the modifiable components of allostatic load by healthcare providers, especially among individuals who experience discrimination.

Trends in prevalence of depression and serious psychological distress in United States immigrant and non-immigrant populations, 2010 - 2016.

OBJECTIVE: To examine the prevalence of depression and serious psychological distress (SPD) among adult United States (US) immigrants and US-born; and to investigate trends in depression and SPD. METHODS: National Health Interview Survey data (2010 - 2016) was analyzed. Chi-square tests were used to measure differences in prevalence of SPD between US-born and immigrants, and differences in prevalence of depression. Logistic regression models were used to measure the association between mental health outcomes (depression, SPD) and predictors (nativity, length of residence). General linear models were used to investigate depression and SPD trends. RESULTS: 101,142 US adults were included in the analysis. Immigrants were found to be 11% (OR 0.89, 95% CI [0.85,0.95]) less likely to suffer from depression compared to US-born. US-born (p<0.0001) had a higher prevalence of depression compared to immigrants, and prevalence of depression decreased overtime (p=0.011) for immigrants and US-born individuals. Immigrants who lived in the US 15+ years were 17% (OR 1.17, 95% CI [1.00,1.36]) more likely to have SPD compared to those who were born in the US. Among immigrants, as length of residence increased the prevalence of SPD (p=0.002) and depression (p<0.0001) increased. LIMITATIONS: This study examines immigrants as an entire population, not accounting for differences in immigrant status or immigrant ethnicity. CONCLUSIONS: While the prevalence of depression is lower in immigrants compared to US-born, being an immigrant in the US for more than 15 years increases risk of SPD to the point of surpassing that of US-born individuals and increases risk of depression.