Racial and ethnic differences in the associations between social integration, C-reactive protein and depressive symptoms

This study evaluates whether the associations between social integration, inflammation, and depressive symptoms vary by race/ethnicity in the United States. Our study includes 5,634 respondents age 40 and older from the National Health and Nutrition Examination Survey for 2005-2008. We fit multivariate logistic regression models with interactions between C-reactive protein (CRP) and race/ethnicity as well as social integration and race/ethnicity to test our hypotheses. We find that social integration and CRP operate independently in their associations with depressive symptoms by race/ethnicity. Higher levels of social integration are associated with lower predicted probability of depressive symptoms for White and Black populations. This association is not statistically significant for the Hispanic population. CRP is associated with depressive symptoms for the White population, but not the Black or Hispanic populations. Our results suggest that studying depressive symptoms, and other mental health outcomes, among the US population without considering variation by race/ethnicity may restrict scholarly understanding of health disparities. Population-based assessments of associations between physiological processes or social integration should consider whether these variables operate differently by race/ethnicity and work to explain why differences may emerge. Furthermore, interventions aimed at social integration may improve mental health among older adults in the United States; especially for the least socially integrated.

Social isolation and vulnerability to heatwave-related mortality in the urban elderly population: A time-series multi-community study in Korea

Although several studies have reported that social isolation is one of the important health risk factors in the elderly population living in urban areas, its effects on vulnerability to heatwaves have been studied relatively less than climatic and other socio-economic factors. Thus, we investigated the association between social isolation levels and heatwave-related mortality risk in the elderly population in 119 urban administrative districts in Korea, using a time-series multi-city dataset (2008-2017). We used a two-stage analysis. In the first stage, we estimated the heatwave-related mortality risk in the elderly population (age ≥ 65) for each district using a time-series regression with a distributed lag model. Subsequently, in the second stage, we applied meta-regressions to pool the estimates across all the districts and estimate the association between social isolation variables and heatwave-related mortality risk. Our findings showed that higher social gathering and mutual aid levels were associated with lower heatwave-related mortality risk. Further, the lower percentage of single elderly households living in detached houses was also related to higher heatwave-related mortality risk. The associations were generally more evident in males compared to females. Our findings suggest that vulnerability to heatwave-related mortality among the urban, city-dwelling, elderly population may be amplified by higher isolation indicators.