Purpose: A well-established literature has shown that social integration strongly patterns health, including mortality risk. However, the extent to which living in high-poverty neighborhoods and having few social ties jointly pattern survival in the United States has not been examined.
Methods: We analyzed data from the Third National Health and Nutrition Examination Survey (1988-1994) linked to mortality follow-up through 2006 and census-based neighborhood poverty. We fit Cox proportional hazards models to estimate associations between social integration and neighborhood poverty on all-cause mortality as independent predictors and in joint-effects models using the relative excess risk due to interaction to test for interaction on an additive scale.
Results: In the joint-effects model adjusting for age, gender, race/ ethnicity, and individual-level socioeconomic status, exposure to low social integration alone was associated with increased mortality risk (hazard ratio [HR]: 1.42, 95% confidence interval [CI]: 1.28-1.59) while living in an area of high poverty alone did not have a significant effect (HR: 1.10; 95% CI: 0.95-1.28) when compared with being jointly unexposed. Individuals simultaneously living in neighborhoods characterized by high poverty and having low levels of social integration had an increased risk of mortality (HR: 1.63; 95% CI: 1.35-1.96). However, relative excess risk due to interaction results were not statistically significant.
Conclusions: Social integration remains an important determinant of mortality risk in the United States independent of neighborhood poverty.
Keywords: Mortality; Neighborhood; Social determinants of health; Social support.
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