Intense debate in social epidemiology surrounds the income inequality hypothesis, which asserts that ecological income inequality is detrimental for health due to reduced social or material resources, and the relative position hypothesis, which proposes lower hierarchical position of individuals is harmful for health. Debate centers on both the relevance of these theories as they apply to health and the appropriate mechanism(s) underlying the relationship.
I draw from Wilkinson’s (1992) paper that suggests that the distribution of income is more important in predicting health in wealthy nations due to relationships between relative deprivation, negative emotions, and social cohesion, and contrast it with Wilson’s (1996) theory of the benefits of affluence that posits economic heterogeneity is beneficial in poor neighborhoods because affluent residents model mainstream norms and uphold neighborhood institutions. I extend current research by examining these relationships in U.S. neighborhoods and by considering whether inequality is differentially important across individual income and race-ethnicity. Finally, I assess the relationship between relative position and health, and how it is associated with local context.
Hierarchical multilevel Poisson and logistic regression models are used on data from the Los Angeles Family and Neighborhood Survey, the Los Angeles County Health Department, and the decennial census to test the strong and weak versions of the income inequality hypothesis on local age-specific and race-ethnic-specific mortality rates, and in multilevel models on individual morbidity. Then, I test relative position within neighborhoods on three morbidity outcomes; hypertension, obesity, and self-rated health. Collective efficacy, a local social resource based on cohesion, trust, and intervention for the common good, is tested as a mediator of the relationship.
Results regularly suggest neighborhood context matters for mortality and morbidity. Economic well-being is relevant for mortality across race-ethnicity, while inequality was not important for all cause mortality among blacks or Latinos, but was detrimental for Whites in lower income neighborhoods. The strong and weak versions of the income inequality hypothesis are disputed in multilevel models. Instead, results indicate economic heterogeneity is beneficial on average for hypertension, obesity, and self-rated health.
Some race-ethnic differences were found wherein whites benefit more so than other groups from economic heterogeneity. Collective efficacy mediates a portion of the relationship between neighborhood affluence and health, but, though consistently associated with better health and lower mortality, it did not mediate the effects of inequality, suggesting that social resources are not the mechanism though which inequality operates. Results indicate the relative position hypothesis applies to self-rated health and that the relationship is mediated by individual sense of control. Collective efficacy did not mediate the relationship between relative position and morbidity and effects of relative position did not vary across the level of local inequality.
I conclude that low relative position may be problematic for health, but neighborhood economic heterogeneity is not detrimental for individual health in local communities. Instead, I suggest economically heterogeneous (or unequal) neighborhoods, perhaps especially in Los Angeles County, may contain characteristics that promote health. Implications for policy and future research are discussed.