Understanding social disparities in hypertension prevalence, awareness, treatment, and control: The role of neighborhood context

Abstract

The spatial segregation of the US population by socioeconomic position and especially race/ethnicity suggests that the social contexts or “neighborhoods” in which people live may substantially contribute to social disparities in hypertension. The Chicago Community Adult Health Study did face-to-face interviews, including direct measurement of blood pressure, with a representative probability sample of adults in Chicago. These data were used to estimate socioeconomic and racial–ethnic disparities in the prevalence, awareness, treatment, and control of hypertension, and to analyze how these disparities are related to the areas in which people live. Hypertension was significantly negatively associated with neighborhood affluence/gentrification, and adjustments for context eliminated the highly significant disparity between blacks/African-Americans and whites, and reduced the significant educational disparity by 10–15% to borderline statistical significance. Awareness of hypertension was significantly higher in more disadvantaged neighborhoods and in places with higher concentrations of blacks (and lower concentrations of Hispanics and immigrants). Adjustment for context completely eliminated blacks’ greater awareness, but slightly accentuated the lesser awareness of Hispanics and the greater levels of awareness among the less educated. There was no consistent evidence of either social disparities in or contextual associations with treatment of hypertension, given awareness. Among those on medication, blacks were only 40–50% as likely as whites to have their hypertension controlled, but context played little or no role in either the level of or disparities in control of hypertension. In sum, residential contexts potentially play a large role in accounting for racial/ethnic and, to a lesser degree, socioeconomic disparities in hypertension prevalence and, in a different way, awareness, but not in treatment or control of diagnosed hypertension.

Introduction

Understanding and reducing socioeconomic and racial/ethnic disparities in health is arguably the most significant challenge facing US public health research and policy. Despite abundant research on these social disparities in health, important questions remain regarding the reasons for the observed differences, which do not appear to be fully “explained” by the traditional individual-level risk factors included in most analyses. Reasons for social disparities in the individual-level risk factors for health are also not well understood. Given the spatial segregation of the population of the US and other nations by socioeconomic position and race/ethnicity, the social contexts in which people live are increasingly recognized as additional potential determinants of health and factors contributing to health disparities, over and above the effects of individual and household risk factors. Research is beginning to document such effects of social context, though their nature and magnitude are variable and disputed and their role in understanding and explaining racial/ethnic and socioeconomic disparities in health is even less clear (Diez-Roux, 2000; Morenoff & Lynch, 2004).

In this paper, we consider the extent to which individual-level racial/ethnic and to a lesser degree socioeconomic disparities in hypertension may be linked to the spatial locations of these groups. We focus on hypertension because it is a significant health problem in the US, which is unevenly distributed across socioeconomic and, especially racial/ethnic groups (Hertz, Unger, Cornell, & Saunders, 2005), and there are compelling theoretical reasons for expecting that the spatial locations of racial/ethnic and, to a lesser degree, socioeconomic groups may be linked to hypertension. The goal of this paper is to assess the extent to which social disparities in four aspects of hypertension—prevalence, awareness, treatment, and control—are associated with differences in the areas where these groups tend to live. We accomplish this by decomposing racial/ethnic and socioeconomic disparities in hypertension prevalence, awareness, treatment, and control into within- and between-area components. This is a necessary first step in assessing the extent to which neighborhood residential context matters for social disparities in all these aspects of hypertension. It will thus target and focus future research that aims to identify whether and through what specific mechanisms residential environments may be causally related to hypertension and aspects of its diagnosis and treatment.