Racial/ethnic disparities in type 2 diabetes: The role of neighborhood

Racial/ethnic disparities in type 2 diabetes (T2D) are a major public health problem in the US, with black and Hispanic Americans at a greater risk relative to whites. The search for contributors to disparities in T2D tends to focus on four major areas: (1) lifestyle and behavioral risk factors, (2) biochemical parameters, (3) genetics, and (4) socioeconomic factors. We hypothesize an additional, complementary, contributor to racial/ethnic disparities: (5) neighborhood level socioeconomic factors. Participants were drawn from the Boston Area Community Health (BACH) Survey, a racially/ethnically diverse, (AA: 866; HA: 871; CA: 995) longitudinal cohort study of community-dwelling residents of Boston. Participants' residential addresses were geo-coded and merged with neighborhood-level data obtained from the US Census. Within this cohort, we identified 2732 subjects without diabetes at baseline who were followed an average of 7.2 years for diabetes incidence. The in-person interview included validated questionnaires on demographics, health care access/utilization, lifestyles, health status and behaviors, physical measures, and biochemical parameters. In age-, gender-, and BMI- adjusted models, black and Hispanic participants were twice as likely to develop T2D (black: OR=2.27, 95% CI [1.30-3.97]; Hispanic: 1.91, [ 1.14-3.18]) versus white participants. Individual socioeconomic status attenuated these results considerably (black: 1.67, [0.94-2.96], Hispanic: 1.26, [0.73-2.17]). There were significant differences in the incidence of T2D by neighborhood (p=0.03) even after adjustment for individual race/ethnicity, age, gender, BMI and SES. However, adjustment for neighborhood SES did not attenuate the racial/ethnic disparities further. Future analyses are planned to identify specific characteristics of neighborhoods that explain these disparities (i.e. built environment, racial segregation, or further neighborhood socioeconomic factors like poverty, unemployment, or violent crime). While studies of neighborhood contributions appear promising, their contribution to disparities remains uncertain. There is a need to identify specific characteristics of neighborhoods that explain disparities in disease.