Table 2.
Associations of Racial Residential Segregation1 and Racial Discrimination2 with Incident Diabetes3,4
| HR for Incident Diabetes (95% CI) | |||||
| Model Type | Segregation Category | Model 1 | Model 2 | Model 3 | Model 4 |
| Baseline Values | High | Reference | Reference | Reference | Reference |
| Medium | 0.94 (0.71, 1.25) | 0.97 (0.72, 1.30) | 0.96 (0.71, 1.29) | 1.01 (0.75, 1.37) | |
| Low | 0.79 (0.52, 1.21) | 0.75 (0.49, 1.15) | 0.85 (0.55, 1.31) | 0.93 (0.59, 1.46) | |
| Time-Varying Values | High | Reference | Reference | Reference | Reference |
| Medium | 0.75 (0.59, 0.97) | 0.79 (0.61, 1.02) | 1.04 (0.80, 1.35) | 0.97 (0.74, 1.28) | |
| Low | 0.97 (0.76, 1.22) | 0.98 (0.77, 1.24) | 1.20 (0.94, 1.53) | 1.09 (0.82, 1.43) | |
| HR for Incident Diabetes (95% CI) | |||||
| Model Type | Discrimination Category | Model 1 | Model 2 | Model 3 | Model 3 |
| Baseline Values | No Experiences | Reference | Reference | Reference | Reference |
| 1–2 Experiences | 0.95 (0.70, 1.30) | 0.94 (0.69, 1.29) | 0.96 (0.69, 1.33) | 0.96 (0.69, 1.34) | |
| 3+ Experiences | 1.03 (0.79, 1.35) | 1.00 (0.77, 1.31) | 1.06 (0.81, 1.39) | 1.07 (0.82, 1.41) | |
| Time-Varying Values | No Experiences | Reference | Reference | Reference | Reference |
| 1–2 Experiences | 0.97 (0.74, 1.27) | 0.97 (0.74, 1.28) | 0.89 (0.68, 1.17) | 0.91 (0.69, 1.19) | |
| 3+ Experiences | 0.92 (0.72, 1.19) | 0.94 (0.73, 1.21) | 0.87 (0.66, 1.14) | 0.87 (0.67, 1.14) | |
HR: hazard ratio
Racial residential segregation categorized into high, medium, and low use the value of the local Gi* statistic, which measures the deviation of the census tract’s racial composition from that of the larger metropolitan area. A Gi* statistic z-score <0 was categorized as low, 0 to 1.96 as medium, and >1.96 as high segregation.
Racial discrimination was assessed via survey. Participants reported whether they had experienced discrimination in any of 7 domains (e.g. school, getting a job, work, getting housing, getting medical care, on the street or in a public setting, from the police or in the courts). Discrimination was categorized as no experiences, 1–2 experiences, or 3+ experiences.
Diabetes defined as fasting glucose ≥ 126 mg/dL, self-reported use of medications for the treatment of diabetes mellitus, 2-hour glucose during the oral glucose tolerance test of ≥ 200 mg/dL, or HbA1c ≥ 6.5%.
Results are from Cox proportional hazards regression models and include the entire study population (n=2175). Baseline value models estimated associations for baseline segregation category (or baseline racial discrimination category) and adjusted for baseline covariates only. Time-varying value models estimated associations for time-varying segregation category (or time-varying racial discrimination) and adjusted for time-varying covariates. Model 1 was unadjusted. Model 2 adjusted for baseline age, sex, study center, parental history of diabetes, education, and marital status; Model 3 additionally adjusted for smoking status, alcohol use, physical activity, diet score, waist circumference, and depressive symptoms. Model 4 additionally adjusted for census tract poverty and population density.