Table 2.
Studies assessing the association between historical HOLC grade and subsequent environmental determinants of health
| Location | Outcome(s) | Unit of analysis (sample size) | HOLC variable | Control variables | Abbreviated findings | |
|---|---|---|---|---|---|---|
| Hoffman et al. [48] | 108 urban areas nationwide |
(1) Summertime land surface temperature (LST) (2) Developed impervious surface land cover (3) Tree canopy coverage |
HOLC polygons (N not stated) | Categorical: A, B, C, D | None | LST was elevated in D- relative to A-graded areas in 94% of urban areas (2.6 °C warmer on average). Impervious surface land cover was higher in D-graded areas and tree canopy cover was lower |
| Lane et al. [43] | 202 urban areas nationwide | Annual ambient concentration predictions of (1) nitrogen dioxide (NO2) and (2) fine particulate matter (PM2.5) | Census block (N = 562,078) | Categorical: A, B, C, D | None | Across all cities, NO2 concentrations are 56% higher in D-graded areas than A-graded areas, while PM2.5 concentrations are 4% higher. Population-weighted mean NO2 levels were higher in D-graded areas than overall in 80% of cities (55% for PM2.5), and were lower in A-graded areas than overall in 84% of cities (68% for PM2.5) |
| Lee et al. [25] | 6 cities, San Francisco Bay Area, CA | Density of off-premise alcohol outlets | Census block groups (N = 520) | Categorical: A (ref), B, C, D, ungraded | Local and adjacent population, median household income | D grade was associated with higher density of off-premise alcohol outlet density relative to A grade (RR = 1.90 [0.81, 4.84]) |
| Li & Yuan [31] | 102 urban areas nationwide | mRFEI Index of healthiness of the food environment, ranging from 0 (worst) to 100 (best) | Census tract (N = 11,651) | Categorical: A (ref), B, C, D, ungraded (< 50% of land graded) | CT sociodemographic characteristics and population density, city-level racial segregation and natural log of the population | D-graded areas had 0.83 [0.77, 0.97] times the mRFEI score of A-graded areas |
| Locke et al. [63] | 37 urban areas, with sub-analysis of 8 | Tree canopy coverage | HOLC polygon (N = 3188) | Categorical: A (ref), B, C, D | City random effect | D grade was associated with decreased percent tree canopy cover relative to A grade (M = − 20.79 percentage points [− 22.27, − 19.31]) |
| Nardone et al. [45] | 102 urban areas nationwide | Summer and annual average NDVI, ranging from -1 (least green) to 1 (most green) | HOLC polygon (N = 4141) | Categorical: adjacent grades (B vs. A, C vs. B, and D vs. C) | 1940 CT sociodemographic characteristics, 1940 population density, ecoregion, Census region | Unadjusted annual average mean NDVI increased on a gradient from D to A grade. Poorer HOLC grade was associated with a 0.024–0.39 unit decrease in annual average NDVI compared to the adjacent grade in adjusted models using a restricted, propensity score matched sample |
| Nowak et al. [77] | All available cities nationwide | Tree cover, impervious cover, tree cover stocking (proportion of non-impervious area occupied by tree canopies), and ecosystem service value (pollution removal, carbon sequestration, avoided runoff) | Census incorporated and designated places (N = 1259) | Categorical: A, B, C, D | None | Poorer grade was associated with lower % tree cover, % stocking, and ecosystem service values, and higher % impervious cover. For example, tree cover was about twice as high a proportion of A-graded areas as D-graded areas. 88.6% of cities had greater % tree cover, and 86.4% had lower % impervious cover, in A-graded areas than D-graded areas |
| Sadler et al. [47] | Baltimore, MD | Healthy food access score ranging from 1 to 1145 | Residential tax parcels (N not stated) | Continuous variable with change from A to B, B to C, and C to D considered 1 unit increase | Socioeconomic distress index, racial composition, housing age | A 1-unit increase in redlining was associated with a 48–52 point increase in food access score |
| Saverino et al. [41] | Richmond, VA | Afternoon mean temperature during a heat wave | Census block group (N not stated) | Continuous: quartiles of proportion A/B combined and C/D combined | None | Areas in the fourth quartile of percentage C- or D-graded were on average 0.53 °C warmer than areas in the lowest quartile, while areas in the fourth quartile of percentage A- or B-graded were on average 0.26 °C cooler than areas in the lowest quartile |
| Schinasi et al. [46] | Philadelphia, PA | Land cover and housing characteristics linked to enhanced heat vulnerability, including roof color, shape, and shape and color combined, and presence of immediately adjacent mature or immature tree canopy | Residential properties (N = 400) | Categorical: A (ref), B, C, D | 1940 racialized economic segregation and CT sociodemographic characteristics | Compared to properties in A-graded areas, properties in D-graded areas had elevated risk of low or no mature tree canopy, in both models adjusting for historic characteristics (RR = 5.09 [2.78–9.32]) and for present-day characteristics (RR = 5.96 [5.76, 6.16]) |
| Schwartz et al. [35] | 13 Ohio urban areas | Tobacco retailer density | Modified CTs (N = 3846) | Categorical: A (ref), B, C, D, ungraded; all pairwise comparison | CT sociodemographic characteristics, city fixed effect | D grade was associated with higher density of tobacco retailers relative to A (RR = 1.98 [1.52, 2.60]) |
| Trangenstein et al. [78] | Baltimore, MD | Clusters of four types of alcohol outlets | Census block groups (N = 537) | Categorical: B, C, D, ungraded (ref) | Population density, sociodemographic characteristics, concentrated disadvantage index, residential stability, social control or disinvestment, built environment characteristics | Compared to ungraded areas, D grade was associated with higher odds of being in a general (OR = 8.82 [2.99, 25.98]), off-premise (OR = 7.32 [2.00, 26.79]), on-premise (OR = 8.07 [2.26, 28.77]), or LBD-7 (combined on/off-premise) (OR = 8.60 [2.93, 25.30]) alcohol outlet cluster |
| Wilson [79] | Baltimore, MD; Dallas, TX; Kansas City, MO | 1) LST, two summer days and 2) NDVI, two summer days | HOLC polygons | Categorical: A, B, C, D | None | C- and D-graded areas had higher median land surface temperatures than A or B in all cities (P < 0.01, Kruskal–Wallis test). Mean NDVI was lower in C- and D-graded areas compared to A- and B-graded areas in all cities |
NDVI normalized difference vegetation index; OR risk ratio; RR risk ratio