Table 1.
Descriptive Statistics for the Overall Sample and by Neighborhood Greenness Level (ie, Lowest, Middle, and Highest Tertiles on Block‐Level NDVI)
| Variable | Overall Sample (−0.40 to 0.429) (All NDVI) | Low NDVI (−0.40 to −0.06) (Lowest Tertile on NDVI) | Medium NDVI (−0.06 to 0.006) (Middle Tertile on NDVI) | High NDVI (0.006–0.429) (Highest Tertile on NDVI) | F (χ2) Test | P Value | ||||
|---|---|---|---|---|---|---|---|---|---|---|
| No. (%) | Mean (SD) | No. (%) | Mean (SD) | No. (%) | Mean (SD) | No. (%) | Mean (SD) | |||
| No. (beneficiaries) | 249 405 (100.00) | ··· | 82 790 (33.20) | ··· | 83 314 (33.41) | ··· | 83 301 (33.40) | ··· | ··· | ··· |
| Main predictor: NDVIa | ··· | −0.02 (0.09) | ··· | −0.11 (0.04) | ··· | −0.03 (0.02) | ··· | 0.07 (0.06) | 376 387a | <0.0001 |
| Neighborhood median household incomeb | ··· | 51.4 (30.7) | ··· | 40.1 (21.9) | ··· | 48.4 (23.8) | ··· | 65.8 (37.9) | 17 167.3a | <0.0001 |
| Individual sociodemographics | ||||||||||
| Age | ··· | 76.33 (7.50) | ··· | 76.71 (7.55) | ··· | 76.30 (7.43) | ··· | 75.98 (7.51) | 196.40a | <0.0001 |
| Female sex | 58.33 | ··· | 58.79 | ··· | 58.66 | ··· | 57.53 | (32.9a) | <0.0001 | |
| Race/ethnicity (RTI)c | (21 963.2a) | <0.0001 | ||||||||
| Hispanic, % | 65.56 | ··· | 80.29 | ··· | 68.77 | ··· | 47.71 | ··· | ||
| Non‐Hispanic white, % | 23.29 | ··· | 16.25 | ··· | 18.21 | ··· | 35.35 | ··· | ||
| Black, % | 11.15 | ··· | 3.45 | ··· | 13.02 | ··· | 16.94 | ··· | ||
| Biological risk factorsd | ||||||||||
| Diabetes mellitus diagnosis, % | 15.55 | ··· | 18.12 | ··· | 14.42 | ··· | 14.14 | ··· | (623.3a) | <0.0001 |
| Hypertension diagnosis, % | 27.88 | ··· | 31.21 | ··· | 25.72 | ··· | 26.74 | ··· | (703.1a) | <0.0001 |
| Hyperlipidemia diagnosis, % | 22.72 | ··· | 25.23 | ··· | 20.51 | ··· | 22.43 | ··· | (533.2a) | <0.0001 |
| Outcome variablese | ||||||||||
| AMI, % | 0.29 | 0.36 | 0.25 | 0.26 | (21.4a) | <0.0001 | ||||
| IHD, % | 20.68 | 23.92 | 18.92 | 19.22 | (793.0a) | <0.0001 | ||||
| HF, % | 7.56 | 9.06 | 7.05 | 6.58 | (412.4a) | <0.0001 | ||||
| AF, % | 2.61 | 2.37 | 1.89 | 3.02 | (90.3a) | <0.0001 | ||||
| Any heart disease, %e | 22.41 | 25.58 | 20.55 | 21.12 | (721.6a) | <0.0001 | ||||
RTI, Research Triangle Institute race code.
Mean normalized difference vegetation index (NDVI) was used to assess greenness/vegetative presence/absence at the Census block level (possible theoretical range of −1 to +1).
Neighborhood median household income is reported in thousands of dollars at the Census block‐group level using 2011 US Census data.
Race and ethnicity was assessed by US Centers for Medicare & Medicaid Services (CMS) for each beneficiary.
Biological risk factors and outcome variables were identified for each Medicare beneficiary, using CMS Beneficiary Summary File, Chronic Conditions segment.
Any heart disease refers to having any of the 4 forms of heart disease in the CMS Chronic Conditions Segment (acute myocardial infarction [AMI], ischemic heart disease [IHD], heart failure [HF], and atrial fibrillation [AF]).