Table 1.
Descriptive statistics of all U.S. Medicare fee-for-service beneficiaries (n = 63,009,173) from 2000 through 2016.a
| Individual-level covariates | Demographics at study entry | N (%) |
|---|---|---|
|
| ||
| Sex | Female | 34,725,534 (55.1) |
| Age entry | 65–74 years | 48,240,802 (76.6) |
| 75–84 years | 10,819,118 (17.2) |
|
| 85+ years | 3,949,253 (6.3) |
|
| Race | White | 53,262,938 (84.5) |
| Black | 5,511,612 (8.7) |
|
| Other/unknown | 4,234,623 (6.7) |
|
| Medicaid eligibility | Not eligible | 55,164,043 (87.5) |
| Eligible | 7,845,130 (12.5) |
|
| Region | Northeast | 12,374,875 (19.6) |
| South | 24,085,710 (38.2) |
|
| Midwest | 15,254,270 (24.2) |
|
| West | 11,294,318 (17.9) |
|
| Zip code-level covariates a | Aggregated data (2000–2016) | Median (IQR) |
| Natural environment measures | % Park cover NDVI % Blue space cover (1000 m buffer) % Blue space cover (no buffer) |
7.5 (15.9) 0.52 (0.27) 0.5 (3.2) 0.3 (1.3) |
| U.S. census covariates | Population density (persons/mile2) Median home value ($1000) Median household income ($1000) % with less than a high school degree % below the poverty level % owner-occupied housing units % Black % Hispanic |
517.4 (2919.0) 139.4 (145.3) 46.0 (24.9) 24.7 (21.6) 8.6 (8.2) 71.8 (21.4) 3.7 (13.5) 5.0 (14.0) |
| BRFSS covariate | % ever smoked | 46.2 (9.1) |
| Other environmental exposures | summer temperature (°C) summer specific humidity (g of water vapor/kg of dry air) summer total precipitation (mm, daily total) PM2.5 (ĝ/m3) NO2 (ppb) |
29.9 (5.2) 12.0 (4.0) 3.1 (2.3) 9.7 (4.0) 16.3 (13.9) |
a
Descriptive statistics of the zip code level covariates are given for the strata (aggregated data based on zip code, year, sex, race, Medicaid eligibility, 2-year categories of age at study entry and year of follow-up) based on the CVD cohort. Descriptive statistics of the zip code level covariates for the RSD cohort are shown in Table S2.