Table 1.

Distribution of variables in all Medicare beneficiaries $\ge 65\mathrm{y}$ of age residing in the states of Maine, New Hampshire, Vermont, Massachusetts, Rhode Island, Connecticut, New York, New Jersey, Delaware, Pennsylvania, Maryland, Washington, DC, Virginia, and West Virginia who were enrolled during 2000–2013 ($n=\mathrm{16,965},154$; $\text{person-years}=\mathrm{129,341},959$).

Variable	Percentile
	25th	50th	75th	Mean
Age (y)	69.00	74.00	81.00	75.5
Male (%)	41.0	44.2	47.6	44.8
Medicaid coverage (%)	4.8	8.2	13.7	11.0
Black	0	0.6	4.4	6.9
Asian	0	0.3	0.9	0.9
Other race	0	0.3	1.0	1.5
Area-based covariates
Median income (USD)a	38,000	48,600	66,900	55,700
Percentage below poverty levela	4.8	7.7	12.0	10.6
Population density (people–${\mathrm{km}}^{-2}$)a	26	114	752	1453
Median housing value (USD)a	95,900	160,600	263,800	208,000
Percentage owner occupieda	68	78	84	72
Percentage $<\text{high \hspace{0.17em} school}$a	20	28	38	30
BMI (${\text{kgm}}^{-2}$)b	26.9	27.5	28.2	27.6
HbA1c (% screened)c	81.3	84.0	86.3	83.6
LDL-C (% screened)c	77.7	80.7	82.9	80.2
Mammography (%)c	62.9	65.6	70.0	65.2
Lung cancer rate ($\times {10}^{-5}$)d	27.6	39.2	53.2	48.0
Ever Smoker (%)b	45.4	48.6	51.3	48.2
Percentage ZIP code blacke	0.3	1.6	7.6	8.0
Percentage ZIP code Hispanice	0.9	1.8	4.9	5.2
Percentage annual checkupc	74.9	78.3	81.6	77.5
${\mathrm{PM}}_{2.5}$ (${\mathrm{\mu }\mathrm{g}/\mathrm{m}}^3$)	9.2	10.4	11.4	10.3

Note: Percentiles of the distribution of the variables are over all observations.

^aZIP code data (U.S. Census Bureau 2010).

^bCounty level (CDC 2013).

^cDartmouth Health Atlas Hospital Catchment Area data.

^dRate of hospital admissions of all Medicare enrollees in the ZIP code, computed from CMS data (ResDAC 2018).

^ePercentage of all inhabitants in ZIP code, not just Medicare cohort participants (U.S. Census Bureau 2010).