Table 1.
Variables used to explain life expectancy (variables log transformed).
| Variable | Abbreviation | Data Sources | Mean (SD) |
|---|---|---|---|
| Endogenous Variables | |||
| Average life expectancy | Life expectancy | IMHE 2010 [50] | 78.14 (2.03) |
| Annual vehicle miles traveled per household | VMT per household | EPA 2011 [51] | 27,015 (8500) |
| Air quality index | Air quality index | EPA 2010 [52] | 1.72 (3.48) |
| Average body mass index | Body mass index | BRFSS 2010 [53] | 30.99 (2.01) |
| Violent crime rate per 100,000 population | Violent crime rate | FBI Uniform Crime Statistics 2010 [54] | 346.17 (230.6) |
| Ever smoked | Ever smoked | NIH 2003 [55] | 0.471 (0.057) |
| Exogenous Variables | |||
| Metropolitan population | Metropolitan Pop. | Census 2010 | 1,931,779 (3,340,260) |
| Socio-economic status (SES) index | SES index | Yost et al. (2001) [56,57] | 37,480 (7936) |
| Percentage of white population | White Pop. (%) | Census 2010 | 78.25 (14.94) |
| Percentage of male population | Male Pop. (%) | Census 2010 | 49.17 (1.07) |
| County compactness index for 2010 | Compactness index | Ewing and Hamidi, 2017 [58] | 106.76 (19.84) |