TABLE 2.
COMPARISON OF SELECTED CHARACTERISTICS OF HIGH-RISK AND LOW-RISK COUNTIES FOR PULMONARY NONTUBERCULOUS MYCOBACTERIAL DISEASE AMONG U.S. MEDICARE BENEFICIARIES 65 YEARS OF AGE AND OLDER
| Variable* | High-Risk County | Low-Risk County | P Value |
| Demographic | |||
| Median age | 37.8 | 38.3 | 0.37 |
| ≥65 yr old, % | 16.1 | 16.0 | 0.85 |
| Female, % | 50.2 | 50.5 | 0.07 |
| Race/ethnicity | |||
| White | 63.3 | 92.0 | <0.0001 |
| Black | 8.6 | 2.2 | <0.0001 |
| Asian | 4.9 | 0.6 | <0.0001 |
| Hispanic | 19.1 | 1.8 | <0.0001 |
| Socioeconomic | |||
| Population density, per square mile | 391 | 85 | <0.0001 |
| Bachelor’s degree or higher, % | 22 | 16 | <0.0001 |
| Median household income, $ | 40,941 | 36,331 | 0.0002 |
| Deaths per 1,000 persons | 9.3 | 10.7 | 0.0001 |
| Environmental | |||
| Total area, square miles | 1,861 | 827 | <0.0001 |
| Proportion of area as surface water, % | 19.0 | 5.9 | <0.0001 |
| Mean precipitation, inches | 85.9 | 74.2 | 0.0006 |
| Mean daily potential evapotranspiration, mm | 6.5 | 4.8 | <0.0001 |
| Mean minimal temperature, °C | 12.9 | 3.0 | <0.0001 |
| Mean maximal temperature, °C | 24.8 | 14.9 | <0.0001 |
| Elevation, m | 227.7 | 398.3 | <0.0001 |
| Geochemical soil levels, ppm | |||
| Selenium | 0.3 | 0.4 | 0.02 |
| Mercury | 0.09 | 0.06 | 0.08 |
| Lead | 22.8 | 21.3 | 0.41 |
| Zinc | 52.4 | 69.1 | 0.0005 |
| Copper | 17.4 | 15.6 | 0.14 |
| Aluminum | 3.7 | 4.7 | <0.0001 |
| Sodium | 0.8 | 0.7 | 0.14 |
| Manganese | 401.7 | 743.1 | <0.0001 |
| Iron | 2.0 | 2.6 | 0.0005 |
*
All population-level demographic factors are based on year 2000 U.S. Census Bureau data.