Table 2.
Geometric mean ratio (GMR) and 95% CI of mean community water system (CWS) arsenic (2006–2011per increase in measures of socioeconomic vulnerability corresponding to the interquartile range (proportion of adults with a high school diploma, median household income, and CDC/ATSDR’s overall socioeconomic vulnerability score), nationwide and stratified by region and metropolitan vs non-metropolitan counties (N= 2,604 counties.
| Proportion of adults with a high school diploma | Median household income | Overall socioeconomic vulnerability score | |
|---|---|---|---|
| Unit of change (nationwide IQR) | 0.15 | $11,552 | 0.5 |
| Nationwide (N= 2,604) | |||
| Model 1 | 1.02 (0.98, 1.06) | 1.01 (0.99, 1.04) | 0.95 (0.91, 0.99) |
| Model 2 | 1.00 (0.96, 1.04) | 1.01 (0.98, 1.04) | 0.93 (0.88, 0.98) |
|
| |||
| Metropolitan versus non-metropolitan counties | |||
| Non-metropolitan counties (N= 1,634) | |||
| Model 1 | 1.03 (0.97, 1.09) | 1.09 (1.04, 1.15) | 0.88 (0.83, 0.93) |
| Model 2 | 1.01 (0.95, 1.07) | 1.09 (1.03, 1.15) | 0.85 (0.79, 0.92) |
| Metropolitan counties (N= 970) | |||
| Model 1 | 1.02 (0.95, 1.09) | 1.01 (0.97, 1.05) | 0.97 (0.90, 1.04) |
| Model 2 | 1.00 (0.92, 1.07) | 0.99 (0.95, 1.04) | 0.95 (0.87, 1.03) |
|
| |||
| By region | |||
| Central Midwest (N= 401) | |||
| Model 1 | 1.05 (0.94, 1.18) | 0.97 (0.88, 1.06) | 0.85 (0.75, 0.95) |
| Model 2 | 1.13 (0.99, 1.29) | 0.98 (0.89, 1.08) | 0.74 (0.64, 0.85) |
| Eastern Midwest (N= 555) | |||
| Model 1 | 0.80 (0.70, 0.91) | 1.06 (0.98, 1.15) | 1.03 (0.92, 1.17) |
| Model 2 | 0.82 (0.71, 0.94) | 1.07 (0.98, 1.17) | 0.99 (0.86, 1.13) |
| Mid-Atlantic (N=157) | |||
| Model 1 | 1.04 (0.85, 1.26) | 0.99 (0.92, 1.06) | 1.09 (0.89, 1.34) |
| Model 2 | 0.95 (0.76, 1.18) | 1.02 (0.94, 1.12) | 1.11 (0.88, 1.41) |
| New England (N= 53) | |||
| Model 1 | 0.65 (0.34, 1.26) | 0.93 (0.72, 1.19) | 1.61 (1.09, 2.39) |
| Model 2 | 0.65 (0.31, 1.36) | 0.97 (0.74, 1.28) | 1.60 (1.00, 2.57) |
| Pacific Northwest (N= 198) | |||
| Model 1 | 1.05 (0.90, 1.23) | 0.95 (0.81, 1.11) | 1.18 (0.94, 1.46) |
| Model 2 | 1.10 (0.94, 1.30) | 0.96 (0.81, 1.13) | 1.06 (0.79, 1.43) |
| Southeast (N= 849) | |||
| Model 1 | 0.99 (0.94, 1.03) | 1.01 (0.98, 1.04) | 0.95 (0.91, 1.01) |
| Model 2 | 0.98 (0.93, 1.02) | 0.99 (0.96, 1.03) | 0.98 (0.92, 1.04) |
| Southwest (N=390) | |||
| Model 1 | 0.84 (0.73, 0.97) | 0.98 (0.89, 1.06) | 1.17 (0.98, 1.39) |
| Model 2 | 0.83 (0.71, 0.98) | 1.00 (0.90, 1.11) | 1.17 (0.94, 1.47) |
CDC/ATSDR = Centers for Disease Control and Prevention (CDC) and Agency for Toxic Substances and Disease Registry (ATSDR). IQR = interquartile range. Spatial autocorrelation was modeled in Lagrange models with autoregressive correlation structure. Model 1 adjusts for the percentage of public water drawn from groundwater sources and population density. Model 2 further adjusts for county racial/ethnic composition (the proportion of residents who are non-Hispanic Black, American Indian/Native Alaskan, non-Hispanic Asian, non-Hispanic White, and Hispanic/Latino. Findings were also similar when models were further adjusted for either metropolitan versus non-metropolitan county status or county Rural-Urban Continuum Code. States included in each region are as follows: Central Midwest (North Dakota, South Dakota, Nebraska, Kansas, and Missouri), Eastern Midwest (Wisconsin, Illinois, Indiana, Michigan, Ohio, Minnesota, and Iowa), Mid-Atlantic (Pennsylvania, Maryland, District of Columbia, Delaware, New York, New Jersey, Connecticut, and Rhode Island), New England (Massachusetts, Vermont, New Hampshire, and Maine), Pacific Northwest (Washington, Oregon, Montana, Wyoming, and Idaho), Southeast (Oklahoma, Arizona, Louisiana, Mississippi, Alabama, Florida, Georgia, Tennessee, Kentucky, South Carolina, North Carolina, Virginia, and West Virginia), and Southwest (California, Nevada, Utah, Colorado, Arizona, New Mexico, and Texas).