TABLE 8.
Summary statistics for covariates in the NHANES data. Means and sd for lead, age, income‐to‐poverty level and family size, proportions for education, missing income, race, army service, marriage indicator, and birth country
| Nonsmokers | Smokers | Overall | ||||
|---|---|---|---|---|---|---|
| Variables |
|
|
|
|||
| Blood lead level (μg/dL) | 1.91 (1.70) | 2.77 (2.37) | 2.15 (1.95) | |||
| Age | 48.7 (17.5) | 46.0 (14.7) | 48.0 (16.0) | |||
| Education | ||||||
| Less than 9th grade | 131 (13.0%) | 51 (13.2%) | 182 (13.1%) | |||
| 9–11th grade | 126 (12.5%) | 99 (25.6%) | 225 (16.2%) | |||
| High school graduate | 243 (24.2%) | 132 (34.2%) | 375 (26.9%) | |||
| Some college | 238 (23.7%) | 86 (22.3%) | 324 (23.3%) | |||
| College | 268 (26.6%) | 18 (14.7%) | 286 (20.5%) | |||
| Income | ||||||
| Income‐to‐poverty level | 2.79 (1.55) | 2.14 (1.48) | 2.61 (1.56) | |||
| Missing | 86 (8.5%) | 23 (6.0%) | 109 (7.8%) | |||
| Not missing | 920 (91.5%) | 363 (94.0%) | 1283 (92.2%) | |||
| Race | ||||||
| White | 428 (42.5%) | 241 (62.4%) | 669 (48.1%) | |||
| Black | 190(18.9%) | 78 (20.2%) | 268 (19.3%) | |||
| Mexican American | 206 (20.5%) | 24 (6.2%) | 230 (16.5%) | |||
| Other Hispanic | 120 (11.9%) | 22 (5.7%) | 142 (10.2%) | |||
| Other races | 62 (6.2%) | 21 (5.4%) | 83 (6.0%) | |||
| Served in Army | ||||||
| Yes | 192 (19.1%) | 90 (23.3%) | 282 (20.2%) | |||
| No | 814 (80.9%) | 296 (76.7%) | 1100 (79.7%) | |||
| Married | ||||||
| Yes | 640 (46.0%) | 164 (11.8%) | 804 (57.8%) | |||
| No | 366 (26.3%) | 222 (15.9%) | 588 (42.2%) | |||
| Birth country | ||||||
| Born in 50 U.S. states or Washington, DC | 685(68.0%) | 341 (88.3%) | 1026 (73.7%) | |||
| Born in Mexico | 126 (12.5%) | 10(2.6%) | 136(9.8%) | |||
| Born in other Spanish speaking country | 97 (9.6%) | 17 (4.4%) | 116 (8.3%) | |||
| Born in other Non‐Spanish speaking country | 98 (9.7%) | 18 (4.7%) | 114 (8.2%) | |||
| Family size | 3.04 (1.67) | 2.87 (1.76) | 2.99 (1.70) |