Weighted frequency of selected characteristics for children aged 6–15 years with and without parental report of attention deficit hyperactivity disorder (ADHD), NHANES, 1999–2004
| Characteristics | Parent-reported ADHD | |
| Yes (n=200) | No (n=2339) | |
| N (95% CI) | N (95% CI) | |
| Gender* | ||
| Female | 25.1 (17.1 to 33.2) | 50.2 (47.4 to 53.0) |
| Male | 74.9 (66.8 to 82.9) | 49.8 (47.0 to 52.6) |
| Race/ethnicity* | ||
| Non-Hispanic white | 71.7 (62.8 to 80.7) | 59.6 (54.2 to 65.1) |
| Non-Hispanic black | 13.0 (9.5 to 16.6) | 15.7 (12.4 to 19.1) |
| Mexican American | 4.7 (2.7 to 6.7) | 12.4 (9.3 to 15.4) |
| Other | 10.5 (2.6 to 18.5) | 12.2 (7.8 to 16.5) |
| Poverty-to-income ratio | ||
| <1 | 27.1 (18.5 to 35.7) | 22.2 (19.8 to 24.6) |
| 1–2 | 28.2 (20.0 to 36.4) | 25.8 (22.5 to 29.1) |
| ≥2 | 44.6 (34.6 to 54.7) | 52.0 (48.5 to 55.4) |
| Blood lead levels (μg/dl) | ||
| 1st tertile (≤1.0) | 39.0 (27.7 to 50.4) | 42.5 (38.1 to 46.9) |
| 2nd tertile (1.0–1.7) | 30.6 (21.6 to 39.5) | 28.6 (25.7 to 31.5) |
| 3rd tertile (≥1.7) | 30.4 (19.0 to 41.8) | 28.9 (25.5 to 32.3) |
| Maternal prenatal tobacco use* | ||
| Yes | 33.5 (23.7 to 43.2) | 16.7 (13.8 to 19.6) |
| No | 66.5 (56.8 to 76.2) | 83.3 (80.4 to 86.2) |
| Infant birth weight | ||
| <2500 g | 13.2 (6.2 to 20.1) | 6.9 (5.9 to 8.0) |
| ≥2500 g | 86.8 (79.8 to 93.8) | 93.0 (92.0 to 94.1) |
| Serum cotinine levels (ng/ml)* | ||
| 1st tertile (≤0.035) | 21.1 (11.4 to 30.9) | 36.8 (31.7 to 41.9) |
| 2nd tertile (0.035–0.283) | 23.0 (15.5 to 30.4) | 30.0 (26.6 to 33.4) |
| 3rd tertile (≥0.283) | 55.9 (47.3 to 64.5) | 33.2 (29.7 to 36.70) |
| Child age (years)* | 11.2 (10.7 to 11.6) | 10.4 (10.2 to 10.6) |
↵* p value from a Wald χ2 test is less than 0.05.