TABLE 3.
Characteristics of and Exposures Among 11- to 12-Year-Olds Exposed and Not Exposed, Respectively, to Prenatal Smoking by the Mother
| Prenatal Smoking (N = 766) |
LBW (N = 126) |
|||||
|---|---|---|---|---|---|---|
| Yes | No | Pa | Yes | No | Pa | |
| Prenatal smoking, % | — | — | — | 40.5 | 23.8 | <.001 |
| Smoking first year, % | 90.2 | 18.4 | <.001 | 44.6 | 26.6 | <.001 |
| Smoking, age 7–8 y, % | 79.7 | 15.0 | <.001 | 52.0 | 30.1 | <.001 |
| 0–4 cigarettes per d | 7.1 | 5.0 | — | 8.9 | 5.3 | — |
| 5–14 cigarettes per d | 53.5 | 9.0 | — | 33.3 | 19.4 | — |
| 15–24 cigarettes per d | 18.1 | 1.0 | — | 8.9 | 5.1 | — |
| ≥25 cigarettes per d | 1.1 | 0 | — | 0.8 | 0.2 | — |
| Smoking, age 11–12 y, % | 72.8 | 12.0 | <.001 | 45.1 | 26.2 | <.001 |
| 0–4 cigarettes per d | 8.1 | 4.0 | — | 7.4 | 4.7 | — |
| 5–14 cigarettes per d | 50.9 | 7.0 | — | 33.6 | 17.3 | — |
| 15–24 cigarettes per d | 13.2 | 1.0 | — | 3.3 | 4.0 | — |
| ≥25 cigarettes per d | 0.7 | 0 | — | 0.8 | 0.2 | — |
| Birth weight, mean (SD) | 3360 (553) | 3571 (568) | <.001 | 2126 (351) | 3578 (497) | <.001 |
| LBW, % | 6.9 | 3.3 | <.001 | — | — | — |
| Parental asthma, % | 18.9 | 17.5 | .357 | 22.2 | 17.5 | .173 |
| Allergic sensitization, % | 31.3 | 30.5 | .758 | 28.0 | 30.7 | .620 |
| Respiratory tract infections, % | 59.5 | 57.9 | .442 | 66.7 | 58.1 | .057 |
| Breastfeeding <3 mo, % | 30.9 | 11.6 | <.001 | 35.2 | 15.6 | <.001 |
| Damp house, % | 5.8 | 4.4 | .128 | 4.0 | 4.9 | .649 |
| Male gender, % | 48.8 | 51.5 | 0.202 | 45.2 | 50.9 | 0.211 |
| Birth order, mean (SD) | 1.99 (1.16) | 1.98 (1.06) | 0.765 | 1.87 | 1.99 | 0.237 |
a
χ2 test for dichotomous outcomes and 1-way analysis of variance for comparisons of means.