Table 1.
Maternal and Child Characteristics of the Study Population in the Danish National Birth Cohort, 1996–2002
| Characteristic | Prenatal Exposure to Acetaminophen (n = 40,934) | Postnatal Exposure to Acetaminophena (n = 27,742) | ||
|---|---|---|---|---|
| % Yes (n = 21,670) | % No (n = 19,264) | % Yes (n = 2,855) | % No (n = 24,887) | |
| Mother’s age, years | ||||
| ≤24 | 7.1 | 6.9 | 6.9 | 6.3 |
| 25–29 | 38.0 | 38.4 | 40.5 | 37.3 |
| 30–34 | 38.8 | 38.6 | 39.1 | 39.2 |
| ≥35 | 16.1 | 16.2 | 13.5 | 17.1 |
| Child’s sex | ||||
| Female | 52.4 | 50.5 | 49.0 | 52.0 |
| Male | 47.6 | 49.5 | 51.0 | 48.1 |
| Parental socio-occupational status | ||||
| Low | 2.7 | 2.0 | 1.8 | 2.4 |
| Medium | 24.6 | 22.3 | 21.0 | 24.5 |
| High | 68.4 | 69.7 | 73.7 | 69.6 |
| Missing | 4.3 | 6.0 | 3.5 | 3.5 |
| Parity | ||||
| 1 | 43.2 | 49.0 | 51.2 | 44.4 |
| 2 | 37.6 | 33.4 | 34.7 | 36.0 |
| >2 | 16.5 | 14.5 | 11.2 | 16.9 |
| Missing | 2.7 | 3.1 | 2.9 | 2.7 |
| Mother’s prepregnancy body mass indexb | ||||
| <18.5 | 3.6 | 4.3 | 4.4 | 3.9 |
| 18.5–24.9 | 65.1 | 69.0 | 68.4 | 67.6 |
| 25.0–29.9 | 18.5 | 14.7 | 16.1 | 17.4 |
| ≥30.0 | 7.4 | 4.7 | 6.3 | 6.4 |
| Missing | 5.5 | 7.3 | 4.8 | 4.7 |
| Maternal smoking during pregnancy, cigarettes/day | ||||
| Never | 75.5 | 79.4 | 79.0 | 78.8 |
| ≤9 | 12.7 | 10.6 | 12.2 | 11.2 |
| >9 | 11.3 | 8.3 | 8.8 | 10.0 |
| Missing | 0.5 | 1.7 | 0.0 | 0.01 |
| Maternal ever alcohol intake during pregnancy | 73.9 | 70.0 | 73.9 | 72.4 |
| Missing | 0.5 | 1.6 | 0.0 | 0.01 |
| Mother ever had psychiatric illness | 17.0 | 13.2 | 16.9 | 15.0 |
| Fever during pregnancy | 32.1 | 21.1 | 29.6 | 26.7 |
| Muscle and joint disease during pregnancy | 11.9 | 7.6 | 11.9 | 9.9 |
| Infection and inflammation during pregnancy | 17.0 | 12.1 | 17.9 | 15.0 |
| Prenatal use of nonsteroidal antiinflammatory drugs | 13.6 | 11.7 | 14.6 | 12.4 |
| Infection or inflammation of the index child | N/A | N/A | 67.4 | 61.0 |
| Fever episode of the index child | N/A | N/A | 67.7 | 44.2 |
| Preterm birth | N/A | N/A | 4.3 | 4.0 |
| Birth weight, g | ||||
| <2,500 | N/A | N/A | 2.7 | 2.8 |
| 2,500–4,999 | N/A | N/A | 92.4 | 92.5 |
| ≥4,500 | N/A | N/A | 5.0 | 4.7 |
| Duration of breast feeding | ||||
| No | N/A | N/A | 3.8 | 2.9 |
| <3 moths | N/A | N/A | 13.7 | 12.3 |
| 3–6 months | N/A | N/A | 15.2 | 14.9 |
| >6 months | N/A | N/A | 60.3 | 64.6 |
| Missing | N/A | N/A | 7.0 | 5.3 |
| Parent’s behavioral scores during their own childhood | ||||
| 1–3 | 67.1 | 69.8 | 69.4 | 70.7 |
| 4–7 | 11.4 | 9.1 | 11.9 | 10.6 |
| 8–12 | 2.2 | 1.6 | 1.7 | 1.9 |
| Missing | 19.3 | 19.5 | 17.0 | 16.8 |
Abbreviation: N/A, not applicable.
a During infancy in the first 18 months after birth.
b Weight (kg)/height (m)2.