Table 1.
Maternal- and twin-reported characteristics2
| Mothers who did not smoke when twins were 3+ years (n=922) (%) | Mothers who smoked when twins were 3+ years (n=661) (%) |
|---|---|---|
Demographic characteristics (maternal report) |
|
|
African American | 10.4 | 14.18* |
Mother married to biological father at interview | 70.1 | 48.010*** |
Mother’s education |
|
|
Less than high school degree | 4.4 | 15.810*** |
High school degree, no college | 35.4 | 45.210*** |
Some college | 29.6 | 29.6 |
College degree or higher | 30.7 | 9.610*** |
Household income <$50,000 | 49.3 | 71.710*** |
Maternal smoking history |
|
|
Lifetime |
|
|
Never | 35.5 | --- |
<100 lifetime | 49.0 | --- |
100+ but quit before twins were born | 11.0 | --- |
100+ but quit when twins were <3 years | 4.6 | --- |
100+ and smoked when twins were 3+ years3 | – | 100 |
Smoking during pregnancy (of 100+ lifetime smokers; n=127 who did not smoke and n=637 who smoked when the twins were 3+ years) |
|
|
None | 71.7 | 18.510*** |
Smoked during part of pregnancy (1 week to 8 months) | 22.8 | 34.28* |
Smoked for >8 months of pregnancy | 5.5 | 47.310*** |
Maternal report of psychopathology |
|
|
Mother self-reported childhood inattention | 4.9 | 9.710*** |
Mother self-reported childhood hyperactivity | 2.8 | 4.78* |
Mother self-reported lifetime depression | 26.8 | 40.010*** |
Mother self-reported 3+ alcohol-dependence symptoms lifetime | 3.0 | 7.610*** |
Mother reported biological father was a problem drinker (lifetime) | 23.2 | 41.510*** |
Mother reported twin DSM-IV inattention (in 3000 twins)4 | 4.5 | 6.6 |
Mother reported twin DSM-IV hyperactivity (in 2998 twins)5 | 1.0 | 4.010*** |
Mother reported twin DSM-IV ODD (in 2988 twins)6 | 8.5 | 16.810*** |
Maternal report of parenting (when twins were 6 to 13 years old) |
|
|
Mother reported hitting twin with a “belt or stick or something like that”, “sometimes” or “often” | 5.2 | 7.6 |
Mother reported being more strict than most parents | 51.0 | 49.0 |
Mother reported “often” being interested in the twins’ friends and activities | 94.3 | 87.010*** |
Mother reported being “very close” to the twins | 92.6 | 84.710*** |
Mother reported arguing “often” with the twins | 7.4 | 12.910*** |
Mother reported the coparent hitting twin with a “belt or stick or something like that”, “sometimes” or “often”7 | 3.0 | 4.5 |
Twin report of childhood physical and sexual abuse | Twins whose mother did not smoke when they were 3+ years of age (n=1762) | Twins whose mother smoked when they were 3+ years of age (n=1239) |
Twin-reported childhood physical abuse | 16.1 | 23.610*** |
Twin-reported childhood sexual abuse | 7.7 | 14.710*** |
2 N=1583 biological interviewed mothers had data on smoking during the twins’ childhood; there was minimal missing data on individual measures; all mother-reported measures had b1580 mother responses, except for household income (N=1538), her smoking during pregnancy (N=1542), her own childhood inattention and hyperactivity (N=1542), her own alcohol-dependence history (N=1572), her report of biological father’s alcohol history (N=1563), her own history hitting the twins (N=1551), and her own strictness (N=1549).
3 Includes N=49 mothers who quit when twins were 3–6 years, N=86 who quit when twins were 7+ years, and N=526 who never quit.
4 A total of 1418 mothers reporting on complete pairs and 164 reporting on only one member of a twin pair; 6+ of 9 DSM-IV inattention symptoms, for 6+ months, before the age of 7, with impairment (causing problems at home or school, or consulted a health professional about problems).
5 A total of 1417 mothers reporting on pairs and 164 reporting on only one member of a twin pair; 6+ of 9 DSM-IV hyperactive symptoms, for 6+ months, before age 7, with impairment (causing problems at home or school, or consulted a health professional about problems).