TABLE 3.
Generalized estimating equations and fixed-effects models of the association between maternal smoking during pregnancy and children's mental and physical development in the Collaborative Perinatal Project, 1959–1974
| No. of children | Mean (standard deviation) or no. | % | Level of maternal smoking during pregnancy (cigarettes/day) |
χ2 or F (3 df) | p value | ||||||
| 1–9 |
10–19 |
≥20 |
|||||||||
| OR* or β† | 95% CI* | OR or β | 95% CI | OR or β | 95% CI | ||||||
| Birth | |||||||||||
| Birth weight (g) | |||||||||||
| Full sample, adjusted‡ | 46,559 | 3,185.5 (529.7) | −69.03 | −82.25, −55.81 | −165.48 | −180.95, −150.01 | −247.66 | −260.98, −234.35 | 1,354.4 | <0.001 | |
| Siblings, adjusted§ | 13,575 | 3,211.9 (530.5) | −50.25 | −78.44, −22.07 | −153.55 | −184.53, −122.57 | −255.43 | −282.16, −228.70 | 333.4 | <0.001 | |
| Siblings, fixed effects¶ | 13,575 | 3,211.9 (530.5) | −2.04 | −37.69, 33.61 | −62.08 | −106.04, −18.13 | −85.63 | −131.91, −39.34 | 6.1 | <0.001 | |
| 5-minute Apgar score | |||||||||||
| Full sample, adjusted | 43,768 | 9.0 (1.1) | −0.04 | −0.07, −0.01 | −0.05 | −0.09, −0.02 | −0.08 | −0.11, −0.05 | 34.9 | <0.001 | |
| Siblings, adjusted | 12,360 | 9.0 (1.1) | −0.03 | −0.09, 0.03 | −0.01 | −0.07, 0.05 | −0.04 | −0.09, 0.01 | 3.0 | 0.396 | |
| Siblings, fixed effects | 12,360 | 9.0 (1.1) | −0.04 | −0.14, 0.07 | 0.01 | −0.12, 0.14 | 0.00 | −0.13, 0.14 | 0.3 | 0.810 | |
| Age 4 years | |||||||||||
| Stanford-Binet IQ* | |||||||||||
| Full sample, adjusted | 34,390 | 97.6 (16.6) | −0.33 | −0.76, 0.09 | 0.11 | −0.40, 0.62 | −0.63 | −1.06, −0.19 | 10.9 | 0.012 | |
| Siblings, adjusted | 9,578 | 98.7 (16.5) | −0.18 | −1.06, 0.70 | 0.57 | −0.46, 1.59 | 0.02 | −0.84, 0.88 | 1.8 | 0.607 | |
| Siblings, fixed effects | 9,578 | 98.7 (16.5) | 0.48 | −0.86, 1.83 | 1.24 | −0.41, 2.89 | 0.63 | −1.09, 2.35 | 0.8 | 0.521 | |
| Age 7 years | |||||||||||
| Neurologic soft signs | |||||||||||
| Full sample, adjusted | 36,088 | 4,313 | 12.0 | 0.95 | 0.87, 1.05 | 0.92 | 0.82, 1.02 | 1.13 | 1.04, 1.22 | 15.7 | 0.001 |
| Siblings, adjusted | 10,933 | 1,385 | 12.7 | 1.05 | 0.89, 1.24 | 0.90 | 0.74, 1.10 | 1.14 | 0.99, 1.32 | 5.9 | 0.119 |
| Siblings, fixed effects | 10,933 | 1,385 | 12.7 | 0.83 | 0.57, 1.22 | 0.77 | 0.48, 1.22 | 0.86 | 0.53, 1.37 | 1.4 | 0.698 |
| Wechsler verbal IQ | |||||||||||
| Full sample, adjusted | 35,566 | 94.6 (14.2) | −0.54 | −0.91, −0.18 | −0.18 | −0.59, 0.24 | −0.77 | −1.12, −0.41 | 22.0 | <0.001 | |
| Siblings, adjusted | 10,593 | 94.4 (13.8) | −0.72 | −1.41, −0.03 | −0.19 | −0.98, 0.59 | −0.28 | −0.96, 0.41 | 4.3 | 0.234 | |
| Siblings, fixed effects | 10,593 | 94.4 (13.8) | −0.13 | −1.24, 0.95 | −0.33 | −1.64, 0.99 | 0.20 | −1.19, 1.60 | 0.0 | 0.828 | |
| Wechsler performance IQ | |||||||||||
| Full sample, adjusted | 35,567 | 98.9 (15.2) | −1.06 | −1.46, −0.66 | −1.09 | −1.55, −0.63 | −1.64 | −2.02, −1.26 | 83.2 | <0.001 | |
| Siblings, adjusted | 10,594 | 98.9 (15.1) | −0.76 | −1.55, 0.03 | −0.85 | −1.71, 0.01 | −1.04 | −1.76, −0.32 | 9.8 | 0.021 | |
| Siblings, fixed effects | 10,594 | 98.9 (15.1) | −0.46 | −1.76, 0.84 | −0.39 | −1.99, 1.20 | 0.38 | −1.31, 2.07 | 0.6 | 0.634 | |
| Wechsler full-scale IQ | |||||||||||
| Full sample, adjusted | 35,795 | 96.1 (14.9) | −0.77 | −1.14, −0.40 | −0.66 | −1.09, −0.23 | −1.27 | −1.64, −0.90 | 51.2 | <0.001 | |
| Siblings, adjusted | 10,712 | 95.9 (14.6) | −0.94 | −1.67, −0.20 | −0.44 | −1.25, 0.36 | −0.75 | −1.45, −0.05 | 8.2 | 0.042 | |
| Siblings, fixed effects | 10,712 | 95.9 (14.6) | −0.38 | −1.51, 0.75 | −0.34 | −1.73, 1.05 | 0.24 | −1.22, 1.71 | 0.5 | 0.716 | |
| WRAT* spelling score | |||||||||||
| Full sample, adjusted | 34,764 | 96.0 (12.8) | −0.27 | −0.61, 0.07 | −0.70 | −1.09, −0.30 | −0.99 | −1.33, −0.65 | 36.5 | <0.001 | |
| Siblings, adjusted | 10,170 | 96.5 (12.7) | −0.31 | −0.98, 0.36 | −0.33 | −1.08, 0.41 | −0.77 | −1.42, −0.12 | 5.4 | 0.147 | |
| Siblings, fixed effects | 10,170 | 96.5 (12.7) | −0.12 | −1.25, 1.01 | −0.09 | −1.47, 1.29 | −0.33 | −1.80, 1.14 | 0.1 | 0.970 | |
| WRAT reading score | |||||||||||
| Full sample, adjusted | 34,784 | 98.8 (15.6) | −0.63 | −1.03, −0.23 | −0.74 | −1.22, −0.26 | −1.41 | −1.82, −1.00 | 47.1 | <0.001 | |
| Siblings, adjusted | 10,185 | 99.1 (15.3) | −0.79 | −1.59, 0.01 | −0.33 | −1.26, 0.60 | −1.22 | −2.01, −0.43 | 10.6 | 0.014 | |
| Siblings, fixed effects | 10,185 | 99.1 (15.3) | −0.09 | −1.40, 1.22 | 0.56 | −1.04, 2.16 | −0.42 | −2.12, 1.28 | 0.7 | 0.538 | |
| WRAT arithmetic score | |||||||||||
| Full sample, adjusted | 34,765 | 96.6 (11.0) | −0.30 | −0.61, 0.02 | −0.07 | −0.42, 0.29 | −0.25 | −0.54, 0.04 | 5.1 | 0.167 | |
| Siblings, adjusted | 10,173 | 97.0 (10.9) | 0.08 | −0.55, 0.72 | 0.20 | −0.48, 0.87 | 0.12 | −0.44, 0.68 | 0.4 | 0.945 | |
| Siblings, fixed effects | 10,173 | 97.0 (10.9) | −0.69 | −1.71, 0.33 | −1.05 | −2.30, 0.20 | −0.59 | −1.92, 0.74 | 1.0 | 0.376 | |
| Body mass index# | |||||||||||
| Full sample, adjusted | 30,043 | 16.0 (2.0) | 0.08 | 0.01, 0.14 | 0.20 | 0.13, 0.27 | 0.19 | 0.13, 0.25 | 49.8 | <0.001 | |
| Siblings, adjusted | 8,060 | 16.0 (1.8) | 0.11 | −0.02, 0.23 | 0.22 | 0.08, 0.35 | 0.24 | 0.12, 0.36 | 19.7 | <0.001 | |
| Siblings, fixed effects | 8,060 | 16.0 (1.8) | 0.11 | −0.08, 0.31 | 0.14 | −0.09, 0.38 | 0.17 | −0.07, 0.42 | 0.8 | 0.523 | |
| Overweight** | |||||||||||
| Full sample, adjusted | 30,043 | 1,615 | 5.4 | 1.15 | 0.99, 1.33 | 1.35 | 1.15, 1.58 | 1.17 | 1.02, 1.34 | 15.0 | 0.002 |
| Siblings, adjusted | 8,058 | 346 | 4.3 | 1.56 | 1.11, 2.17 | 1.61 | 1.15, 2.26 | 1.35 | 1.00, 1.82 | 11.1 | 0.011 |
| Siblings, fixed effects | 8,058 | 346 | 4.3 | 2.90 | 1.30, 6.49 | 2.47 | 1.00, 6.10 | 2.55 | 1.01, 6.44 | 7.2 | 0.066 |
| Conduct problems scale score | |||||||||||
| Full sample, adjusted | 35,677 | 0.2 (0.8) | 0.02 | −0.00, 0.04 | 0.03 | 0.00, 0.06 | 0.05 | 0.03, 0.07 | 20.4 | <0.001 | |
| Siblings, adjusted | 10,659 | 0.2 (0.8) | 0.04 | −0.00, 0.09 | 0.03 | −0.02, 0.08 | 0.04 | −0.01, 0.08 | 5.1 | 0.165 | |
| Siblings, fixed effects | 10,659 | 0.2 (0.8) | 0.05 | −0.03, 0.14 | 0.04 | −0.07, 0.14 | 0.04 | −0.07, 0.15 | 0.5 | 0.665 | |
| Asthma | |||||||||||
| Full sample, adjusted | 36,107 | 1,980 | 5.5 | 1.09 | 0.96, 1.23 | 1.01 | 0.87, 1.18 | 1.19 | 1.05, 1.34 | 8.2 | 0.043 |
| Siblings, adjusted | 10,945 | 502 | 4.6 | 1.05 | 0.81, 1.36 | 0.88 | 0.64, 1.19 | 1.14 | 0.90, 1.45 | 2.9 | 0.405 |
| Siblings, fixed effects | 10,945 | 502 | 4.6 | 0.88 | 0.51, 1.51 | 1.12 | 0.56, 2.25 | 1.89 | 0.85, 4.19 | 4.5 | 0.214 |
OR, odds ratio; CI, confidence interval; IQ, intelligence quotient; WRAT, Wide Range Achievement Test.
Odds ratios from logistic regression models are shown for neurologic soft signs, overweight, and asthma; linear regression coefficients (β) are shown for all other dependent variables.
Full Collaborative Perinatal Project sample. Generalized estimating equations models included adjustment for the presence of multiple siblings per family. P values from chi-squared tests of the significance of maternal smoking during pregnancy are shown in the last column. The following covariates were included in the models: sex, race/ethnicity, maternal and paternal age, household crowding, paternal and maternal history of psychiatric or substance-use disorder, maternal psychiatric or neurologic problems during pregnancy, maternal marital status, maternal employment, number of prior pregnancies, and family socioeconomic status percentile.
Generalized estimating equations models for the sample of Collaborative Perinatal Project offspring with one or more siblings enrolled; results were adjusted for the same covariates as listed above. P values from chi-squared tests of the significance of maternal smoking during pregnancy are shown in the last column.
Models fitted among siblings conditioning on family fixed effects (family-specific intercepts). P values from F tests shown in the last column are from linear regression models; p values from chi-squared tests are from logistic regression models.
Weight (kg)/height (m)2.
≥95th percentile of body mass index for age and sex.