Table 4.
Effects of maternal smoking during pregnancy on outcome, both unrelated (cohort) analyses and within relative analyses; Estimate (95% confidence interval)
| Effect measure | Cohort | Within relatives | |||||
|---|---|---|---|---|---|---|---|
| Crude | Adjusted | Half-cousins | Full-cousins | Half-siblings | Full-siblings | ||
| Birth weight (grams) | Regression coefficients | −201 (−203, −198) | −181 (−184, −179) | −205 (−218, −191) | −185 (−192, −177) | −135 (−146, −123) | −92 (−97, −86) |
| Preterm birth | Odds ratio | 1.34 (1.31, 1.36) | 1.29 (1.27, 1.32) | 1.23 (1.14, 1.34) | 1.19 (1.14, 1.26) | 1.18 (1.04, 1.34) | 1.21 (1.12, 1.30) |
| Born small for gestational age | Odds ratio | 2.52 (2.48, 2.55) | 2.45 (2.41, 2.48) | 2.41 (2.23, 2.59) | 2.29 (2.19, 2.39) | 1.83 (1.63, 2.06) | 1.64 (1.54, 1.75) |
| Low academic achievement | Odds ratio | 2.84 (2.80, 2.89) | 2.67 (2.63, 2.71) | 1.91 (1.74, 2.09) | 1.62 (1.54, 1.70) | 1.07 (0.92, 1.25) | 0.93 (0.87, 1.01) |
| General cognitive abilitya (9-point score) | Regression coefficients | −0.63 (−0.65, −0.62) | −0.57 (−0.59, −0.55) | −0.24 (−0.43, −0.04) | −0.27 (−0.35, −0.18) | −0.03 (−0.41, 0.36) | −0.00 (−0.10, 0.09) |
| Criminality | Odds ratio | 1.98 (1.95, 2.02) | 1.90 (1.86, 1.94) | 1.62 (1.40, 1.87) | 1.32 (1.23, 1.42) | 0.92 (0.67, 1.28) | 0.95 (0.86, 1.05) |
| Violent criminality | Odds ratio | 3.02 (2.90, 3.14) | 2.77 (2.66, 2.89) | 2.07 (1.57, 2.73) | 1.59 (1.37, 1.86) | 0.82 (0.45, 1.51) | 0.94 (0.75, 1.17) |
| Drug misuse | Odds ratio | 2.13 (2.07, 2.19) | 2.00 (1.94, 2.05) | 1.55 (1.25, 1.93) | 1.47 (1.32, 1.64) | 0.83 (0.47, 1.46) | 0.92 (0.78, 1.07) |
Note: All models except Crude model, adjusted for gender, birth year in categories (for birth weight in three year intervals; for preterm birth and born small for gestational age in four year intervals; for low academic achievement in two year intervals; for general cognitive ability, criminality, violent criminality and drug misuse in 1 year intervals; all starting in 1983), and maternal age at childbirth in categories (for birth weight <17, 17–19, then two year intervals, 42–44 and >44; for preterm birth <20, then four year intervals, >44; for born small for gestational age <20, then three year intervals, 44–45, >45; for low academic achievement <19, then four year intervals, >42; for general cognitive ability <20, then two year intervals, >39; for criminality, violent criminality and drug misuse <20, then five year intervals, >39).
Sub-cohort includes only males.