Lambe Mats, Hultman Christina, Torrång Anna, Maccabe James, Cnattingius Sven
Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, SE-171 77 Stockholm, Sweden.
Epidemiology. 2006 Sep;17(5):524-30. doi: 10.1097/01.ede.0000231561.49208.be.
Smoking during pregnancy has been suggested to have long-term consequences for neuropsychologic development in the offspring, including behavioral problems, attention deficit disorders, and antisocial behavior. Also, findings from several studies indicate an association with impaired cognitive function in the children.
In a population-based Swedish cohort study, we examined possible associations between maternal smoking in pregnancy and educational achievement in the offspring at age 15 years among more than 400,000 male and female students born 1983 through 1987. Generalized estimating equation models were used to evaluate associations of maternal smoking, other maternal characteristics, and birth characteristics with school performance. Odds ratios (ORs) were used as a measure of risk.
In a model adjusted for maternal characteristics, maternal smoking compared with no tobacco use during pregnancy was associated with an increased risk of poor scholastic achievement: for 1-9 cigarettes per day, the OR was 1.59 (95% confidence interval = 1.59-1.63) and for 10 or more cigarettes per day, the OR was 1.92 (1.86-1.98). These risks remained unchanged when we also adjusted for smoking-related pregnancy outcomes such as fetal growth restriction and preterm birth. However, if the mother had smoked in her first pregnancy, but not in her second pregnancy, the younger sibling was also at increased risk of poor school performance.
Observed associations between maternal smoking during pregnancy and poor cognitive performance in the offspring might not be causal. We suggest that associations reported in earlier studies may instead reflect the influence of unmeasured characteristics that differ between smokers and nonsmokers.
孕期吸烟被认为会对后代的神经心理发育产生长期影响，包括行为问题、注意力缺陷障碍和反社会行为。此外，多项研究结果表明，这与儿童认知功能受损有关。
在一项基于瑞典人群的队列研究中，我们调查了1983年至1987年出生的40多万名男女学生在15岁时，母亲孕期吸烟与后代学业成绩之间的可能关联。使用广义估计方程模型来评估母亲吸烟、其他母亲特征和出生特征与学业表现之间的关联。比值比（OR）用作风险衡量指标。
在对母亲特征进行调整的模型中，与孕期不吸烟相比，母亲吸烟与学业成绩不佳风险增加有关：每天吸1 - 9支烟，OR为1.59（95%置信区间 = 1.59 - 1.63）；每天吸10支或更多烟，OR为1.92（1.86 - 1.98）。当我们也对与吸烟相关的妊娠结局（如胎儿生长受限和早产）进行调整时，这些风险保持不变。然而，如果母亲在第一次怀孕时吸烟，但在第二次怀孕时不吸烟，年幼的兄弟姐妹学业成绩不佳的风险也会增加。
观察到的母亲孕期吸烟与后代认知能力差之间的关联可能并非因果关系。我们认为，早期研究中报告的关联可能反而反映了吸烟者和非吸烟者之间未测量特征的影响。
