The Generation R Study Group, Erasmus Medical Center, Rotterdam, The Netherlands.
Nicotine Tob Res. 2011 Dec;13(12):1250-6. doi: 10.1093/ntr/ntr117. Epub 2011 Oct 12.
Single assessment of smoking during pregnancy may lead to misclassification due to underreporting or failure of smoking cessation. We examined the percentage of mothers who were misclassified in smoking status based on single assessment, as compared with repeated assessment, and whether this misclassification leads to altered effect estimates for the associations between maternal smoking and neonatal complications.
This study was performed in 5,389 mothers participating in a prospective population-based cohort study in the Netherlands. Smoking status was assessed 3 times during pregnancy using questionnaires. Information on birth weight and neonatal complications was obtained from hospital records.
For categorizing mothers per smoking status, Cohen's Kappa coefficient was .86 (p < .001) between single and repeated assessments. Of all mothers who reported nonsmoking or first trimester-only smoking in early pregnancy, 1.7% (70 of 4,141) and 33.7% (217 of 643), respectively, were reclassified to continued smoking based on repeated assessment. Younger, shorter lower educated mothers who had non-European ethnicity experienced more stress, consumed more alcohol, and did not use folic acid supplements had higher risk of underreporting their smoking status or failure of smoking cessation. Marginal differences were found on the associations of maternal smoking with neonatal complications between single or repeated assessment.
Our results suggest that single assessment of smoking during pregnancy leads to underestimation of the continued smoking prevalence, especially among mothers who reported quitting smoking in first trimester. However, this underestimation does not materially change the effect estimates for the associations between maternal smoking and neonatal outcomes.
单次评估孕期吸烟情况可能会导致由于漏报或戒烟失败而导致分类错误。我们研究了基于单次评估与重复评估相比，因吸烟状况分类错误而改变的母亲比例，以及这种分类错误是否会改变母亲吸烟与新生儿并发症之间关联的效应估计值。
本研究在荷兰进行了一项前瞻性基于人群的队列研究，共有 5389 名母亲参与。在孕期使用问卷进行了 3 次吸烟状况评估。出生体重和新生儿并发症的信息来自医院记录。
为了根据吸烟状况对母亲进行分类，单次评估和重复评估之间的 Cohen's Kappa 系数为 0.86（p<0.001）。在所有报告早期妊娠期间不吸烟或仅第一孕期吸烟的母亲中，分别有 1.7%（4141 名中的 70 名）和 33.7%（643 名中的 217 名）根据重复评估重新分类为持续吸烟。年龄较小、身高较矮、受教育程度较低、非欧洲裔、压力较大、饮酒较多、未服用叶酸补充剂的母亲，漏报或戒烟失败的风险更高。在单次或重复评估中，母亲吸烟与新生儿并发症的关联存在边际差异。
我们的结果表明，孕期吸烟的单次评估会导致持续吸烟的流行率被低估，尤其是在报告第一孕期戒烟的母亲中。然而，这种低估不会实质性地改变母亲吸烟与新生儿结局之间关联的效应估计值。
