Boyd N R, Windsor R A, Perkins L L, Lowe J B
Fox Chase Cancer Center, Philadelphia, Pennsylvania, USA.
Matern Child Health J. 1998 Jun;2(2):77-83. doi: 10.1023/a:1022936705438.
The objectives of this paper were to determine the rate of misclassification of smoking and nonsmoking status by self-reports and saliva continine of pregnant women participating in a smoking cessation trial, determine the relationship of the number of cigarettes smoked per day and saliva continine, and examine whether misclassification was due to an inappropriate saliva continine cutoff point.
End of pregnancy self-reports of smoking status and saliva continine were used to calculate misclassification rates.
The findings revealed that 61 of 441 self-reported smokers had biochemical values inconsistent with smoking status for a smoking misclassification rate of 13.8%. The results also revealed that 28 of 107 self-reported quitters had continine values consistent with smoking status for a nonsmoking misclassification rate of 26.2%. Receiver Operating Characteristic (ROC) curves were then plotted to determine whether misclassification resulted from an inappropriate cutoff point. The continine cutoff point that maximized sensitivity and specificity for all women was 24 ng/ml. Racial ROC comparisons indicated a higher cutoff point for blacks than whites. Use of any of the ROC indicated cutoff points would not change the misclassification rates.
These findings suggest that underreporting of smoking status during pregnancy is high and that social desirability of nonsmoking status may have contributed to the lack of precision in saliva continine to distinguish smoking status in this study.
本文的目的是确定参与戒烟试验的孕妇通过自我报告和唾液可替宁对吸烟和非吸烟状态的误分类率，确定每日吸烟量与唾液可替宁的关系，并检查误分类是否归因于唾液可替宁临界值设置不当。
使用孕期结束时的吸烟状态自我报告和唾液可替宁来计算误分类率。
研究结果显示，441名自我报告的吸烟者中有61人的生化值与吸烟状态不一致，吸烟误分类率为13.8%。结果还显示，107名自我报告的戒烟者中有28人的可替宁值与吸烟状态相符，非吸烟误分类率为26.2%。然后绘制受试者工作特征（ROC）曲线，以确定误分类是否由不当的临界值导致。对所有女性而言，使敏感性和特异性最大化的可替宁临界值为24 ng/ml。种族ROC比较表明，黑人的临界值高于白人。使用任何ROC确定的临界值均不会改变误分类率。
这些发现表明，孕期吸烟状态的漏报率很高，并且非吸烟状态的社会期望性可能导致了本研究中唾液可替宁在区分吸烟状态方面缺乏精确性。
