Dalla Lana School of Public Health, University of Toronto, 155 College Street, 6th Floor, Toronto, Ontario, Canada M5T 3M7.
Nicotine Tob Res. 2010 Jan;12(1):43-52. doi: 10.1093/ntr/ntp171. Epub 2009 Dec 2.
Discrete classification of smokers by intention to quit is desirable in many public health and clinical settings.
Two methodological studies examine measurement properties of measures of discrete-time intention to quit smoking used in population-based tobacco surveillance surveys: an ecological comparison of rates of positive intention in relation to the form of measure used and a prospective analysis examining predictive validity of self-reported quit intentions using multiple possible points of dichotomization of an ordinal measure of intention to quit. The prospective analysis used a repeated measures design and follow-up to 1 year for 2,047 smokers in the Ontario Tobacco Survey cohort.
The estimated percent of smokers intending to quit was significantly higher using the Stages of Change intention measure, relative to another single question measure. Significant dose-response effects were found. The sooner one intended to quit the more likely one was to make an attempt or achieve at least 30 days abstinence in the next 6 months. Intending to quit in a month or later was not associated with cessation during follow-up among respondents without prior attempts. Examination of cutpoints revealed no value, which maximized both positive and negative prediction. Regardless of quit attempt history, greatest predictive validity was found where respondents stated that they had no intention at all.
Measures of intentions quit smoking in specific time periods and expressed as dichotomies have limited psychometric properties but utility in applied research. Our findings suggest a possible measurement effect warranting caution in comparisons across studies.
在许多公共卫生和临床环境中，按戒烟意向对吸烟者进行离散分类是很有必要的。
两项方法学研究检验了基于人群的烟草监测调查中用于离散时间戒烟意向的测量工具的测量特性：使用不同形式的测量工具来评估意向的阳性率的生态比较，以及使用意向戒烟的有序测量的多种二分法来检验自我报告的戒烟意向的预测效度的前瞻性分析。前瞻性分析采用重复测量设计，对安大略烟草调查队列中的 2047 名吸烟者进行了为期 1 年的随访。
与另一个单一问题的衡量标准相比，使用变化阶段意向衡量标准估计的戒烟意向百分比明显更高。发现了显著的剂量反应效应。戒烟意向越强烈，在接下来的 6 个月内尝试戒烟或至少实现 30 天戒断的可能性就越大。在没有先前尝试的受访者中，计划在一个月或更晚戒烟与随访期间的戒烟无关。对切点的检查表明，没有一个切点可以同时最大化阳性和阴性预测。无论戒烟尝试的历史如何，在受访者表示完全没有戒烟意向的情况下，预测效度最大。
在特定时间段内表达为二分法的戒烟意向测量工具具有有限的心理测量特性，但在应用研究中有一定的实用性。我们的研究结果表明，可能存在测量效应，这在跨研究比较时需要谨慎。
