Sylvestre Marie-Pierre, Lauzon Béatrice, Dugas Erika N, Mesidor Miceline, O'Loughlin Jennifer L
Centre de recherche du centre hospitalier de l'Université de Montréal (CRCHUM), Montréal, QC, Canada.
Department of Social and Preventive Medicine, Université de Montréal, Montréal, QC, Canada.
Nicotine Tob Res. 2022 Mar 1;24(4):598-605. doi: 10.1093/ntr/ntab170.
Most studies modeling adolescent cigarette smoking trajectories use age as the time axis, possibly obscuring depiction of the natural course of cigarette smoking. We used a simulated example and real data to contrast smoking trajectories obtained from models that used time since smoking onset or calendar time (age) as the time axis.
Data were drawn from a longitudinal investigation of 1293 grade 7 students (mean age 12.8 years) recruited from 10 high schools in Montreal, Canada in 1999-2000, who were followed into young adulthood. Cigarette consumption was measured every 3 months during high school, and again at mean ages 20.4 and 24.0. Analyses using time since onset of smoking as the time metric was restricted to 307 incident smokers; analysis using calendar time included 645 prevalent and incident smokers. Smoking status and nicotine dependence (ND) were assessed at mean ages 20.4 and 24.0. Simulated data mimicked the real study during high school.
Use of different time metrics resulted in different numbers and shapes of trajectories in the simulated and real datasets. Participants in the calendar time analyses reported more ND in young adulthood, reflecting inclusion of 388 prevalent smokers who had smoked for longer durations.
Choosing the right time metric for trajectory analysis should be balanced against research intent. Trajectory analyses using the time since onset metric depict the natural course of smoking in incident smokers. Those using calendar time offer a snapshot of smoking across ages during a given time period.
This study uses simulated and real data to show that trajectory analyses of cigarette smoking that use calendar time (e.g., age) versus time since onset as the time axis metric tell a different story. Trajectory analyses using the time since onset metric depict the natural course of smoking in incident smokers. Those using calendar time offer a snapshot of smoking across ages during a given time period. Choosing the right time metric should be balanced against research intent.
大多数对青少年吸烟轨迹进行建模的研究将年龄作为时间轴，这可能会模糊吸烟自然过程的描述。我们使用了一个模拟示例和真实数据，以对比从以吸烟开始后的时间或日历时间（年龄）为时间轴的模型中获得的吸烟轨迹。
数据取自1999 - 2000年从加拿大蒙特利尔10所高中招募的1293名7年级学生（平均年龄12.8岁）的纵向调查，这些学生被追踪至青年期。在高中期间每3个月测量一次香烟消费量，并在平均年龄20.4岁和24.0岁时再次测量。以吸烟开始后的时间作为时间度量的分析仅限于307名初次吸烟者；使用日历时间的分析包括645名现患和初次吸烟者。在平均年龄20.4岁和24.0岁时评估吸烟状况和尼古丁依赖（ND）。模拟数据模仿了高中期间的真实研究。
在模拟和真实数据集中，使用不同的时间度量会导致轨迹的数量和形状不同。日历时间分析中的参与者在青年期报告的尼古丁依赖更多，这反映了纳入了388名吸烟时间更长的现患吸烟者。
为轨迹分析选择合适的时间度量应与研究目的相平衡。使用吸烟开始后的时间度量进行的轨迹分析描绘了初次吸烟者吸烟的自然过程。那些使用日历时间的分析提供了给定时间段内各年龄段吸烟情况的快照。
本研究使用模拟和真实数据表明，以日历时间（如年龄）与吸烟开始后的时间作为时间轴度量进行的吸烟轨迹分析讲述了不同的情况。使用吸烟开始后的时间度量进行的轨迹分析描绘了初次吸烟者吸烟的自然过程。那些使用日历时间的分析提供了给定时间段内各年龄段吸烟情况的快照。选择合适的时间度量应与研究目的相平衡。
