Does Effectiveness of Adolescent Smoking-Cessation Intervention Endure Into Young Adulthood? 7-Year Follow-Up Results from a Group-Randomized Trial

BackgroundThe Hutchinson Study of High School Smoking was the first randomized trial to show effectiveness of a smoking cessation intervention on 6-months prolonged smoking abstinence at one year post-intervention in a large population-based sample of adolescent smokers. An important question remains: Do the positive effects from teen smoking cessation interventions seen at up to 12 months post-intervention endure into young adulthood? This study examines for the first time whether such positive early effects from teen smoking cessation intervention can endure into young adulthood in the absence of additional intervention.MethodsHigh school smokers (n = 2,151) were proactively recruited into the trial from fifty randomly selected Washington State high schools randomized to the experimental (Motivational Interviewing + Cognitive Behavioral Skills Training telephone counseling intervention) or control (no intervention) condition. These smokers were followed to 7 years post high school to ascertain rates of six-year prolonged smoking abstinence in young adulthood. All statistical tests are two-sided.ResultsNo evidence of intervention impact at seven years post high school was observed for the main endpoint of six-year prolonged abstinence, neither among all smokers (14.2% in the experimental condition vs. 13.1% in the control condition, difference = +1.1%, 95% confidence interval (CI) = -3.4 to 5.8, p = .61), nor among the subgroups of daily smokers and less-than-daily smokers, nor among other a priori subgroups. But, observed among males was some evidence of an intervention impact on two endpoints related to progress towards quitting: reduction in number of days smoked in the past month, and increase in the length of the longest quit attempt in the past year.ConclusionsThere was no evidence from this trial among adolescent smokers that positive effectiveness of the proactive telephone intervention for smoking abstinence, observed previously at one year post-intervention, was sustained for the long-term into young adulthood. In light of the positive short-term effectiveness consistently observed from this and other trials for teen smokers, together with the lack of evidence from this study that such short-term impact can endure into young adulthood, sustained interventions that continue into young adulthood should be developed and tested for long-term impact.Trial RegistrationClinicalTrials.gov NCT00115882

背景：哈钦森高中吸烟研究（Hutchinson Study of High School Smoking）是首个在大样本青少年吸烟者人群中，证实戒烟干预在干预后1年时可实现6个月持续戒烟的随机对照试验。仍有一个关键问题有待解答：在干预后最长12个月时观察到的青少年戒烟干预正向效应，能否持续至青年早期？本研究首次探讨：在无额外干预的情况下，青少年戒烟干预的此类早期正向效应能否持续至青年早期。

方法：研究从华盛顿州50所随机抽取的高中中主动招募了2151名高中生吸烟者，将其随机分配至试验组（动机访谈（Motivational Interviewing）+认知行为技能训练（Cognitive Behavioral Skills Training）电话咨询干预）或对照组（无干预）。对这些吸烟者进行随访至高中毕业后7年，以明确青年早期的6年持续戒烟率。所有统计检验均采用双侧检验。

结果：针对主要终点6年持续戒烟率，在高中毕业后7年时未观察到干预效应，无论在全部吸烟者（试验组14.2%，对照组13.1%，差值为+1.1%，95%置信区间（CI）为-3.4~5.8，p=0.61）、每日吸烟者与非每日吸烟者亚组，还是其他预先设定的亚组中均是如此。但在男性亚组中，观察到干预对两项与戒烟进展相关的终点存在一定效应：过去1个月内吸烟天数减少，以及过去1年内最长戒烟持续时长增加。

结论：本试验针对青少年吸烟者的研究未证实：此前在干预后1年时观察到的主动电话戒烟干预的正向效应，能够持续至青年早期的长期随访阶段。鉴于本研究与其他同类试验均一致观察到青少年戒烟干预的短期正向效应，且本研究未发现此类短期效应可持续至青年早期，因此应开发并测试持续至青年早期的长效干预措施，以评估其长期效应。

试验注册：ClinicalTrials.gov NCT00115882