The Protective Effects of Physical Activity on AdolescentSmoking Progression

描述（由申请人提供）：吸烟是美国发病率和死亡率的主要可预防原因。约23%的青少年是经常吸烟者。为了进一步减少青少年吸烟，需要确定防止青少年吸烟的因素，并随后将其纳入青少年吸烟预防计划。体力活动可能是防止青少年吸烟开始和发展的重要保护因素。虽然对吸烟和身体活动的纵向研究表明，较高水平的身体活动降低了青少年吸烟开始和发展的几率，但这种关系的性质，解释这种保护关系的机制，赋予保护作用所需的身体活动量，以及青少年因其身体活动水平而面临吸烟风险的情况仍不清楚。我们建议建立一个由1 000名青少年（14岁）组成的队列，并对他们进行为期四年的跟踪调查（18岁），以弥补这一差距。将收集对吸烟和缺乏身体活动的社会环境、行为和心理影响。拟议研究的目的是（1）澄清吸烟和身体活动之间关系的性质，（2）评估解释身体活动不足和吸烟关系的机制，（3）经验性地确定不同的纵向路径或吸烟-身体活动不足轨迹，以确定最佳干预时机和防止吸烟所需的身体活动量，以及（4）通过社会环境、行为和心理变量来描述这些轨迹，以在青少年的身体活动习惯的背景下识别吸烟风险。感兴趣的具体结果包括：（a）发展为经常吸烟和缺乏身体活动的几率和速率，以及（B）纵向模式或吸烟-缺乏身体活动轨迹。这将是第一个同时全面评估从青春期中期到晚期吸烟和身体活动的研究之一，以阐明和量化保护关系，并探索基于理论的机制如何与吸烟习惯发展的关键点相关。这项研究的结果可以用来告知青少年吸烟预防和干预计划的时间，类型，身体活动量，目标变量和重要的亚群。吸烟和缺乏运动是两种危害健康的行为，通常形成于青春期，并持续到成年。虽然，现有的吸烟和体育活动的纵向研究表明，更高水平的体育活动减少了青少年吸烟开始和发展的几率50%，这种关系的性质，为什么体育活动是保护性的，以及提供保护作用所需的体育活动量尚不清楚。这些信息对于确定青少年吸烟预防干预的内容、时间和目标至关重要，其中包括身体活动部分。

DESCRIPTION (provided by applicant): Cigarette smoking is the leading preventable cause of morbidity and mortality in the U.S. About 23% of adolescents are regular smokers. To further reduce adolescent smoking, factors that protect against adolescent smoking need to be identified and subsequently incorporated into youth smoking prevention programs. Physical activity may be an important protective factor against youth smoking initiation and progression. Although longitudinal studies of smoking and physical activity indicate that higher levels of physical activity reduce the odds of adolescent smoking initiation and progression, the nature of this relationship, the mechanisms explaining this protective relationship, the amount of physical activity needed to confer a protective effect, and the adolescents at risk for smoking due to their levels of physical activity remain unclear. We propose to address this gap by creating a cohort of 1,000 adolescents (age 14 years) and following them over a four-year period (age 18 years). Socio-environmental, behavioral and psychological influences on smoking and physical inactivity will be collected. The aims of the proposed study are to (1) clarify the nature of the relationship between smoking and physical activity, (2) evaluate the mechanisms explaining the physical inactivity and smoking relationship, (3) empirically identify distinct longitudinal paths or smoking-physical inactivity trajectories to determine optimal intervention timing and the amount of physical activity needed to protect against smoking, and (4) characterize these trajectories by socio-environmental, behavioral and psychological variables to identify adolescents at risk for smoking within the context of their physical activity habits. Specific outcomes of interest include (a) odds and rates of progression to regular smoking and physical inactivity, and (b) longitudinal patterns or smoking-physical inactivity trajectories. This will be one of the first studies to concurrently and comprehensively evaluate smoking and physical activity from mid to late adolescence, to elucidate and quantify the protective relationship, and to explore how theory-based mechanisms relate to critical points in the development of a smoking habit often carried into adulthood. Results from this study can be used to inform the timing, type, amount of physical activity, target variables and important subpopulations for adolescent smoking prevention and intervention programs. Smoking and physical inactivity are two health risk behaviors often formed in adolescence and carried into adulthood. Although, the available longitudinal studies of smoking and physical activity indicate that higher levels of physical activity reduce the odds of adolescent smoking initiation and progression by 50%, the nature of this relationship, why physical activity is protective, and the amount of physical activity needed to confer a protective effect are unclear. This information is critical to for determining the content, timing, and targets for youth smoking prevention intervention that incorporates a physical activity component.