Abstract P142: Smoking Cessation and Long-term Changes in Physical Activity Level: The Coronary Artery Risk Development in Young Adults (CARDIA) Study
Background Physical activity (PA) might improve health outcomes in smokers that quit smoking. However, longitudinal cohort studies have not addressed whether PA changes after smoking cessation.
Aims We estimated PA trajectories for persons who quit smoking, adjusting for age trends, and relative to the expected trajectory if smoking had continued.
Methods We used data from the CARDIA Study, a population-based study of African American and European American recruited at age 18-30 years in 1985/6 and followed over 25 years. Physical activity was self-reported during clinical visits at years 0 (1985/6), 2, 5, 7, 10, 15, 20 and 25 (2010/11); smoking status was reported each year (at visits or by phone, and imputed where missing). We used mixed linear models to estimate PA trajectories for persons who stopped smoking, relative to levels that would have been expected if smoking had continued. The analysis was stratified by race and sex, and controlled for fixed (education, age at smoking start) and time-varying (age, calendar year, marital status, and years of smoking at cessation) factors. We assessed sensitivity to inclusion of body mass index (BMI), a potential time-dependent confounder/mediator, using marginal structural models.
Results The 5115 participants contributed a total of 32,472 clinical visits over 25 years; 40% of participants (n=2042) reported smoking during a visit and 22% (n=1126) stopped smoking during follow-up. The PA trajectory for persons who quit progressively diverged from the trajectory that would have been expected had these persons continued smoking (Figure). This divergence varied in magnitude by race and sex. For example, the net increase in PA was 18% higher (95% CI: 9% to 28%, p<0.001) for white women 5 years after stopping but only 6% higher (-6% to 20%, p=0.21) for black women. Accounting for BMI using marginal structural models showed similar results.
Conclusion Smoking cessation was associated with an increase in long-term self-reported physical activity relative to continuing smokers.
- © 2013 by American Heart Association, Inc.