Accelerometer-based sedentary time and physical activity with incident and progressive tobacco smoking in 2503 children: A 13-year mediation and temporal longitudinal study.

BACKGROUND

Long-term accelerometer-based studies examining whether engaging in physical activity (PA) reduces the risk of smoking in children are lacking, and whether directly measured adiposity increases smoking risk is uncertain.

METHODS

From the Avon Longitudinal Study of Parents and Children (ALSPAC), UK birth cohort, 2503 children aged 11 years with complete smoking and at least one valid time-point movement behaviour data were followed up until age 24 years. ActiGraph assessed sedentary time (ST), light PA (LPA), and moderate-to-vigorous PA (MVPA) at ages 11, 15, and 24-year clinic visits and smoking-based questionnaires were administered, whilst fat mass was measured with dual-energy x-ray absorptiometry scanner. Data were analysed with generalized linear-mixed effect models with logit-links and structural equation models.

RESULTS

Mean [SD] age at baseline was 11.71 [0.20] years and the prevalence of smoking at ages 13, 15, and 24 years were 1.5%, 13.5%, and 26.6%, respectively. Higher MVPA at age 11 years was significantly associated with lower odds of smoking at age 13 years (odds ratio, 0.991; [95% CI, 0.983-0.999], P = 0.035). Cumulative MVPA during ages 11-24 years was significantly associated with lower odds of progressive smoking during growth from ages 13-24 years (0.992; [95% CI, 0.989-0.996], P < 0.001). Cumulative ST and LPA had no significant associations with smoking. Higher fat mass suppressed (10% suppression) the inverse relationship between MVPA and smoking. In path analysis, higher MVPA at age 15 years temporally preceded reduced smoking at age 24 years.

CONCLUSION

In the present study, engaging in MVPA from age 11 years may prevent 9 in 1000 children from starting smoking at the age of 13 years when smoking prevalence was 15 in 1000 children, i.e potentially preventing 60% of children from initiating smoking. However, the MVPA preventive approach diminished as children grew into young adults.