The Association between leisure time physical activity and smoking in adolescence: an examination of potential mediating and moderating factors.
BACKGROUND
Although physical activity has been associated negatively with smoking in adolescence, the association is not well understood.


OBJECTIVE
This study examines the relationship between adolescents' leisure time physical activity and smoking behavior, while considering BMI, weight concern, sense of coherence, and physically active self-concept as potential mediating and moderating variables.


METHODS
Data were obtained through a postal survey among 3,940 Danes aged 16 to 20. Bivariate and multivariate logistic regressions were performed to identify significant associations as well as mediating and moderating effects.


RESULTS
In the bivariate model, leisure time physical activity was negatively associated with smoking; adolescents who were active at least one hour per week were up to half as likely to smoke as inactive adolescents. In the adjusted model, however, the association disappeared. Further analyses revealed that physically active self-concept acted both as a mediator and as a moderator of the studied relationship.


CONCLUSIONS
The data suggest that participation in leisure time physical activity is indeed inversely associated with adolescent smoking, but only when physical activity is perceived as an important part of the self. Hence, interventions designed to promote physical activity among youth may also aim to boost physically active self-concepts.
Verkooijen
Kirsten T
KT
Unit for Health Promotion Research, University of Southern Denmark, Wageningen University, The Netherlands. Kirsten.verkooijen@wur.nl
Nielsen
Gert A
GA
Kremers
Stef P J
SP
D000293:Adolescent; D000328:Adult; D001294:Attitude to Health; D015992:Body Mass Index; D001835:Body Weight; D003718:Denmark; D015444:Exercise / Q000523:psychology*; D005260:Female; D006801:Humans; D007389:Internal-External Control; D007899:Leisure Activities; D008297:Male; D015999:Multivariate Analysis; D012307:Risk Factors; D012649:Self Concept; D012907:Smoking / Q000453:epidemiology / Q000523:psychology*