PHYSICAL-ACTIVITY AND THE INITIATION OF HIGH-RISK HEALTH BEHAVIORS INADOLESCENTS

The association of physical activity to the initiation of health risk behaviors was examined in a 3-yr prospective study of a population-bas ed cohort of 1245 adolescents aged 12-16 yr. Four hundred thirty-seven students (36% of the cohort) were identified at baseline via self-rep ort survey as never having smoked cigarettes, consumed alcohol, used m arijuana, or carried a weapon. Three measures of physical activity wer e obtained at baseline: leisure-time physical activity (LTPA), level o f aerobic fitness (AF), and participation in competitive athletics. Si gnificant associations, with notable gender differences, were observed between physical activity and the initiation of cigarette smoking and alcohol use. The cumulative proportion of male students initiating al cohol use was 48%, 42%, and 24% for high, moderate, and low LTPA, resp ectively (P < 0.01). Males who participated in competitive athletics w ere significantly more likely than nonathletes to initiate alcohol use (44% vs 17%, P < 0.01). The cumulative proportion of female students initiating cigarette use was 10%, 23%, and 22% for high, moderate, and low LTPA, respectively (P < 0.05) and 7%, 28%, and 16% for high, mode rate, and low AF, respectively (P < 0.05). No association was found be tween physical activity and weapon carrying. These results indicate th at in this cohort of adolescents, the most active or most fit females were less likely to initiate cigarette smoking. In contrast, the most active males or males who participated in competitive athletics appear ed more at-risk for initiating alcohol consumption than their less act ive counterparts.