T. Olsen

The epidemiology of low back pain in an adolescent population.

We assessed the prevalence of low back pain (LBP) in a cohort of 1242 adolescents (aged 11 through 17) currently participating in a 4-year prospective study of medically treated injuries. Overall, 30.4% of the adolescents reported LBP. The impact of LBP in adolescents was considerable, with one third resulting in restricted activity and 7.3% seeking medical attention. Life-table analysis demonstrated that by age 15, the prevalence of LBP increased to 36%. There were few differences by gender or race. These results suggest that LBP in adolescents is a serious public health problem.

The epidemiology of leisure physical activity in an adolescent population.

A cohort of 1245 adolescents, 12-16 yr old and participating in a prospective study of risk factors for injury, were surveyed annually to assess past year leisure physical activity. This report describes the development and reproducibility of the questionnaire and provides the descriptive epidemiology of leisure physical activity in adolescents. The questionnaire was self-administered twice, a year apart, and had a 1 yr test-retest rank order correlation of 0.55. The past year estimate of leisure activity was also shown to be related to fitness (rho = -0.37), which was defined as the time needed to complete a 1-mile run. Males reported significantly more activity than females (P < 0.05) and whites reported more activity than nonwhites (P < 0.05). However, socioeconomic status was not found to be a determinant of activity levels in either males or females. In females, a negative association between activity and age was found (P < 0.05); however, this association was not evident in males. In summary, an activity questionnaire has been developed and was shown to be both reproducible and feasible. Therefore, it was used to examine habitual leisure physical activity patterns of adolescents.

Physical activity and the initiation of high-risk health behaviors in adolescents.

The association of physical activity to the initiation of health risk behaviors was examined in a 3-yr prospective study of a population-based cohort of 1245 adolescents aged 12-16 yr. Four hundred thirty-seven students (35% of the cohort) were identified at baseline via self-report survey as never having smoked cigarettes, consumed alcohol, used marijuana, or carried a weapon. Three measures of physical activity were obtained at baseline: leisure-time physical activity (LTPA), level of aerobic fitness (AF), and participation in competitive athletics. Significant 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 alcohol use was 48%, 42%, and 24% for high, moderate, and low LTPA, respectively (P < 0.01). Males who participated in competitive athletics were 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, moderate, and low AF, respectively (P < 0.05). No association was found between physical activity and weapon carrying. These results indicate that 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 appeared more at-risk for initiating alcohol consumption than their less active counterparts.

Surveillance of serious recreational injuries: a capture-recapture approach.

Serious injury from sport and recreation is a leading cause of morbidity and mortality in the United States. Historically, occurrences of diseases with substantial public health impact have been monitored via surveillance systems in order to obtain information concerning the frequency with which the diseases occur. Surveillance leads to efforts that identify risk factors, and eventually, control measures to reduce the incidence of disease. Currently, the surveillance of sports injury represents only limited coverage in the U.S. It is important to begin discussions regarding approaches toward the development of surveillance of these injuries. Methods based upon the communicable disease surveillance model could potentially be used to monitor serious sports injuries. One method of surveillance, using the statistical approach of capture-mark-recapture, is presented as an example by which a national system of surveillance of serious sports injury could be established.