Determinants of adolescent physical activity and inactivity patterns

Objectives. Despite recognition of the important influence of environmental determinants on physical activity patterns, minimal empirical research has been done to assess the impact of environmental/contextual determinants of physical activity. This article aims to investigate environmental and soci odemographic determinants of physical activity and inactivity patterns amon g subpopulations of US adolescents. We define environmental determinants as modifiable factors in the physical environment that impose a direct influe nce on the opportunity to engage in physical activity. The present research examines environmental and sociodemographic determinants of physical activ ity and inactivity with the implication that these findings can point towar d societal-level intervention strategies for increasing physical activity a nd decreasing inactivity among adolescents. Study Design and Methodology. The study population consists of nationally r epresentative data from the 1996 National Longitudinal Study of Adolescent Health on 17 766 US adolescents enrolled in US middle and high schools (inc luding 3933 non-Hispanic blacks, 3148 Hispanics, and 1337 Asians). Hours/we ek of inactivity (TV/video viewing and video/computer games) and times/week of moderate to vigorous physical activity were collected by questionnaire. Outcome variables were moderate to vigorous physical activity and inactivi ty, which were broken into categories (physical activity: 0-2 times/week, 3 -4 times/week, and >5 times/week; inactivity: 0-10 hours/week, 11-24 hours/ week, and >25 hours/week). Sociodemographic and environmental correlates of physical activity and inactivity were used as exposure and control variabl es and included sex, age, urban residence, participation in school physical education program, use of community recreation center, total reported inci dents of serious crime in neighborhood, socioeconomic status, ethnicity, ge neration of residence in the United States, presence of mother/father in ho usehold, pregnancy status, work status, in-school status, region, and month of interview. Logistic regression models of high versus low and medium physical activity and inactivity were used to investigate sex and ethnic interactions in rela tion to environmental and sociodemographic factors to examine evidence for the potential impact of physical education and recreation programs and soci odemographic factors on physical activity and inactivity patterns. Results. Moderate to vigorous physical activity was lower and inactivity hi gher for non-Hispanic black and Hispanic adolescents. Participation in scho ol physical education programs was considerably low for these adolescents a nd decreased with age. Participation in daily school physical education (PE ) program classes (adjusted odds ratio [AOR]: 2.21; confidence interval [CI ]: 1.82-2.68) and use of a community recreation center (AOR: 1.75; CI: 1.56 -1.96) were associated with an increased likelihood of engaging in high lev el moderate to vigorous physical activity. Maternal education was inversely associated with high inactivity patterns; for example, having a mother wit h a graduate or professional degree was associated with an AOR of .61 (CI: .48-.76) for high inactivity. High family income was associated with increa sed moderate to vigorous physical activity (AOR: 1.43; CI: 1.22-1.67) and d ecreased inactivity (AOR: .70; CI: .59-.82). High neighborhood serious crim e level was associated with a decreased likelihood of falling in the highes t category of moderate to vigorous physical activity (AOR: .77; CI: .66-.91 ). Conclusions. These results show important associations between modifiable e nvironmental factors, such as participation in school PE and community recr eation programs, with activity patterns of adolescents. Despite the marked and significant impact of participation in school PE programs on physical a ctivity patterns of US adolescents, few adolescents participated in such sc hool PE programs; only 21.3% of all adolescents participated in 1 or more d ays per week of PE in their schools. In addition to the more readily modifi able factors, high crime level was significantly associated with a decrease in weekly moderate to vigorous physical activity. The key modifiable factors that had an impact on physical activity did not affect inactivity. Thus, it is clear that physical activity and inactivity were associated with very different determinants. Although physical activit y was most associated with environmental factors, inactivity was most assoc iated with sociodemographic factors. The data presented here confirm what researchers and pediatricians have kno wn intuitively; however, these relationships have not been tested empirical ly, nor have they been studied in any nationally representative survey of U S school-aged children. These findings show that patterns in inactivity can not be explained using the environmental factors studied here and, thus, it is clearly important that researchers search for other environmental deter minants likely to impact inactivity. National-level strategies must include attention to school PE and community recreation programs, particularly for segments of the US population withou t access to resources and opportunities that allow participation in physica l activity. Research to measure and explore the effects of other environmen tal determinants of activity and to ascertain whether there are any environ mental determinants of inactivity are important future research directions.