title: Activity Levels for Four Years in a Cohort of Urban-Dwelling Adolescent Females.
abstract: Evidence suggests that female adolescents and those living in urban environments may have lower physical activity (PA) levels compared with their peers. Yet few studies report PA for urban adolescent females, and there is no consensus regarding potential causes for low PA in this subgroup. We examined PA levels, in a large, diverse cohort of 14- to 17-yr-old urban-dwelling females and assessed the effect of socioeconomic, personal, and neighborhood/environmental factors on PA.
  
  
  
  One week of time-stamped step count data were collected on 926 girls from the Pittsburgh Girls Study at four annual visits. Valid recordings (worn at least 10 h on 3+ d) were examined and compared with normalized step count values from a U.S. population-representative sample. Relationships between important covariates and average steps per day were examined with regression models.
  
  
  
  Adjusted mean ± SD step counts per day at baseline were 5614 ± 2434 after controlling for important covariates with less than 6% of girls achieving at least 10,000 steps per day. The girls from the Pittsburgh Girls Study accrued ~45% of their steps during school hours. Age-specific median step counts per day for study participants were similar to the 25th percentile of U.S. population normalized values and did not significantly change during follow-up. Non-Hispanic African American race/ethnicity was associated with higher average step counts per day; obesity and a recent childbirth were associated with lower average step counts per day.
  
  
  
  Step counts in this cohort of urban adolescent girls were considerably lower than expected for U.S. adolescent females. Targeted efforts to improve PA levels in urban youth should consider the importance of school-based activity while increasing PA opportunities outside of school.
authors.affiliation: 1Department of Epidemiology, University of Pittsburgh, Pittsburgh, PA; 2Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA; 3Department of Kinesiology, Health, and Sport Science, University of Indiana, Indiana, PA; and 4School of Medicine, University of Pittsburgh, Pittsburgh, PA.
authors.forename: Bonny
authors.initials: B
authors.lastname: Rockette-Wagner
authors.forename: Alison E
authors.initials: AE
authors.lastname: Hipwell
authors.forename: Andrea M
authors.initials: AM
authors.lastname: Kriska
authors.forename: Kristi L
authors.initials: KL
authors.lastname: Storti
authors.forename: Kathleen M
authors.initials: KM
authors.lastname: McTigue
mesh_terms: D056044:Actigraphy; D000293:Adolescent; D000367:Age Factors; D004779:Environment Design; D015444:Exercise; D005260:Female; D006801:Humans; D008019:Life Style / Q000208:ethnology; D010414:Pennsylvania; D012111:Residence Characteristics; D012574:Schools; D012959:Socioeconomic Factors; D014505:Urban Population