title: Longitudinal trends in gasoline price and physical activity: the CARDIA study.
abstract: OBJECTIVE
  To investigate longitudinal associations between community-level gasoline price and physical activity (PA).
  
  
  METHODS
  In the Coronary Artery Risk Development in Young Adults study, 5115 black and white participants aged 18-30 at baseline 1985-86 were recruited from four U.S. cities (Birmingham, Chicago, Minneapolis and Oakland) and followed over time. We used data from 3 follow-up exams: 1992-93, 1995-96, and 2000-01, when the participants were located across 48 states. From questionnaire data, a total PA score was summarized in exercise units (EU) based on intensity and frequency of 13 PA categories. Using Geographic Information Systems, participants' residential locations were linked to county-level inflation-adjusted gasoline price data collected by the Council for Community & Economic Research. We used a random-effect longitudinal regression model to examine associations between time-varying gasoline price and time-varying PA, controlling for age, race, gender, baseline study center, and time-varying education, marital status, household income, county cost of living, county bus fare, census block-group poverty, and urbanicity.
  
  
  RESULTS
  Holding all control variables constant, a 25-cent increase in inflation-adjusted gasoline price was significantly associated with an increase of 9.9 EU in total PA (95% CI: 0.8-19.1).
  
  
  CONCLUSIONS
  Rising prices of gasoline may be associated with an unintended increase in leisure PA.
authors.affiliation: Department of Nutrition, School of Public Health, University of North Carolina at Chapel Hill, Chapel Hill, NC 27516, USA.
authors.forename: Ningqi
authors.initials: N
authors.lastname: Hou
authors.forename: Barry M
authors.initials: BM
authors.lastname: Popkin
authors.forename: David R
authors.initials: DR
authors.lastname: Jacobs
authors.forename: Yan
authors.initials: Y
authors.lastname: Song
authors.forename: David K
authors.initials: DK
authors.lastname: Guilkey
authors.forename: Ka
authors.initials: K
authors.lastname: He
authors.forename: Cora E
authors.initials: CE
authors.lastname: Lewis
authors.forename: Penny
authors.initials: P
authors.lastname: Gordon-Larsen
mesh_terms: D000328:Adult; D005260:Female; D005742:Gasoline / Q000191:economics*; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D009043:Motor Activity; D012923:Social Class; D011795:Surveys and Questionnaires; D014481:United States
chemical_list: D005742:Gasoline