title: Modifying effects of sex, age, and education on 22-year trajectory of leisure-time physical activity in a Canadian cohort.
abstract: BACKGROUND
  We investigated the population trajectory of leisure time physical activity (LTPA) in adults age 18 to 60 y (n = 881), who were recruited in 1981 for the Canada Fitness Survey and followed-up through the Campbell's Survey on Well-Being (1988) and the Physical Activity Longitudinal Study (2002/04).
  
  
  METHODS
  Data on involvement in LTPA were collected by questionnaire and used to estimate average daily energy expenditure (EE) (kcal . kg-1 . d-1) during leisure time. Growth trajectory modeling was used to describe the overall population trajectory of LTPA and the extent to which average trajectories varied between sub-groups defined by age, sex, and education.
  
  
  RESULTS
  The population trajectory of LTPA over time was modified by baseline age, but not by sex or by level of education. Disparities in LTPA related to sex and education persisted over two decades.
  
  
  CONCLUSIONS
  This longitudinal investigation improves our understanding of the processes underlying patterns of LTPA in adults.
authors.affiliation: Dept of Social and Preventive Medicine, Groupe de Recherche Interdisciplinaire de Sante, Université de Montréal, Montreal, PQ H3C 3J7.
authors.forename: Tracie A
authors.initials: TA
authors.lastname: Barnett
authors.forename: Lise
authors.initials: L
authors.lastname: Gauvin
authors.forename: Cora L
authors.initials: CL
authors.lastname: Craig
authors.forename: Peter T
authors.initials: PT
authors.lastname: Katzmarzyk
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D002170:Canada; D002648:Child; D004522:Educational Status; D015444:Exercise / Q000502:physiology* / Q000523:psychology; D005260:Female; D015438:Health Behavior; D006306:Health Surveys; D006801:Humans; D007899:Leisure Activities / Q000523:psychology*; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D009043:Motor Activity / Q000502:physiology*; D010809:Physical Fitness / Q000502:physiology*; D012737:Sex Factors