Relationship between parent and child pedometer-determined physical activity: a sub-study of the CANPLAY surveillance study

Background: Understanding parental influences on their children's physical activity (PA) provides insight into developing effective family-based interventions. This study examines whether children's objectively monitored PA is associated with that of their parents. Methods: Participants (children and parents) were recruited to a sub-study of the Canadian Fitness and Lifestyle Research Institute's annual Canadian Physical Activity Levels among Youth (CANPLAY) surveillance study. In total, 539 of 1,187 eligible children (age range 5-19 years) and at least one of their parents participated. Participants logged pedometer steps for 7 days. Descriptive statistics were used to examine parental mean daily steps by their children's age, sex and steps/day. Associations between steps/day for parents and children (controlling for their age and sex) were estimated using general linear and logistic regression. Results: Children's mean steps/day did not differ by parents' age or sex, nor by whether one or both parents participated in the study. There were quantifiable relationships between parents' and children's steps/day. For every 1,000 step increase in a father's steps/day, his son's increased by 329-407 steps/day and his daughter's increased by 273 steps/day (adjusted model only). Every 1,000 step increase in a mother's steps/day was associated with 263-439 extra steps/day for her son's steps/day and 195-219 steps/day for her daughter. A 3,000 step increment in a father's or mother's steps/day was associated with 1.9-2.5 fold increase in the odds that their child's activity level would be in the upper two tertiles of steps/day. Conclusions: These cross-sectional data indicate that children's PA is related to that of their parents in distinct and quantifiable ways. Interventions are warranted to evaluate the direction of this relationship, confirm the magnitude of influence, and illuminate mediating and moderating mechanisms by which both parents may have influence over their own children's PA.