A count model to study the correlates of 60 min of daily physical activity in Portuguese children

Int J Environ Res Public Health. 2015 Feb 26;12(3):2557-73. doi: 10.3390/ijerph120302557.


This study aimed to present data on Portuguese children (aged 9-11 years) complying with moderate-to-vigorous physical activity (MVPA) guidelines, and to identify the importance of correlates from multiple domains associated with meeting the guidelines. Physical activity (PA) was objectively assessed by accelerometry throughout seven days on 777 children. A count model using Poisson regression was used to identify the best set of correlates that predicts the variability in meeting the guidelines. Only 3.1% of children met the recommended daily 60 min of MVPA for all seven days of the week. Further, the Cochrane-Armitage chi-square test indicated a linear and negative trend (p<0.001) from none to all seven days of children complying with the guidelines. The count model explained 22% of the variance in meeting MVPA guidelines daily. Being a girl, having a higher BMI, belonging to families with higher income, sleeping more and taking greater time walking from home to a sporting venue significantly reduced the probability of meeting daily recommended MVPA across the seven days. Furthermore, compared to girls, increasing sleep time in boys increased their chances of compliance with the MVPA recommendations. These results reinforce the relevance of considering different covariates' roles on PA compliance when designing efficient intervention strategies to promote healthy and active lifestyles in children.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Accelerometry
  • Child
  • Exercise
  • Female
  • Humans
  • Male
  • Models, Theoretical
  • Motor Activity*
  • Poisson Distribution
  • Portugal
  • Sex Factors
  • Time Factors