Physical activity and sedentary lifestyle among children from private and public schools in Northern Brazil

OBJECTIVE: To analyze factors associated with physical activity and the mean time spent in some sedentary activities among school-aged children. METHODS: A cross-sectional study was carried out in a random sample of 592 schoolchildren aged nine to 16 years in 2005, in Sao Luis, Northern Brazil. Data were collected by means of a 24-Hour Physical Activity Recall Questionnaire, concerning demographic and socioeconomic variables, physical activities practiced and time spent in certain sedentary activities. Physical activities were classified according to their metabolic equivalents (MET), and a physical activity index was estimated for each child. Sedentary lifestyle was estimated based on time spent watching television, playing videogames and on the computer/internet. Chi square test was used to compare proportions. Linear regression analysis was used to establish associations. Estimates were adjusted for the effect of the sampling design. RESULTS: The mean of the physical activity index was 605.73 MET-min/day (SD = 509.45). School children that were male (coefficient=134.57; 95%CI 50.77; 218.37), from public schools (coefficient.=94.08; 95%CI 12.54; 175.62 and in the 5th to 7th grade (coefficient.=95.01; 95%CI 8.10;181.92 presented higher indices than females, children from private schools and in the 8th to the 9th grade (p<0.05). On average, students spent 2.66 hours/day in sedentary activities. Time spent in sedentary activities was significantly lower for children aged nine to 11 years (coefficient.=-0.49 hr/day; 95%CI -0.88; -0.10) and in lower socioeconomic classes (coefficient.=-0.87; 95%CI -1.45,-0.30). Domestic chores (59.43%) and walking to school (58.43%) were the most common physical activities. CONCLUSIONS: Being female, in private schools and in the 8th to 9th grade were factors associated with lower levels of physical activity. Younger schoolchildren and those from low economic classes spent less time engaged in sedentary activities.