Meta-analysis of the prevalence of physical inactivity among Brazilian adolescents.

A systematic review and meta-analysis were carried out to investigate the prevalence of physical inactivity among adolescents in Brazil. We identified articles that had been published up to August 2010 and the search was conducted using six electronic databases. We did not enforce any search limitations. Forest plot-type graphs were generated using the prevalence of physical inactivity stratified by region and sex. Meta-regression models were fitted to identify possible sources of heterogeneity in the prevalence estimates. Of the 1,496 articles initially identified, 37 were deemed appropriate for the systematic review. Prevalence rates ranged from 2% to 80% for male and from 14% to 91% for female subgroups. The lowest prevalence rates of physical inactivity were found to be for the Southern region, whereas the highest rates were observed in the North-Northeast. The methods employed to evaluate physical inactivity in Brazilian adolescents also differed among the studies. This variation demonstrates the need for standardised and validated methods of measuring physical activity in epidemiological investigation.