Factors associated with physical inactivity in adolescents aged 10-14 years, enrolled in the public school network of the city of Salvador, Brazil.

Objective: To investigate the factors associated to the physical inactivity among teenagers in Salvador, BA.

Methodology: A cross-sectional study was made with 803 teenagers from 10 to 14 years old, enrolled in public high schools in Salvador, BA. Information concerning physical activity levels (dependent variable), sedentary behavior, demographic, anthropometric, socioeconomic and maternal characteristics (independent variables) were collected. The Poisson multivariate analysis was chosen to analyze the statistical data.

Results: The prevalence of physical inactivity was 49,6% (CI 95% 46,14 - 53,06); with higher standards between females (girls: 59,9%; boys: 39%, p < 0,001). With the multivariate analyses, it was verified a inverse association between physical inactivity and family economical condition that was classified in D/E worse economical levels either among males (PR = 0,73, CI 95%, 0,54 - 0,046), as among females (PR = 0,79; CI 95%; 0,66 - 0,96). In complementary analysis according to domains of physical activity, It was observed a significant decrease of physical inactivity in displacement domain between teenagers of lower economical levels (Boys - Classes B1/B2/C1 = 20,6%, C2 = 11%, D/E = 6%, p = 0,001; Girls - Classes B1/B2/C1 = 26,7%, C2 = 12,5%, D/E = 10,8%, p = 0,003).

Conclusions: The prevalence of physical inactivity is high among the studied teenagers. Youths with lower economical levels are more active comparing with those with higher economical standards. Moreover, the association between physical activity and economical condition is influenced by physical activity domain that was investigated.