Socioeconomic difference in physical activity in children and their parents: The childhood and adolescence surveillance and prevention of adult noncommunicable disease study.

Background: As a health-related behavior, physical activity (PA) differs according to individual's socioeconomic status (SES). This study aimed to assess the socioeconomic difference in leisure-time PA among Iranian students and their parents at national and regional levels.

Study design: Nationwide cross-sectional study.

Methods: This study was conducted as part of a national survey conducted in 2015 among 14400 Iranian students and their parents. Total PA level was measured as the average hours spent on PA per week. Nonlinear principal component analysis was used to construct the households' SES based on household's assets, type of house ownership, occupation of fathers and the educational levels of fathers and mothers. Concentration index was applied to measure the inequality in the PA level in parents and students.

Results: Complete data of 13313 students and their parents were available. At the national level, students spent more hours of PA per week (3.753 h per week [h/w]) as compared to their parents. Moreover, PA h/w was higher in fathers (3.488 h/w) as compared to mothers (2.763 h/w). The lowest means of mother's and student's PA were found in the highest SES region. At national level, the concentration indices (CI) of father's and mother's PA were -0.050 (95% CI = -0.067 ~ -0.030) and -0.028 (95% CI = -0.044 ~ -0.012), respectively, indicating pro-poor inequality, but the CI value of student PA was non-significant (CI = -0.007, 95% CI = -0.023-0.008).

Conclusions: Given that the mother's and student's PA level was low in the high SES regions, it is suggested that focused PA planning may further increase the level of PA across higher SES regions and might be effective in reducing the PA inequality.