Socio-economic status is an important determinant of physical activity, sedentary behaviour and body mass index, but these associations are contradictory in younger children. We investigated the associations between parental socio-economic status, physical activity, sedentary behaviour and body mass index in six-year-old children, to identify possible differences in physical activity between socio-economic groups.
The study comprised 621 children from Stockholm suburbs, recruited from, A healthy school start, a cluster-randomised controlled intervention study. A cross-sectional study was performed using baseline data. Physical activity and sedentary behaviour were assessed by accelerometry, body weight and height were measured, and body mass index was calculated. Sedentary behaviour was also assessed using a questionnaire.
We found that 12% of the study population were overweight and 9% were obese. Children from families with low socio-economic status were more physically active and slightly less sedentary, but were almost twice as likely to be overweight or obese than children from high socio-economic status, irrespective of the child's sex.
Low socio-economic status was associated with higher physical activity, lower sedentary behaviour and an unhealthier weight status compared to high socio-economic status, suggesting a role of diet as a cause of the higher overweight and obesity prevalence.