Socioeconomic inequalities in children's exposure to tobacco retailing based on individual-level GPS data in Scotland.

Background: Identifying factors shaping knowledge of and attitudes towards tobacco products in preadolescence is a key component supporting tobacco control policies aimed at preventing smoking initiation. This study quantified exposure to tobacco retailing environments within the individual-level activity spaces of children across a socioeconomic gradient.

Methods: One week of global positioning system (GPS) tracking data were collected at 10 s intervals from a nationally representative sample of 10-11-year olds (n=692). Proximity of GPS locations (n=~16 M) to the nearest tobacco retailer (n=9030) was measured and exposure defined when a child came within 10 m of a retailer. Duration, frequency, timing and source of exposure were compared across income deprivation quintiles, along with retail density within children's home neighbourhoods.

Results: On average, children were exposed to tobacco retailing for 22.7 min (95% CI 16.8 to 28.6) per week in 42.7 (35.2-50.1) independent encounters. However, children from the most deprived areas accumulated six times the duration and seven times the frequency of exposure as children from the least deprived areas. Home neighbourhood retail densities were 2.6 times higher in deprived areas, yet the average number of businesses encountered did not differ. Most exposure came from convenience stores (35%) and newsagents (15%), with temporal peaks before and after school hours.

Conclusions: By accounting for individual mobility, we showed that children in socially disadvantaged areas accumulate higher levels of exposure to tobacco retailing than expected from disparities in home neighbourhood densities. Reducing tobacco outlet availability, particularly in areas frequently used by children, might be crucial to policies aimed at creating 'tobacco-free' generations.