Criterion Distances of Walking to School among Children in Hong Kong

Abstract

Distance between home and school is an important determinant of active commuting to school in children. Criterion distance of active commuting to school has been determined in Western countries, but it remains unknown how far children walk to school in highly dense urban contexts, such as Hong Kong. PURPOSE: To determine the criterion distance of walking to school among children in Hong Kong using the Receiver Operating Characteristic (ROC) curve analyses. METHODS: Participants were 1,279 grades 4-6 children (45% boys, mean age = 10.9 ± 1.0 years) from 9 primary schools in Hong Kong. Based on the self-reported number of trips walking to and from school, children were classified as active (≥6 walking trips per week) and passive commuters (<6 walking trips per week). Self-reported residential addresses were geo-coded by using the Geographic Information System (GIS) to calculate the distance from home to the attended schools. The threshold distance that best discriminates active from passive commuters was determined by the ROC curve analyses with the Youden index maximized. The area under the curve (AUC) was calculated as the indicator of the overall discrimination ability. All analyses were conducted separately for boys and girls. RESULTS: 46.2% of boys and 37.2% of girls were classified as active commuters. Criterion distance of walking to school was 828 meters for boys (Youden index = 1.726; AUC = 0.872, P<0.001) and 939 meters for girls (Youden index = 1.742; AUC = 0.859, P<0.001). CONCLUSION: The criterion distance of walking to school was determined for children in Hong Kong. Future interventions to promote active commuting should consider the distance that children actually walk.