Bicycling to school during the transition from childhood into adolescence: a six-year longitudinal study.

Little is known about bicycling to school as children age. At baseline (2002) self-report data from 1070 children were gathered (51.9% boys; mean age: 10 years).The measurements were repeated in 2003 (n = 1039), 2004 (n = 907), 2005 (n = 549) and 2008 (n = 515). The rates of children bicycling to school significantly varied across time points from 46% at the age of ten, 69% at the age of 11, 83% at the age of 12, 70% at the age of 13 toward 78% at the age of 16. Starting from the age of 11, the average duration of time spent bicycling to school significantly increased over time. According to multilevel regression analyses 13.6% of the variance in rates of bicycling to school was situated at the school level, 39.6% at the pupil level and 46.7% at the measurement level. The differences in rates and durations across time points were independent from gender, BMI, SES and having siblings. Pupils engaging in bicycling to school at younger ages had a higher change of engaging in bicycling to school at 16 years old (ORs: 2.69-7.61; ICC bicycling rates: 0.46, ICC bicycling durations: 0.82). This finding emphasizes the need for promoting bicycling to school at young age.