Longitudinal associations between cycling to school and weight status

The objective of the present study was to assess the longitudinal association between cycling to school and weight status in two cities where cycling to school is common - Kristiansand (Norway) and Rotterdam (The Netherlands).Data from two studies ENDORSE (Rotterdam) and YOUTH IN BALANCE (Kristiansand) were used. Both studies were longitudinal with two years between time (T) 1 and T2 measurements, and with mean age at T1 of 13.2 and 13.4 years, respectively. The sample was categorized into the following groups according to responses about main mode of commuting to school at the two time points: NO cycling, STARTED cycling, STOPPED cycling and CONTINUED cycling. Measured weight and height were obtained at both time points, and weight status (overweight vs. not overweight) was calculated using international classification criteria for BMI. The two datasets were analyzed separately and together.In multilevel logistic regression models of the combined sample, adjusting for weight status at Time 1, those who stopped cycling had greater odds of being overweight at T2 (OR = 3.19; 95% CI = 1.41?7.24) while those continued cycling had lower odds of being overweight (OR = 0.44; 95% CI = 0.21?0.88), separately compared to the other three groups together. The same trend was observed in both study samples.This study shows that there are longitudinal associations between cycling to school and weight status in two cities where cycling to school is common, implying that interventions aiming at reducing overweight/obesity among adolescents might consider the promotion of sustained cycling behaviour.