Effect of ACIVITAL 2-yr-intervention program on screen time, PA and fitness according to weight status and fitness levels in adolescents

Purpose: Compared to normal weigh and fit adolescents, overweight and unfit adolescents are more likely to develop cardiovascular disease in adulthood. Despite this, there is insufficient evidence regarding the effectiveness of general schoolbased interventions in these high-risk groups. We assessed if overweight/obese and unfit adolescents responded differently to a school-based health promotion intervention compared to normal weight or fit adolescents.

Methods: A cluster-randomized pair matched trial was performed in 20 urban schools located in Cuenca city -Ecuador (October 2009 to May 2012). Adolescents of grade 8 and 9 (12.3 and 13.3 years respectively) participated in the trial, which included an individual and environmental component. At baseline, the adolescents were classified into groups according to their BMI values in normal weight and overweigh/obese and according to aerobic capacity scores in fit and unfit. Mixed linear model were used to assess the intervention effect on physical fitness (EUROFIT test battery), screen time (questionnaires) and physical activity (accelerometer).

Results: The overweight/obese prevalence was 21.5% while the 84.8% of the adolescents were classified as unfit. The intervention effect on speed shuttle run (β=-1.5 s, P=0.03), sedentary time (β=-90.3 min/day, P=<0.01) and light physical activity (β=55.5 min/day, P=<0.01), was significantly higher in overweight adolescents compared to normal weight peers. In addition, the intervention effect on vertical jump was higher in unfit adolescents (β=2.43 cm, P=0.02) compared to their fit peers.

Conclusions: A school-based culturally appropriate multi-component program is more effective in overweight/obese and unfit adolescents compared to normal weight or fit adolescents.