Mean differences in knowledge, attitudes and habits (KAH) scores after 1-year follow-up in children (overall and by age). (A) KAH-overall. (B) KAH-diet. (C) KAH-physical activity. (D) KAH-heart and body. P values relate to overall mean differences in score changes between intervention and control groups. P trend values test whether the treatment effect varies with children’s age (by class year). **P<0.005. *P<0.05.