Strengths and difficulties questionnaire Parents were asked to complete the standardized ��Strengths and Difficulties Questionnaire�� Calcitriol structure (SDQ) (reliability: ICC=0.80; concurrent validity: r=0.70) [46], reporting the emotional problems of their child over the past six months. For each of the 25 statements, parents could answer: ��not true�� (0), ��somewhat true�� (1) and ��certainly true�� (2). The statements were divided in 5 subscales of 5 items each: emotional problems, conduct problems, hyperactivity-inattention behavior, peer problems, and prosocial behavior. Subscale scores were computed by summing scores on relevant items (after recoding reversed items). Higher scores on the prosocial behavior subscale reflect strengths, whereas higher scores on the other four subscales reflect difficulties [47].

Body composition measurements Routine anthropometry The routine anthropometric measurements were carried out by two trained observers at school to improve intra- and inter-observer reliability. Routine anthropometric measurements included measurement of the child��s weight, height, body mass index, leg-to-leg impedance, skin fold thicknesses (triceps and subscapular), circumference of mid-upper arm, hip, waist and neck and were performed in accordance with the standardized procedures of the IDEFICS project [17,48,49]. Fat mass determination by air displacement plethysmography (ADP) To obtain reliable and valid body composition measurements, the ADP technique was conducted by the same person over all survey periods.

This method is currently considered a good reference technique for body composition measurements with a quick, comfortable, automated, non-invasive and safe measurement process, making it feasible for children [50]. Body volume was measured by ADP (BODPOD?, Software version 4.2.4, Life Measurement Inc, Cranlea and Co, Birmingham, United Kingdom) using standardized procedures [51]. Children had to refrain from physical activity and food consumption two hours before the measurement. The device was calibrated daily according to the manufacturer’s guidelines. Children were measured twice in tight-fitting bathing suit with swim cap to rule out air trapped in clothes and hair. Thoracic gas volume was predicted by the software with a validated child-specific equation [50] and fat mass percentage was calculated using the equation reported by Wells [52]. If the first and second measurement of the body Drug_discovery volume differed more than 150ml, a third measurement was performed. Diet Children��s Eating habits questionnaire (CEHQ)- food frequency questionnaire (FFQ) (parent-reported) The CEHQ-FFQ investigates food consumption frequency and behaviors associated with obesity and general health in children.