Adverse health outcomes of sedentary behavior, which is characterized by a low energy expenditure while in a sitting or reclining posture,¹ are increasingly acknowledged in children and adolescents.^2-4 A growing body of evidence suggests that sedentary behaviors may be detrimental even at a very young age.⁵ Electronic media use incorporating television viewing and use of computers and electronic games (e-games) is one type of sedentary behavior. Evidence suggests that electronic media use (mainly in the form of television viewing, which is the most widely studied electronic media behavior) may be particularly detrimental to health outcomes during childhood and into adulthood.^2,6

Evidence suggests possible synergetic effects of multiple lifestyle behaviors on health risks like obesity and other health outcomes. A better insight in the clustering of those behaviors, could help to identify groups who are at risk in developing chronic diseases. This study examines the prevalence and clustering of physical activity, sedentary and dietary patterns among European adolescents and investigates if the identified clusters could be characterized by socio-demographic factors. The study comprised a total of 2084 adolescents (45.6% male), from eight European cities participating in the HELENA (Healthy Lifestyle in Europe by Nutrition in Adolescence) study. Physical activity and sedentary behavior were measured using self-reported questionnaires and diet quality was assessed based on dietary recall. Based on the results of those three indices, cluster analyses were performed. To identify gender differences and associations with socio-demographic variables, chi-square tests were executed. Five stable and meaningful clusters were found. Only 18% of the adolescents showed healthy and 21% unhealthy scores on all three included indices. Males were highly presented in the cluster with high levels of moderate to vigorous physical activity (MVPA) and low quality diets. The clusters with low levels of MVPA and high quality diets comprised more female adolescents. Adolescents with low educated parents had diets of lower quality and spent more time in sedentary activities. In addition, the clusters with high levels of MVPA comprised more adolescents of the younger age category. In order to develop effective primary prevention strategies, it would be important to consider multiple health indices when identifying high risk groups.

The aims of this study were to assess the relative validity and reproducibility of a semi-quantitative food-frequency questionnaire (FFQ) applied in a large region-wide survey among 2.5-6.5 year-old children for estimating food group intakes. Parents/guardians were used as a proxy. Estimated diet records (3d) were used as reference method and reproducibility was measured by repeated FFQ administrations five weeks apart. In total 650 children were included in the validity analyses and 124 in the reproducibility analyses. Comparing median FFQ1 to FFQ2 intakes, almost all evaluated food groups showed median differences within a range of ± 15%. However, for median vegetables, fruit and cheese intake, FFQ1 was > 20% higher than FFQ2. For most foods a moderate correlation (0.5-0.7) was obtained between FFQ1 and FFQ2. For cheese, sugared drinks and fruit juice intakes correlations were even > 0.7. For median differences between the 3d EDR and the FFQ, six food groups (potatoes & grains; vegetables Fruit; cheese; meat, game, poultry and fish; and sugared drinks) gave a difference > 20%. The largest corrected correlations (>0.6) were found for the intake of potatoes and grains, fruit, milk products, cheese, sugared drinks, and fruit juice, while the lowest correlations (<0.4) for bread and meat products. The proportion of subjects classified within one quartile (in the same/adjacent category) by FFQ and EDR ranged from 67% (for meat products) to 88% (for fruit juice). Extreme misclassification into the opposite quartiles was for all food groups < 10%. The results indicate that our newly developed FFQ gives reproducible estimates of food group intake. Overall, moderate levels of relative validity were observed for estimates of food group intake.