Background: Adequate sleep is a critical factor for adolescent's health and health-related behaviors. Objective: (a) to describe sleep duration in European adolescents from nine countries, (b) to assess the association of short sleep duration with excess adiposity and (c) to elucidate if physical activity (PA), sedentary behaviors and/or inadequate food habits underlie this association. Design: A sample of 3311 adolescents (1748 girls) aged 12.5-17.49 years from 10 European cities in Austria, Belgium, France, Germany, Greece, Hungary, Italy, Spain and Sweden was assessed in the Healthy Lifestyle in Europe by Nutrition in Adolescence Study between 2006 and 2008. We measured anthropometric data, sleep duration, PA (accelerometers and questionnaire), television watching and food habits (Food Frequency Questionnaire). Results: Average duration of daily sleep was 8 h. Shorter sleepers showed higher values of BMI, body fat, waist and hip circumferences and fat mass index (Po0.05), particularly in females. Adolescents who slept o8 h per day were more sedentary, as assessed by accelerometry, and spent more time watching TV (Po0.05). The proportion of adolescents who eat adequate amounts of fruits, vegetables and fish was lower in shorter sleepers than in adolescents who slept X8 h per day, and so was the probability of having adequate food habits (Po0.05). Correlation analysis indicated that short sleep is associated with higher obesity parameters. Conclusions: In European adolescents, short sleep duration is associated with higher adiposity markers, particularly in female adolescents. This association seems to be related to both sides of the energy balance equation due to a combination of increased food intake and more sedentary habits.

Objective: Since inadequate food consumption patterns during adolescence are not only linked with the occurrence of obesity in youth but also with the subsequent risk of developing diseases in adulthood, the establishment and maintenance of a healthy diet early in life is of great public health importance. Therefore, the aim of the present study was to describe and evaluate the food consumption of a well-characterized sample of European adolescents against food-based dietary guidelines for the first time. Design: The HELENA (Healthy Lifestyle in Europe by Nutrition in Adolescence) Study is a cross-sectional study, whose main objective was to obtain comparable data on a variety of nutritional and health-related parameters in adolescents aged 12?5-17?5 years. Setting: Ten cities in Europe. Subjects: The initial sample consisted of more than 3000 European adolescents. Among these, 1593 adolescents (54 % female) had sufficient and plausible dietary data on energy and food intakes from two 24 h recalls using the HELENA-DIAT software. Results: Food intake of adolescents in Europe is not optimal compared with the two food-based dietary guidelines, Optimized Mixed Diet and Food Guide Pyramid, examined in this study. Adolescents eat half of the recommended amount of fruit and vegetables and less than two-thirds of the recommended amount of milk (and milk products), but consume much more meat (and meat products), fats and sweets than recommended. However, median total energy intake may be estimated to be nearly in line with the recommendations. Conclusion:The results urge the need to improve the dietary habits of adolescents in order to maintain health in later life. Keywords Food intakeEurope Adolescents HELENA StudyInadequate food consumption patterns during childhood and adolescence are linked not only with the occurrence of obesity in youth (1) , but also with the subsequent risk of developing diseases such as cancer (2) , obesity (3) and CVD (4) in adulthood. Adolescence is a potentially critical period for body composition in later life and the development of y See Appendix for full list of HELENA Study Group members.

Food-based dietary guidelines (FBDG) aim to address the nutritional requirements at population level in order to prevent diseases and promote a healthy lifestyle. Diet quality indices can be used to assess the compliance with these FBDG. The present study aimed to investigate whether the newly developed Diet Quality Index for Adolescents (DQI-A) is a good surrogate measure for adherence to FBDG, and whether adherence to these FBDG effectively leads to better nutrient intakes and nutritional biomarkers in adolescents. Participants included 1804 European adolescents who were recruited in the Healthy Lifestyle in Europe by Nutrition in Adolescence (HELENA) Study. Dietary intake was assessed by two, non-consecutive 24 h recalls. A DQI-A score, considering the components' dietary quality, diversity and equilibrium, was calculated. Associations between the DQI-A and food and nutrient intakes and blood concentration biomarkers were investigated using multilevel regression analysis corrected for centre, age and sex. DQI-A scores were associated with food intake in the expected direction: positive associations with nutrient-dense food items, such as fruits and vegetables, and inverse associations with energy-dense and low-nutritious foods. On the nutrient level, the DQI-A was positively related to the intake of water, fibre and most minerals and vitamins. No association was found between the DQI-A and total fat intake. Furthermore, a positive association was observed with 25-hydroxyvitamin D, holo-transcobalamin and n-3 fatty acid serum levels. The present study has shown good validity of the DQI-A by confirming the expected associations with food and nutrient intakes and some biomarkers in blood

Objective: An adequate nutritional intake in childhood and adolescence is crucial for growth and the prevention of youth and adult obesity and nutrition-related morbidities. Improving nutrient intake in children and adolescents is of public health importance. The purpose of the present study was to describe and evaluate the nutrient intake in a European sample using the D-A-CH nutrient intake recommendations and the Nutritional Quality Index (NQI). Design: The HELENA (Healthy Lifestyle in Europe by Nutrition in Adolescence) Study is a cross-sectional study, the main objective of which is to obtain comparable data on a variety of nutritional and health-related parameters in adolescents aged 12?5-17?5 years. Setting: Eight cities in Europe. Subjects: The initial sample consisted of 3528 European adolescents. Among these, 1590 adolescents (54 % female) had sufficient and plausible dietary data on energy and nutrient intakes from two 24 h recalls using the HELENA-DIAT software. Results: The intakes of most macronutrients, vitamins and minerals were in line with the D-A-CH recommendations. While the intakes of SFA and salt were too high, the intake of PUFA was too low. Furthermore, the intakes of vitamin D, folate, iodine and F were less than about 55 % of the recommendations. The median NQI was about 71 (of a maximum of 100). Conclusions: The intakes of most nutrients were adequate. However, further studies using suitable criteria to assess nutrient status are needed. Public health initiatives should educate children and adolescents regarding balanced food choices.

Evidence has grown supporting the role for short sleep duration as an independent risk factor for weight gain and obesity. The purpose of the present study was to examine the relationship between sleep duration and dietary quality in European adolescents. The sample consisted of 1522 adolescents (aged 12.5-17.5 years) participating in the European multi-centre cross-sectional ‘Healthy Lifestyle in Europe by Nutrition in Adolescence’ study. Sleep duration was estimated by a self-reported questionnaire. Dietary intake was assessed by two 24 h recalls. The Diet Quality Index for Adolescents with Meal index (DQI-AM) was used to calculate overall dietary quality, considering the components dietary equilibrium, dietary diversity, dietary quality and a meal index. An average sleep duration of ≥ 9 h was classified as optimal, between 8 and 9 h as borderline insufficient and < 8 h as insufficient. Sleep duration and the DQI-AM score were positively associated (β = 0.027, r 0.130, P< 0.001). Adolescents with insufficient (62.05 (sd 14.18)) and borderline insufficient sleep (64.25 (sd 12.87)) scored lower on the DQI-AM than adolescents with an optimal sleep duration (64.57 (sd 12.39)) (P< 0.001; P= 0.018). The present study demonstrated in European adolescents that short sleep duration was associated with a lower dietary quality. This supports the hypothesis that the health consequences of insufficient sleep may be mediated by the relationship of insufficient sleep to poor dietary quality.