Clinical and physical characteristics of thinness in adolescents: the HELENA study.

PURPOSE: Thinness in adolescence has not been studied as extensively as overweight or obesity. The aim of this study was to assess the prevalence, characteristics, and health impacts of thinness in a European adolescent population. METHODS: This study included 2711 adolescents (1479 girls, 1232 boys). Blood pressure, physical fitness, sedentary behaviors, physical activity (PA), and dietary intake were assessed. A medical questionnaire was used to report any associated diseases. A blood sample was collected in a subgroup of the population. Thinness and normal weight were identified using the IOTF scale. Thin adolescents were compared with adolescents of normal weight. RESULTS: Two hundred and fourteen adolescents (7.9%) were classified as being thin; the prevalence rates were 8.6% in girls and 7.1% in boys. Systolic blood pressure was significantly lower in adolescents with thinness. The age at the first menstrual cycle was significantly later in thin female adolescents than in those with normal weight. Upper-body muscular strength measured in performance tests and time spent in light PA were significantly lower in thin adolescents. The Diet Quality Index was not significantly lower in thin adolescents, but the percentage of adolescents who skipped breakfast was higher in adolescents with a normal weight (27.7% vs 17.1%). Serum creatinine level and HOMA-insulin resistance were lower and vitamin B12 level was higher in thin adolescents. CONCLUSIONS: Thinness affects a notable proportion of European adolescents with no physical adverse health consequences.

Using reduced rank regression methods to identify dietary patterns associated with obesity: a cross-country study among European and Australian adolescents.

This study aims to examine repeatability of reduced rank regression (RRR) methods in calculating dietary patterns (DP) and cross-sectional associations with overweight (OW)/obesity across European and Australian samples of adolescents. Data from two cross-sectional surveys in Europe (2006/2007 Healthy Lifestyle in Europe by Nutrition in Adolescence study, including 1954 adolescents, 12-17 years) and Australia (2007 National Children's Nutrition and Physical Activity Survey, including 1498 adolescents, 12-16 years) were used. Dietary intake was measured using two non-consecutive, 24-h recalls. RRR was used to identify DP using dietary energy density, fibre density and percentage of energy intake from fat as the intermediate variables. Associations between DP scores and body mass/fat were examined using multivariable linear and logistic regression as appropriate, stratified by sex. The first DP extracted (labelled 'energy dense, high fat, low fibre') explained 47 and 31 % of the response variation in Australian and European adolescents, respectively. It was similar for European and Australian adolescents and characterised by higher consumption of biscuits/cakes, chocolate/confectionery, crisps/savoury snacks, sugar-sweetened beverages, and lower consumption of yogurt, high-fibre bread, vegetables and fresh fruit. DP scores were inversely associated with BMI z-scores in Australian adolescent boys and borderline inverse in European adolescent boys (so as with %BF). Similarly, a lower likelihood for OW in boys was observed with higher DP scores in both surveys. No such relationships were observed in adolescent girls. In conclusion, the DP identified in this cross-country study was comparable for European and Australian adolescents, demonstrating robustness of the RRR method in calculating DP among populations. However, longitudinal designs are more relevant when studying diet-obesity associations, to prevent reverse causality.

[From the influence of genes to the influence of family and urban environment on the nutritional status, activity, and physical condition of european urban adolescents]. / Le statut nutritionnel, l'activité et la condition physique des adolescents sous influence - Résultats de l'étude HELENA.

HELENA was a cross-sectional study carried out from 2006 to 2007 in more than 3500 adolescents aged from 12.5 to 17.5 years old through 10 Europeans towns from 9 countries. Its objective was to assess adolescent nutritional status including: body composition, biological markers, physical activity and fitness. This study shown the high impact of socio-economic condition, life style and personal and collective environment, dietary pattern (including breastfeeding), some genetic mutations involved in adiposity and metabolism, physical activity level and fitness on adolescent nutritional status.

The n-3 long-chain PUFAs modulate the impact of the GCKR Pro446Leu polymorphism on triglycerides in adolescents.

Dietary n-3 long-chain PUFAs (LC-PUFAs) are associated with improvement in the parameters of the metabolic syndrome (MetS). Glucokinase regulatory protein (GCKR) is a key protein regulating intracellular glucose disposal. Our aim was to investigate: i) the relationship between the GCKR rs1260326 (Pro446Leu) polymorphism and parameters of the MetS; and ii) a potential influence of n-3 and n-6 LC-PUFA levels on this relationship in the HELENA study (1,155 European adolescents). Linear regression analyses were performed to study the association between rs1260326 and the outcomes of interest. Interactions between rs1260326 and LC-PUFA levels on outcomes were explored. The T allele of rs1260326 was associated with higher serum TG concentrations compared with the C allele. In contrast to n-6 LC-PUFA levels, a significant interaction (P = 0.01) between rs1260326 and total n-3 LC-PUFA levels on serum TG concentrations was observed. After stratification on the n-3 LC-PUFA median values, the association between rs1260326 and TG concentration was significant only in the group with high n-3 LC-PUFA levels. In conclusion, this is the first evidence that n-3 LC-PUFAs may modulate the impact of the GCKR rs1260326 polymorphism on TG concentrations in adolescents. Several molecular mechanisms, in link with glucose uptake, could explain these findings.

Main characteristics and participation rate of European adolescents included in the HELENA study.

BACKGROUND: Participation rate and response rate are key issues in a cross sectional large-scale epidemiological study. The objective of this paper is to describe the study population and to evaluate participation and response rate as well as the key nutritional status variables in male and female adolescents involved in the HELENA study. METHODS: A multi-stage random cluster sampling with a target sample of 3000 adolescents aged [12.5 to 17.5] years, stratified for geographical location and age, was carried out. Information for participants and non-participants (NP) was compared, and participation and response rates to specific questionnaires were discussed. RESULTS: 3,865 adolescents aged [12.5 to 17.5] years (1,845 females) participated in the HELENA study, of whom 1,076 (568 females) participated in the blood sampling. 3,528 (1,845 females) adolescents were finally kept for statistical analysis. Participation rates for the schools and classes differed importantly between countries. The participation rate of pupils within the participating classes also differed importantly between countries. Sex ratio, mean age and BMI were similar between NP and participating adolescents within each centre, and in the overall sample. For all the questionnaires included in the database, the response rate of questionnaires was high (more than 80% of questions were completed). CONCLUSION: From this study it could be concluded that participation rate differed importantly between countries, though no bias could be identified when comparing the key study variables between participants and non-participants. Response rate for questionnaires was very high. Future studies investigating lifestyle and health in adolescents can optimize their methods when considering the opportunities and barriers observed in the HELENA study.