Multiple genetic loci have been associated with body mass index (BMI) and obesity. The aim of this study was to investigate the effects of established adult BMI and childhood obesity loci in a Greek adolescent cohort. For this purpose, 34 variants were selected for investigation in 707 (55.9% females) adolescents of Greek origin aged 13.42 ± 0.88 years. Cumulative effects of variants were assessed by calculating a genetic risk score (GRS-34) for each subject. Variants at the FTO, TMEM18, FAIM2, RBJ, ZNF608 and QPCTL loci yielded nominal evidence for association with BMI and/or overweight risk (p < 0.05). Variants at TFAP2B and NEGR1 loci showed nominal association (p < 0.05) with BMI and/or overweight risk in males and females respectively. Even though we did not detect any genome-wide significant associations, 27 out of 34 variants yielded directionally consistent effects with those reported by large-scale meta-analyses (binomial sign p = 0.0008). The GRS-34 was associated with both BMI (beta = 0.17 kg/m2/allele; p < 0.001) and overweight risk (OR = 1.09/allele; 95% CI: 1.04–1.16; p = 0.001). In conclusion, we replicate associations of established BMI and childhood obesity variants in a Greek adolescent cohort and confirm directionally consistent effects for most of them.

Quantitative alcohol consumption and frequency of consumption were positively and inversely associated, respectively, with both BMI and WC among alcohol-consuming adults. Surveys are needed that evaluate both the quantity and frequency of consumption. The lowest BMI and WC were associated with a 'Mediterranean' drinking style (i.e. relatively little, but more frequently).

Objective: To document the prevalence of dieting and to compare body composition markers, dietary intakes and eating behaviours across dieting categories. Design: Prospective, cross-sectional study. Setting: Twenty-four randomly selected secondary public schools located in Attica, Greece. Subjects: Anthropometric, medical and dietary information was obtained from 857 (54?9 % females) adolescents (mean age 13?4 (SD 0?9) years). Meal patterns, eating behaviours and eating style score, reflecting conditions around eating, were assessed. Adolescents were asked about their dieting involvement and were categorised as 'never dieters', 'current dieters' or 'past dieters'. Results: Overall, 20?1 % of the adolescents were currently dieting and 15?2 % reported past dieting. Mean BMI and body fat percentage of never dieters were significantly lower than those of both groups of dieters (P , 0?001). Breakfast skipping (x 2 5 10?92, P 5 0?004) and eating large quantities of food (x 2 5 7?18, P 5 0?028) differed significantly across dieting groups in females. Significant differences in dinner skipping were observed in both males (x 2 5 10?55, P 5 0?005) and females (x 2 5 20?91, P , 0?001). Female past dieters had significantly higher eating style scores than never dieters (P 5 0?010) and current dieters (P 5 0?042), indicating less well-structured feeding practices and food intake for reasons other than hunger. Conclusions: The present study showed a high prevalence of dieting among adolescents. Current dieters and past dieters had higher BMI and body fat percentage than never dieters. Eating behaviours differed significantly depending on dieting involvement, especially in females; while an apparently healthier, ordered eating style adopted by dieters during the dieting period seemed not to be maintained in the long term.