S. Gómez

Body size at birth modifies the effect of fat mass and obesity associated (FTO) rs9939609 polymorphism on adiposity in adolescents: the Healthy Lifestyle in Europe by Nutrition in Adolescence (HELENA) study

The present study was intended to examine whether ponderal index (PI) at birth modifies the effect of the fat mass and obesity associated (FTO) rs9939609 polymorphism on adiposity in European adolescents. A total of 628 adolescents aged 14·4 (se 1·3) years (56·8 % female) were recruited. PI was calculated from parental reports of birth weight and length (kg/m³), and the BMI (kg/m²), body fat percentage and fat mass index (FMI, kg/m²) were calculated. The rs9939609 polymorphism was genotyped and physical activity assessed by accelerometry. Sex, duration of pregnancy, pubertal status, centre and physical activity were used as confounders in all the analyses. The minor A allele of the FTO rs9939609 was significantly associated with higher BMI, body fat percentage and FMI (all P < 0·05) but not with PI. Significant interactions between PI and the rs9939609 polymorphism in terms of body fat percentage (P = 0·002) and FMI (P = 0·017) were detected. However, this polymorphism was only significantly associated with higher BMI, body fat percentage and FMI (all P < 0·05) in adolescents in the lower PI tertile. Indeed, both body fat percentage and FMI were higher in those adolescents in the lower PI tertile carrying the A allele of the FTO rs9939609 polymorphism than in those with the TT genotype (25·0 (se 0·8) v. 22·1 (se 1·0) %, adjusted P = 0·030 and 5·6 (se 0·3) v. 4·6 (se 0·4) kg/m2, P = 0·031, respectively). Our findings suggest that those adolescents born with lower PI could be more vulnerable to the influence of the A risk allele of the FTO polymorphism on total adiposity content.

High fitness is associated with a healthier programming of body composition at adolescence

The programming effect of birth weight on later body composition has become of increasing interest in recent years. This programming effect is affected by factors such as gender. Physical fitness could be another factor of influence. This study aimed to examine whether handgrip strength (HG) or cardiovascular fitness (CVF) modify the associations between birth weight and body composition in adolescents. A sample of 1,740 (942 females) adolescents aged 13 to 18.5 years, born at more than 35 weeks of gestation, from the AVENA study was studied. Waist circumference was measured, percentage body fat was calculated from skinfold thicknesses and fat free mass was derived by subtracting fat mass from total body weight. HG and CVF were assessed using the HG test and the 20 m shuttle run test, respectively. Birth weight was positively associated with fat free mass in females with high (above the median) CVF (P < 0.001), but not in those with low (below the median) CVF. In contrast, birth weight was positively associated with total and central adiposity in males with low HG (both P = 0.002), but not in those with high HG. These results suggest that the programming effect of birth weight on later body composition is dependent on gender and fitness level. A high birth weight may have a healthy programming effect on body composition in those adolescents with a high fitness level, being associated with increased fat free mass levels in females and not showing the increased adiposity levels observed in unfit males. Am. J. Hum. Biol., 2008.

CL186 - L’allaitement maternel n’est pas associé avec le statut inflammatoire chez l’adolescent sain, étude HELENA

L’allaitement maternel (AM) a ete implique dans la reduction du risque cardiovasculaire a l’âge adulte. Une inflammation de bas grade caracterise le risque cardiovasculaire, meme chez des enfants apparemment sains. L’objectif etait d’evaluer le possible effet modulateur de l’allaitement sur les marqueurs de l’inflammation d’adolescents sains. Les informations sur l’AM etaient recueillies par questionnaire parental, chez 484 des 1040 adolescents de l’etude HELENA. Les marqueurs doses etaient la proteine reactive C ultra sensible, les facteurs 3 and 4 du complement, la L-selectine et E-selectine soluble, la molecule soluble d’adhesion vasculo-cellulaire 1, la molecule d’adhesion intercellulaire 1 et le facteur de croissance mitogene beta 1. Apres une analyse univariee, un score de propension entrait les facteurs de confusion potentiels pour etudier le lien entre l’AM et les marqueurs selectionnes. Il n’existait pas d’association significative entre l’AM et aucun de marqueurs de l’inflammation apres ajustement sur le score de propension et le sexe. Cette etude ne met pas en evidence d’association entre l’AM dans l’enfance et l’inflammation de bas grade d’adolescents sains, suggerant que le benefice cardio vasculaire de l’AM est lie a un autre mecanisme que l’inflammation.

Sobrepeso y valores elevados de leucocitos: ¿factores asociados a un riesgo cardiovascular temprano en adolescentes? Estudio AVENA

Objetivo En adultos, un recuento elevado de celulas blancas parece estar asociado prospectivamente con la enfermedad cardiovascular. Para una temprana prevencion de procesos que afectan el desarrollo de enfermedades en edad adulta, es de crucial importancia identificar comportamientos en la adolescencia, relacionados con marcadores de riesgo. Diseno Los resultados presentados forman parte del estudio transversal multicentrico, AVENA, que ha evaluado el estado nutricional en una muestra representativa de adolescentes espanoles. Los adolescentes se dividieron en: adolescentes con peso adecuado y adolescentes con sobrepeso/obesidad, usando los valores estandarizados del International Obesity Task Force (IOTF). Sujetos Para los estudios que requieren muestras sanguineas se ha utilizado una submuestra de 542 adolescentes, con edades comprendidas entre los 13 y 18 anos (279 chicos y 263 chicas). Parametros Se determinaron el recuento total y porcentaje de celulas blancas (leucocitos, neutrofilos y monocitos), asi como su capacidad fagocitica y oxidativa. Ademas se realizo una antropometria detallada, para la clasificacion IOTF. Resultados Los valores correspondientes al recuento de celulas blancas, neutrofilos y monocitos mostraron en general valores mayores en los sujetos con sobrepeso/obesidad que en los adolescentes con normopeso, llegando a ser diferencias significativas en el grupo de varones. No se observaron diferencias en la funcion fagocitica ni oxidativa de las celulas blancas. Conclusion Estos resultados confirman la reciente hipotesis sobre la importancia de la etiologia de la inflamacion cronica, moderadamente elevada en el adolescente obeso, y su relacion con el comienzo del riesgo de desarrollar aterogenesis a una temprana edad. Por este motivo, es importante hacer enfasis en la importancia de mantener un peso adecuado durante la adolescencia. Proyecto financiado por el Ministerio de Sanidad y Consumo (FIS 00/0015). Becas financiadas por Madaus S.A., Procter & Gamble S.A y Panrico S.A.