Television viewing time and risk of eating disorders in Spanish adolescents: AVENA and AFINOS studies.

BACKGROUND: Effective preventive interventions for both eating disorders and obesity in adolescence should be focused on shared risk factors. We analyzed the association between television (TV) viewing time and the risk of eating disorders, as well as the potential role of obesity in this association. METHODS: The sample consisted of a total of 3458 Spanish adolescents, aged 13-18.5 years, from the Food and Assessment of the Nutritional Status of Adolescents (AVENA) and Physical Activity as a Preventive Measure of the Development of Overweight, Obesity, Allergies, Infections, and Cardiovascular Risk Factors in Adolescents (AFINOS) studies. Adolescents' TV time was assessed by self-report. Body mass index was calculated and the adolescents were classified into non-overweight and overweight-obesity. The risk of eating disorders was evaluated using the SCOFF questionnaire. RESULTS: Adolescents who watched TV >1 h/day had a higher risk for eating disorders, compared with those adolescents who watch TV <1 h/day. Also, overweight-obese adolescents had a higher risk for eating disorders than those who were non-overweight. Analyses across groups of TV viewing time and weight status showed similar trends, so that the higher the time spent in TV viewing, the higher the risk of eating disorders, regardless of weight status. CONCLUSIONS: TV viewing time might be a focal point for prevention of both eating disorders and obesity in adolescence.

Influence of sex, age, pubertal maturation and body mass index on circulating white blood cell counts in healthy European adolescents­the HELENA study.

UNLABELLED: Percentiles 10th, 25th, 50th, 75th and 90th are presented for circulating white blood cells (WBC), neutrophils, lymphocytes, monocytes, eosinophils and basophils in healthy European adolescents (12.5-17.5 years, n = 405, 48.9% boys), considering age, sex, puberty and body mass index (BMI). CD3(+) (mature T cells), CD4(+) (T helper), CD8(+) (T cytotoxic), CD16(+)56(+) (natural killer), CD19(+) (B cells), CD3(+)CD45RA(+), CD4(+)CD45RA(+), CD8(+)CD45RA(+) (naïve), CD3(+)CD45RO(+), CD4(+)CD45RO(+) and CD8(+)CD45RO(+) (memory) lymphocytes were also analysed by immunophenotyping. Girls presented higher WBC, neutrophil, CD3(+)CD45RO(+) and CD4(+)CD45RO(+) cell counts and CD3(+)/CD19(+) ratio, and lower CD3(+)CD45RA(+) and CD4(+)CD45RA(+) counts than boys. Age was associated with higher neutrophil counts and CD3(+)/CD19(+), and lower CD19(+) counts; in boys, with lower CD3(+)CD45RA(+), CD4(+)CD45RA(+) and CD8(+)CD45RA(+) counts as well; in girls, with higher WBC, CD3(+)CD45RO(+) and CD4(+)CD45RO(+) counts. Pubertal maturation in boys was associated with lower WBC and lymphocyte counts; in girls, with higher basophil, CD3(+)CD45RO(+) and CD4(+)CD45RO(+) values. BMI was associated with higher WBC counts; in boys, also with higher lymphocyte counts; in girls, with higher neutrophil, CD4(+), CD3(+)CD45RO(+) and CD4(+)CD45RO(+) counts. CONCLUSION: Our study provides normative values for circulating immune cells in adolescents, highlighting the importance of considering sex, age, pubertal maturation and BMI when establishing reference ranges for WBC in paediatric populations.

Length of residence and risk of eating disorders in immigrant adolescents living in madrid. The AFINOS study.

OBJECTIVES: This study was designed to compare the risk of having an eating disorder (ED) among immigrant and native adolescents living in Madrid and to determine the possible influence of length of residence (LOR) on the risk of the immigrants. METHODS: A cross-sectional survey was conducted from november 2007 to february 2008 in a representative sample of adolescents aged 13 to 17 years (n = 2,077, 1,052 girls) living in the Madrid region. Data were collected using the Spanish version of the SCOFF Eating Disorders Questionnaire. Further factors considered were country of birth, LOR and several biological, sociodemographic, lifestyle and health-related variables. RESULTS: According to the three logistic regression models constructed, female immigrant adolescents on the whole showed a greater ED risk (OR = 1.95; 95% CI 1.29- 2.95; p = 0.001) than native adolescents. Moreover, the likelihood of ED was higher among female immigrants living in Spain for <6 years than for Spanish native females (OR = 2.44; 95% CI 1.42-4.18; p = 0.001), while no significant differences were found when female natives were compared with female immigrants living in this country for ≥ 6 years. Similarly, no differences were observed in the ED risk recorded for male native and immigrant adolescents, both as a whole and by length of residence in Spain. CONCLUSIONS: The immigrant status and the length of Spanish residence are relevant factors in regard to the ED risk in adolescents living in Madrid.

Objetivos: Este estudio fue diseñado para comparar el riesgo de trastornos de conducta alimentaria (TCA) entre adolescentes nativos e inmigrantes residentes en Madrid, así como para determinar la posible influencia del tiempo de residencia en el riesgo de los inmigrantes. Métodos: Se llevó a cabo un estudio transversal durante el periodo comprendido entre noviembre 2007 y febrero 2008 sobre una muestra representativa de adolescentes residentes en Madrid, con edades de entre 13 y 17 años (n = 2.077, 1.052 mujeres). Los datos se recogieron usando la versión española del cuestionario SCOFF para la detección de trastornos alimentarios. Otros factores considerados fueron el país de nacimiento, el tiempo de residencia y diversas variables biológicas, socio-demográficas, relativas a estilo de vida y la salud. Resultados: Según los tres modelos de regresión logística construidos, las mujeres adolescentes inmigrantes en conjunto mostraron un mayor riesgo de TCA (OR = 1,95; 95%CI 1,29-2,95; p = 0,001) que las nativas. Además, la probabilidad de sufrir TCA fue mayor entre las adolescentes inmigrantes con una residencia en España < 6 años que en las nativas (OR = 2,44; 95%CI 1,42-4,18; p = 0,001), mientras que no se encontraron diferencias entre las adolescentes nativas y las inmigrantes con un tiempo de residencia ≥6 años. No se observaron diferencias en el riesgo de TCA entre los adolescentes varones nativos y los inmigrantes, tanto en conjunto como según tiempo de residencia. Conclusiones: La condición de inmigrante y el tiempo de residencia son factores relevantes a la hora de considerar el riesgo de TCA en adolescentes residentes en Madrid.

Follow-up in healthy schoolchildren and in adolescents with Down syndrome: psycho-environmental and genetic determinants of physical activity and its impact on fitness, cardiovascular diseases, inflammatory biomarkers and mental health; the UP&DOWN study.

BACKGROUND: An objective diagnosis of sedentary behaviour as well as of the physical activity and fitness levels in youth and to better understand how lifestyle is associated with cardiovascular disease risk factors and other phenotypes is of clinical and public health interest, and might be informative for developing intervention studies focused on the promotion of physical activity in these population. The aim of this methodological paper is to describe the design and assessment in the UP&DOWN study. METHODS/DESIGN: The UP&DOWN study is a multi-center follow-up design where 2225 Spanish primary and secondary schoolchildren from Cadiz and Madrid, respectively, as well as 110 Spanish adolescents with Down syndrome from Madrid and Toledo were recruited to be assessed. Nine main measurement categories are assessed: i) socio-demographic and early determinants; ii) environmental determinants; iii) physical activity and sedentary behaviour; iv) health-related fitness; v) blood pressure and resting heart rate; vi) mental health; vii) dietary patterns; viii) blood samples; and ix) genetic analysis. During the 3-yr follow-up study, socio-demographic and early determinants, and genetic analysis are only assessed in the first year. Blood sampling is assessed in the first year and the third year (2nd follow-up), and all the other measurements are assessed every year. DISCUSSION: The findings of the UP&DOWN study may help the Health Information Systems and policy makers to identify the target population for primary prevention and health promotion policies, and to develop and test preventive strategies. Moreover, these data will allow following the trends at population level, as well as to modify/adapt/create new evidence-based physical activity guidelines at national level. The findings will also serve as a scientific platform for interventional studies.

Influence of health behaviours on the incidence of infection and allergy in adolescents: the AFINOS cross-sectional study.

BACKGROUND: Some health behaviours are liable to affect the incidence of allergies and/or common infections in young people; however, the extent and ways in which these might occur are mostly unknown. This study examines the association of health behaviours related to physical activity, sedentariness, diet and sleep with allergy and infection symptoms in adolescents, and also with biological markers that might mediate disease incidence. METHODS: The study comprised a total of 2054 adolescents (50.7% girls) from the Madrid region of Spain. The incidence of infection and allergy symptoms three months prior to the study was obtained from a self-administered questionnaire. Physical and sedentary activities, height and weight, food habits and sleep duration were also self-reported and their influence on infection and allergy incidence was assessed by logistic regression analysis. Blood biomarkers (IgE, eosinophil percentage, leptin, interleukin (IL)-2, IL-4, IL-5 and IL-10) were evaluated in a subsample of 198 subjects. RESULTS: Adequate sleep duration (OR = 0.79, 95%CI: 0.64 to 0.97) and unhealthy weight status (overweight/obesity) (OR = 1.35, 95%CI: 1.04-1.74) were independently associated with decreased and increased allergy incidence, respectively. No significant association was observed with infection incidence. IgE and leptin differed between adolescents with and without allergy symptoms. In regression models IgE was significantly associated with inadequate sleep duration and leptin with weight status. CONCLUSION: Excess weight and inadequate sleep duration are independently associated with the incidence of allergy symptoms in adolescents. Adequate sleep duration and weight during adolescence might be relevant for a decreased risk of suffering allergy symptoms.

Six-year trend in active commuting to school in Spanish adolescents. The AVENA and AFINOS Studies.

BACKGROUND: Promoting daily routine activities, such as active commuting to school, may have important health implications for young people. PURPOSE: The aim of the study was to examine the secular trend of active commuting to school in Spanish adolescents over a 6-year period (2001-2002 to 2006-2007). We also examined several factors that might explain this trend. METHODS: Data comes from two separate cross-sectional studies, both representatives from the city of Madrid (Spain): AVENA and AFINOS studies. These took place in 2001-2002 and 2006-2007 and included 415 (198 girls) and 891 (448 girls) adolescents aged 13-17, respectively. Commuting to school was assessed using a standardized question about their habitual mode of transportation to school: walking, cycling, bus/subway, car, or motorcycle. Chi-square and binary logistic regression were used. RESULTS: Percentage of active commuting girls decreased significantly from 61 % to 48 % (p = 0.002) from 2001-2002 to 2006-2007. Walking declined from 61 % to 46 % and the use of bus/subway increased from 25 % to 37 % in girls. Girls belonging to average/small families had lower odds of being active commuters than girls of large families (OR, 95 % CI: 0.69, 0.48 to 0.98). There were no significant differences in mode of commuting to school for boys (p = 0.269). CONCLUSION: Spanish adolescent girls in 2007-2008 had lower levels of active commuting to school, mainly walking, than their counterparts 6 years before. Belonging to a large family was related with higher active commuting in girls.