Germán Vicente-Rodríguez

Harmonization process and reliability assessment of anthropometric measurements in a multicenter study in adolescents

Objective:To describe the standardization process and reliability of anthropometric and bioelectrical impedance analysis (BIA) measurements. We examined both intra- and interobserver errors for skinfolds, circumferences and BIA.Methods:For the intraobserver error assessment, first of all, 202 adolescents in the pilot study (110 boys, 92 girls, aged 13.64±0.78 years) were assessed. For the second intraobserver and interobserver assessments, 10 adolescents were studied (5 boys and 5 girls).Results:The pilot studys intraobserver technical errors of measurement (TEMs) were between 0.12 and 2.9u2009mm for skinfold thicknesses, and between 0.13 and 1.75u2009cm for circumferences. Intraobserver reliability for skinfold thicknesses was greater than 69.44% and beyond 78.43% for circumferences. The final workshops intraobserver TEMs for skinfold thicknesses and circumferences were smaller than 1; for BIA resistance TEMs were smaller than 0.1u2009Ω and for reactance they were smaller than 0.2u2009Ω. Intraobserver reliability values were greater than 95, 97, 99 and 97% for skinfold thicknesses, circumferences, BIA resistance and reactance, respectively. Interobserver TEMs for skinfold thicknesses and circumferences ranged from 1 to 2u2009mm; for BIA they were 1.16 and 1.26u2009Ω for resistance and reactance, respectively. Interobserver reliability for skinfold thicknesses and circumferences were greater than 90%, and for BIA resistance and reactance they were greater than 90%.Conclusions:After the results of the pilot study, it was necessary to optimize the quality of the anthropometric measurements before the final survey. Significant improvements were observed in the intraobserver reliabilities for all measurements, with interobserver reliabilities being higher than 90% for most of the measurements.The Healthy Lifestyle in Europe by Nutrition in Adolescence Study aims to describe total body fat percentage and anthropometric indices of body fat distribution in European adolescents.

Television watching, videogames, and excess of body fat in Spanish adolescents: The AVENA study

OBJECTIVEnWe assessed the individual association of sedentary behaviors with the risk of overweight and excess body fat (overfat) in adolescents.nnnMETHODSnA representative sample (1960 subjects, 1012 males, age 13-18.5 y) of Spanish adolescents was studied within the framework of the Alimentación y Valoración del Estado Nutricional de los Adolescentes (AVENA) study. Television (TV) watching, videogame and computer usage, doing homework, and the way students got to school, physical activity, and socioeconomic status were analyzed. Anthropometrics were measured to describe overweight (International Obesity Task Force cutoffs for body mass index) and overfat (body fat percentage >85th percentile).nnnRESULTSnWhen all subjects were considered as an entire group, the overweight risk increased by 15.8% (P < 0.05) per increasing hour of TV watching. The overweight risks decreased by 32.5% in females, 22% per increasing year of age, and 12.5% by increasing socioeconomic status by 1 U (all Ps < 0.05). The obesity risks decreased with age by 17.8% per year in males and 27.1% in females (both Ps < 0.05). The overfat risks increased by 26.8% and 9.4% per increasing hour of TV and weekend videogame usage, respectively (both Ps < 0.05). In males, the overfat risk increased by 21.5% per increasing hour in weekend videogame usage (P < 0.05). Each hour of TV use increased the overfat risks by 22% in males and 28.3% in females (both Ps < 0.05).nnnCONCLUSIONSnTime spent watching TV increased the risk of overweight and obesity in Spanish adolescents, but the effect was influenced by age, sex, and socioeconomic status. Moreover, an excess of body fat was more directly explained by the time spent watching TV and playing videogames during the weekend.

Association of objectively assessed physical activity with total and central body fat in Spanish adolescents; the HELENA Study.

Objectives:To examine the association of objectively assessed physical activity (PA) with markers of total and central body fat in adolescents, and to determine whether meeting the current PA recommendations (⩾60u2009minu2009day−1 of at least moderate intensity PA) is associated with reduced levels of total and central body fat.Subjects/Methods:A total of 365 Spanish adolescents aged 12.5–17.5 years participated in this cross-sectional study. PA was assessed by accelerometry and expressed as average PA (counts per minute), and minu2009day−1 of light, moderate, moderate to vigorous (MVPA) and vigorous PA. MVPA was dichotomized into <60u2009minu2009day−1 and ⩾60. Total body fat was measured by DXA, BodPod and the sum of six skinfolds. Central body fat was measured by DXA at three regions (R1, R2 and R3), and waist circumference.Results:All markers of central body fat were negatively associated with vigorous PA (P<0.01) after controlling for sex, age and pubertal status. Abdominal adiposity measured at R1, R2 and R3 was also negatively associated with MVPA (P⩽0.001), and with average PA (P<0.01). All markers of total body fat were negatively associated with vigorous PA (P<0.01), MVPA (P<0.01) and average PA (P<0.05). Adolescents engaged on at least 60u2009minu2009day−1 MVPA presented lower levels of total (P<0.05) and central body fat (P⩽0.01).Conclusions:The results suggest that vigorous PA may have a greater effect on preventing obesity in adolescents than does PA of lower intensity, whereas both average PA and at least moderate PA may have an impact on total and central body fat in youth.

Excessive sedentary time and low cardiorespiratory fitness in European adolescents: the HELENA study

Background The aims of this study were to examine what amount of sedentary time is associated with low cardiorespiratory fitness (CRF) in adolescents and whether this association is independent of physical activity. Methods The study comprised 1808 adolescents aged 12.5–17.5 years from 10 European cities. Sedentary time and moderate-to-vigorous physical activity (MVPA) were measured by accelerometer. CRF was assessed by the 20 m shuttle-run test. Adolescents were divided into two groups (high/low) according to FITNESSGRAM guidelines. Receiver-operating characteristic (ROC) analysis was used to determine thresholds that best discriminate between high and low CRF in adolescents. Results Adolescent girls had more sedentary time than boys (p<0.001). ROC analysis showed that girls spending ≥69% of waking time in sedentary activities had low CRF, but no significant threshold discriminated between high and low CRF in boys. Adolescent girls who exceeded this threshold had lower levels of CRF (p≤0.001) and were more likely to have a low CRF (OR 1.68, 95% CI 1.22 to 2.31) independent of centre, age and body mass index. The negative influence of excessive sedentary time on CRF remained significant (p=0.045) in adolescent girls who did not meet the physical activity guidelines (<60 min/day in MVPA) but was abolished (p>0.05) in those who met the recommendation (≥60 min/day in MVPA). Conclusion Excessive sedentary time is associated with low CRF in adolescent girls but not in boys. However, this adverse effect might be attenuated if adolescent girls meet the current physical activity guidelines.

Independent and combined effect of nutrition and exercise on bone mass development.

Food intake provides the necessary components for adequate metabolic functions in bone. Calcium, phosphorus, vitamin D, magnesium, proteins, and fluoride are some of the most important nutrients in this regard. These have different effects on bone mass. Additionally, exercise has been shown to elicit osteogenic responses in bone development; indeed, it seems to potentiate, for example, the effect of calcium supplementation on bone mass. However, the nutrition-exercise-bone mass relationship is complex and needs further in-depth investigation. As a first step, therefore, we reviewed current knowledge about the role of nutrition on the development of bone tissue and how physical activity affects the nutrient-bone relationship.

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

BackgroundParticipation 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.MethodsA 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.Results3,865 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).ConclusionFrom 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.

Excessive TV viewing and cardiovascular disease risk factors in adolescents. The AVENA cross-sectional study

BackgroundExcessive television (TV) viewing might play an important role in the development of cardiovascular disease (CVD). The aim of this study was to examine the independent associations between TV viewing and CVD risk factors in adolescents.MethodsA sample of 425 adolescents, aged 13- to 18.5-year-old, was included in this study. Body mass index (BMI), waist circumference (WC), glucose, total cholesterol, triglycerides, HDL-cholesterol, LDL-cholesterol, apolipoprotein (apo) A-1, apo B-100, and lipoprotein(a) levels were determined. A composite CVD risk score was computed based on age-, sex-, sexual maturation- and race-standardized triglycerides, HDL-cholesterol, LDL-cholesterol and glucose. TV viewing was self-reported.ResultsTwo hundred and twenty-five adolescents (53%) who spent >3 hrs/day watching TV were considered as the high TV viewing group. Ninety-nine adolescents (23%) from the total sample were classified as overweight according to International age- and sex-specific BMI values. The high TV viewing group had significantly less favorable values of HDL-cholesterol, glucose, apo A1 and CVD score, independent of age, sex, sexual maturation, race and weight status. There was a significant interaction effect of TV viewing × weight status (P = 0.002) on WC, and the negative influence of TV viewing on WC persisted in the overweight group (P = 0.031) but was attenuated in non-overweight adolescents (P > 0.05).ConclusionExcessive TV viewing seems to be related to an unfavorable CVD risk factors profile in adolescence. Reducing TV viewing in overweight adolescents might be beneficial to decrease abdominal body fat.

Are Muscular and Cardiovascular Fitness Partially Programmed at Birth? Role of Body Composition

OBJECTIVEnTo determine whether birth weight is associated with handgrip strength and cardiovascular fitness in adolescence and, if so, how these associations are influenced by current body composition.nnnSTUDY DESIGNnA total of 1801 adolescents (983 females), age 13 to 18.5 years, from the AVENA (Alimentación y Valoración del Estado Nutricional de los Adolescentes Españoles [Food and Assessment of the Nutritional Status of Spanish Adolescents]) study were evaluated. Handgrip strength and cardiovascular fitness were assessed using the handgrip test and the 20-m shuttle run test, respectively.nnnRESULTSnBirth weight was positively associated with handgrip strength in females after controlling for current age, gestational age, breast-feeding, and adolescent body mass index (P = .002), body fat percentage (P < .001), or waist circumference (P = .005), but not after controlling for fat-free mass. The associations were similar yet weaker in males. Females with high birth weight (>90th percentile) had greater handgrip strength than those with normal (10th to 90th percentile) or low (<10th percentile) birth weight, after adjusting for body fat percentage (P = .004). All of the differences became nonsignificant after adjusting for adolescent fat-free mass. Birth weight was not associated with cardiovascular fitness.nnnCONCLUSIONSnHigh birth weight is associated with greater handgrip strength in adolescents, especially in females, yet these associations seem to be highly explained by fat-free mass.

Contribution of social marketing strategies to community-based obesity prevention programmes in children

Objectives:To review child and adolescent obesity prevention programmes to determine whether they have included the Social Marketing Benchmark Criteria (BC). In addition, we analysed whether there was a relationship between the presence of the criteria and the effectiveness of the programme.Methods:Interventions had to be aimed at preventing obesity through behaviour changes relating to diet, physical activity, lifestyle and social support, separately or in combination. A total of 41 interventions were identified in PubMed and Embase that fulfilled the inclusion criteria.Results:The more recent the studies, the greater the number of the BC that seem to have been used. However, regarding behaviour changes, we found the most effective period to be 1997–2002, with 100% of the interventions resulting in behaviour changes (9/9). In addition, almost all interventions resulted in improvements in body composition variables: 5 of 6 for body mass index or overweight/obesity prevalence and 6 of 6 for skin-folds.Conclusions:The presence of a higher number of BC does not assure higher effectiveness. Further research is required in this field. At the moment, studies aimed at preventing obesity in children and adolescents have not included social marketing aspects in their interventions in a comprehensive manner.

Reliability and Intermethod Agreement for Body Fat Assessment Among Two Field and Two Laboratory Methods in Adolescents

To increase knowledge about reliability and intermethods agreement for body fat (BF) is of interest for assessment, interpretation, and comparison purposes. It was aimed to examine intra‐ and inter‐rater reliability, interday variability, and degree of agreement for BF using air‐displacement plethysmography (Bod‐Pod), dual‐energy X‐ray absorptiometry (DXA), bioelectrical impedance analysis (BIA), and skinfold measurements in European adolescents. Fifty‐four adolescents (25 females) from Zaragoza and 30 (14 females) from Stockholm, aged 13–17 years participated in this study. Two trained raters in each center assessed BF with Bod‐Pod, DXA, BIA, and anthropometry (DXA only in Zaragoza). Intermethod agreement and reliability were studied using a 4‐way ANOVA for the same rater on the first day and two additional measurements on a second day, one each rater. Technical error of measurement (TEM) and percentage coefficient of reliability (%R) were also reported. No significant intrarater, inter‐rater, or interday effect was observed for %BF for any method in either of the cities. In Zaragoza, %BF was significantly different when measured by Bod‐Pod and BIA in comparison with anthropometry and DXA (all P < 0.001). The same result was observed in Stockholm (P < 0.001), except that DXA was not measured. Bod‐Pod, DXA, BIA, and anthropometry are reliable for %BF repeated assessment within the same day by the same or different raters or in consecutive days by the same rater. Bod‐Pod showed close agreement with BIA as did DXA with anthropometry; however, Bod‐Pod and BIA presented higher values of %BF than anthropometry and DXA.