Jesús Fleta

Waist circumference for the screening of the metabolic syndrome in children

Aim: To identify the best anthropometric predictor of the metabolic syndrome in children. Methods: Screening performance was evaluated in a clinical setting. The study included 140 children: 72 non‐obese and 68 with non‐syndromal obesity. Body mass index (BMI), waist circumference and triceps/subscapular skinfolds ratio were used as predictor variables, and systolic blood pressure, diastolic blood pressure, glucose, uric acid, fasting insulin, triglycerides and HDL‐C as metabolic syndrome variables. Results: The areas under the receiver operating characteristic (ROC) curves were 0.849 (95% CI: 0.780,0.919) for BMI, 0.868 (95% CI: 0.801,0.934) for waist circumference and 0.834 (95% CI: 0.757,0.910) for the triceps/subscapular skinfolds ratio. No statistically significant differences were found for the three areas under the ROC curves. The point on the ROC curve closest to 1 corresponded to the 65th percentile for BMI, to the 70th percentile for waist, and to the 40th percentile for the triceps/subscapular skinfolds ratio.

Overweight, obesity and body fat composition in spanish adolescents. The AVENA Study.

Objective: To describe the prevalence of overweight and obesity in the Spanish adolescent population and its relationship with the socioeconomic status, and to assess their body fat composition and compare these results with previous data from our own country. Design: Cross-sectional multicenter study conducted in five Spanish cities (Granada, Madrid, Murcia, Santander and Zaragoza) in 2000–2002. Subjects: 2,320 adolescents with complete set of anthropometric measurements, 1,192 boys and 1,128 girls. Measurements: Body mass index calculated from weight and height measurements, and body fat percentage calculated from skinfold thickness measurements. Results: Overweight + obesity prevalences were 25.69 and 19.13% in boys and girls, respectively. Overweight + obesity prevalence increased in boys from high to medium-low socioeconomic status categories (p = 0.015); meanwhile, there was not a significant effect of socioeconomic status in girls. In males, overweight + obesity prevalence changed from 1985 to 2000–2002 from 13 to 35% and in females from 16 to 32%. The rate of change in overweight + obesity prevalences seems to increase in the last years; from 0.88 (1985 to 1995) to 2.33%/year (1995 to 2000–2002) in males and from 0.5 (1985 to 1995) to 1.83%/year (1995 to 2000–2002) in females. The rate of body fat percentage increase was similar between 1980 and 1995 and between 1995 and 2000–2002: 0.26 and 0.23%/year, respectively, at 13 years of age, and 0.16 and 0.17%/year, respectively, at 14 years of age. Conclusion: We observed elevated overweight and obesity prevalences in Spanish adolescents, similar to those observed in other European countries. There is a significant inverse relationship between socioeconomic status and overweight + obesity, but only in boys. The rate of change in overweight prevalence in Spanish adolescents seems to increase, and the rate of increase of body fat percentage seems to be similar as in previous years.

Trends in body mass index and overweight prevalence among children and adolescents in the region of Aragón (Spain) from 1985 to 1995.

OBJECTIVE: To analyse trends in body mass index (BMI) and overweight prevalence for children and adolescents in the region of Aragón (Spain), from 1985 to 1995.DESIGN: Nine cross-sectional examinations of schoolchildren conducted yearly from 1985 to 1995.SUBJECTS: A total of 90,997 children (45,970 males and 45,027 females) in the first school year (6–7 y of age); 106,284 scholars (52,772 males and 53,512 females) in the last school year (13–14 y of age).MEASUREMENTS: Heights and weights were measured and BMI (kg/m2) was calculated.RESULTS: We observed a trend to higher BMI values across the surveys, by sex and age. The secular trends in BMI showed the largest increases at the upper ends of the distribution, especially in males. In children in the first school year, prevalences of overweight were higher in females than in males (P<0.001); however, in adolescents in the last school year, prevalences were higher in males than in females (P<0.001). We observed a significant trend in overweight prevalence from 1985 to 1995 in children from the first school year (P=0.0183, in males and P=0.0168, in females). In children in the last school year there was only a significant trend in males (P<0.0001).CONCLUSION: Significant changes in BMI occurred in the population studied during the period 1985–1995, but these changes differ by age and sex. The increasing skewness of BMI in the upper percentiles of the population, especially in boys, suggests that, not only is the pediatric population getting fatter, but the fatter members are becoming more obese. Our results also show a striking increase in the prevalence of overweight children in the region of Aragón (Spain) during the 1985–1995 decade.

Body fat measurement in adolescents: comparison of skinfold thickness equations with dual-energy X-ray absorptiometry.

Objective:To compare the most commonly used equations to predict body fatness from skinfold thickness, in male and female adolescents, with dual-energy X-ray absorptiometry (DXA) as a reference method of fatness measurement.Design:Cross-sectional nutrition survey.Setting:General adolescent population from Zaragoza (Spain).Subjects and methods:A total of 238 Caucasian adolescents (167 females and 113 males), aged 13.0–17.9 y, were recruited from 15 school groups in 11 public and private schools. The percentage fat mass (%FM) was calculated by using skinfold-thickness equations. Predicted %FM was compared with the reference %FM values, measured by DXA. The lack of agreement between methods was assessed by calculating the bias and its 95% limits of agreement.Results:Most equations did not demonstrate good agreement compared with DXA. However, in male adolescents, Slaughter et al equations showed relative biases that were not dependent on body fatness and the limits of agreement were narrower than those obtained from the rest of equations. In females, Brooks equation showed nonsignificant differences against DXA and the narrowest 95% limits of agreement. Only biases from Brook and Slaughter et al equations were not dependent on body fatness in female adolescents.Conclusions:Accuracy of most of the skinfold-thickness equations for assessment of %FM in adolescents was poor at the individual level. Nevertheless, to predict %FM when a relative index of fatness is required in field or clinical studies, Slaughter et al equations may be used in adolescents from both sexes and the Brook equation in female adolescents.Sponsorship:Instituto de Salud Carlos III, Spain.

Waist circumference values in Spanish children—Gender related differences

Objective: To obtain reference values of the waist circumference in Spanish children, and to investigate their dependence on age and gender.Design: Cross-sectional study.Setting: General school-age population.Subjects: A representative sample of the schools in Zaragoza, Spain, was drawn from seven schools. The population selected comprised 1728 children with ages ranging from 6.0–14.9 y. Of the original sample, 368 children (21.29%) were excluded because of chronic diseases or refusal. Finally, 1360 children and adolescents: 701 boys and 659 girls, were studied.Interventions: Waist and hip circumferences were measured with an unelastic tape.Results: Waist circumference tended to be higher in males than in females and this difference was significant after 11.5 y. In general, hip circumference was higher in females than in males (statistically significant differences at 7.5, 10.5, 12.5 and 13.5 y). In general, percentile values of waist circumference were higher in males than in females, especially after 12.5 y. Difference between males and females on percentile 95 at 14.5 y was 7.6 cm. Hip was greater than waist in both sexes, and the two curves run nearly parallel in males. In females, while hip enlarges continuously, waist shows the reverse tendency between 11.5 and 14.5 y.Conclusions: Waist circumference showed higher values in boys than in girls, especially after 11.5 y, and waist values increase with age both in males and females. These findings justify the use of age and gender specific reference standards.Sponsorship: This work was supported by grant 216-02 from Universidad de Zaragoza, Zaragoza, Spain.

Skinfold thickness measurements are better predictors of body fat percentage than body mass index in male Spanish children and adolescents

Objective: To develop equations, from some simple anthropometric measurements, for the prediction of body density from underwater weighing in male spanish children and adolescents.Subjects: One hundred and seventy-five males, aged 7.0–16.9 y, participated in this study, they were recruited from primary and secondary schools.Measurements: Body weight and height and skinfold thicknesses by anthropometry, body density by underwater weighing.Results: Correlations between body density and body mass index (BMI) were high until 14.0–16.9 y. Correlations between body density and log Σ 4 skinfolds were higher than those with BMI at all ages. Log Σ 4 skinfolds explained between 61% (14.0–16.9 y) and 68% (11.0–13.9 y) of the body density variance. Regression equations for body density from BMI and triceps skinfold thickness explained between 51% (14.0–16.9 y) and 68% (7.0–10.9 y) of the body density variance.Conclusions: The best estimators of body density in the children and adolescents studied were log Σ 4 skinfolds and a combination of BMI and triceps skinfold.Sponsorship: Universidad de Zaragoza

Body mass index, triceps skinfold and waist circumference in screening for adiposity in male children and adolescents.

Simple anthropometric measurements and indices are the most commonly used tools for assessing body composition. Only a few papers have examined the sensitivity and specificity of the body mass index (BMI) against total body fat percentage (TBF%) from underwater weighing in children and adolescents. The objective of the study was to evaluate the screening performance of BMI, triceps skinfold thickness and waist circumference for excess TBF%. A total of 175 healthy volunteer males, aged 7.0–16.9 y, participated in the study. TBF% was measured using underwater weighing as the reference method. Receiver operating characteristic (ROC) curves were constructed to assess the value of the three anthropometric measurements as a screening measure for total adiposity. Sensitivity and specificity were calculated at several percentile cut‐offs for BMI, triceps skinfold and waist circumference. The areas under the ROC curves were also calculated, and were 0.86 for BMI, 0.90 for triceps skinfold and 0.88 for waist circumference. The point on the ROC curve closest to 1 corresponded to the 70th percentile for BMI, to the 75th percentile for triceps skinfold, and to the 70th percentile for waist circumference.

Indices of body fat distribution in Spanish children aged 4.0 to 14.9 years.

BACKGROUND Reference values for the main indices of body fat distribution in children are not available. METHODS The study population comprised 1638 Caucasian children and adolescents: 848 boys and 790 girls, with ages ranging from 4.0 to 14.9 years, and living in the central part of Spain (Provincia de Zaragoza). The waist-to-hip circumference ratio and the triceps-to-subscapular skinfold thickness ratio were measured. RESULTS In boys, mean waist-to-hip circumference ratio ranges from 0.834, at 13.5 years, to 0.896 at 4.5 years. In girls, waist-to-hip circumference ratio ranges from 0.756, at 14.5 years, to 0.877, at 4.5 years. We observed a decrease of waist-to-hip circumference ratio with age, especially in girls. In boys, triceps-to-subscapular skinfold thickness ratio ranges from 1.360, at age 14.5, to 1.704, at age 5.5. In girls, triceps-to-subscapular skinfold thickness ratio ranges from 1.468, at age 13.5, to 1.727, at age 9.5. We observed a decrease with age only in boys. CONCLUSIONS We present reference values for the main indices of body fat distribution, which could be useful in clinical practice. However, research is needed that will compare these indices with data on body fat distribution obtained by a gold standard method, such as computed tomography or magnetic resonance imaging.

Trends of Dietary Habits in Adolescents

Lifestyle plays an important role in the development of obesity during childhood and adolescence. We provide up-to-date information about the relationship between obesity and food intake and dietary patterns in adolescents. Scientific evidence is increasing about the dietary factors associated with this relationship, specifically a low meal frequency, skipping breakfast, and a high consumption of sugar sweetened beverages. Maybe some of the reviewed dietary factors could cluster in the same population of adolescents, increasing the individual risk. There is little information about dietary patterns and current time trends in adolescents; however, the available data seem to show that the tendency in the adolescent population worldwide is to increase those dietary factors related with obesity development. Public health efforts should be emphasized in order to decrease the current tendency. Regular family meals could serve as role models for healthy eating behaviors. Educational intervention programs for parents, aiming to modify the healthfulness of the diet, seems to be one of the most adequate tools to deal with the worldwide obesity epidemic.

Body fat distribution reference standards in Spanish adolescents: the AVENA Study

Objective:To present body fat patterning reference standards to identify children with a predominant distribution of body fat in the abdominal or truncal region of the body.Design:Cross-sectional study in a representative sample of Spanish adolescents aged 13–18 years.Subjects:A total of 2160 adolescents with a complete set of anthropometric measurements (1109 males and 1051 females).Measurements:Weight, height, body mass index, skinfold thickness (biceps, triceps, subscapular, suprailiac, thigh, calf) and waist and hip circumferences.Results:In the majority of the age groups, subscapular/triceps skinfolds ratio, trunk-to-total skinfolds percent (TTS%)and waist circumference values were significantly higher in males than in females; hip circumference was higher in females than in males, except at 15.5 years. In males, age showed a significant effect for all the body fat distribution indices; however, in females, the effect was only significant for triceps skinfold, waist and hip circumferences and waist-to-hip ratio. Smoothed age- and sex-specific triceps skinfold, subscapular skinfold, subscapular/triceps skinfolds ratio, TTS%, waist circumference and hip circumference, waist-to-hip and waist-to-height ratio percentile values for male and female adolescents have been established.Conclusion:These reference data for waist circumference and the other fat patterning indices, together with data from other countries, will help to establish international central obesity criteria for adolescents. The presented percentile values will give the possibility to estimate the proportion of adolescents with high or low regional adiposity amounts.