Waist Circumferences of Chilean Students: Comparison of the CDC-2012 Standard and Proposed Percentile Curves

Cross-sectional association between physical fitness and cardiometabolic risk in Chilean schoolchildren: the fat but fit paradox

BACKGROUND

Previous studies have examined the "fat but fit" paradox, revealing that greater levels of physical fitness may diminish the harmful consequences of excess weight on cardiometabolic risk. Despite the above, specific information about the "fat but fit" paradox in prepuberal population is scarce. The aim of this study was to determine the relationship between cardiometabolic risk across (individual and combined) physical fitness and excess weight status and whether the "fat but fit" paradox is met in the sample of schoolchildren analyzed.

METHODS

A cross-sectional study was conducted including 452 children (59.1% girls), aged 7-9 years from Santiago (Chile). Physical fitness was assessed as cardiorespiratory fitness and muscular fitness. Cardiorespiratory fitness was determined by the 6-minute-walk-test and muscle strength was assessed by the handgrip and standing long jump tests. Excess weight (overweight and obesity) was computed through body mass index (z-score). Cardiometabolic risk was established by summing the z-score of the serum glucose, triglycerides, high-density lipoprotein, insulin and waist-to-height ratio.

RESULTS

Schoolchildren with high physical fitness (individual or combined) showed the lowest cardiometabolic risk mean scores (P for trend <0.001 for all physical fitness groups). Conversely, schoolchildren with low physical fitness (individual or combined) showed the highest cardiometabolic risk mean scores (P for trend <0.001 for all categories). Additionally, schoolchildren without excess weight and with high individual or combined physical fitness status exhibits lower cardiometabolic risk mean scores compared to schoolchildren with excess weight and low physical fitness status (individual or combined) (P for trend <0.001 for all physical fitness groups). A lower odd of having high cardiometabolic risk was found in schoolchildren without excess weight and with both high physical fitness (both cardiorespiratory fitness and muscular fitness) [odds ratio (OR) =0.08; 95% confidence interval (CI): 0.04 to 0.16] in comparison to those with excess weight and low physical fitness.

CONCLUSIONS

Our results suggest that improvements in both fatness and aerobic fitness could be associated with lower cardiometabolic risk.

Comparison of Anthropometric Indicators That Assess Nutritional Status From Infancy to Old Age and Proposal of Percentiles for a Regional Sample of Chile

Objectives: Anthropometric variables are used to evaluate health, dietary status, disease risks, and changes in body composition. The purpose of this study was to compare weight, height, and Body Mass Index (BMI) with American references from the National Center for Health Statistics (NCHS-2012), using BMI and Tri-Ponderal Mass Index (TMI) to propose percentiles for evaluating nutritional status of children, adolescents, and adults, ages 5-80 years old. Methods: A descriptive cross-sectional study was conducted in 15,436 (8,070 males and 7,366 females) children, youths and adults in the Maule region (Chile). The age range ranged from 5.0 to ~80 years of age. Weight and height were assessed. Body mass index BMI and tri-ponderal mass index (TMI) were calculated. The LMS method was used to generate percentiles. Results: The results illustrated that children were heavier and had more BMI during childhood compared to the NCHS references. During adolescence, reference values were greater until approximately ages 70-79. For height, children were relatively similar to those of the NCHS references, but during adolescence, differences became evident. Adolescence until approximately age 80, the population showed lower values for height. Percentiles were calculated using BMI and TMI by age range and sex. Differences occurred between the American NCHS references and the population with regard to the anthropometric variables of weight, height, and in BMI. Conclusion: Discrepancies with the American NCHS reference were verified in the anthropometric variables of weight, height and BMI. Reference percentiles of BMI and TMI were developed for the evaluation of the nutritional status of the regional population of Maule (Chile). Its use is suggested in clinical and epidemiological contexts.

Handgrip strength cut-off points for early detection of cardiometabolic risk in Chilean children

The aim of this study was to determine whether handgrip strength is associated with cardiometabolic risk in children. The secondary aim was to establish sex-specific handgrip strength cut-off points for early detection of cardiometabolic risk. A total sample of 452 Chilean children (267 girls and 185 boys) aged 7-9 years old was analyzed. Muscle fitness was measured by an adjustable dynamometer and normalized by body mass (i.e., handgrip strength/body mass). Sex-specific cardiometabolic risk scores were computed as the sum of the waist-to-height ratio (Equation 1) or waist circumference (Equation 2) and insulin, triglycerides, high-density lipoproteins, and glycemia levels. Receiver operating curve (ROC) analyses were performed to identify those with cardiometabolic risk scores > 1 standard deviation above the mean. ROC analyses showed a significant discriminating accuracy of normalized handgrip strength in identifying cardiometabolic risk in boys (≤ 0.33) and girls (≤ 0.40) using both equations. The highest sensitivity was offered by Equation 2 for boys [46%; 95% CI (32-59%)] and for girls [71%; 95% CI (60-80)]. The greatest specificity was also offered by Equation 2 for boys [82%; 95% CI (74-88)] and girls [63%; 95% CI (55-70)]. Since the values obtained by ROC analyses are low (especially in boys), caution is warranted regarding the strength of the existing evidence base.Conclusion: These specific cut-off points according to sex for possible cardiometabolic risk could be used by Chilean health professionals and school staff as an initial assessment in the field setting. What is known • There is strong evidence for the importance of muscular fitness during childhood and adolescence for cardiometabolic risk. • There has been no research to establish minimum handgrip strength capacity levels to predict cardiometabolic risk among Chilean children. What is new • Cut-off points for handgrip strength relative to body mass to identify cardiometabolic risk in Chilean children are 0.33 in boys and 0.40 in girls. • The early use of these cut-off points and its appropriate identification could have benefits of preventive and diagnostic therapeutic intervention and as a starting point to define adequate levels of handgrip strength.

[Proposal of percentiles to evaluate physical growth and body adiposity as a function of maturity status in Chilean children and adolescents]

INTRODUCTION

during childhood and adolescence there is great individual variability in growth and biological maturation, resulting in differences in size, shape and body composition in children and adolescents of similar age.

OBJECTIVE

to propose percentiles to assess physical growth and body adiposity as a function of maturity status (SM) in Chilean children and adolescents.

METHODS

a descriptive (cross-sectional) study was designed in 7,292 children and adolescents (4214 boys and 3084 girls) from the Maule region (Chile). The age range was 6.0 to 17.9 years. Weight, height and waist circumference (WC) were evaluated. Body mass index (BMI), waist-height index (WHtR) and SM were calculated through a non-invasive anthropometric technique based on chronological age and standing height. The LMS method was used to calculate percentiles.

RESULTS

the SM calculated in boys was observed at 13.7 ± 0.6 APHV (years of peak growth speed) and in girls at 12.1 ± 0.6 APHV. Percentiles were created for weight, height, WC, BMI, and WHtR. All anthropometric variables increase as MS increases in PHV years.

CONCLUSION

the proposed percentiles are an alternative to evaluate physical growth and body adiposity as a function of SM in Chilean children and adolescents. The results suggest the use of this non-invasive technique to be applied in clinical and epidemiological contexts.

Physical growth and body adiposity patterns in children and adolescents at high altitudes in Peru: Proposed percentiles for assessment

OBJECTIVES

This study's purpose was to compare physical growth (PG) patterns of children and adolescents living at high elevations with those of other geographic regions, relate body adiposity indicators, and develop percentile reference tables for assessing physical growth and body adiposity.

METHODS

The sample included 1536 children and adolescents ages 5.0 to 17.9 years from Puno (Peru) located between 3821 and 4349 m above sea level. Weight, height, arm and waist circumferences (WC), and three skinfolds measurements were recorded. Body mass index (BMI) and waist-height Index (WHI) were calculated.

RESULTS

PG patterns for children living at a high altitude reflected similar values for weight, height, and arm circumference (AC) to those of their counterparts living in Puno (Peru) and La Paz (Bolivia). When compared with children living at moderate altitudes in Peru, they showed slightly lower PG values. BMI explained between 41% and 64% of the variance in sum of the skinfolds, while WC explained between 47% and 66%. HWI was not a strong predictor of variation in sum of skinfolds. Percentiles were generated for WC and the sum of skinfolds.

CONCLUSION

Weight, height, and, arm and waist circumference patterns for children and adolescents living at high altitudes were similar to those of La Paz (Bolivia). WC and the sum of the skinfolds were better indicators for analyzing abdominal obesity compared to BMI and WHI. The percentiles proposed may be a useful tool for identifying high risk of developing overweight disorders in pediatric populations living at high altitudes.

Daily Step-Based Recommendations Related to Moderate-to-Vigorous Physical Activity and Sedentary Behavior in Adolescents

Among adolescents empirical studies examining the total daily steps translation of the moderate-to-vigorous physical activity recommendation are scarce and inconsistent, and there are no previous studies with cadence-based steps and related to sedentary behavior. The main objective of the present study was to establish and compare the accuracy of daily step-based recommendations related to the moderate-to-vigorous physical activity and sedentary behavior thresholds in adolescents. The present study followed a cross-sectional design. A total of 126 adolescents (56 girls) aged 12-15 years old were assessed by ActiGraph GT3X accelerometers for eight consecutive days (moderate-to-vigorous physical activity, sedentary behavior, and steps) and the multistage 20-meter shuttle run test (cardiorespiratory fitness). ROC curve analyses showed that total daily steps (AUC = 0.94, 0.89-0.99; Threshold ≥ 11,111 steps/ day; P = 0.93; k = 0.67; p < 0.001) was a more appropriate indicator than cadence-based daily steps for distinguishing between physically active and inactive adolescents. Daily step-based thresholds represent a promising way to translate a total daily sedentary behavior threshold (e.g., total daily steps, AUC = 0.87, 0.81-0.93; Sensitivity = 0.87; Specificity = 0.70). Adolescents who met a favorable combination of step-based recommendations related to both physical activity and sedentary behavior thresholds had a higher probability of having a healthy cardiorespiratory fitness profile than those who did not meet either of them (e.g., risk ratio = 5.05, 1.69-15.08) or only the one related to physical activity (e.g., risk ratio = 4.09, 1.36-12.29). These findings may help policy-makers to provide accurate daily step-based recommendations that would simplify the physical activity and sedentary behavior thresholds for adolescents.

Assessing the relationship between smoking and abdominal obesity in a National Survey of Adolescents in Brazil

Abdominal obesity is even a stronger risk factor than overall obesity for noncommunicable chronic diseases. We examined the association between smoking and abdominal obesity among adolescents. Analyses were based on 38,813 subjects aged 15-17 years from the Study of Cardiovascular Risks in Adolescents (ERICA), a Brazilian school-based national survey. Abdominal obesity was defined considering waist circumference (WC) percentiles. Statistical analyses, stratified by sex, considered the sample complex design. Poisson regression with robust variance was used to estimate smoker-to-nonsmoker abdominal obesity prevalence ratio (PR), adjusting by sociodemographic and lifestyle variables. Higher prevalence of abdominal obesity was observed among adolescents who consumed >1 cigarettes/day, comparing to nonsmokers: considering WC >80th percentile, adjusted-PR for boys was 1.27 [95%CI:1.05,1.52] and, for girls, 1.09 [95%CI:1.00,1.19]; using the 90th percentile, adjusted-PR were 2.24 [95%CI:1.70,2.94] and 1.27 [95%CI:1.12,1.46], respectively for male and female adolescents. Our findings suggest a positive association between cigarette consumption and the prevalence of abdominal obesity, for both boys and girls. Although other studies had found this association in adults, our study contributes to this discussion by assessing it in adolescents using a nationwide representative sample of medium and large municipalities.