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OBJECTIVE: To verify whether triponderal mass index (TMI) has a greater accuracy than body mass index (BMI), waist circumference (WC) and waist-to-height ratio (WHtR) as predictors of obesity in young people and older adults in a region of Chile. MATERIAL AND METHODS: A cross-sectional descriptive study was carried out in 1176 adults (565 men and 611 women) from the Maule region (Chile). Their ages ranged from 20 to 80 years. The percentage of fat mass (%FM) was evaluated by means of dual energy X-ray absorptiometry (DXA). Weight, height and waist circumference (WC) were evaluated. TMI, BMI and WHtR were calculated. RESULTS: The %FM predictions for BMI were 0.47% for men and 0.50% for women; for TMI, it was 0.50% for men and 0.51% for women; for WC, it was 0.28% for men and 0.21% for women; and finally, for WHtR, it was 0.28% in men and 0.21% in women. The area under the curve (AUC) for BMI was 0.85 in men and 0.85 in women; for TMI, it was 0.87 in men and 0.86 in women; for WHtR, it was 0.76 in men and 0.72 in women; and for WC, the AUC was 0.72 in men and 0.71 in women. CONCLUSION: It was shown that TMI is the indicator that presented the greatest association with %FM and estimates body fat levels with greater precision than BMI, WC and WHtR. The results suggest its use and application as an indicator that discriminates obesity in young, middle-aged and elderly adults.

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Introduction: Measurement of hand grip strength (HGS) has been proposed as a key component of frailty and has also been suggested as a central biomarker of healthy aging and a powerful predictor of future morbidity and mortality. Objectives: (a) To determine whether a nonlinear relationship model could improve the prediction of handgrip strength (HGS) compared to the linear model and (b) to propose percentiles to evaluate HGS according to age and sex for a regional population of Chile from infancy to senescence. Methods: A cross-sectional descriptive study was developed in a representative sample of the Maule region (Chile). The volunteers amounted to 5,376 participants (2,840 men and 2,536 women), with an age range from 6 to 80 years old. Weight, height, HGS (right and left hand) according to age and sex were evaluated. Percentiles were calculated using the LMS method [(L (Lambda; asymmetry), M (Mu; median), and S (Sigma; coefficient of variation)]. Results and discussion: There were no differences in HGS from 6 to 11 years of age in both sexes; however, from 12 years of age onwards, males presented higher HGS values in both hands (p < 0.05). The linear regression between age with HGS showed values of R 2 = 0.07 in males and R 2 = 0.02 in females. While in the non-linear model (cubic), the values were: R 2 = 0.50 to 0.51 in men and R 2 = 0.26 in women. The percentiles constructed by age and sex were: P5, P15, P50, P85, and P95 by age range and sex. This study demonstrated that there is a nonlinear relationship between chronological age with HGS from infancy to senescence. Furthermore, the proposed percentiles can serve as a guide to assess and monitor upper extremity muscle strength levels at all stages of life.

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OBJECTIVE: To verify whether tri-ponderal mass index (TMI) has a higher accuracy than body mass index (BMI), waist circumference (WC) and waist-to-height ratio (WHtR) as predictors of obesity in young people and older adults in a region of Chile. MATERIAL AND METHODS: A cross-sectional descriptive study was carried out in 1,176 adult subjects (565 men and 611 women) from the Maule region (Chile). The age range was from 20 to 80 years old. The percentage of fat mass (%FM) was evaluated by means of dual energy X-ray absorptiometry (DXA). Weight, height and WC were evaluated. TMI, BMI and WHtR were calculated. RESULTS: The predictions of %FM for BMI were 0.47% for men and 0.50% for women, for TMI it was 0.50% for men and 0.51% for women, for WC it was 0.28% for men and 0.21% for women, and finally, for the WHtR it was 0.28% in men and 0.21% in women. The area under the curve (AUC) for the BMI was 0.85 in both men and women, for the TMI, it was 0.87 in men and 0.86 in women, for the WHtR, in men it was 0.76 and in women it was 0.72, and for WC, the AUC in men was 0.72 and in women it was 0.71. CONCLUSION: It was shown that TMI is the indicator that presented the greatest association with %FM and estimates body fat levels with greater precision than BMI, WC and WHtR. The results suggest its use and application as an indicator that discriminates obesity in young, middle and late-aged adults.

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Objectives: The goal of this study was to develop regression equations to estimate LM with anthropometric variables and to propose percentiles for evaluating by age and sex. Methods: A cross sectional study was conducted with 2,182 Chilean students (1,347 males and 835 females). Ages ranged from 5.0 to 17.9 years old. A total body scan was carried out with the double energy X-ray anthropometry (DXA) to examine and measure lean muscle mass of the entire body. Weight, height, and the circumference of the relaxed right arm were also measured. Results: Four anthropometric equations were generated to predict lean mass for both sexes (R 2 = 83-88%, SEE = 3.7-5.0%, precision = 0.90-0.93, and accuracy = 0.99). The Lambda-mu-sigma method was used to obtain the sex-specific and age-specific percentile curves of lean mass (p3, p5, p10, p15, p25, p50, p75, p85, p90, p95, and p97). Conclusion: The four proposed equations were acceptable in terms of precision and accuracy to estimate lean mass in children and adolescents. The percentiles were created by means of anthropometric equations and real values for DXA. These are fundamental tools for monitoring LM in Chilean children and adolescents of both sexes.

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Objetivos. Los objetivos del estudio fueron los siguientes: a) construir un instrumento válido y confiable que evaluara, por autoinforme, los trastornos del sueño en adolescentes escolares chilenos y b) desarrollar valores percentílicos según la edad y el sexo. Metodología. Se efectuó un estudio de tipo descriptivo de corte transversal en 2310 adolescentes escolares de la Región del Maule, Chile. Se construyó el autoinforme de trastornos del sueño considerando cinco categorías (duración, alteraciones, problemas en la respiración, fatiga y uso de estimulantes). Se validó por medio del análisis factorial confirmatorio. La fiabilidad se evaluó por la consistencia interna. Se crearon percentiles a través del método LMS (L: asimetría, M: mediana y S: coeficiente de variación). Resultados. Las preguntas 3, 9 y 12 presentaron saturaciones inferiores a 0,40, y las demás preguntas reflejaron saturaciones superiores a 0,41. El valor de adecuación Kaiser-Meyer-Olkin fue 0,749 y la prueba de esfericidad de X2= 4790,09; el porcentaje de la varianza explicó el 62,1 %. El alfa de Cronbach mostró valores entre 0,71 y 0,76. Conclusión. El autoinforme desarrollado para medir los trastornos del sueño en los adolescentes puede ser aplicado de forma válida y confiable en programas de ciencias de la salud, de la educación y del deporte. Se sugiere el uso de percentiles para identificar los patrones normales y/o trastornos del sueño por edad y género.

Objectives. The objectives of this study included: a) to develop a valid and reliable self-reporting instrument to assess sleep disorders among Chilean adolescent students and b) to develop percentiles for age and sex. Methodology. This was a descriptive, crosssectional study in 2310 adolescent students conducted in the Maule Region, Chile. The sleep disorder self-report was developed considering five categories: duration, alterations, breathing problems, fatigue, and stimulant use. The instrument was validated using a confirmatory factor analysis. Reliability was assessed based on internal consistency. Percentiles were developed using the LMS method (L: lambda, asymmetry; M: mu, median; S: sigma, coefficient of variation). Results. Questions 3, 9, and 12 showed saturation values below 0.40, while the rest had saturation values above 0.41. The Kaiser-Meyer-Olkin measure of adequacy was 0.749 and the test of sphericity X2 was 4790.09; the percentage of variance accounted for 62.1%. Cronbach's alpha ranged between 0.71 and 0.76. Conclusion. The self-report developed to measure sleep disorders in adolescents is valid and reliable for its use in health, education, and sports science programs. Percentiles should be used to identify normal patterns and/or sleep disorders by sex and age.

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OBJECTIVES: The objectives of this study included: a) to develop a valid and reliable self-reporting instrument to assess sleep disorders among Chilean adolescent students and b) to develop percentiles for age and sex. METHODOLOGY: This was a descriptive, crosssectional study in 2310 adolescent students conducted in the Maule Region, Chile. The sleep disorder self-report was developed considering five categories: duration, alterations, breathing problems, fatigue, and stimulant use. The instrument was validated using a confirmatory factor analysis. Reliability was assessed based on internal consistency. Percentiles were developed using the LMS method (L: lambda, asymmetry; M: mu, median; S: sigma, coefficient of variation). RESULTS: Questions 3, 9, and 12 showed saturation values below 0.40, while the rest had saturation values above 0.41. The Kaiser-Meyer-Olkin measure of adequacy was 0.749 and the test of sphericity X2 was 4790.09; the percentage of variance accounted for 62.1 %. Cronbach's alpha ranged between 0.71 and 0.76. CONCLUSION: The self-report developed to measure sleep disorders in adolescents is valid and reliable for its use in health, education, and sports science programs. Percentiles should be used to identify normal patterns and/or sleep disorders by sex and age.

Objetivos. Los objetivos del estudio fueron los siguientes: a) construir un instrumento válido y confiable que evaluara, por autoinforme, los trastornos del sueño en adolescentes escolares chilenos y b) desarrollar valores percentílicos según la edad y el sexo. Metodología. Se efectuó un estudio de tipo descriptivo de corte transversal en 2310 adolescentes escolares de la Región del Maule, Chile. Se construyó el autoinforme de trastornos del sueño considerando cinco categorías (duración, alteraciones, problemas en la respiración, fatiga y uso de estimulantes). Se validó por medio del análisis factorial confirmatorio. La fiabilidad se evaluó por la consistencia interna. Se crearon percentiles a través del método LMS (L: asimetría, M: mediana y S: coeficiente de variación). Resultados. Las preguntas 3, 9 y 12 presentaron saturaciones inferiores a 0,40, y las demás preguntas reflejaron saturaciones superiores a 0,41. El valor de adecuación Kaiser-Meyer-Olkin fue 0,749 y la prueba de esfericidad de X2= 4790,09; el porcentaje de la varianza explicó el 62,1 %. El alfa de Cronbach mostró valores entre 0,71 y 0,76. Conclusión. El autoinforme desarrollado para medir los trastornos del sueño en los adolescentes puede ser aplicado de forma válida y confiable en programas de ciencias de la salud, de la educación y del deporte. Se sugiere el uso de percentiles para identificar los patrones normales y/o trastornos del sueño por edad y género.

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OBJECTIVES: The aim of the present study was to examine the stability of physical fitness, and the interrelationships among intra-individual changes in fitness and fatness among elementary school children. METHODS: A longitudinal study was conducted among 372 adolescents (196 boys) and followed up over 3 years (from childhood to adolescence). Physical fitness was estimated using three indicators: cardiorespiratory fitness (through a 9-minute running test), flexibility (through a sit-and-reach test), and muscle resistance (through maximal abdominals in 1 minute). Body adiposity was obtained through triceps and subscapular skinfolds. Somatic maturation was assessed by the peak of height velocity. Kappa and Lin's tests of concordance as well as logistic regression analyses were conducted with P < 0.05 in STATA 15.1. RESULTS: Tracking of physical fitness from childhood to adolescence was moderate for both sexes [boys: kappa = 0.441 (P < 0.001); LCCC = 0.591 (P < 0.001). Girls: kappa = 0.335 (P < 0.001); LCCC = 0.534 (P < 0.001)]. A larger increment in body fat was associated with a higher likelihood to decrease a tertile in physical fitness among boys [OR: 4.17 (95% CI: 1.31-13.22)] and with a lower likelihood to increase a tertile in physical fitness among both sexes [boys: OR = 0.25 (95% CI: 0.09-0.67); girls: OR: 0.37 (95% CI: 0.15-0.92)]. CONCLUSIONS: Health-related physical fitness has moderate tracking from childhood to adolescence. Increases in body adiposity from childhood to adolescence are associated with a reduction in physical fitness tertile.

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Introducción. Existe preocupación progresiva por estudiar el crecimiento físico de diversas regiones del mundo, aunque no se considera la altitud como factor de ajuste. Objetivos. Comparar variables de crecimiento físico y patrones de índice de masa corporal (IMC) con la referencia del Centro para el Control y Prevención de Enfermedades 2012 (CDC según siglas en inglés) y desarrollar percentiles para niños y adolescentes. Metodología. Se investigaron escolares de moderada altitud de Bogotá (Colombia). Se evaluó el peso, la estatura y se calculó el IMC. Las variables antropométricas fueron comparadas con referencia al CDC-2012, Brasil, Perú y Argentina. Se construyeron curvas por el método LMS (least-mean-square algorithm). Resultados. Se estudió a 2241 escolares (1159 mujeres), entre 6,0 y 17,9 años. No hubo diferencias significativas en el peso e IMC entre 6 y 8 años con relación al CDC-2012; sin embargo, desde los 9 a 17 años, esta muestra evidenció valores inferiores de peso e IMC en relación con el CDC-2012. En la estatura, en ambos sexos, se mostraron valores inferiores del CDC-2012. Las comparaciones con las curvas regionales de Argentina, Perú y Brasil fueron relativamente similares, excepto en el IMC en mujeres, que presentron valores inferiores desde 13 a 17 años. Conclusión. Las variables de crecimiento de los escolares fueron inferiores con referencia al CDC-2012. Hubo ligeras discrepancias en el crecimiento físico y en el IMC con las curvas de Argentina, Brasil y Perú. Se construyeron curvas para evaluar el crecimiento y el IMC de escolares de moderada altitud de Colombia.

Introduction. There is increasing concern over the study of physical growth in different regions of the world, although altitude is not considered an adjustment factor. Objectives. Compare physical growth variables and body mass index (BMI) patterns with the Centers for Disease Control and Prevention (CDC) 2012 reference data and develop percentiles for children and adolescents. Methodology. School children living at moderate altitude in Bogotá (Colombia) were studied. Their weight and height were evaluated and their BMI was calculated. Anthropometric variables were compared against reference data of the CDC-2012, Brazil, Peru and Argentina. Curves were constructed using the least mean square (LMS) method. Results. A total of 2241 school children (1159 girls) aged 6.0 to 17.9 years were included. There were no significant differences in weight and BMI in 6 to 8 year-olds relative to CDC-2012 reference data; in 9 to 17 year-old children, however, this sample evidenced lower values in terms of weight and BMI as compared to those of the CDC-2012. As far as height is concerned, in both sexes, values were lower than those of the CDC-2012. Comparisons against the regional curves of Argentina, Peru and Brazil yielded relatively similar results, with the exception of girls' BMI, as 13 to 17 year-old girls exhibited lower values. Conclusion. Growth variables of school children were lower relative to the CDC-2012 reference data. There were slight discrepancies in physical growth and BMI in relation to the curves of Argentina, Peru and Brazil. Curves were constructed to evaluate growth in school children living at moderate altitude in Colombia.

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INTRODUCTION: There is increasing concern over the study of physical growth in different regions of the world, although altitude is not considered an adjustment factor. OBJECTIVES: Compare physical growth variables and body mass index (BMI) patterns with the Centers for Disease Control and Prevention (CDC) 2012 reference data and develop percentiles for children and adolescents. METHODOLOGY: School children living at moderate altitude in Bogotá (Colombia) were studied. Their weight and height were evaluated and their BMI was calculated. Anthropometric variables were compared against reference data of the CDC-2012, Brazil, Peru and Argentina. Curves were constructed using the least mean square (LMS) method. RESULTS: A total of 2241 school children (1159 girls) aged 6.0 to 17.9 years were included. There were no significant differences in weight and BMI in 6 to 8 year-olds relative to CDC-2012 reference data; in 9 to 17 year-old children, however, this sample evidenced lower values in terms of weight and BMI as compared to those of the CDC-2012. As far as height is concerned, in both sexes, values were lower than those of the CDC-2012. Comparisons against the regional curves of Argentina, Peru and Brazil yielded relatively similar results, with the exception of girls' BMI, as 13 to 17 year-old girls exhibited lower values. CONCLUSION: Growth variables of school children were lower relative to the CDC-2012 reference data. There were slight discrepancies in physical growth and BMI in relation to the curves of Argentina, Peru and Brazil. Curves were constructed to evaluate growth in school children living at moderate altitude in Colombia.

INTRODUCCIÓN: Existe preocupación progresiva por estudiar el crecimiento físico de diversas regiones del mundo, aunque no se considera la altitud como factor de ajuste. OBJETIVOS: Comparar variables de crecimiento físico y patrones de índice de masa corporal (IMC) con la referencia del Centro para el Control y Prevención de Enfermedades 2012 (CDC según siglas en inglés) y desarrollar percentiles para niños y adolescentes. METODOLOGÍA: Se investigaron escolares de moderada altitud de Bogotá (Colombia). Se evaluó el peso, la estatura y se calculó el IMC. Las variables antropométricas fueron comparadas con referencia al CDC-2012, Brasil, Perú y Argentina. Se construyeron curvas por el método LMS (least-mean-square algorithm). RESULTADOS: Se estudió a 2241 escolares (1159 mujeres), entre 6,0 y 17,9 años. No hubo diferencias significativas en el peso e IMC entre 6 y 8 años con relación al CDC-2012; sin embargo, desde los 9 a 17 años, esta muestra evidenció valores inferiores de peso e IMC en relación con el CDC-2012. En la estatura, en ambos sexos, se mostraron valores inferiores del CDC-2012. Las comparaciones con las curvas regionales de Argentina, Perú y Brasil fueron relativamente similares, excepto en el IMC en mujeres, que presentron valores inferiores desde 13 a 17 años. CONCLUSIÓN: Las variables de crecimiento de los escolares fueron inferiores con referencia al CDC-2012. Hubo ligeras discrepancias en el crecimiento físico y en el IMC con las curvas de Argentina, Brasil y Perú. Se construyeron curvas para evaluar el crecimiento y el IMC de escolares de moderada altitud de Colombia.

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BACKGROUND: Maintaining and building healthy bones during the lifetime requires a complicated interaction between a number of physiological and lifestyle factors. Our goal of this study was to analyze the association between hand grip strength and the maximum peak expiratory flow with bone mineral density and content in adolescent students. METHODS: The research team studied 1427 adolescent students of both sexes (750 males and 677 females) between the ages of 11.0 and 18.9 years in the Maule Region of Talca (Chile). Weight, standing height, sitting height, hand grip strength (HGS), and maximum peak expiratory flow (PEF) were measured. Furthermore, bone mineral density (BMD) and total body bone mineral content (BMC) were determined by using the Dual-Energy X-Ray Absorptiometry (DXA). Hand grip strength and PEF were categorized in tertiles (lowest, middle, and highest). Linear regression was performed in steps to analyze the relationship between the variables. Differences between categories were determined through ANOVA. RESULTS: In males, the hand grip strength explained 18-19% of the BMD and 20-23% of the BMC. For the females, the percentage of variation occurred between 12 and 13% of the BMD and 17-18% of the BMC. The variation of PEF for the males was observed as 33% of the BMD and 36% of the BMC. For the females, both the BMD and BMC showed a variation of 19%. The HGS and PEF were divided into three categories (lowest, middle, and highest). In both cases, significant differences occurred in bone density health between the three categories. CONCLUSIONS: In conclusion, the HGS and the PEF related positively to the bone density health of both sexes of adolescent students. The adolescents with poor values for hand grip strength and expiratory flow showed reduced values of BMD and BMC for the total body. Furthermore, the PEF had a greater influence on bone density health with respect to the HGS of the adolescents of both sexes.

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