Comparação do equilíbrio postural entre adolescentes do sexo feminino e masculino

A adolescência compreende a fase entre os 10 e 19 anos de idade, a qual se caracteriza por uma aceleração no crescimento e desenvolvimento dos indivíduos. No entanto, essas mudanças não ocorrem no mesmo ritmo para ambos os sexos, o que pode trazer diferenças no equilíbrio postural. Este estudo tem como objetivo comparar o equilíbrio postural entre adolescentes dos sexos masculino e feminino. O grupo de estudo foi composto por 11 adolescentes do sexo feminino e 19 do sexo masculino. A análise da altura do centro de gravidade foi obtida com o uso de uma prancha de reação, e o equilíbrio postural por meio de uma plataforma de força Advanced Mechanical Technologies, Inc. modelo OR6-6. As variáveis avaliadas foram calculadas a partir do Centro de Pressão (COP): amplitude de deslocamento ântero-posterior do COP (COPap), amplitude de deslocamento médio-lateral do COP (COPml) e velocidade média de deslocamento do COP (COPvel). Os adolescentes do sexo feminino apresentaram amplitude de deslocamento do COPap (p=0,011) e COPml (p=0,003) significativamente menor na condição de olhos abertos que o sexo masculino, e na condição de olhos fechados nas três variáveis avaliadas, COPap (p=0,001), COPml (p=0,001) e COPvel p=0,004, sugerindo menor oscilação postural para as adolescentes deste estudo. Acredita-se que os resultados encontrados podem ser advindos das diferenças nas características antropométricas entre os sexos. Conclui-se que os adolescentes do sexo feminino apresentaram melhor equilíbrio postural quando comparados aos do sexo masculino

Children grow and horses race: is the adiposity rebound a critical period for later obesity?

BACKGROUND: The adiposity rebound is the second rise in body mass index that occurs between 3 and 7 years. An early age at adiposity rebound is known to be a risk factor for later obesity. The aim here is to clarify the connection between the age at rebound and the corresponding pattern of body mass index change, in centile terms, so as to better understand its ability to predict later fatness. DISCUSSION: Longitudinal changes in body mass index during adiposity rebound, measured both in original (kg/m(2)) and standard deviation (SD) score units, are studied in five hypothetical subjects. Two aspects of the body mass index curve, the body mass index centile and the rate of body mass index centile crossing, determine a child's age at rebound. A high centile and upward centile crossing are both associated separately with an early rebound, while a low centile and/or downward centile crossing correspond to a late rebound. Early adiposity rebound is a risk factor for later fatness because it identifies children whose body mass index centile is high and/or crossing upwards. Such children are likely to have a raised body mass index later in childhood and adulthood. This is an example of Peto's "horse racing effect". The association of centile crossing with later obesity is statistical not physiological, and it applies at all ages not just at rebound, so adiposity rebound cannot be considered a critical period for future obesity. Body mass index centile crossing is a more direct indicator of the underlying drive to fatness. SUMMARY: An early age at adiposity rebound predicts later fatness because it identifies children whose body mass index centile is high and/or crossing upwards. Such children are likely to have a raised body mass index later. Body mass index centile crossing is more direct than the timing of adiposity rebound for predicting later fatness

Association between anthropometric indices and cardiometabolic risk factors in pre-school children

ABSTRACT: The world health organization (WHO) and the Identification and prevention of dietary- and lifestyle-induced health effects in children and infants- study (IDEFICS), released anthropometric reference values obtained from normal body weight children. This study examined the relationship between WHO [body mass index (BMI) and triceps- and subscapular-skinfolds], and IDEFICS (waist circumference, waist to height ratio and fat mass index) anthropometric indices with cardiometabolic risk factors in pre-school children ranging from normal body weight to obesity. Methods: A cross-sectional study with 232 children (aged 4.1 ± 0.05 years) was performed. Anthropometric measurements were collected and BMI, waist circumference, waist to height ratio, triceps- and subscapular-skinfolds sum and fat mass index were calculated. Fasting glucose, fasting insulin, homeostasis model analysis insulin resistance (HOMA-IR), blood lipids and apolipoprotein (Apo) B-100 (Apo B) and Apo A-I were determined. Pearson’s correlation coefficient, multiple regression analysis and the receiver-operating characteristic (ROC) curve analysis were run. Results: 51 % (n = 73) of the boys and 52 % (n = 47) of the girls were of normal body weight, 49 % (n = 69) of the boys and 48 % (n = 43) of the girls were overweight or obese. Anthropometric indices correlated (p 0.68 to AUC < 0.76). Conclusions: WHO and IDEFICS anthropometric indices correlated similarly with fasting insulin and HOMA-IR. The diagnostic accuracy of the anthropometric indices as a proxy to identify children with insulin resistance was similar. These data do not support the use of waist circumference, waist to height ratio, triceps- and subscapular- skinfolds sum or fat mass index, instead of the BMI as a proxy to identify pre-school children with insulin resistance, the most frequent alteration found in children ranging from normal body weight to obesity

Body fat measurement by bioelectrical impedance and air displacement plethysmography: a cross-validation study to design bioelectrical impedance equations in Mexican adults

<p>Abstract</p> <p>Background</p> <p>The study of body composition in specific populations by techniques such as bio-impedance analysis (BIA) requires validation based on standard reference methods. The aim of this study was to develop and cross-validate a predictive equation for bioelectrical impedance using air displacement plethysmography (ADP) as standard method to measure body composition in Mexican adult men and women.</p> <p>Methods</p> <p>This study included 155 male and female subjects from northern Mexico, 20–50 years of age, from low, middle, and upper income levels. Body composition was measured by ADP. Body weight (BW, kg) and height (Ht, cm) were obtained by standard anthropometric techniques. Resistance, R (ohms) and reactance, Xc (ohms) were also measured. A random-split method was used to obtain two samples: one was used to derive the equation by the "all possible regressions" procedure and was cross-validated in the other sample to test predicted versus measured values of fat-free mass (FFM).</p> <p>Results and Discussion</p> <p>The final model was: FFM (kg) = 0.7374 * (Ht²/R) + 0.1763 * (BW) - 0.1773 * (Age) + 0.1198 * (Xc) - 2.4658. R²was 0.97; the square root of the mean square error (SRMSE) was 1.99 kg, and the pure error (PE) was 2.96. There was no difference between FFM predicted by the new equation (48.57 ± 10.9 kg) and that measured by ADP (48.43 ± 11.3 kg). The new equation did not differ from the line of identity, had a high R²and a low SRMSE, and showed no significant bias (0.87 ± 2.84 kg).</p> <p>Conclusion</p> <p>The new bioelectrical impedance equation based on the two-compartment model (2C) was accurate, precise, and free of bias. This equation can be used to assess body composition and nutritional status in populations similar in anthropometric and physical characteristics to this sample.</p

Childhood body mass index trajectories: modeling, characterizing, pairwise correlations and socio-demographic predictors of trajectory characteristics

Background: Modeling childhood body mass index (BMI) trajectories, versus estimating change in BMI between specific ages, may improve prediction of later body-size-related outcomes. Prior studies of BMI trajectories are limited by restricted age periods and insufficient use of trajectory information. Methods: Among 3,289 children seen at 81,550 pediatric well-child visits from infancy to 18 years between 1980 and 2008, we fit individual BMI trajectories using mixed effect models with fractional polynomial functions. From each child's fitted trajectory, we estimated age and BMI at infancy peak and adiposity rebound, and velocity and area under curve between 1 week, infancy peak, adiposity rebound, and 18 years. Results: Among boys, mean (SD) ages at infancy BMI peak and adiposity rebound were 7.2 (0.9) and 49.2 (11.9) months, respectively. Among girls, mean (SD) ages at infancy BMI peak and adiposity rebound were 7.4 (1.1) and 46.8 (11.0) months, respectively. Ages at infancy peak and adiposity rebound were weakly inversely correlated (r = -0.09). BMI at infancy peak and adiposity rebound were positively correlated (r = 0.76). Blacks had earlier adiposity rebound and greater velocity from adiposity rebound to 18 years of age than whites. Higher birth weight z-score predicted earlier adiposity rebound and higher BMI at infancy peak and adiposity rebound. BMI trajectories did not differ by birth year or type of health insurance, after adjusting for other socio-demographics and birth weight z-score. Conclusions: Childhood BMI trajectory characteristics are informative in describing childhood body mass changes and can be estimated conveniently. Future research should evaluate associations of these novel BMI trajectory characteristics with adult outcomes

Obesity, sodium intake, and blood pressure in adolescents.

SUMMARY It has been postulated that increased dietary sodium associated with greater food intake by obese people is a mechanism for the relationship between obesity and blood pressure (BP). We hare evaluated this hypothesis by exploring the Interrelationships of measures of obesity, sodium intake, and BP in 248 'normal' adolescents, 16 to 17 years of age. As an index of sodium intake, the sodium excretion in three overnight urine collections was used. As a more specific index of saltiness of diet, we used a ratio of sodium excretion to calorie intake, with calories estimated from 3-day diet records and dietary interview. Body weight and other measures of obesity showed a positive relationship with systolic blood pressure (SBP), but not with dlastolic (K B) blood pressure (DBP,). Measures of overnight sodium excretion were positively correlated with body weight and calculated body fat percentage, suggesting that heavier people indeed ingest more sodium. This may result not from Increased intake of food per se, but from increased saltiness of diet, since calorie intake did not increase with body weight. No significant relationships were found between BP and concurrent measures of sodium excretion or diet saltiness. (Hypertension 2 (suppl I)I-78-I-82, 1980

Influência dos estágios de maturação sexual no estado nutricional, antropometria e composição corporal de adolescentes Influence of the stages of sexual maturation in the nutritional status, anthropometrics and corporal composition of adolescents

Os fenômenos puberais apresentam variabilidade no que diz respeito às idades de início e término, à velocidade e magnitude com que se expressam e as suas inter-relações. Tais fenômenos influenciam as modificações antropométricas e de composição corporal que caracterizam o processo de crescimento e desenvolvimento da adolescência. O artigo tem como objetivo analisar a influência dos estágios de maturação sexual, no estado nutricional, antropometria e composição corporal de adolescentes de ambos os sexos. A revisão de literatura foi realizada utilizando-se os termos "Adolescent, Puberty and Body Composition", por meio de consulta na base de dados do HighWire Press®. Trabalhou-se com artigos publicados desde janeiro de 1995 até julho de 2006, incluindo, outros relevantes ao tema, publicados anteriormente. Na adolescência, para se avaliar o estado nutricional e as modificações antropométricas e de composição corporal, é de extrema importância a consideração não somente da idade cronológica, mas também do estágio de maturação sexual. Cabe ressaltar as consideráveis dificuldades metodológicas existentes nos estudos acerca do estadiamento pubertário. Destaca-se a importância da realização de mais estudos, no sentido de elucidar a influência dos estágios de maturação sexual na evolução dos parâmetros antropométricos e de composição corporal, possibilitando a construção e utilização sistemática de referências que considerem o desenvolvimento pubertário.<br>Puberty phenomena concerning ages of onset and ending, speed and magnitude of expression, and interrelations are variable. Such phenomena influence anthropometric and body composition changes characterizing the process of growth and development during adolescence. This article has the objective of analyzing the influence of sexual maturing status on nutritional status, anthropometry and body composition in adolescents of both sexes. Literature review was accomplished through the use of the terms "Adolescent, Puberty and Body Composition" through consultation to the HighWire Press® database. Articles published from January 1995 to July 2006 were utilized, including others previously published and relevant to the subject. To assess nutritional status, anthropometric and body composition changes, during adolescence it is extremely important that consideration is not restricted to chronological age but extended to sexual maturity as well. The considerable methodological difficulties related to puberty staging should be emphasized. There is a need to accomplish further studies to clarify sexual maturing staging in anthropometric and body composition parameters, enabling systematic building and use of references considering puberty development