[Muscle and fat indicators in boys of the upper socioeconomic strata of Caracas].
A sample of 271 boys, aged four, eight and 12 years, belonging to the upper socioeconomic strata of Caracas, was studied in order to test the sensibility and specificity of arm muscle and fat indicators, as evaluators of the muscle and fat tissues development, as well as of the nutritional status. Weight, height, arm circumference and triceps skinfold were measured following standardized techniques; muscle and fat areas were calculated from arm circumference and skinfold measurements. For statistical analysis, results were compared with North American reference standards, and correlation and regression analyses were performed. Nutritional assessment was performed using weight-for-age, height-for-age and weight-for-height, arm circumference and skinfold, plus the two derived areas. Malnourished children were identified using WHO guidelines in height and weight. Prevalences were compared and the sensibility, specificity and predictive values were studied. Malnourished children were analyzed individually. Arm circumference was the best predictor of nutritional status and triceps skinfold the worst predictor; muscle and fat areas were moderate predictors. On the average, four-year olds were smaller, lighter and much leaner than the reference, and eight and 12-year olds were taller, heavier and more muscular than the reference. Low fat was most prevalent in four-year olds, while high muscle increased with age and was highest at age 12, consistent with pubertal development. Obesity was most prevalent in eight-year olds. Twenty-eight per cent of the 50 children identified as malnourished in weight and height according to WHO, were normal in muscle and fat, and 66% of the 100 identified as malnourished in muscle and fat were normal according to WHO guidelines. Furthermore, 24% of children classified as overweight by weight-for-height were not obese but high in muscle. It is concluded that muscle and fat areas reflect muscle and fat components but are poor indicators of malnutrition, expressed in terms of weight and height. On the other hand, weight and height do not measure body composition. Weight-for-height should be used in combination with muscle and fat areas. National reference standards are needed and cut-off points should be revised, in order to maximize the efficiency and predictive values of these indicators.
López-Contreras de Blanco
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Universidad Simón Bolivar, Jefe de la Unidad de Investigaciones Biológicas, Fundacredesa, Chacao, Caracas, Venezuela.
D000273:Adipose Tissue / Q000033:anatomy & histology; D000367:Age Factors; D000704:Analysis of Variance; D000886:Anthropometry; D015992:Body Mass Index; D002648:Child; D002675:Child, Preschool; D006801:Humans; D008297:Male; D009132:Muscles / Q000033:anatomy & histology; D009752:Nutritional Status; D012016:Reference Values; D012680:Sensitivity and Specificity; D012959:Socioeconomic Factors; D014687:Venezuela
Indicadores de músculo y grasa en varones de los estratos socioeconómicos altos de Caracas.