Referencias argentinas de estatura sentada y longitud de miembros inferiores de 0 a 18 años / Argentine reference values for sitting height and lower limb length between 0 and 18 years of age

Para el seguimiento del crecimiento de niños con severa malformación de miembros inferiores o de columna, disponer de referencias de estatura sentada (ES) y de miembros inferiores (MI) según edad es una herramienta de gran utilidad. Objetivos: estimar los centilos de ES y MI para ambos sexos, entre 0 a 18 años de edad y evaluar la utilidad de estas referencias en niños con malformaciones localizadas en MI o columna. Material y Métodos: los centilos 3°,10°, 25°, 50°, 75°, 90° y 97° de ES y MI según Edad (SE/E y MI/E) fueron estimados en una población sana de 4803 y 4818 varones y mujeres respectivamente, por el método LMS que utiliza la transformación BOX-COX para normalizar la distribución de los datos a cada edad. Resultados: en los primeros años de edad, la mediana de ES en ambos sexos fue similar. Entre los 11 y 13 años, las niñas tuvieron una ES mayor a la de los varones, pero luego se invirtió y se mantuvo así hasta la adultez. En MI la mediana también fue similar en ambos sexos durante los primeros años, pero a partir de los 12 el incremento fue mayor en los varones. A los 12 años la diferencia fue 0,71 cm, finalizando con 9 cm a los 18 años. El uso de estas referencias en niños con malformaciones de columna ó MI mostró un crecimiento patológico de estatura total y del segmento corporal comprometido, con un tamaño y crecimiento normal del segmento no afectado. Conclusión: los centilos de segmentos corporales según la edad constituyen una herramienta útil para la supervisión del crecimiento de niños con severa malformación de columna o miembros inferiores (AU)

For the follow-up of growth of children with severe lower-limb or spinal deformities, reference values for sitting height (SH) and lower-limb (LL) length according to age are extremely useful. Aims: To define percentiles of SH and LL for both sexes between 0 and 18 years of age and evaluate the usefulness of these references in children with LL or spinal deformities. Material and Methods: 3rd,10th, 25th, 50th, 75th, 90th, and 97th percentiles for SH and LL according to age (SE/age and LL/age) were estimated for a healthy population of 4803 and 4818 boys and girls, respectively, with the LMS method that uses the Box-Cox power exponential (BCPE) to normalize data distribution for age. Results: In the first years of life, mean SH was similar for both sexes. Between 11 and 13 years of age, girls had a greater SH than boys, but this relationship subsequently inverted and remained so until adulthood. The median length of LL was also similar in the first years of life, but after 12 years of age growth was increased in boys. At 12 years of age the difference was 0.71 cm, with a final difference of 9 cm at 18 years of age. The use of these reference values in children with spinal or LL deformities showed pathological growth of the whole body and the body segment involved with normal growth of the nonaffected segment. Conclusion: percentiles of the body segments according to age are a useful tool for the monitoring of growth of children with severe deformities of the spine or lower limbs (AU)

Nutritional status in two Mbyá-Guaraní communities from misiones (Argentina).

Growth and nutritional status of children and adults in two Mbyá-Guaraní communities from Argentina, was assessed. Height, weight, sitting height, upper arm circumference, triceps and subscapular skinfold were measured on 120 individuals aged from 2 to 60 between March and May, 2001. Data were transformed to z-scores using United States references (NHANES I and NHANES II). A z-score of less than -2 was used as the cut-off point to determine the prevalence of stunting and wasting respectively. Mean z-scores for weight, height, and upper arm circumference lie below the reference (0 > Z > -3), while in sitting height ratio and muscular area for females they were above the US standard (0 < Z < 2). Skinfold thicknesses and muscular area for males were similar to the reference (2 > Z > -1). Our findings are in agreement with others South American Indian research that the prevalence of stunting (36.7%) is significantly higher than wasting (1.8%). The presence of parasitic infections and nutritional environment previously described in this population could be related to the short stature.

Rapid change in height and body proportions of Maya American children.

Maya families from Guatemala migrated to the United States in record numbers from the late 1970s to the early 1990s. Births to Maya immigrant women have created a sizable number of Maya American children. The height and sitting height of 5 to 12 years children (n = 431) were measured in 1999 and 2000. Leg length was estimated and the sitting height ratio was calculated. These data were compared with a sample of Maya children living in Guatemala measured in 1998 (n = 1,347). Maya American children are currently 11.54 cm taller and 6.83 cm longer-legged, on average, than Maya children living in Guatemala. Consequently, the Maya Americans have a significantly lower average sitting height ratio (i.e., relatively longer legs in proportion to length of the head and trunk) than do the Maya in Guatemala. These results add support to the hypothesis that both the height and body proportions of human populations are sensitive indicators of the quality of the environment for growth.

Growth of skeletal components in the young squirrel monkey (Saimiri sciureus boliviensis): a longitudinal experiment.

A functional skeletal criterion, as an extension of the van der Klaauw's cranial theory, was adopted in the present study. The null hypothesis tested was: "The major skeletal components of the platyrrhine body grow linearly, regardless of their functional dependence to different demands." The acceptance of the hypothesis will imply that all Saimiri skeletal growth may be satisfactorily explained by independent variables in a single equation. The rejection will suggest that such skeletal growth patterns have to be explained by variables in several different equations, and perhaps these equations may vary with the effect of sex and undernutrition. Control and undernourished squirrel monkeys were radiographed monthly for 2 years; they were also measured; and their volumetric and morphometric neurocranial, facial, and pelvic indices were calculated. The curves that best described each of the 24-point sequences were obtained. Three main growth patterns were observed: 1) Simple linear (femur length for all groups, and pelvic index for control and undernourished females), for which the simple regression equation explained more than 95% of the variation; 2) Complex linear (pelvic index for control and undernourished males, and neurocranial and facial indices for all of the groups), for which more than 95% of the variation was explained by one of the four four-function type equations; and 3) Noncorrelated with age (neurofacial index for undernourished males, and pelviofemoral index for control females and undernourished males and females), which showed nonsignificant correlations with respect to age. The food intake and the oscillations of the environmental temperature might help to explain the undulating growth trajectory observed in the complex linear components.

Body growth and food intake in moderately and severely malnourished rats.

A longitudinal study with eighty-six rats (Rattus norvegicus albinus var. Wistar) of both sexes was made. The aim was to express adaptability to malnutrition in terms of Age-of-Fitness Point (AFP) and Trend-to-Fitness Stage (TFS). The AFP means the age in which both control and malnourished animals show the same Relative Food Intake (RFI) value, expressed in mg of food intake per g of body weight. The TFS means the percent of RFI reached by the malnourished animals at a given age stage. A TFS=70 for example, means that the animals have to gain 30% of RFI to reach its AFP. Growing animals were submitted to one of the following treatments: control (fed on a stock diet ad libitum), moderate malnutrition (fed on 1/2 of the daily stock diet of a control of the same age and sex) and severe malnutrition (fed on 1/3 of the mentioned diet). Body weight and food intake of all of the animals were registered every ten days, when they were from 20 to 80 days old. Relative Food Intake (RFI) was calculated dividing the food intake (mg) of each animal/day by its respective body weight (g). The RFI data series belonging to each sex and treatment was obtained. The significance of the three independent variables (age, sex, and nutrition) was tested by multiple regressions. Covariation and degree of linearity between RFI and age were tested by simple correlation and simple regression tests. The intercepts of the regressions were all significant. For both sexes they were greater in controls than in the moderately malnourished group, in the latter being greater than in the severely malnourished group. The slopes were significant and negative in all of the groups. While, in males and females, control and moderately malnourished rats showed little differences, the severely malnourished slopes were, respectively, 3.2 and 2.4 times lower than in controls. In controls there were sexual differences for RFI correlated with age which were not present in the malnourished groups. The AFP was calculated by extrapolation: 80-90 days of age in males, with RFI of 80 mg/g, and 100-110 days of age in females, with RFI of 70 mg/g. In males TFS was 29.5% and 88.6 % in moderate and severe malnutrition, respectively. In females these values were 9.1% and 63.2%, respectively. Sexual dimorphism in TFS was significant in the moderately malnourished animals and nonsignificant in the severely malnourished ones.

[Effect of gonadal hormones on sexual dimorphism in malnutrition substrates]. / Efecto de las hormonas gonadales sobre el dimorfismo sexual en substrato de desnutrición.

The environmental effect on growth and sexual dimorphism is mediated by endocrinological dysfunctions. It was shown that malnutrition acts on the hypotalamus-pituitary-glandular axis. An experiment was made in Wistar rats to determine the effect of some gonadic hormones on the functional components of the skull to which sex dimorphism was alterated by a postnatal undernutrition. The effects of these hormones in restoring sexual cranial dimorphism was tested. Four treatments were applied: control, with food intake ad-libitum; undernutrition (50% of the control food intake); undernutrition plus periodic injections of testosterone and estradiol to males and females, respectively and sham-operated animals, which were injected with oil vehicle only. A radiological longitudinal study was performed between 20 and 80 days of postnatal age. The length width and height of the neural and facial components were measured on each radiograph. Data were processed by ANOVA and Mann-Whitney statistical tests were performed by means of the SYSTAT 7.0 statistical package. Results showed that gonadic hormones restored the sexual cranial dimorphism by stimulating (testosterone) or suppressing (estradiol) the growth of the cranial components.