RESUMO

Durante muchos años se han usado los valores de perímetro braquial inferiores a cierto límite como índice alternativo del estado nutricional de los menores de 5 años de edad en épocas de hambruna o crisis de refugiados y también como método adicional de tamizaje en situaciones normales. Sin embargo, recientemente se ha puesto en duda la independencia del perímetro braquial respecto de la edad y el sexo. Tras revisar las pruebas científicas en las que se basan el uso y la interpretación del perímetro braquial, un Comité de Expertos de la OMS recomendó nuevos valores de referencia de perímetro braquial según la edad en menores de 5 años. Sin embargo, en algunas situaciones es difícil evaluar la edad de un niño y en tales circunstancias el perímetro braquial según la altura puede ser una buena alternativa. La regla QUAC (del inglés Quaker arm circumference) para medir la altura es un medio sencillo para determinar el punto de corte del perímetro braquial correspondiente a una altura dada. Este artículo describe los valores de referencia del perímetro braquial y la construcción y uso del medidor QUAC, así como la utilización del método de curvas de características funcionales (receiver operating characteristic curve) para evaluar el rendimiento del perímetro braquial, el perímetro braquial según la edad y el perímetro braquial según la altura en la detección de niños malnutridos.

Mid-upper-arm circumference (MUAC) based on a single cut-off value for all children under 5 years of age has been used for many years as an alternative nutritional status index for children during famines or refugee crises, and as an additional screening tool in nonemergencies. However, it has recently been questioned whether MUAC is age- and sex-independent. After reviewing the scientific evidence underlying the use and interpretation of MUAC, a WHO Expert Committee recommended a new MUAC-for-age reference for under-5-year-olds. In some settings, however, it is difficult to assess a child's age and in such circumstances MUAC-for height may be a good alternative. The height-based QUAC stick offers a simple means of adjusting MUAC cut-offs according to height, and the MUAC-for-height reference and construction and use of the QUAC stick are described in this article. Also described is the use of the receiver operating characteristic (ROC) curve method to evaluate the performance of MUAC, MUAC-for-age, and MUAC-for-height in screening malnourished children.

Assuntos

RESUMO

The current international growth reference, the National Center for Health Statistics (NCHS) reference, is widely used to compare the nutritional status of populations and to assess the growth of individual children throughout the world. Recently, concerns were raised regarding the adequacy of this reference for assessing the growth of breast-fed infants. We used the NCHS reference to evaluate infant growth in one of the most developed areas of Brazil. Infants who were exclusively or predominantly breast-fed for the first 4-6 mo, and partially breast-fed thereafter, grew more rapidly than the NCHS reference in weight and length during the first 3 mo, but appeared to falter thereafter. The average growth of all infants, regardless of feeding pattern, was faster than the NCHS reference until approximately 6 mo, after which their growth became slower than that of the NCHS sample. To substantiate this finding, the NCHS growth curves were then compared with growth data of breast-fed infants in developed countries from pooled published studies, formula-fed North American and European infants and predominantly bottle-fed U.S. infants monitored by the Centers for Disease Control and Prevention (CDC) Pediatric Surveillance System. In all three cases, weights showed the same pattern as the Brazilian infants-higher than NCHS in the early months but an apparent decline thereafter. The pattern for length gain was similar but less marked. Breast-fed infants showed more pronounced declines than those who were predominantly bottle-fed. These findings suggest that the infancy portion of the NCHS reference does not adequately reflect the growth of either breast-fed or artificially fed infants. This probably results from characteristics of the original sample and from inadequate curve-fitting procedures. The development of an improved international growth reference that reflects the normal infant growth pattern is indicated.

PIP: The National Center for Health Statistics (NCHS) reference is the international standard widely used to compare the nutritional status of populations and to assess the growth of individual children around the world. There has, however, recently been concern over the adequacy of this reference for assessing the growth of breast-fed infants. Findings are presented from an evaluation of infant growth using the NCHS reference in the city of Pelotas, Brazil, one of the most developed areas of the country. The 5304 children enrolled in the study comprised all but 0.3% of all hospital births occurring in the city in 1993. Infants who were either exclusively or mainly breast-fed for the first 4-6 months, and partially breast-fed thereafter, grew faster than the NCHS reference in weight and length during the first 3 months, but appeared to falter thereafter. The average growth of all infants, regardless of feeding pattern, was faster than the NCHS reference until approximately age 6 months, after which they grew slower than did the NCHS sample. A comparison of NCHS growth curves with growth data on breast-fed infants in developed countries from pooled published studies, formula-fed North American and European infants, and mainly bottle-fed US infants monitored by the Centers for Disease Control and Prevention (CDC) Pediatric Surveillance System found infant weights in all cases to exhibit the same pattern as that of the Brazilian infants. The pattern for length gain was similar, but less marked. Breast-fed infants showed more pronounced declines than those who were mainly bottle-fed. An improved international growth reference should be developed and used.

Assuntos

Assuntos

Assuntos

RESUMO

The objective of this study was to evaluate the benefit of screening for anemia in infants in relation to their previous diet. The iron status of 854 nine-month-old infants on three different feeding regimens and on a regimen including iron dextran injection was determined by analysis of hemoglobin, serum ferritin, and erythrocyte protoporphyrin levels and of serum transferrin saturation. Infants were categorized as having iron deficiency if two or three of the three biochemical test results were abnormal and as having iron deficiency anemia if, in addition, the hemoglobin level was less than 110 gm/L. The prevalence of iron deficiency was highest in infants fed cow milk formula without added iron (37.5%), intermediate in the group fed human milk (26.5%), much lower in those fed cow milk formula with added iron (8.0%), and virtually absent in those injected with iron dextran (1.3%). The corresponding values for iron deficiency anemia were 20.2%, 14.7%, 0.6%, and 0%, respectively. The use of iron supplements is therefore justified in infants fed cow milk formula without added iron, even when there is no biochemical evidence of iron deficiency. The low prevalence of iron deficiency in the group fed iron-fortified formula appears to make it unnecessary to screen routinely for anemia in such infants. These results also support the recommendation that infants who are exclusively fed human milk for 9 months need an additional source of iron after about 6 months of age.

PIP: The objective of this study was to evaluate the benefit of screening for anemia in infants in relation to their previous diet. The iron status of 854 9-month old infants on 3 different feeding regimens and on a regimen including iron dextran infection was determined by analysis of hemoglobin, serum ferritin, and erythrocyte protoporphyrin levels and of serum transferrin saturation. Infants were categorized as having iron deficiency if 2 or 3 of the 3 biochemical test results were abnormal; if the hemoglobin level was 110 gm/L, then a diagnosis of iron deficiency anemia was also made. The prevalence of iron deficiency was highest in infants who were fed cow's milk formula without added iron (37.5%), intermediate in the group fed human milk (26.5%), much lower in those fed cow's milk formula with added iron (8.0%), and virtually absent in those injected with iron dextran (1.3%). The corresponding values for iron deficiency anemia were 20.2%, 14.7%, 0.6% and 0%, respectively. The use of iron supplements is therefore justified in infants who received cow's milk formula without added iron, even when there is no biochemical evidence of iron deficiency. The low prevalence of iron deficiency in the group fed iron-fortified formula appears to make it unnecessary to screen routinely for anemia in such infants. These results also support the recommendation that infants who receive human milk exclusively for 9 months require an additional source of iron after about 6 months of age.

Assuntos

Assuntos

RESUMO

To assess the possible influence of altitude on childhood growth in the United States, we used data collected by the Centers for Disease Control Pediatric Nutrition. Surveillance System from eight mountain states to determine the height and weight status of children aged 5 years or younger enrolled in various public health programs between 1982 and 1984. The mean birth weight, height-for-age, weight-for-age, and weight-for-height indicators were found to decline significantly with increasing altitude, starting at an elevation greater than 1500 m (p less than 0.001, ANOVA). The reduction in growth was observed for all age groups and all birth weight groups studied. Part of the observed reduction in growth could be attributed to the lower birth weight of children born at higher altitude. However, the reduced growth status persisted after controlling for birth weight, suggesting the presence of an extrauterine growth retardation effect related to altitude.

Assuntos

RESUMO

The effect of altitude on birth weight was measured with data in U.S. natality records from 1978 to 1981 after correlation with the mean altitude of the mother's resident county. For comparison of the low birth weight (LBW) rate at different altitudes, certain socioeconomic risk factors known to affect birth weight were controlled by the selection of an idealized subpopulation of singleton births. With 500 m gradations for altitude, a curvilinear dose-response relationship of birth weight reduction with increasing altitude was demonstrated (P less than 0.001). In comparison with neonates born at sea level, neonates born at higher altitudes (greater than 2000 m) had a twofold to threefold increase in LBW rate, mainly related to a higher incidence of intrauterine growth retardation. Comparison of the LBW rate on the basis of small geographic divisions in the mountain states showed a positive correlation between the LBW rate and the high altitude. The birth weight frequency distribution curves of the idealized subpopulation at each altitude approximate normal distributions and parallel one another, indicating that altitude has a general effect on all births. Such nearly normal birth weight distributions allowed the determination of altitude-specific LBW cutoff limits that can be used to detect areas of greater risk for LBW but independent of the altitude effect.

Assuntos

RESUMO

Birth certificates of infants born in Tennessee during 1979 to 1984 were linked with the birth certificates of their mothers, who were born in Tennessee during 1959 to 1966 (n = 43,891) to study the association between maternal and infant birth weights. A highly significant association (P less than 0.0001) between maternal and infant birth weights was found for both blacks and whites. Women who weighed 4000 to 4499 g at birth were at lowest risk for delivery of a small for gestational age (SGA) infant (5.9% for whites, 4.8% for blacks). The risk of giving birth to an SGA infant increased with decreasing maternal birth weight, reaching a maximum of 19.8% for white mothers who weighed 2000 to 2499 g at birth, and 20.0% for black mothers who weighed 1000 to 1499 g at birth. In contrast, the rate of preterm birth varied much less by maternal birth weight for both whites and blacks. These data suggest that maternal birth weight exerts a stronger influence on intrauterine growth than on the duration of gestation. Women who were smaller than average at birth should be considered at high risk for delivery of an SGA infant.

Assuntos

RESUMO

In this study of 467 healthy term infants seen for routine 1-year health maintenance examination, we determined the influence of mild prior infection on the concentration of hemoglobin and other laboratory evidence of iron deficiency. In addition we studied the Hgb response in 261 infants randomized to receive a 3-month course of treatment with either iron or placebo. Infants who had had one or more clinic visits because of infection during the previous 3 months or who were reported as not being entirely well during the past month or who had an elevated sedimentation rate were more likely to have anemia or "low normal" Hgb, higher erythrocyte protoporphyrin and serum ferritin values, and lower serum iron concentration than infants who had been well. Hgb response greater than or equal to 1 gm/dl after iron treatment occurred more commonly in infants who had had prior visits because of infection. The results indicate that upper respiratory and other mild antecedent infections commonly predispose to iron deficiency (probably because of a decrease in iron absorption).

Assuntos

RESUMO

Iron deficiency and lead toxicity both result in increased erythrocyte protoporphyrin. The purpose of this study was to determine the differences in EP concentration, according to age and sex, obtained in the 2nd National Health and Nutrition Examination Survey of the United States and to determine the extent to which EP differences might be related to iron deficiency or lead toxicity. The highest EP concentrations were found in infants and children. Among adults, women had higher EP values than men. Lead toxicity (blood lead greater than 30 micrograms/dl) and low serum iron concentration/total iron binding capacity (Fe/TIBC less than 16%), often in combination, were associated with elevated EP values in infants and children. In women, elevated EP concentration were related primarily to low Fe/TIBC values, whereas in men there was only a weak association with elevated blood lead concentration. Age/sex differences in EP values diminished markedly when the influences of lead toxicity and iron deficiency were excluded by the above criteria.

Assuntos

Assuntos

Assuntos

Assuntos