Vitamin E deficiency and associated factors among Brazilian school children / Deficiência de vitamina E e fatores associados entre crianças escolares brasileiras

ABSTRACT: Objective: Brazilian national data show a significant deficiency in pediatric vitamin E consumption, but there are very few studies evaluating laboratory-proven nutritional deficiency. The present study aimed to settle the prevalence of vitamin E deficiency (VED) and factors associated among school-aged children attended at a primary health unit in Ribeirão Preto (SP). Methods: A cross-sectional study that included 94 children between 6 and 11 years old. All sub-jects were submitted to vitamin E status analysis. To investigate the presence of factors associated with VED, socio-economic and anthropometric evaluation, determination of serum hemoglobin and zinc levels, and parasitological stool exam were performed. The associations were performed using Fisher's exact test. Results: VED (α-tocopherol concentrations <7 µmol/L) was observed in seven subjects (7.4%). None of them had zinc deficiency. Of the total of children, three (3.2%) were malnourished, 12 (12.7%) were anemic, and 11 (13.5%) presented some pathogenic intestinal parasite. These possible risk factors, in addition to maternal-work, maternal educational level, and monthly income, were not associated with VED. Conclusions: The prevalence of VED among school-aged children attended at a primary health unit was low. Zinc deficiency, malnutrition, anemia, pathogenic intestinal parasite, maternal-work, maternal educational level, and monthly income were not a risk factor for VED. (AU)

RESUMO: Objetivo: Determinar a prevalência da deficiência de vitamina E (DVE) e os fatores associados a essa deficiência em escolares atendidos em uma unidade básica de saúde de Ribeirão Preto (SP). Métodos: Estudo transversal que incluiu 94 crianças entre 6 e 11 anos de idade, atendidas em uma unidade básica de saúde. Todos os indivíduos foram submetidos à análise do status de vitamina E. Para investigar a presença de fatores associados à DVE, foi realizada avaliação socio-econômica e antropométrica, determinação dos níveis séricos de hemoglobina e zinco, e exame parasitológico de fezes. As associações foram realizadas por meio do teste exato de Fisher. Resultados: A DVE (concentrações de α-tocoferol <7 µmol/l) foi observada em sete indivíduos (7,4%). Nenhum sujeito apresentou deficiência sérica de zinco. Do total de crianças, três (3,2%) eram desnutridas, 12 (12,7%) anêmicas e 11 (13,5%) apresentavam algum parasita intestinal patogênico. Estes possíveis fatores de risco, além do trabalho materno, escolaridade materna e renda mensal, não foram associados à DVE (p>0,05). Conclusão: A prevalência de DVE em escolares atendidos em uma unidade básica de saúde foi baixa. Desnutrição, anemia, parasitose intestinal, renda mensal e trabalho e nível educacional maternos não se apre-sentaram como fatores de risco para a DVE. (AU)

IGF-1R mRNA expression is increased in obese children.

OBJECTIVES: Obese children are often taller than age-matched subjects. Reports on GH and IGF-I levels in obese individuals are controversial, with normal and reduced GH-IGF-I levels having been reported in this group of patients. Thus, the aim of this study was to analyse insulin-like growth factor type 1 receptor (IGF-IR) mRNA expression in obese children. METHODS: Forty-seven pre-pubertal children were included in this study: 29 were obese and taller than their target height, and 18 were normal eutrophic controls. Fasting blood samples were collected for IGF-IR mRNA expression in isolated lymphocytes and serum IGF-I, ALS, IGFBP-3, and IGFBP-1 concentration analysis. RESULTS: Relative IGF-IR gene expression (2-ΔΔCT) was significantly (P=0.025) higher in obese children (median 1.87) than in controls (1.15). Fourteen of the 29 obese subjects showed 2-ΔΔCT values greater than or equal to 2, while only 2 individuals in the control group showed values above 2 (P=0.01). Obese children showed significantly (P=0.01) higher IGF-I concentrations than the control group (237ng/ml and 144ng/ml, respectively). Among obese patients, 65.5% had IGF-I values above the 75 percentile of the control group (P=0.02). ALS concentration was significantly (P=0.04) higher in the obese group, while IGFBP-3 levels were similar in obese and control children. IGFBP-1 concentration was lower in obese children, while insulin levels and HOMA-IR index were higher than in controls. CONCLUSIONS: The higher IGF-IR mRNA expression observed in obese children, associated with the higher IGF-I and ALS and the lower IGFBP-1 levels, suggest that the higher stature observed in these children may be due to increased IGF-I bioactivity.

Measurement of salivary cortisol as a marker of stress in newborns in a neonatal intensive care unit.

AIMS: The study was designed to evaluate the newborn (NB) stress response during the inpatient time in the neonatal intensive care unit. METHODS: A quantitative, prospective, observational study was conducted with two NB groups. The first group consisted of 12 NB patients in the neonatal intensive care unit as the experimental group (EG), and the second included 43 NBs who were sent to their own homes and were considered the control group (CG). The EG's salivary cortisol concentration was measured on the 2nd day (D2) and 9th day (D9) of life. The CG's salivary cortisol concentration was measured on the 14th day of life at the child's own home. RESULTS: The salivary cortisol concentration levels for the EG on D2 and D9 and for the CG were 4.3151 ± 2.6492, 1.826 ± 1.2252, and 1.0166 ± 0.8300 ng/dl, respectively. These findings indicated the presence of an adrenal response to stress during the first inpatient days. CONCLUSIONS: The salivary cortisol concentration is an accurate method to indicate neonatal stress. The glucocorticoids frequently used in the prenatal period suppress the adrenal glands and interfere with the stress response.

Impact of hypoxia on IGF-I, IGF-II, IGFBP-3, ALS and IGFBP-1 regulation and on IGF1R gene expression in children.

UNLABELLED: Hypoxia is one of many factors involved in the regulation of the IGF system. However, no information is available regarding the regulation of the IGF system by acute hypoxia in humans. OBJECTIVE: The aim of this study was to evaluate the effect of acute hypoxia on the IGF system of children. DESIGN: Twenty-seven previously health children (14 boys and 13 girls) aged 15 days to 9.5 years were studied in two different situations: during a hypoxemic state (HS) due to acute respiratory distress and after full recovery to a normoxemic state (NS). In these two situations oxygen saturation was assessed with a pulse-oximeter and blood samples were collected for serum IGF-I, IGF-II, IGFBP-1, IGFBP-3, ALS and insulin determination by ELISA; fluoroimmunometric assay determination for GH and also for IGF1R gene expression analysis in peripheral lymphocytes by quantitative real-time PCR. Data were paired and analyzed by the Wilcoxon non-parametric test. RESULTS: Oxygen saturation was significantly lower during HS than in NS (P<0.0001). IGF-I and IGF-II levels were lower during HS than in NS (P<0.0001 and P=0.0004, respectively). IGFBP-3 levels were also lower in HS than in NS (P=0.0002) while ALS and basal GH levels were higher during HS (P=0.0015 and P=0.014, respectively). Moreover, IGFBP-1 levels were higher during HS than in NS (P=0.004). No difference was found regarding insulin levels. The expression of IGF1R mRNA as 2(-ΔΔCT) was higher during HS than in NS (P=0.03). CONCLUSION: The above results confirm a role of hypoxia in the regulation of the IGF system also in humans. This effect could be direct on the liver and/or mediated by GH and it is not restricted to the hepatocytes but involves other cell lines. During acute hypoxia a combination of alterations usually associated with reduced IGF action was observed. The higher expression of IGF1R mRNA may reflect an up-regulation of the transcriptional process.

[Physiology of the GH-IGF axis]. / Fisiologia do eixo GH-sistema IGF.

Growth, the main characteristic of childhood and adolescence, has a similar pattern in the majority of the individuals. Genetic background and GH-IGF axis are the factors that directly influence this process. Pituitary GH acts on growth mainly through the regulation of IGF system. The IGFs (IGF-1 and IGF-2) are growth factors produced in the majority of the organs and body tissues. They have autocrine, paracrine and endocrine actions on metabolism and cell proliferation, growth and differentiation. The IGFs bind with high specificity and affinity to a family of 6 binding proteins, called IGFBPs (1 to 6) that modulate their bioactivity. Most of the known IGF actions are mediated via IGF type 1 receptor (IGF1R). In this article we are going to review the composition and regulation of the GH-IGF axis and the role of each component in the regulation of the growth process.

Fisiologia do eixo GH-sistema IGF / Physiology of the GH-IGF axis

O crescimento, principal característica da infância e da adolescência, apresenta padrão semelhante na maioria dos indivíduos. A herança genética e os componentes do eixo GH-IGF são os fatores que diretamente influenciam esse processo. O GH, produzido na hipófise, exerce sua ação sobre o crescimento mediante regulação do sistema IGF. Os IGFs (IGF-1 e IGF-2) são fatores de crescimento produzidos na maioria dos órgãos e tecidos do organismo, possuindo ações autócrinas, parácrinas e endócrinas sobre o metabolismo intermediário, proliferação, crescimento e diferenciação celular. Associam-se com elevado grau de especificidade e de afinidade à família de seis proteínas carreadoras, denominadas IGFBPs (IGFBP-1 a -6), as quais modulam suas bioati-vidades. A maioria das ações conhecidas dos IGFs é exercida mediante sua ligação com o receptor tipo 1 (IGF-1R). Neste artigo será revisada a composição e a regulação do eixo GH-sistema IGF, assim como a participação de cada um dos seus diferentes componentes no processo de regulação do crescimento humano.

Growth, the main characteristic of childhood and adolescence, has a similar pattern in the majority of the individuals. Genetic background and GH-IGF axis are the factors that directly influence this process. Pituitary GH acts on growth mainly through the regulation of IGF system. The IGFs (IGF-1 and IGF-2) are growth factors produced in the majority of the organs and body tissues. They have autocrine, paracrine and endocrine actions on metabolism and cell proliferation, growth and differentiation. The IGFs bind with high specificity and affinity to a family of 6 binding proteins, called IGFBPs (1 to 6) that modulate their bioactivity. Most of the known IGF actions are mediated via IGF type 1 receptor (IGF1R). In this article we are going to review the composition and regulation of the GH-IGF axis and the role of each component in the regulation of the growth process.

The emergence of the cortisol circadian rhythm in monozygotic and dizygotic twin infants: the twin-pair synchrony.

OBJECTIVE: Studies on the influence of genetic factors on the ontogeny of cortisol circadian rhythm in infants are lacking. This study evaluated the influence of twinning and the heritability on the age of emergence of salivary cortisol rhythm. DESIGN AND SUBJECTS: A longitudinal study was performed using salivary samples obtained during morning and night, at 2, 4, 8, 12, 16, 20 and 24 weeks of postnatal life in 34 infants, 10 monozygotic (MZ) and 7 dizygotic (DZ) twin pairs. Salivary cortisol was determined by radioimmunoassay (RIA). Zigosity was verified by DNA analysis of at least 13 short tandem repeat polymorphisms. Difference of the emergence of cortisol circadian rhythm, within each twin pair, the intraclass correlation coefficient and the heritability index (h(2)) were calculated. RESULTS: The mean (+/- SEM) age of emergence of salivary cortisol circadian rhythm was similar in MZ and DZ (7.8 +/- 1.0 vs 7.4 +/- 1.3 weeks). Seven pairs showed coincidence of the emergence of cortisol rhythm. Ten pairs were not coincident; among them the within-pair difference of emergence of salivary circadian rhythm was similar in both MZ and DZ groups. The intraclass correlation coefficients were rMZ = 0.60, P = 0.02; and rDZ = 0.65, P = 0.03, respectively. The heritability index (h(2)) was 0.21 (ns). CONCLUSIONS: Salivary circadian rhythm appeared at the same postnatal age in MZ and DZ twin infants. Although several physiological aspects might be involved, the heritability index, obtained in the present study, suggests less genetic than environmental impact on the age of the onset of the cortisol circadian rhythm. Our data also indicated that each twin-pair show synchrony because they probably shared prenatal and postnatal environmental synchronizers.