Programação fetal e alterações metabólicas em escolares: metodologia de um estudo caso-controle

Comparative Analysis of the GH/IGF-1 Axis during the First Sixth Months in Children with Low Birth Weight

OBJECTIVE

To analyze the relation between alterations in the growth hormone (GH)/insulin-like growth factor 1 (IGF-1) axis during the first 6 months of life and weight in children born in the lower-middle São Francisco region.

METHODS

This is an analytical cohort and exploratory. Thirty children, were formed two groups, one of low birth weight children (LBW, n = 15) and another of normal weight (NBW = 15) were initially identified in a hospital and reapproached at 3 and 6 months of age. Birth weight and alterations in GH/IGF-1 curves were measured at birth and the third and sixth months of life.

RESULTS

Weight gain during the 6 months of follow-up in newborns with a low birth weight was greater compared to newborns with a normal birth weight. All children who were born with a low birth weight had an altered GH/IGF-1 curve at birth (p = 0.002). Most newborns with a low birth weight maintained the alteration in the GH/IGF-1 curve at the third month of life (p = 0.027). Regarding the GH/IGF-1 curve at the sixth month, alteration persisted in greater proportion among children with a low birth weight.

CONCLUSIONS

Alterations in insulin resistance markers, demonstrated by increased GH without a proportional increase in IGF-1, were observed to be significant in children with a low birth weight with greater adiposity in this group which may increase the risk of metabolic diseases in later life.

Birth weight, life course factors and excess weight among schoolchildren in Niterói, Rio de Janeiro, Brazil in 2010

OBJECTIVE

To investigate the association between birth weight and excess weight among students aged 6-14 years, adjusted for life course confounding factors.

METHODS

Cross-sectional study with 6-14-year-old schoolchildren in 2010; 795 school children from two public schools. In addition, a sub-sample was selected using a case-cohort study approach. Sociodemographic, breastfeeding, food introduction, previous weight gain, family history, current clinical and behavioral variables as well as maternal variables related to pregnancy, were collected. Multivariable weighted logistic regression was used to evaluate the association between birth weight and overweight. All prevalent cases of overweight (n = 160) were selected to compose the case group and a random sub-sample of all students participating in the study (n = 276 students, of whom 88 were cases) were the control group.

RESULTS

An unadjusted 6% increase in the excess weight prevalence ratio (p-value = 0.004) was found for each 100 g increase in birth weight. With adjustment for age, sex and behavioral variables (models 1 and 2), the association of birth weight with excess weight was positive and statistically significant, but it was no longer significant in the final model (model 3) when clinical variables were considered.

CONCLUSIONS

Although some of the secondary associations were statistically significant, we could not identify a significant association between birthweight and excess weight in adolescents.

Validade da informação sobre o peso ao nascer para estudos fundamentados na programação fetal

Peso ao nascer é uma informação essencial nos estudos de programação fetal e, em geral, obtida retrospectivamente. No Sistema de Informações sobre Nascidos Vivos (SINASC), peso ao nascer é uma informação válida, mas nem sempre acessível. Objetivou-se estabelecer um algoritmo para seleção da fonte de dados de maior confiabilidade do peso ao nascer na ausência da informação do SINASC. No estudo seccional de estudantes de 6-14 anos, Niterói, Rio de Janeiro, Brasil, 2010, peso ao nascer foi coletado por meio de questionário de autopreenchimento, entrevista, prontuários do Programa Médico de Família (PMF), além do SINASC. Foram calculados coeficientes de correlação intraclasse (CCI) e diferenças das médias de peso ao nascer. CCIs variaram de 0,90 a 0,99. Todas as fontes apresentaram médias de peso ao nascer maiores do que SINASC, considerando-se aceitáveis diferenças até 100g. O peso ao nascer é registrado no nascimento (SINASC) ou próximo deste (PMF) e, na ausência dessas fontes, a lembrança do peso ao nascer de 6-14 anos após o nascimento é uma opção confiável. Para complementar a informação sobre peso ao nascer na ausência do SINASC, recomenda-se a seguinte ordenação: PMF, entrevista e questionário.