Fatores determinantes da anemia ferropriva no sexto mês de vida com ênfase na reserva de ferro ao nascer e tempo de clampeamento do cordão umbilical: um estudo de coorte

• Autor(a) principal: Oliveira, Fabiana de Cássia Carvalho
• Data de Publicação: 2013
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/385
• topic: Anemia; Deficiência de ferro; Neonato; Criança; Clampeamento; Ferro; Anemia; Iron deficiency; Neonate; Children; Clamping; Iron; CNPQ::CIENCIAS DA SAUDE::NUTRICAO

Iron deficiency anemia is the most common nutritional deficiency in children at 6 to 24 months of age, due to the high demand of iron from the rapid rate of growth and expansion of erythrocyte volume. The factors that determine iron deficiency in childhood are mainly related to the speed of postnatal growth and mineral stores at birth. The delayed clamping of the umbilical cord has been recommended as an easy and low cost strategy to improve ferritin levels at birth and thus prevent anemia in infancy. The aim of this study was to evaluate factors associated with iron status in infants at six months, with emphasis on hematological parameters at birth, diet and living conditions, and to investigate the influence of time of cord clamping on the iron status at birth and at six months of age. This is a cohort study conducted in Viçosa, MG, which evaluated mother-infant pairs from birth to six months. At birth timing of cord clamping was measured and cord blood was collected. Mother and baby received nutritional assistance monthly and performed biochemical analysis on the sixth month. The parameters analyzed in child at birth and both mother and child at six months were complete blood count, serum ferritin, serum iron and C-reactive protein (CRP). Were excluded the results of ferritin in women and children with altered CRP. The bivariate analysis was given by the Student T test, Mann-Whitney, ANOVA, Kruskal-Wallis, Wilcoxon and Chi-Square, and Relative Risks were evaluated. A significance level of less than 5% was adopted to reject the null hypothesis in all tests. To estimate the influence of biological, obstetrics and socioeconomic factors on the ferritin levels at birth, analysis of multiple linear regression was proceeded. The number of children evaluated at birth was 144, and of these, 64 did the tests at six months. At birth, were excluded 15 ferritin results (n=129) and, at six months, 18 (n = 46). At birth, median ferritin was 130.3 μg/L (n=129, minimum=16,4; maximum=420,5 μg/L), the mean serum iron was 137,9 mcg/dL (n = 144, SD=39,29) and mean hemoglobin was 14,7 g/dL (n=144, SD=1,47). The median time of cord clamping was 36 seconds, ranging between 7 and 100. The bivariate analysis detected association between ferritin levels and color of the child, the timing clamping of 45 and 60 seconds, the presence of gestational diabetes and per capita income. In multivariate analysis, the variables per capita income, number of prenatal visits and length at birth contributed with 17% of the variation in ferritin levels. At sixth month, the incidence of anemia in infant at six months was 56.2% and, iron deficiency, 48.4%. Among those anemic at six months, 47.2% had iron deficiency and, among the non-anemic, 50.0% had this deficiency. Only 5.0% of the mothers were anemic and there was no association between maternal and infant anemia. At sixth month, the color of the child (RR: 3.6, 95% CI: 1,27-10.19) and earlier intake of complementary foods (RR: 4.47, 95% CI: 1,84-10.86) constituted risk factors for low ferritin levels at six months and female sex (RR: 0.63, 95% CI: 0.40- 0.98) was protection factor for anemia at this age. Anemic children at six months showed average levels of ferritin at birth lower than non-anemic (124.7 mg/L vs 170.0 mg/L, p=0.01). Children with ferritin values at birth below the 25th percentile (equivalent to 74.9 mg/L) were two times greater risk of developing anemia at six months than those with values above this percentile (RR= 2.03, 95% CI: 1.35-3.07, p=0.003). The delayed timing of clamping (60 seconds) was associated with higher levels of ferritin at six months. It is concluded that the iron stores at birth were influenced by biological, obstetric and social characteristics and, the iron stores at birth, diet and socioeconomic status are among the most significant risk factors for the development of anemia in the first half of life. Thus, tackling this deficiency should involve macrostructural changes in society, the reduction of social inequalities, improve the quality of prenatal care, breastfeeding promotion as well as the effective implementation of a criterion of delayed clamping within the guidelines of labor.