Comparação do estado nutricional de vitamina E entre recém-nascidos termo e pré-termo: uma revisão sistemática e meta-análise

Abstract

Vitamin E deficiency (VED) is associated with several clinical findings in newborns, such as pulmonary bronchodysplasia, retinopathy of prematurity and intracranial hemorrhage. These complications are studied in preterm newborns (PTNB) (< 37 weeks), but low circulating levels of the vitamin were also found in term newborns (TNB). As an inadequacy of vitamin E in the neonatal phase can also compromise cognitive health in childhood, studies are needed to assess whether there is a difference in the nutritional status of vitamin E of newborns according to the gestational age of delivery, to provide support for the protocols of monitoring of neonatal health. Thus, the aim of this study was to compare the vitamin E nutritional status between preterm and full-term newborns. This is a systematic review and metaanalysis based on the Preferred Reporting Items for Systematic Review and Metaanalysis, which included original cross-sectional, case-control and cohort studies in all languages. As eligibility criteria, the analysis of serum/plasma alpha-tocopherol concentration in newborns was adopted, including PTNB and/or TNB and type of observational study. The databases used for the research were PubMed, Medline, EMBASE, Web of Science, SciELO and Capes Periodicals for thesis and dissertation. All data were analyzed and extracted by two independent reviewers. The assessment of methodological quality was performed using the Newcastle-Otawa Scale tool. Mean differences and confidence intervals (95%CI) were calculated using the R software. The revision was registered in PROSPERO under registration CRD42021165152. In the systematic review, 1809 articles were found, and at the end of the search 9 were eligible for the review, with a population of newborns between 14 and 235 evaluated, 04 cohort studies, 04 cross-sectional studies and 01 case-control. Only 03 studies were included in the meta-analysis for using a standardized method for the analytical determination of alpha-tocopherol, for containing information on the mean and standard deviation of alpha-tocopherol and for having performed the analysis in both the PTNB and the TNB. The studies showed high heterogeneity, explained by the sample size, mean serum vitamin E levels and risk of bias. More than 90% of cases were classified with VED in both groups. In the final model, 166 PTNB and 194 TNB were included, with no significant differences found in the means of alpha-tocopherol concentration between the groups (-0.15 [CI 95% -0.72; 0.42], p = 0.61). Despite the need for further studies on the topic, these results demonstrate that regardless of the gestational age at birth, both newborns may have similar vitamin E status, and it is necessary to assess whether these low levels are maintained during the postnatal phase or are transient due to increased use of vitamin E during the birth.