Status de zinco e o transtorno do espectro autista em crianças e adolescentes: uma revisão sistemática

Abstract

Autism Spectrum Disorder (ASD) is a neurodevelopmental disorder and its prevalence in children and adolescents has increased over the years. Studies point to the deficiency of trace elements as one of the factors involved in the etiology of the disorder, with zinc being one of the main trace elements investigated in individuals with ASD. The aim of this study was to conduct a systematic review on the relationship between zinc status and autism in children and adolescents. The protocol of this review is registered in the International Prospective Register of Systematic Reviews (PROSPERO), with registration number: CRD42020157907. The methodological guidelines adopted are in accordance with the statement Preferred Reporting Items for Systematic reviews and Meta Analyzes (PRISMA). The selection of studies was carried out based on an active search in the Pubmed, Scopus and LILACS databases, using the search descriptors: zinc, trace elements, Biometals, Autism, children, adolescent. The evaluation of the methodological quality of the studies was performed using the Newcastle-Ottawa Scale. 41 studies were included (40 Case-controls, one Cohort) carried out in 21 countries, being the USA (19.5%), China (15%) and Russia (15%) which had the highest number of studies. The sample size ranged from 20 to 601 participants, and the age ranged from 2 to 18 years. Nine types of biological matrices were used in the evaluation of zinc concentrations, with hair (49%), serum (24%) and plasma (12%) being the most evaluated. Significant differences between the zinc concentrations of the ASD and control groups were observed in 17 studies, of which 13 (32%) had lower zinc concentrations for the ASD group. The classification of studies for methodological quality resulted in high, moderate, and low quality in 4, 17, and 20 studies, respectively. This review reveals evidence that there is no difference between zinc concentrations of children and adolescents with ASD and this same population without the disorder. However, about a third of individuals with ASD had significantly lower concentrations of zinc, possibly being related to the severity of the disorder.