the association between antioxidant status and excess weight in children: a systematic review and meta-analysis

Background: the prevalence of childhood obesity with its complications has increased inthe world. obesity, along with antioxidants deficiency (due to an unhealthy diet), mightchange the balance in favor of oxidative stress.objectives: the current study aims to assess the literature on the relationship betweenobesity and antioxidant status through a systematic review and meta-analysisresults: β-carotene levels was significantly lower in obese children than non-obese ones(mean difference: 0.13, 95%ci: 0.09-0.16, p<0.001), with significant heterogeneity (p<0.001,i^2=85%). there was a significant difference between obese and non-obese children in bothα-tocopherol (pooled mean difference respectively: 0.36, 95% ci: 0.04-0.96, p<0.001 ) withnon-significant heterogeneity (p>0.05, i2=0.0% ) and α-tocopherol per lipoid (pooled meandifference: 0.42, 95%ci: 0.28-0.55, p<0.001), with significant heterogeneity (p=0.048,i^2=58.8%). there was no significant association between vitamin e level and obesity(pooled mean difference: 0.40, 95%ci: -0.05-0.85, p>0.05), with significant heterogeneity(p<0.001, i^2=84.5%). there was significant association between zinc, magnesium, copper,and selenium level and obesity (p>0.05), with significant heterogeneity (p<0.001).conclusions: this review revealed a significant inverse relationship between childhoodobesity and serum antioxidant levels. more studies are necessary to find the underlyingmechanisms and clinical impacts of this finding. data sources: this systematic review andmeta-analysis were performed among english language articles published until september2020 without any time limit. an electronic search was conducted in international databasesof google scholar, pubmed, web of science, scopus, medline, and cochrane. studyselection: first, 1255 papers were found. after removing duplicates and quality assessment,46 were used in the systemic review, and 19 articles were entered into the meta-analysis.data extraction: two researchers independently searched the following keywords inthe databases: “vitamin c”, “vitamin e”, “vitamin a”, “carotenoids”, “antioxidants”,“selenium”, “magnesium”, “copper”, “zinc”, “ascorbic acid”, “tocopherol”, “obesity”,“overweight”, “childhood”, “pediatric”, and “adolescence”. articles that examined the association between obesity and antioxidant status were included in the study. theresearch on animals, interventional studies, case studies, case reports, and irrelevantstudies were excluded. the research team determined the quality of studies using thestrobe (strengthening the reporting of observational studies in epidemiology) checklist.heterogeneity of studies was evaluated using index (i^2) and probability of diffusion bias byfunnel plot and begg’s and egger’s tests.