ObjectiveTo systematically review the association between maternal folate supplementation during pregnancy and the risk of autism spectrum disorder (ASD) in the offspring.MethodsPubMed, EMbase, Web of Science, The Cochrane Library, Scopus, CNKI, WanFang Data, VIP and CBM databases were electronically searched to collect case-control and cohort studies on the association between maternal folate supplementation during pregnancy and the risk of ASD in the offspring from inception to December 2020. Two reviewers independently screened literature, extracted data and assessed the risk of bias of included studies. Meta-analysis was then performed using RevMan 5.3 and Stata 14.0 software.ResultsA total of 17 studies involving 10 812 cases and 876 241 controls were included. The results of meta-analysis showed that there was no significant association between maternal folate supplementation during pregnancy and the risk of ASD in the offspring in the total population. The subgroup analysis revealed that maternal folate supplementation during pregnancy was statistically associated with a reduced risk of ASD in the offspring in the Asian population (OR=0.71, 95%CI 0.53 to 0.96, P=0.03). However, there were no statistical correlations in European and American populations.ConclusionsCurrent evidence shows that maternal folate supplementation during pregnancy may reduce the risk of ASD in the offspring in the Asian population. Due to limited quality and quantity of the included studies, more high-quality studies are required to verify the above conclusions.
ObjectiveTo systematically review the effectiveness of breastfeeding duration and intensity in reducing the risk of overweight or obesity among offspring exposed to intrauterine hyperglycemia. MethodsThe PubMed, EMbase, Web of Science, CBM, WanFang Data, CNKI and VIP databases were electronically searched to collect observational studies on the associations of breastfeeding with the risk of overweight or obesity among offspring exposed to intrauterine hyperglycemia from inception to September 25th, 2021. Two reviewers independently screened the literature, extracted data and assessed the risk of bias of the included studies. Stata 16.0 software was used for the meta-analysis. ResultsA total of 12 657 participants from 13 observational studies were included. The results of meta-analysis showed that breastfeeding could reduce the risk of overweight or obesity among offspring exposed to intrauterine hyperglycemia (OR=0.67, 95%CI 0.53 to 0.84, P=0.001). Subgroup analysis revealed a protective effect of breastfeeding for both 1-6 months (OR=0.53, 95%CI 0.37 to 0.75, P<0.001) and ≥6 months (OR=0.56, 95%CI 0.46 to 0.69, P<0.001); however, breastfeeding shorter than one month was suggested to increase the risk of overweight or obesity (OR=2.15, 95%CI 1.41 to 3.27, P<0.001). ConclusionAvailable evidence suggests that breastfeeding for more than one month is effective in reducing the risk of overweight or obesity in offspring exposed to intrauterine hyperglycemia, and women with hyperglycemia should be encouraged to breastfeed their offspring for at least 1 month to achieve the effect. Due to the limited quantity and quality of the included studies, more high-quality studies are needed to verify the above conclusion.