Effects Of Supplementation With N-3 Fatty Acids During Pregnancy On Asthma Of Children:A Dose-response Meta-analysis

Background:The incidence of the asthma and wheeze has risen dramatically over recent decades.It aggravates the economic burden on families and society,depressing the life quality of the children.Consequently,prevention for pediatric asthma/wheeze(asthma or wheeze)has been increasingly emphasized.It was reported that increasing prenatal omega-3 fatty acids(n-3 FA)consumption might modify allergen-specific immune responses and reduce the risk of allergic diseases.Previous meta-analysis evaluated the effects of n-3 FA during pregnancy on the incidence of allergic disease with small number of studies,but did not analyze the effects of n-3 FA during pregnancy on the incidence of childhood asthma.Furthermore,some results were inconsistent with newly published evidence.Object:To update and conclude the evidence about the effects of n-3 FA during pregnancy on the incidence of wheeze and asthma of children.Methods:A search was conducted in PubMed,Embase and CENTRAL until September 2017.Randomized controlled trials(RCTs)assessing the effects of n-3 FA during pregnancy on wheeze/asthma of children were included.Two investigators independently searched articles,extracted data,and assessed the quality of included studies.The relative risks(RR)and 95%confidence interval(95%CI)of wheeze and asthma in children were pooled.Subgroup analyses and dose-response analysis were conducted if data were sufficient.The meta-analysis was performed using RevMan 5.3 and the Stata 12.0.Results:Six RCTs involving 2047 children were included.The pooled data revealed the supplementation during pregnancy reduced the incidence of wheeze/asthma(RR 0.81;95%CI 0.66-0.99;p=0.04),but the incidence of childhood asthma was not significantly reduced(RR 0.89;95%CI 0.67-1.17;p=0.40).Dose-response analysis indicated there is a non-linear relationship between the supplementation of n-3 FA and the incidence of wheeze/asthma.The higher the dose,the lower the incidence within certain range.Subgroup analyses indicated that the risk of childhood wheeze/asthma was significantly decreased(1)in studies located in Europe(RR 0.67;95%CI0.51-0.88),(2)in children whose first-degree relatives were diagnosed with allergic disease(RR 0.65;95%CI 0.49-0.85),(3)when a dose of n-3 FA>2000 mg/d was applied(RR 0.61;95%CI 0.45-0.81),(4)in wheeze/asthma without sensitivity(RR 0.71;95%CI 0.54-0.94).Conclusion:The available evidence indicated that n-3 FA supplementation during pregnancy may reduce the incidence of wheeze/asthma of children,but incidence of asthma was not reduced.More well-designed RCTs with large sample sizes need to be conducted to better understand the effectiveness of n-3 FA supplementation during pregnancy with asthma in childhood.