To evaluate the relationship between high adherence to the Mediterranean diet in pregnancy and childhood and the risk of asthma and wheeze in children.
We conducted searches of PubMed, EMBASE, and Cochrane Central Register of Controlled Trials from inception to 30 October 2018. Observational studies providing risk estimates and corresponding confidence intervals on the association of high adherence to the Mediterranean diet in pregnancy or childhood and the risk of asthma or wheeze in childhood were included. The methodological quality of all included studies was assessed. Summary odds ratios (OR) were calculated using a random-effects model.
Eighteen observational studies were included in this review. All studies were of moderate to high quality. The pooled data suggested high adherence to the Mediterranean diet during pregnancy was associated with a reduced incidence of wheeze in the first 12 months (OR, 0.92; 95% confidence interval [CI], 0.88-0.95; P < 0.001), and there was an inverse association between the Mediterranean diet during childhood and the incidence of wheeze in the history (OR, 0.51; 95% CI, 0.37-0.70; P = 0.001) and current wheeze (OR, 0.97; 95% CI, 0.95-0.99; P = 0.013). However, there was no significant association between high adherence of the Mediterranean diet in pregnancy and childhood and any of the other meta-analysis end points including diagnosed asthma.
High adherence to the Mediterranean diet during pregnancy and childhood may have short-term effects on wheeze in children in early life. However, these findings should be interpreted with caution owing to the heterogeneity of the studies.