Results
Thirty-one studies were identified (16 cross-sectional, one case-control, 13 cohort, and one randomized controlled trial), including 12 in adults, 13 in children, five in pregnant woman–child pairs, and one in both children and pregnant woman–child pairs. Six of the 12 adult studies reported significant associations between dietary patterns and asthma outcomes (eg, ever asthma and forced expiratory volume in one second). Seven of ten studies examining the Mediterranean diet showed protective effects on child asthma and/or wheeze. Four of the six studies in mother-child pairs showed that maternal dietary patterns during pregnancy were not associated with child asthma or wheeze. The meta-analysis including six adult studies, the primary outcome of which was the prevalence of current or ever asthma, showed no association with healthy, unhealthy, or neutral dietary patterns.