Maternal diet in pregnancy and child's respiratory outcomes: an individual participant data meta-analysis of 18 000 children.

RATIONALE Severe fetal malnutrition has been related to an increased risk of respiratory diseases later in life, but evidence for the association of a suboptimal diet during pregnancy with respiratory outcomes in childhood is conflicting. We aimed to examine whether a pro-inflammatory or low-quality maternal diet during pregnancy was associated with child's respiratory health. METHODS We performed an individual participant meta-analysis among 18 326 mother-child pairs from seven European birth cohorts. Maternal pro-inflammatory and low-quality diet were estimated by energy-adjusted Dietary Inflammatory Index (E-DIITM) and Dietary Approaches to Stop Hypertension (DASH) scores. Preschool wheezing and school-age asthma were measured by questionnaires and lung function by spirometry. RESULTS After adjustment for lifestyle and sociodemographic factors, we observed that a higher maternal E-DII score (a more pro-inflammatory diet) during pregnancy was associated only with a lower FVC in children (Z-score difference (95% confidence interval (CI)): -0.05 (-0.08, -0.02), per IQR increase). No linear associations of the maternal E-DII or DASH score with child's wheezing or asthma were observed. When exploratively examining the extremes, a very low DASH score (<10th percentile) (a very low dietary quality) was associated with an increased risk of preschool wheezing and a low FEV1/FVC (z-score <-1.64) (OR (95% CI) 1.20 (1.06, 1.36), 1.40 (1.06, 1.85), compared to ≥10th percentile), with corresponding population attributable risk fractions of 1.7% and 3.3%. CONCLUSION Main results from this individual participant data meta-analysis do not support the hypothesis that maternal pro-inflammatory or low-quality diet in pregnancy are related to respiratory diseases in childhood.