Maternal but not paternal BMI is associated with childhood wheeze and infant respiratory infections

Abstract

Background Children of mothers with higher body mass index (BMI) have increased wheeze risk. In utero 9programming9 might explain this. This study uses paternal BMI to assess confounding by shared postnatal environment. Relationships between maternal BMI and childhood atopy, and infant infections and lung function are also assessed. Method Data from 2034 children in the Southampton Women9s Survey birth cohort were analysed. Pre-pregnancy maternal BMI was measured and paternal BMI reported. Prospective questionnaires recorded infections before 1 year and wheeze up to 6 years of age. Lung function was measured in 143 infants. Multivariable regression analysis was used to adjust for confounders and test for association. Results Higher maternal BMI was associated with increased wheeze ever up to 6 years (RR 1.07, 95%CI 1.01-1.12) and transient wheeze before but not after 3 years (RR 1.10, 95%CI 1.03-1.17). Maternal BMI was not associated with childhood asthma or atopy. Paternal BMI was not associated with any asthma or wheeze. Higher maternal BMI was associated with increased infant cough (RR 1.07, 95%CI 1.01-1.13) and lower respiratory tract infection (LRTI) (RR 1.11, 95%CI 1.04-1.17) but not croup, ear infection, or diarrhoea or vomiting. Conclusion Higher maternal BMI is associated with transient wheeze but not asthma or atopy. Lack of association between paternal BMI and childhood wheeze, suggests lesser importance of shared postnatal than prenatal environment. Analysis of infant lung function was underpowered. However, increased risk of cough and LRTI but not of other infections provides indirect evidence that higher maternal BMI is associated with reduced airway calibre.