Associations between post natal weight gain, change in post natal pulmonary function, formula feeding and asthma

Abstract

Objectives. This study examined factors that might influence lung function during infancy and tested the hypothesis that change in weight during infancy is negatively associated with change in lung function.

Patients and methods. Weight, length and maximal flow at functional residual capacity (V’maxFRC) were measured at ages one and 12 months. V’maxFRC was adjusted for length. Asthma symptoms and age at introduction of formula feeds were identified from questionnaires. Groups were dichotomised by V’maxFRC at one month and change in V’maxFRC.

Results. There were 154 infants assessed at ages one and 12 months. Change in V’maxFRC was inversely associated with change in weight (p<0.001). The group with lower V’maxFRC at one month and reduced change in V’maxFRC over infancy had greatest weight gain (p=0.004) and increased risk for asthma symptoms by three years (p=0.017) but not afterwards., Exclusive breast feeding to six months was associated with a mean reduction in weight gain at age 12 months in comparison with earlier introduction of formula milk (mean difference 0.65kg, p=0.001), and was also associated with reduced asthma symptoms at three years (odds ratio 0.44 p=0.043) but not at six or 11 years of age

Conclusions. Weight gain in infancy was inversely associated with change in lung function during infancy. Post natal weight gain may be indirectly associated with early transient asthma symptoms via an influence on lung growth during infancy, and this potentially modifiable by breast feeding. These associations could be relevant to the clinically recognised syndrome of the “fat happy wheezer”.