Infant weight gain raises risk for school-age asthma
MedWire News: School-age children are significantly more likely to be diagnosed with asthma if they have an increased rate of weight gain during infancy, German researchers have discovered.
Studies that have found a link between obesity and asthma have tended to be cross-sectional, from which causality cannot be established. However, there is evidence to suggest that obesity is linked to later risk for asthma in childhood and adolescence, as well as in adulthood.
To examine the link between weight gain in infancy and asthma and wheeze in childhood, Joachim Heinrich, from the German Research Centre for Environmental Health, Neuherberg, and colleagues studied data from the German Infant Nutritional Intervention plus environmental and genetic influences on allergy development (GINIplus) and Influences of Lifestyle-Related Factors on the Immune System and the Development of Allergies in Childhood plus Air Pollution and Genetics (LISAplus) studies, yielding a total of 9086 children.
Using a modified Reed1 model, the team calculated height and weight growth curves through to 2 years of age. In addition, they determined the presence of asthma or wheeze at 1, 2, 4, 6, and 10 years of age. A set of potential confounding factors was also defined.
At 10 years of age, the prevalence of wheeze was twice that of asthma, at 7.94% versus 3.45%. The average peak weight velocity (PWV) was 13.00 kg/year, while the mean peak height gain (PHV) was 44.05 cm/year. The mean age at PWV and PHV was 0.54 months and 0.74 months, respectively.
After adjusting for gender, parental education, parental atopy, breastfeeding, number of siblings, maternal smoking during pregnancy, and study center, the team found that PWV was significantly associated with asthma, at a hazard ratio of 1.26. The relationship remained significant after further adjustment for birthweight and body mass index at age 10 years, at a hazard ratio of 1.22.
The researchers note in the journal Allergy that PHV was not significantly associated with physician-diagnosed asthma, and neither PWV nor PHV were significantly associated with the risk for wheeze.
They say: "To the best of our knowledge, there is no specific mechanism for the association between weight gain and the development of asthma in childhood so far.
"However, one might speculate that experience of illness in early childhood might have an effect on delayed growth and rapid growth after recovery. Consequently, peak velocities of growth might be also considered as proxy of severe diseases in childhood."
By Liam Davenport