Growth Pattern During Early Infancy, Body Mass Index During Childhood and Childhood Asthma

Assess the relationship between BMI and change in body weight during infancy with the risk of developing childhood asthma.

This study included full-term, normal birth weight infants born in Korea in 2008 and 2009 (n = 271 871). The study population was followed from birth until up to 10 years of age or until they were disqualified from health insurance.

This administrative birth cohort study examined the relationships among birth weight, weight change from birth to 6 months of age, and BMI on risk of asthma diagnosis, using the National Health Insurance Service and National Health Screening Program for Infants and Children, which contained data regarding healthcare utilization, patients’ demographic characteristics, parent answered questionnaires, and height and weight. The outcome of physician-diagnosed asthma was defined as 2 or more major diagnoses of asthma separated by 1 year and after the age of 2 years and was collected by using the International Classification of Diseases, 10th Edition codes. Variables known to affect childhood asthma were adjusted for using the Cox proportional hazard regression.

Body weight at 4 to 6 months of age was divided into 3 groups: low, normal, and high.

Weight change status at infancy was also divided into 3 groups: slow, on-track, and rapid, based on changes in z-scores.

The risk of asthma was greater in those with low birth weight, rapid weight gain during early infancy, and with high BMI during childhood. For those with high BMI, rapid weight gain was associated with an increased risk of asthma. For those with low BMI, slow weight gain was associated with an increased risk of asthma. The risk of asthma diagnosis was also higher for the rapid weight change group.

The risk of childhood asthma was increased among children with low birth weight, rapid weight gain at 4 to 6 months, and higher BMI.

This study supports previous work examining early growth and childhood asthma. This study further investigates the relationship between BMI and weight change and their combined effect on prevalence of asthma. Further studies should be done to assess these findings among children of different ancestral and economic backgrounds. Future directions include studying this relationship with more specific criteria to diagnose asthma.