
Children who have a body mass index (BMI) that is above or below normal range are more likely to develop lung impairment as adults. Researchers at the Karolinska Institutet (KI) in Sweden confirmed the association in a new study published in European Respiratory Journal.
Results of the study demonstrated abnormal height and weight early in life can directly impact lung function development into adulthood. This is a significant risk factor since one in 10 people have less lung function development in childhood. In these cases, individuals aren’t able to achieve maximal lung capacity as adults, which can lead to serious health problems such as lung disease, cardiovascular disease or diabetes.
The research group analyzed data collected in the Swedish BAMSE project, which followed more than 4,000 children from birth to age 24. Participants’ BMIs were measured regularly, with 3,200 individuals having at least four BMI measurements in that timeframe.
The researchers divided participants into several BMI groups and used spirometry to measure lung function at three age intervals: 8, 16 and 24. At the end of the project, they also measured participants’ function of the smaller airways by capturing the volume of exhaled nitrogen.
Children whose BMI was consistently high or increasing at a steep rate were often diagnosed with impaired lung function (restricted or obstructed airflow) as adults. A regularly low BMI was also linked to reduced lung function due to insufficient lung growth.
“The focus has been on overweight, but we also need to capture children with a low BMI and introduce nutritional measures,” said first author, Gang Wang, PhD, in a news release. Dr. Wang is a researcher at the Department of Clinical Science and Education at KI.
By better understanding the relationship between height and weight and lung function, and identifying who is at risk, the researchers said health care professionals should intercede and provide treatment options. Children whose BMI normalized during the course of the study saw improvement in lung development and function.
“Interestingly, we found that in the group with an initially high BMI but a normalized BMI before puberty, lung function was not impaired in adulthood,” said principal investigator Erik Melén, MD, PhD, professor of pediatrics at KI and pediatric allergist at Sachs’ Children and Youth Hospital in Stockholm, Sweden. “This highlights how important it is to optimize children’s growth both early in life and during their early school years and adolescence.”
Craig Wheelock, PhD, from KI’s Institute of Environmental Medicine, also collected urine samples from study participants to examine which substances they were metabolizing. Dr. Wheelock reported that those in the high BMI group had elevated levels of metabolites of the amino acid histidine. This finding corresponds to similar observations of patients with high BMI who develop asthma or COPD.