An unusual BMI in children, whether too high or too low, has now been linked to problems with lung function. However, researchers say that if a child’s BMI is normalized before they reach adulthood, these lung function issues can be reversed. This finding comes from researchers at Karolinska Institutet and is based on data from the BAMSE project in Sweden, published in The European Respiratory Journal.
An unusual BMI in children–whether elevated or reduced–has been tied to decreased lung function. Nevertheless, if a child’s BMI is brought back to normal before adulthood, lung function impairment can be mitigated, according to research from Karolinska Institutet. These findings, derived from data collected for the BAMSE project in Sweden, have been published in The European Respiratory Journal.
About 10% of children experience limited lung development and may not achieve full lung capacity as adults, which can elevate the risk for significant health issues, including heart disease, respiratory diseases, and diabetes. A key factor linked to compromised lung development is abnormal weight and height. The most widely used measurement, BMI (body mass index), accounts for weight but does not differentiate between muscle and fat.
Previous research has explored the link between BMI and lung function, but results have been inconsistent. Now, Swedish researchers have established a clear relationship when BMI is either too high or too low.
“This study, the largest of its kind, allows us to track children from birth to 24 years old, encompassing the complete lung function growth period,” states Gang Wang, the lead author and researcher at the Department of Clinical Science and Education at Södersjukhuset, Karolinska Institutet.
Importance of Early Intervention
The participants were categorized into various BMI groups, with noticeable differences appearing as early as age two. Unlike their counterparts with a normal BMI, children with a consistently high BMI or an accelerated increase in BMI showed reduced lung function as adults, mainly due to airflow limitations in the lungs, known as obstruction.
“Interestingly, we discovered that individuals who started with a high BMI but achieved a normal BMI before puberty did not experience lung function impairment in adulthood,” notes Erik Melén, the principal investigator and a professor of pediatrics at the same department at Karolinska Institutet, also a doctor at Sachs’ Children and Youth Hospital. “This underscores the necessity of fostering healthy growth in children early on and during formative school years and adolescence.”
A stable low BMI was also found to be related to compromised lung function, likely due to insufficient lung development. In these instances, BMI did not improve throughout the study.
“Much of the attention has been on overweight children, but it’s equally important to address children with low BMI and implement nutritional strategies,” Dr. Wang emphasizes.
Analysis of Extensive BMI Data
The study utilized data from the BAMSE project, which has tracked over 4,000 children from birth to the age of 24. BMI measurements were conducted multiple times, up to 14 occasions. This analysis includes 3,200 participants who had a minimum of four BMI assessments.
Lung function was assessed using spirometry at ages 8, 16, and finally at 24, where the function of the smaller airways was evaluated by measuring exhaled nitrogen volumes. Urine samples were also collected to analyze metabolized substances in collaboration with Craig Wheelock, a senior lecturer at Karolinska Institutet’s Institute of Environmental Medicine.
Identifiable Biomarkers
The urine samples from individuals in the high BMI category exhibited higher levels of metabolites from the amino acid histidine, supporting findings from other studies that reported similar increases in patients with asthma and chronic obstructive pulmonary disease.
“We are identifying objective biomarkers related to the association we’ve found, even though the exact molecular relationship between high BMI, histidine, and lung development impairment is still unknown,” explains Professor Melén.
Funding for the study came from the European Research Council, the Swedish Research Council, the Swedish Heart-Lung Foundation, Region Stockholm, and the China Postdoctoral Council. Co-author Natalia Hernandez-Pacheco has disclosed funding from the European Academy of Allergy and Clinical Immunology and the European Respiratory Society, as well as lecture fees from OMNI PREX S.L., which were not part of this research.
