A child's body weight pattern is closely linked to long-term health, and a recent study adds further evidence, highlighting its impact on lung function. Researchers found that both high and low BMI values during the critical years of lung development can have lasting harmful effects.

According to researchers from the Karolinska Institutet in Sweden, a child's lung development begins in the womb and lasts through childhood. Managing the BMI during the period at optimal levels can reduce lung function issues.

The study involved 3,200 children from the BAMSE project whose BMI measurements were taken at least four times during childhood. Using spirometry tests, the researchers measured the participants' lung function at ages 8, 16, and 24, assessing lung strength based on the volume of air exhaled and inhaled. They also analyzed urine samples of the participants to study the substances metabolized in the body.

"In this study, the largest so far, we've been able to follow children from birth all the way to the age of 24, covering the entire period of lung function development," said lead investigator Gang Wang in a news release.

During the analysis, the participants were found to fit into six distinct BMI development groups. Those children with a high or increasing BMI had impaired lung function as adults compared to normal BMI. This is due to restricted airflow in the lungs. Urine analysis revealed that higher BMI was also linked to elevated levels of metabolites of the essential amino acid histidine, a pattern similar to people with lung issues such as asthma and chronic obstructive pulmonary disease.

Another interesting finding was that even a low BMI trend during childhood was linked to reduced lung function later in life. The researchers attribute it to inadequate lung growth.

"In our cohort, the persistently high and accelerated increasing BMI groups were associated with obstructive lung function pattern and small airway dysfunction. Having a persistently low BMI was associated with a restrictive pattern. Thus, maintenance of normal somatic growth patterns may lead to improved lung health during childhood," the researchers wrote in the study published in the European Respiratory Journal.

"This highlights how important it is to optimize children's growth both early in life and during their early school years and adolescence," said principal investigator Dr. Erik Melén.

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