Childhood to early adulthood BMI changes can negatively impact lung function

Key takeaways:

• Individuals with BMIs that did not end up within a normal range at age 24 years faced poorer lung function measures.
• A normal BMI in childhood could be important for future lung health.

From birth to 24 years, individuals who ended up with high or low BMIs had reduced lung function, whereas those who ended up with a normal range BMI did not have this outcome, according to results published in European Respiratory Journal.

“An abnormal BMI in childhood — whether high or low — can be linked to impaired lung function,” Gang Wang, MD, PhD, researcher in the department of clinical science and education at Karolinska Institutet, told Healio. “However, if BMI normalizes before adulthood, this impairment may be mitigated.

“These findings suggest that early interventions to help children achieve a normal BMI could positively impact lung health in later life,” Wang continued.

In a prospective study, Wang and colleagues analyzed 3,204 individuals followed from birth to age 24 years in the Swedish BAMSE (Swedish abbreviation for Child [Barn], Allergy, Milieu, Stockholm, Epidemiological study) cohort to uncover the impact of childhood and early adulthood BMI development on lung function development via pre-bronchodilator spirometry (recorded at ages 8, 16 and 24 years), post-bronchodilator spirometry, multiple-breath nitrogen washout and urinary metabolomics data (all three recorded at age 24 years).

Each individual had at least four BMI z-scores tracking how their BMI developed, which researchers used to divide the cohort into six groups.

The group with the most individuals was made up of those with stable normal BMI (n = 1,608), followed by those with above normal BMI (n = 721), persistent low BMI (n = 450), accelerated increasing BMI (n = 209), accelerated resolving BMI (n = 142) and persistent high BMI (n = 74).

Between those with stable normal BMI and those with accelerated increasing BMI defined as “high BMI at an early age, consistently high during childhood, accelerating further in adolescence,” researchers found a lower pre-bronchodilator FEV₁/FVC ratio z-score in the accelerated increasing group at age 24 years (beta = –0.26). The same was true for post-bronchodilator FEV₁/FVC ratio z-score (beta = –0.22).

In terms of lung clearance index (LCI), this measure was higher at age 24 years among individuals classified under accelerated increasing BMI vs. stable normal BMI (beta = 0.3), according to researchers.

During the evaluation of those with a persistent high BMI, defined as “normal BMI at an early age, increased in childhood and persistently increasing in later follow-up,” vs. those with stable normal BMI, lung function growth was decreased between ages 16 and 24 years (beta FEV₁ z-score = –0.24; beta FVC z-score = –0.27).

Similar to above, researchers additionally observed a higher LCI at 24 years among individuals with a persistent high BMI (beta = 0.2).

Switching to focus on those with an accelerated resolving BMI or a “low BMI at an early age, increased in childhood but subsequently resolved to normal range” revealed differing results, according to researchers.

“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,” Wang told Healio. “This highlights how important it is to optimize children’s growth both early in life and during their early school years and adolescence.”

Between ages 8 and 24 years, researchers found reduced measures of FEV₁ and FVC among those with persistent low BMI meaning “normal BMI at an early age, persistently low in later follow-up” vs. stable normal BMI. Lung function growth was also lower in the persistent low BMI group.

Using urinary metabolomics data, a significant link between histidine-related metabolites and pre-bronchodilator FEV₁ was revealed, as was a significant link between histidine-related metabolites and post-bronchodilator FEV₁, according to researchers.

“In the current study, we found that several metabolites that were detected in urine interacted with an accelerated increasing BMI profile to influence the FEV₁ and FVC, and with persistent high BMI to influence small airways,” Wang told Healio. “Future studies should be designed to explore multiple layers such as genetics, epigenomics, transcriptomics, metabolomics and more.”

Reference:

• Children’s BMI can affect their future lung function. https://news.ki.se/childrens-bmi-can-affect-their-future-lung-function. Published Oct. 28, 2024. Accessed Oct. 29, 2024.

For more information:

Gang Wang, MD, PhD, can be reached at wanggang-cn@foxmail.com.