High insulin in childhood is a risk factor for developing asthma
Published: October 14, 2021
Many patients with asthma also struggle with obesity. Studies show that patients with asthma are more prone to become obese, but also that obese persons are at increased risk of developing asthma later in life. This bidirectional relationship between asthma and obesity has prompted clinicians and researchers to look for mechanisms integrating these two conditions. Insulin resistance, which is a common metabolic complication of obesity characterized by increased insulin blood levels and high blood glucose, is even more closely related with asthma risk than obesity alone. However, whether high insulin levels in fact precede and predict the development of asthma is not known.
In an original article in The Journal of Allergy and Clinical Immunology: In Practice, Carr et al. present analyses from two separate birth cohorts that investigate this relationship. The Tucson Children’s Respiratory Study enrolled healthy children between 1980-1984 and was designed to assess early-life risk factors for subsequent respiratory outcomes, with continuous follow up for more than 40 years. In this cohort, the authors found that the subsequent risk of asthma was almost doubled among children who had the highest levels of insulin at age 6, when compared with those who had lower insulin, as measured from nonfasting serum samples. The increased risk was seen throughout adolescence and adult life. These results were not affected by considering concurrent body mass index, participant characteristics, or inflammatory biomarkers of obesity.
A second analysis utilized data from the Avon Longitudinal Study of Parents and Children, a nonselected birth cohort from which a random subgroup was tested for metabolic markers at age 8, including insulin in fasting serum. Carr et al. showed a similar pattern of risk, wherein the children with the highest insulin levels at age 8 had increased risk of asthma development through adolescence. Again, body mass index and relevant inflammatory markers did not explain this relationship.
The authors conclude that increased insulin levels in early childhood may indicate a novel pathway of asthma development that is independent of obesity and obesity-related inflammation.
The Journal of Allergy and Clinical Immunology: In Practice is an official journal of the AAAAI, focusing on practical information for the practicing clinician.
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