TOPLINE

Adults with coexisting asthma and diabetes exhibited the most adverse cardiometabolic and inflammatory biomarker profiles compared with those with neither condition or either condition alone. Formal interaction analysis revealed that the two conditions did not multiply each other’s impact on those measures.

METHODOLOGY

• When asthma and diabetes occur together, they identify people at a higher risk for heart disease, metabolic disorders, and poor glycemic control because both involve chronic low‑grade inflammation. Although studies suggest that the two may influence each other, most prior research has been small or focused on single outcomes.
• Researchers conducted a cross-sectional analysis of 5295 nonpregnant adults aged 20-85 years from the National Health and Nutrition Examination Survey (NHANES) 2015-2020 in the US who had complete fasting data (≥ 8 hours).
• Participants were categorized into the following four mutually exclusive groups based on joint asthma-diabetes status: neither condition (77.0%), asthma only (7.0%), diabetes only (14.1%), or both conditions (1.9%).
• Current asthma was defined by affirmative responses to both a prior physician diagnosis and still having asthma at the time of the survey; diabetes was defined as a self-reported physician diagnosis or current use of insulin or oral glucose-lowering medications.
• Cardiometabolic and inflammatory biomarkers, including fasting plasma glucose, A1c, insulin resistance, lipid profiles, high-sensitivity C-reactive protein (hs-CRP), systemic immune-inflammation index, and systemic inflammation response index (SIRI), were assessed using standardized NHANES laboratory protocols.

TAKEAWAY

• Adults with diabetes alone had substantially worse blood glucose, insulin resistance, and lipid measures than those with neither condition (P < .001 for all); asthma alone was not linked to worse glycemia but was associated with a higher triglyceride‑glucose index, inflammatory cell indices, and slightly higher systolic blood pressure.
• Compared with participants with neither condition, those with both asthma and diabetes had higher fasting glucose levels (beta-coefficient, 58.86 mg/dL; P < .001), A1c levels (beta-coefficient, 1.70%; P < .001), insulin resistance (beta-coefficient, 5.93; P < .001), triglyceride levels (beta-coefficient, 0.35; P < .01), and hs-CRP levels (beta-coefficient, 0.74; P < .001).
• Multiplicative interaction tests showed no evidence of interaction between asthma and diabetes for glycemic or insulin resistance outcomes including fasting glucose (P for interaction = .235), A1c (P for interaction = .248), and insulin resistance (P for interaction = .432), with significant interactions limited to high-density lipoprotein cholesterol (P for interaction = .039) and SIRI (P for interaction = .003), both reflecting subadditive effects.
• Patients with both asthma and diabetes had the highest predicted fasting glucose levels (about 159 mg/dL) and A1c levels (7.07%), followed by those with diabetes alone (151.3 mg/dL and 6.9%, respectively); however, the asthma alone group looked like the group with neither condition.

IN PRACTICE

“[The study] findings support intensified glycaemic monitoring in this population, including consideration of continuous glucose monitoring (CGM), particularly during periods of systemic corticosteroid use,” the authors wrote.

SOURCE

The study was led by Sixtus Aguree, Department of Applied Health Science, School of Public Health-Bloomington, Indiana University, Bloomington, Indiana. It was published online in Diabetes, Obesity and Metabolism.

LIMITATIONS

The cross-sectional design precluded causal inference, and the observed associations may have reflected preexisting susceptibility differences, reverse causality, or shared upstream determinants rather than consequences of comorbidity. Asthma and diabetes status were based on self-report and medication use. The diabetes definition did not distinguish between subtypes.

DISCLOSURES

The authors reported having no relevant conflicts of interest or funding sources for this study.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.