Obesity affects type 2 biomarker levels in asthma

Sharma, V., Ricketts, H. C., Steffensen, F., Goodfellow, A. and Cowan, D. C. (2023) Obesity affects type 2 biomarker levels in asthma. Journal of Asthma, 60(2), pp. 385-392. (doi: 10.1080/02770903.2022.2051548) (PMID:35260034)

Abstract

Objective: Type 2 (T2) inflammation offers a therapeutic target for biologics. Previous trials suggest obesity influences T2-biomarker levels in asthma, though have not accounted for key variables, e.g., inhaled (ICS)/oral corticosteroid (OCS) use. We hypothesized that body mass index (BMI) would affect T2-biomarker levels, after adjusting for covariates. Methods: A retrospective analysis of data from two recent local trials of 153 participants with asthma (102 difficult-to-treat, 51 mild). Measurements included BMI, fractional exhaled nitric oxide (FeNO) and eosinophils. Correlation and regression analysis were performed for each biomarker to describe their relationship with BMI. Data was analysed overall, and by asthma severity, T2-status and BMI tertile. Results: Increasing BMI was associated with reduction in FeNO when stratified by BMI tertile (25ppb lowest tertile, 18ppb highest tertile; p = 0.014). Spearmans rank showed a negative correlation between BMI and FeNO in difficult-to-treat asthma (ρ= -0.309, p = 0.002). Linear regression adjusting for sex, age, smoking, atopy, allergic/perennial rhinitis, ICS and OCS confirmed BMI as a predictor of FeNO overall (β= -2.848, p = 0.019). Eosinophils were reduced in the highest BMI tertile versus lowest in difficult-to-treat asthma (0.2x109/L, 0.3x109/L respectively; p = 0.02). Conclusions: Increasing BMI is associated with lower FeNO in asthma when adjusted for relevant covariates, including steroid use. There also appears to be an effect on eosinophil levels. Obesity, therefore, affects T2 biomarker levels with implications for disease endotyping and determination of eligibility for biologic therapy. Whether this is due to masking of underlying T2-high status or development of a truly T2-low endotype requires further research.

• Item Type: Articles
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Ricketts, Clare and Cowan, Douglas and Sharma, Dr Varun
• Authors: Sharma, V., Ricketts, H. C., Steffensen, F., Goodfellow, A., and Cowan, D. C.
• College/School: College of Medical Veterinary and Life Sciences > School of Medicine, Dentistry & Nursing
• Journal Name: Journal of Asthma
• Publisher: Taylor and Francis
• ISSN: 0277-0903
• ISSN (Online): 1532-4303
• Published Online: 08 March 2022
• Copyright Holders: Copyright © 2022 The Author(s)
• First Published: First published in Journal of Asthma 60(2):385-392
• Publisher Policy: Reproduced under a Creative Commons license