1
|
Scott HA, Ng SH, McLoughlin RF, Valkenborghs SR, Nair P, Brown AC, Carroll OR, Horvat JC, Wood LG. Effect of obesity on airway and systemic inflammation in adults with asthma: a systematic review and meta-analysis. Thorax 2023; 78:957-965. [PMID: 36948588 DOI: 10.1136/thorax-2022-219268] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2022] [Accepted: 02/25/2023] [Indexed: 03/24/2023]
Abstract
BACKGROUND Obesity is associated with more severe asthma, however, the mechanisms responsible are poorly understood. Obesity is also associated with low-grade systemic inflammation; it is possible that this inflammation extends to the airways of adults with asthma, contributing to worse asthma outcomes. Accordingly, the aim of this review was to examine whether obesity is associated with increased airway and systemic inflammation and adipokines, in adults with asthma. METHODS Medline, Embase, CINAHL, Scopus and Current Contents were searched till 11 August 2021. Studies reporting measures of airway inflammation, systemic inflammation and/or adipokines in obese versus non-obese adults with asthma were assessed. We conducted random effects meta-analyses. We assessed heterogeneity using the I2 statistic and publication bias using funnel plots. RESULTS We included 40 studies in the meta-analysis. Sputum neutrophils were 5% higher in obese versus non-obese asthmatics (mean difference (MD)=5.0%, 95% CI: 1.2 to 8.9, n=2297, p=0.01, I2=42%). Blood neutrophil count was also higher in obesity. There was no difference in sputum %eosinophils; however, bronchial submucosal eosinophil count (standardised mean difference (SMD)=0.58, 95% CI=0.25 to 0.91, p<0.001, n=181, I2=0%) and sputum interleukin 5 (IL-5) (SMD=0.46, 95% CI=0.17 to 0.75, p<0.002, n=198, I2=0%) were higher in obesity. Conversely, fractional exhaled nitric oxide was 4.5 ppb lower in obesity (MD=-4.5 ppb, 95% CI=-7.1 ppb to -1.8 ppb, p<0.001, n=2601, I2=40%). Blood C reactive protein, IL-6 and leptin were also higher in obesity. CONCLUSIONS Obese asthmatics have a different pattern of inflammation to non-obese asthmatics. Mechanistic studies examining the pattern of inflammation in obese asthmatics are warranted. Studies should also investigate the clinical relevance of this altered inflammatory response. PROSPERO REGISTERATION NUMBER CRD42021254525.
Collapse
Affiliation(s)
- Hayley A Scott
- School of Biomedical Sciences and Pharmacy, The University of Newcastle, Callaghan, New South Wales, Australia
- Immune Health Research Program, Hunter Medical Research Institute, New Lambton Heights, New South Wales, Australia
| | - Shawn Hm Ng
- School of Medicine and Public Health, The University of Newcastle, Callaghan, New South Wales, Australia
| | - Rebecca F McLoughlin
- School of Nursing and Midwifery, The University of Newcastle, Callaghan, New South Wales, Australia
- National Health and Medical Research Council, Centre of Excellence in Treatable Traits, New Lambton Heights, New South Wales, Australia
- Asthma and Breathing Research Program, Hunter Medical Research Institute, New Lambton Heights, New South Wales, Australia
| | - Sarah R Valkenborghs
- School of Biomedical Sciences and Pharmacy, The University of Newcastle, Callaghan, New South Wales, Australia
- Active Living Research Program, Hunter Medical Research Institute, New Lambton Heights, New South Wales, Australia
| | - Parameswaran Nair
- Division of Respirology, McMaster University and St Joseph's Healthcare, Hamilton, Ontario, Canada
| | - Alexandra C Brown
- School of Biomedical Sciences and Pharmacy, The University of Newcastle, Callaghan, New South Wales, Australia
- Immune Health Research Program, Hunter Medical Research Institute, New Lambton Heights, New South Wales, Australia
| | - Olivia R Carroll
- School of Biomedical Sciences and Pharmacy, The University of Newcastle, Callaghan, New South Wales, Australia
- Immune Health Research Program, Hunter Medical Research Institute, New Lambton Heights, New South Wales, Australia
| | - Jay C Horvat
- School of Biomedical Sciences and Pharmacy, The University of Newcastle, Callaghan, New South Wales, Australia
- Immune Health Research Program, Hunter Medical Research Institute, New Lambton Heights, New South Wales, Australia
| | - Lisa G Wood
- School of Biomedical Sciences and Pharmacy, The University of Newcastle, Callaghan, New South Wales, Australia
- Immune Health Research Program, Hunter Medical Research Institute, New Lambton Heights, New South Wales, Australia
| |
Collapse
|
2
|
Thompson CA, Eslick SR, Berthon BS, Wood LG. Asthma medication use in obese and healthy weight asthma: systematic review/meta-analysis. Eur Respir J 2021; 57:13993003.00612-2020. [PMID: 32943399 DOI: 10.1183/13993003.00612-2020] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2020] [Accepted: 08/31/2020] [Indexed: 12/17/2022]
Abstract
BACKGROUND Obesity is a common comorbidity in asthma and associated with poorer asthma control, more frequent/severe exacerbations, and reduced response to asthma pharmacotherapy. OBJECTIVE This review aims to compare use of all classes of asthma medications in obese (body mass index (BMI) ≤30 kg·m-2) versus healthy-weight (BMI <25 kg·m-2) subjects with asthma. DESIGN Databases including CINAHL (Cumulative Index to Nursing and Allied Health Literature), Cochrane, Embase and MEDLINE were searched up to July 2019 for English-language studies that recorded medication use or dose in obese and healthy-weight adults with asthma. A critical appraisal checklist was utilised for scrutinising methodological quality of eligible studies. Meta-analysis was performed and heterogeneity was examined with the use of the Chi-squared test. This review was conducted based on a published protocol (www.crd.york.ac.uk/PROSPERO CRD42020148671). RESULTS Meta-analysis showed that obese subjects are more likely to use asthma medications, including short-acting β2-agonists (OR 1.75, 95% CI 1.17-2.60; p=0.006, I2=41%) and maintenance oral corticosteroids (OR 1.86, 95% CI 1.49-2.31; p<0.001, I2=0%) compared to healthy-weight subjects. Inhaled corticosteroid (ICS) dose (µg·day-1) was significantly higher in obese subjects (mean difference 208.14, 95% CI 107.01-309.27; p<0.001, I2=74%). Forced expiratory volume in 1 s (FEV1) % predicted was significantly lower in obese subjects (mean difference -5.32%, 95% CI -6.75--3.89; p<0.001, I2=42%); however, no significant differences were observed in FEV1/forced vital capacity (FVC) ratio between groups. CONCLUSIONS We found that obese subjects with asthma have higher use of all included asthma medication classes and higher ICS doses than healthy-weight asthma subjects, despite lower FEV1 and a similar FEV1/FVC %. A better understanding of the factors driving increased medication use is required to improve outcomes in this subgroup of asthmatics.
Collapse
Affiliation(s)
- Cherry A Thompson
- Priority Research Centre for Healthy Lungs, Hunter Medical Research Institute, School of Biomedical Sciences and Pharmacy, Faculty of Health and Medicine, University of Newcastle, Callaghan, Australia
| | - Shaun R Eslick
- Priority Research Centre for Healthy Lungs, Hunter Medical Research Institute, School of Biomedical Sciences and Pharmacy, Faculty of Health and Medicine, University of Newcastle, Callaghan, Australia
| | - Bronwyn S Berthon
- Priority Research Centre for Healthy Lungs, Hunter Medical Research Institute, School of Biomedical Sciences and Pharmacy, Faculty of Health and Medicine, University of Newcastle, Callaghan, Australia
| | - Lisa G Wood
- Priority Research Centre for Healthy Lungs, Hunter Medical Research Institute, School of Biomedical Sciences and Pharmacy, Faculty of Health and Medicine, University of Newcastle, Callaghan, Australia
| |
Collapse
|