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. 2018 Sep;10(5):503-515.
doi: 10.4168/aair.2018.10.5.503.

Association Between Airway Parameters and Abdominal Fat Measured via Computed Tomography in Asthmatic Patients

Min Suk Yang  1 , Sanghun Choi  2 , Yera Choi  3 , Kwang Nam Jin  4
Affiliations

Association Between Airway Parameters and Abdominal Fat Measured via Computed Tomography in Asthmatic Patients

Min Suk Yang et al. Allergy Asthma Immunol Res. 2018 Sep.

Abstract

Purpose: We aimed to investigate whether airway parameters, assessed via computed tomography (CT), are associated with abdominal fat areas and to compare the clinical characteristics of asthmatic patients with and without elevated visceral to subcutaneous fat area ratio (EV).

Methods: Asthmatic patients (aged ≥40 years) were prospectively recruited. Chest (airway) and fat areas were assessed via CT. Airway parameters, including bronchial wall thickness (WT), lumen diameter (LD), lumen area (LA), wall area (WA), total area (TA), as well as WA/TA percentage (wall area %) were measured at the apical segmental bronchus in the right upper lobe. Visceral (VFA), subcutaneous (SFA) and total (TFA) fat areas (cm²) were also measured. The correlations between abdominal fat areas and airway parameters were assessed. EV was defined as VFA/SFA ≥ 0.4.

Results: Fifty asthmatic patients were included (mean age 62.9 years; 52% female); 38% had severe asthma. Significant correlations were found between VFA and both LD and LA (r = -0.35, P = 0.01; r = -0.34, P = 0.02, respectively), and SFA and both WA and TA (r = 0.38, P = 0.007; r = 0.34, P = 0.02, respectively). Exacerbations, requiring corticosteroid therapy or ER visitation, were significantly more frequent in subjects without EV (83% vs. 34%, P = 0.05).

Conclusions: Abdominal fat is associated with asthma, according to the location of fat accumulation. In asthmatic subjects, visceral fat seems to be attributable to the bronchial luminal narrowing, while subcutaneous fat may be related to thickening of bronchial wall.

Keywords: Asthma; abdominal fat; multidetector computed tomography.

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Conflict of interest statement

There are no financial or other issues that might lead to conflict of interest.

Figures

Fig. 1
Fig. 1. Computed tomographic measurement of airway parameters at the right upper lobe apical segmental bronchus. The red and pink line is outer and inner border of the right upper lobe apical segmental bronchus, respectively. Bronchial LD, WT and WA % was estimated as 2.8 mm, 2.2 mm and 85%, respectively.
LD, lumen diameter; WT, wall thickness; WA, wall area.
Fig. 2
Fig. 2. Abdominal fat area assessed via CT in a 44-year-old man. The fat area was marked green. Abdominal TFA was calculated as 56.7 cm2 (A) and VFA as 36.6 cm2 (B).
CT, computed tomography; TFA, total fat area; VFA, visceral fat area.
Fig. 3
Fig. 3. Scatter diagrams and line of best fit showing correlation between VFA (A) or SFA (B) and airway parameters including bronchial LD, bronchial WT, bronchial LA, bronchial WA, bronchial TA and bronchial WA %.
VFA, visceral fat area; SFA, subcutaneous fat area; LD, lumen diameter; WT, wall thickness; LA, lumen area; WA, wall area; TA, total area.
See this image and copyright information in PMC

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