Association of obesity-related inflammatory pathways with lung function and exercise capacity

Respir Med. 2021 Jul;183:106434. doi: 10.1016/j.rmed.2021.106434. Epub 2021 Apr 30.

Abstract

Background: Obesity has multifactorial effects on lung function and exercise capacity. The contributions of obesity-related inflammatory pathways to alterations in lung function remain unclear.

Research question: To examine the association of obesity-related inflammatory pathways with pulmonary function, exercise capacity, and pulmonary-specific contributors to exercise intolerance.

Method: We examined 695 patients who underwent cardiopulmonary exercise testing (CPET) with invasive hemodynamic monitoring at Massachusetts General Hospital between December 2006-June 2017. We investigated the association of adiponectin, leptin, resistin, IL-6, CRP, and insulin resistance (HOMA-IR) with pulmonary function and exercise parameters using multivariable linear regression.

Results: Obesity-related inflammatory pathways were associated with worse lung function. Specifically, higher CRP, IL-6, and HOMA-IR were associated with lower percent predicted FEV1 and FVC with a preserved FEV1/FVC ratio suggesting a restrictive physiology pattern (P ≤ 0.001 for all). For example, a 1-SD higher natural-logged CRP level was associated with a nearly 5% lower percent predicted FEV1 and FVC (beta -4.8, s.e. 0.9 for FEV1; beta -4.9, s.e. 0.8 for FVC; P < 0.0001 for both). Obesity-related inflammatory pathways were associated with worse pulmonary vascular distensibility (adiponectin, IL-6, and CRP, P < 0.05 for all), as well as lower pulmonary artery compliance (IL-6 and CRP, P ≤ 0.01 for both).

Interpretation: Our findings highlight the importance of obesity-related inflammatory pathways including inflammation and insulin resistance on pulmonary spirometry and pulmonary vascular function. Specifically, systemic inflammation as ascertained by CRP, IL-6 and insulin resistance are associated with restrictive pulmonary physiology independent of BMI. In addition, inflammatory markers were associated with lower exercise capacity and pulmonary vascular dysfunction.

Keywords: Adipokines; Cardiopulmonary exercise test; Dysfunction; Inflammation; Obesity; Pulmonary function; Pulmonary vascular.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Adiponectin / metabolism
  • C-Reactive Protein / metabolism
  • Exercise Test
  • Exercise Tolerance*
  • Female
  • Hemodynamics
  • Humans
  • Inflammation
  • Inflammation Mediators / metabolism*
  • Insulin Resistance
  • Interleukin-6 / metabolism
  • Leptin / metabolism
  • Lung / physiopathology*
  • Male
  • Obesity / metabolism*
  • Obesity / physiopathology*
  • Respiratory Function Tests*
  • Signal Transduction / physiology*

Substances

  • Adiponectin
  • IL6 protein, human
  • Inflammation Mediators
  • Interleukin-6
  • Leptin
  • C-Reactive Protein