Effect of age, gender and body habitus upon exhaled breath volatiles in COPD and health

Abstract

Aim/Background: Chronic obstructive pulmonary disease (COPD) is a heterogeneous condition. Breathomics presents an opportunity to phenotype this heterogeneity, but how breath volatile organic compounds (VOCs) relate to age, sex and body mass index (BMI) is uncertain.

Methods: 80 subjects with moderate-to-severe COPD (male=57) and 70 healthy (male=35) were recruited in a single centre prospective study. The breath VOCs were examined using Proton Transfer Reaction-Time Flight-Mass Spectrometry (PTR-TOF-MS). Univariate spearman r correlations of the individual VOC mass channels were undertaken against age, gender and BMI in COPD or health alone and combined. P values <0.05 were considered as significant correlations.

Results: 179 mass channels were identified. The COPD and healthy subjects had a median age of 71 (50-84) versus 65 (46-73) years respectively. Median BMI was 26.7 (17.5–42) and 27.2 (20.8–51) in the COPD and healthy groups. BMI showed correlations in 108 out of 179 mass channels in patients with COPD, 6 with healthy patients and 147 when combined. Correlation was noted in 4 out of 179 channels with regards to patient age with COPD but no significant mass channels in the healthy but when combined this increased to 142 mass channels. Patient’s sex had effect in both groups alone. Patients with COPD had correlation in 151 out of 179 mass channel with healthy in 123 but this effect reduced to 34 mass channels when combined.

Conclusion: Age, BMI and sex does affect breath VOC in PTR-TOF-MS when comparing health and COPD combined.