Wood smoke is a risk factor for COPD in Colombia. To study its pathophysiology we determined the presence of bronchial hyperreactivity (BHR) to methacholine (MC) in women with wood smoke and cigarette COPD.
The methacholine challenge test was done according to ATS in 14 patients with stable wood smoke COPD and in 10 patients with stable cigarette COPD with FEV1 >50% (Crapo reference values). COPD was defined using ATS criteria. Spirometry was done with a V-MAX 29C (Sensormedics, Inc, Yorba Linda, CA) and MC challenge with a SM-IR dosimeter (Rosenthal). The Shapiro Wilk test was used to evaluate the normality of distributions of the variables. Parametric analyses (Students′t-test) were used to compare group means. Values of p<0.05 were considered significant.
There was no difference in the spirometric indices (FEV1 and IC) or the severity of dyspnea before and after the methacholine challenge test (maximal dose used) between the two groups. In all patients there was a ≥ 20% decrease of the FEV1, a decrease of the IC and an increase of the dyspnea score. However, there was a significant difference in the geometric mean of PC20 between the wood smoke COPD (0.26 mg/dL) and the cigarette smoke COPD (1.24 mg/dL) (p: 0.036) (TableWood smoke (n=14)Cigarette (n=10)BaselinePost MCBaselinePost MCFEV1 % pred64.3 ± 10.246.8 ± 9.864.3 ± 10.243.6 ± 5.4Fall FEV1 %−27.8 ± 6.2−28.1 ± 5.2CI % pred78.8 ± 16.360.2 ± 8.687.6 ± 20.660.9 ± 18.6Fall IC %−23.7 ± 12.9−30.6 ± 12.9Dyspnea, Borg0.58 ± 0.92.17 ± 1.80.6 ± 0.62.35 ± 2.1PC20 mg/dL*0.26 (0.06-1.9)‡1.24 (0.34-9.39)*
Geometric mean and range.‡
We found BHR in all patients but it was significantly more severe in patients with wood smoke COPD suggesting that it might be an important physiopathologic feature in this group.
The significant degree of BHR in the group with wood smoke COPD may suggest a determinant role of an inflammatory mechanism and the possibility of a response to steroids administration (systemic or inhaled) that should be determined in future studies.
C. Torres-Duque, None.