Phenotypic comparison between smoking and non-smoking chronic obstructive pulmonary disease

Abstract

Background Although COPD among non-smokers (NS-COPD) is common, little is known about this phenotype. We compared NS-COPD subjects with smoking COPD (S-COPD) patients in a rural Indian population using a variety of clinical, physiological, radiological, sputum cellular and blood biomarkers. Methods Two hundred ninety subjects (118 healthy, 79 S-COPD, 93 NS-COPD) performed pre- and post-bronchodilator spirometry and were followed for 2 years to study the annual rate of decline in lung function. Body plethysmography, impulse oscillometry, inspiratory-expiratory HRCT, induced sputum cellular profile and blood biomarkers were compared between 49 healthy, 45 S-COPD and 55 NS-COPD subjects using standardized methods. Spirometric response to oral corticosteroids was measured in 30 female NS-COPD patients. Results Compared to all male S-COPD subjects, 47% of NS-COPD subjects were female, were younger by 3.2 years, had greater body mass index, a slower rate of decline in lung function (80 vs 130 mL/year), more small airways obstruction measured by impulse oscillometry (p < 0.001), significantly less emphysema (29% vs 11%) on CT scans, lower values in lung diffusion parameters, significantly less neutrophils in induced sputum (p < 0.05) and tended to have more sputum eosinophils. Hemoglobin and red cell volume were higher and serum insulin lower in S-COPD compared to NS-COPD. Spirometric indices, symptoms and quality of life were similar between S-COPD and NS-COPD. There was no improvement in spirometry in NS-COPD patients after 2 weeks of an oral corticosteroid. Conclusions Compared to S-COPD, NS-COPD is seen in younger subjects with equal male-female predominance, is predominantly a small-airway disease phenotype with less emphysema, preserved lung diffusion and a slower rate of decline in lung function.

A comparative study of chest CT findings regarding the effects of regional dust exposure on patients with COPD living in urban areas and rural areas near cement plants

“…For instance, non-smoker and female patients with COPD had less emphysema and air-trapping, as detected by HRCT, thicker basement membranes and greater endobronchial pigmentation [ 12 ]. Non-smoker COPD subjects had lower emphysema scores and airway diseases predominant patterns in CT scan than smokers, as per a recent study [ 22 ]. The biomass also showed a variation in pattern in CT scans with lower emphysema and higher air trapping [ 10 ].…”

“…Data are presented as mean ± standard deviation for continuous variables or number (%) for categorical variables Statistical differences between the two groups were estimated by independent sample t-test for parametric values and Mann-Whitney U-test for non-parametric values after log-transformation, or chi-square test for categorical variables Subject criterion: COPD (post FEV1/FVC < 0.7) and pack-year ≥ 10 BDR was calculated as follows: FEV1(L) post-bronchodilator minus FEV1(L) pre-bronchodilator / FEV1(L) pre-bronchodilator × 100% BMI body mass index, CT computed tomography, BDR bronchodilator response, FEV1 forced expiratory volume in 1 s, FVC forced vital capacity, CAT COPD assessment test, WBC white blood cell, RBC red blood cell, hs-CRP high-sensitivity c-reactive protein * COPD medication includes LAMA, LABA, SABA, or ICS/LABA For instance, non-smoker and female patients with COPD had less emphysema and air-trapping, as detected by HRCT, thicker basement membranes and greater endobronchial pigmentation [12]. Non-smoker COPD subjects had lower emphysema scores and airway diseases predominant patterns in CT scan than smokers, as per a recent study [22]. The biomass also showed a variation in pattern in CT scans with lower emphysema and higher air trapping [10].…”

<p>Characteristics of Patients with Chronic Obstructive Pulmonary Disease Exposed to Different Environmental Risk Factors: A Large Cross-Sectional Study</p>

“…We defined occupational exposure as exposure to dust, gases/fumes, insecticides, chemical substances, paints, and metals at work for at least 8 hours per day for more than 1 year. [13][14][15] The COPD Assessment Test (CAT), a validated eightquestion health-status instrument, includes cough, phlegm, chest tightness, shortness of breath, limited at home, confidence leaving home, sound sleep, and energy, with scores ranging from 0 to 5. 16 The total score is calculated by simply adding all scores, with higher scores indicating greater symptom severity.…”

“…Biomass smoke exposure was associated with small airway obstruction, and more air trapping was demonstrated in a cross-sectional study 33 and recently in another study from India. 13 Biomass smoke has also been shown to cause more hypoxemia. 34 All these findings may explain why COPD patients with biomass smoke exposure were more symptomatic.…”

Scores of Health-Related Quality of Life Questionnaire Worsen Consistently in Patients of COPD: Estimating Disease Progression over 30 Years by SReFT with Individual Data Collected in SUMMIT Trial

“…We selected the covariates that affect disease progression in stepwise forward-selection and backward-elimination methods. Smoking is well known to contribute to the development and progression of COPD [ 19 ]. In addition, patient exacerbation frequency, body mass index (BMI) and gender have also been accepted as factors affecting the progression of the disease [ 20 , 21 , 22 ].…”