Prevalence characteristics of COPD in never smokers

BackgroundChronic obstructive pulmonary disease (COPD) is currently the 4th leading cause of death all over the world. Smoking is by far the most important documented (and preventable) cause for COPD. However, COPD can still be recorded among a good percentage of non smoker patients, due to other different causes.MethodsThis study was performed in the Chest Department, Menoufiya University, in the period from April 2009 to August 2011, on randomly selected 300 COPD patients, 230 patients (76.66%) were men and 70 patients (23.34%) were women. The mean age of the patients was 60.7 ± 5.35 years (range 42–83 years), and all patients were diagnosed as having COPD (FEV1/FVC < 70%), with the use of spirometry (prebronchodilator and postbronchodilator inhalation), according to the GOLD criteria. For each patient, the personal history (including his or her education level), smoking history, health status, and exposure to risk factors for COPD, were assessed according to a prewritten questionnaire.ResultsOut of the 300 COPD patients included in this study, 120 (40%) were never smokers and 180 (60%) were ever smokers. Women made up 41.7% of the never smokers (50 of 120) and 11% of the ever smokers (20 of 180). Never smokers were significantly older than smokers [65.08 ± 5.03 years vs 56.33 ± 5.67 years (P < 0.001)] and were more likely to be women [41.7% vs 11% (P < 0.001)]. Never smokers made up to 40% (120/300) of all COPD cases: 78% (70/90) of all GOLD stage II cases, 45.5% (50/110) of all GOLD stage III cases. Among never smokers, 58.3% (70/120) fulfilled the criteria for GOLD stage II and 41.7% (50/120) fulfilled the criteria for GOLD stage III and no patients fulfilled the criteria of either GOLD stage I or GOLD stage IV. Never smokers were shown to have more occupational exposure to organic and inorganic dust and irritant gases at work place [41.7% (50/120) vs 27.7% (50/180), P < 0.05], more biomass exposure [41.7% (50/120) vs 0% (0/180), P < 0.001], less education [41.7% (50/120) vs 72.2% (130/180), P < 0.001], more exposure to passive smoking [75% (90/120) vs 22.2% (40/180), P < 0.001]. When compared with never smoker patients with moderate COPD (GOLD stage II), never smokers with severe COPD (GOLD stage III) were older in age (70.6 ± 2.44 years vs 61.14 ± 1.25 years, P < 0.001), have a higher female percentage (60% vs 28.6%, P < 0.001), lower BMI (21.2 ± 0.76 vs 26.14 ± 2.43, P < 0.001), more occupational exposure (27.5 ± 2.56 years vs 13.33 ± 2.39 years, P < 0.001), more biomass exposure (35 ± 4.15 years vs 20 ± 10 years, P < 0.001), less education (0% vs 71.4 educated, P < 0.001), more exposure to passive smoking (29 ± 2.02 years vs 13.75 ± 4.19 years, P < 0.001).ConclusionsThis study revealed that never smokers constitute a significant proportion of the Egyptian COPD patients. When dealing with COPD management, clinicians must be oriented with the different risk factors, other than tobacco smoke, that play a key role in the development and pathogenesis of COPD, because despite smoking is the most important risk factor, its absence doesn’t exclude COPD diagnosis.