Association of Pulmonary Symptoms and Co-Morbidity Diseases with Lung Function in Adult Smokers

This study aims to evaluate the relationship of pulmonary symptoms and co-morbidity diseases with lung function in adult smokers.

Three hundred and fifty men adults over the age of 20 were involved. Spirometry tests were performed for measuring FVC, FEV1, and FEV1% FVC. COPD was categorized into four stages (I-IV) by the (GOLD) criteria of post-bronchodilator FEV1/FVC <0.70. For comparing the mean of pulmonary functions regarding the following variables, pulmonary symptoms, and co-morbidity diseases, t-test was used. Spearman's correlation analysis was performed to get association between stages of COPD and study variables. Further analysis using multiple regressions was conducted to confirm the predictors of the pulmonary functions. The level of significance is taken as P < 0.05.

The mean age of participants was 54.7543 ± 13.44. A total of 43 (19.5%) participants were COPD; 7% of them were Stage I, 23.3% were Stage II, 39.5% were Stage III, and 30.2% were Stage IV. The mean of FEV1 in participants with shortness of breath (P < 0.001), cough (P = 0.001), wheezing (P = 0.023), as well as cardiovascular disease (P = 0.038) was significantly less in compared to those without these symptoms and disease. Also the mean of FVC in participants with shortness of breath (P < 0.001) and cough (P = 0.029) was significantly less in compared to others. Finally, the mean of FEV1/FVC in participants with shortness of breath (P < 0.001), cough (P = 0.001), and wheezing (P = 0.01) was less. The relationship between stages of COPD and other variables indicated a significant association between stages of COPD and diabetes mellitus (β = -.342P = 0.030). According to linear regression model, shortness of breath was the only influential variable on FEV1 (B = -.383CI: -23.729, -12.155 P < 0.001), FVC (B = -.296CI: -.365CI: -15.336, -6.082 P < 0.001), and FEV1/FVC (B = -.365, CI: -18.362, -9.029 P < 0.001).

Pulmonary symptoms including shortness of breath, cough, and wheezing influenced the lung function in adult smokers. Additionally, shortness of breath was associated with FEV1, FVC, and FEV1/FVC. Cardiovascular disease decreased FEV1 in smokers, whereas diabetes mellitus was associated with milder COPD stages.