Prevalence of COPD and follow up of lung functions in COPD and non COPD individuals of a middle age rural community after 8-years.

Abstract

 Introduction: Chronic obstructive pulmonary disease (COPD) is a common preventable and treatable disease which represents an important public health challenge and is expected to increase in coming years. It is characterized by progressive worsening of the airway obstruction measured by accelerated decline in the lung functions particularly Forced Expiratory Volume in 1 second (FEV1) over a period of time.

Aim: This study is aimed to estimate the prevalence of  spirometrically defined chronic airflow limitation (CAL) in a middle age rural community  and to measure the absolute and relative decline of the lung functions in participants, with and without COPD from their baseline after 8 years of initial evaluation.

Material and Method: Using Burden of Obstructive Lung Disease (BOLD) survey methods, we administered questionnaires to a retrospective cohort group aged ≥40 years at two villages of  District Bandipora in North Kashmir. Post-bronchodilator spirometry was also performed to estimate the prevalence of CAL and simultaneously measured the absolute and relative change in FEV1 and forced vital capacity (FVC) in these participants enrolled in BOLD-I project in relation to participants age, sex, BMI ,smoking status, presence or absence of post bronchodilator airflow limitation and the stage of CAL. The duration of follow up was 8 years.

Results: In our study group of 124 participants, the prevalence of CAL in this particular study group had increased from 25.8% to 41.1%. Among all risk factors, tobacco smoking showed a significant correlation with prevalence of CAL. We could also find that mean annual FEV1 decline  was 40.5ml/yr with a -12.56% relative decline and mean annual FVC decline was 34.6ml/yr with -7.4% relative decline from baseline. The rate of decline in FEV1 was similar between former smokers and active smokers, though it was more than never smokers. There was a rapid decline of in FEV1 among participants developing CAL over a period of time which was 61.3ml/year and -22.4% decrease from baseline which was significantly more than absolute decline in FEV1 of 25.9ml/year with -5.7% of relative decline in normal individuals (p value <0.05).There were no statistically significant associations between sex, age, BMI and stages of diagnosed COPD with the rate of decline in FEV1 and FVC.

Conclusion: There was a definite upsurge in prevalence of CAL over a given period of time. Smoking of any kind came up to be the  most significant risk factor associated with CAL. There was an age related decline in FEV1, FVC and FEV1/FVC in the studied participants. The relative decline of lung functions was accelerated with smoking. Stopping of smoking did not bring the rate of decline in FEV1 down to the never-smoker level.