WHAT IS KNOWN AND OBJECTIVE
Chronic-obstructive pulmonary disease (COPD) is
the leading cause of chronic morbidity (1) and to
date among the five most frequent causes of death
in the world (2, 3). Current prevalence is estimated
to range between 4 and 10% (1, 2) and incidence is
predicted to further increase with ageing populations
if smoking bans continue to fail (2, 3).
The disease is characterized by an irreversible
narrowing of the airways caused by a chronic
inflammatory reaction which is becoming manifest
as chronic bronchitis and emphysema in the lung
alveoli (4). Consequently, patients suffer from
progressive dyspnoea and expectoration of sputum