Bronchial mechanics in healthy subjects and patients with longlasting asthma

Asthma is one of the most common chronic diseases in children and adults in the Netherlands and in other countries with a 'Western Lifestyle'. It is characterized by recurrent excessive, mostly reversible, narrowing of airway caliber, in response to a variety of endogenous and exogenous stimuli. Increased bronchial responsiveness to the inhalation of non specific irritants is a hallmark of asthma and includes an increase in reactivity as well as in sensitivity of the airway. Asthma is considered to be a life long disease: it starts at a very young age and persists in approximately 40% - 60% of the children into adulthood. More than 50% of the adult patients with asthma still have symptoms after 25 years. Decreased airway patency in asthma is mainly caused by bronchoconstriction caused by an increased bronchial smooth muscle tone, hypersecretion and edema of the airway wall. These are the result of (chronic) inflammation of the airway wall, nowadays considered to be the major factor in the pathogenesis of asthma in association with bronchial hyperresponsiveness and the level of severity of the disease.