<qa>  What is the main cause of asthma?Asthma affects 7 - 12 of the population in North America and results in substantial morbidity and health care costs. Management of asthma is focused towards reducing airway inflammation through a combination of avoidance of inciting and triggering pro-inflammatory agents as well as anti-inflammatory medication. Corticosteroids and anti-leukotrienes are efficacious, but are neither universally effective nor free of side effects. Statins, which are currently widely prescribed and used safely to improve serum lipids and cholesterol, have anti-inflammatory properties which may be clinically useful in asthma either in addition to or perhaps instead of corticosteroids. 