For every 1% increase in smoking prevalence in the asthma population, there is a 1% increase in asthma- related admissions to hospital (Purdy et al, 2011). Active smokers will experience more severe asthma
symptoms, accelerated decline in lung function and impaired short term therapeutic responses to corticosteroids compared to non- smokers with asthma — smoking will also increase the clearance of theophylline (drug used for respiratory diseases such as COPD and asthma) from the liver (Thomson and Spears, 2005; Polosa and Thomson, 2012).