Asthma, asthma control and risk of stroke: the Nord-Trøndelag Health Study (HUNT)

Abstract

Introduction: Asthma, a chronic inflammatory airway disease, shares several common pathophysiological mechanisms with stroke. Research of the association between asthma, asthma control and stroke risk are lacking. Aims and Objectives: To assess the association between asthma, levels of asthma control and stroke risk. Methods: This prospective population cohort utilized data on 58 540 adults from a second and third examinations of “The Nord-Trondelag Health Study” in Norway free from stroke at baseline. Self-reported asthma was categorized as ever asthma and active asthma (i.e., being on asthma medication within 12 months of the baseline). Asthma control was defined according to the Global Initiative for Asthma guidelines and was categorized into controlled, partly-controlled and uncontrolled asthma. Stroke was ascertained by linking HUNT data with Nord-Trondelag hospital records and Norwegian Patient Registry. Results: During a mean follow-up of 17.27 ± 5.33 years, 2 029 participants (3.5%) developed stroke. Active asthma was associated with small borderline increased risk of stroke (adjusted HR 1.20, 95% CI 0.99-1.45). Subgroup analyses revealed stronger association between active asthma and stroke risk among male participants (adjusted HR 1.35, 95% CI 1.06-1.73) and among smokers (adjusted HR 1.35, 95% CI 1.09-1.68). Associations were not explained by C-reactive protein levels and physical activity. There were no significant associations in asthma control groups (p for trend >0.100). Conclusions: Active asthma was associated with modest increased risk of stroke in males and smokers independently of other conventional cardiovascular risk factors.