Influenza-Like Illness is Associated with Increased Short-Term Risk of Cervical Artery Dissection

Non-traumatic Cervical Artery Dissection (CeAD) is a leading cause of ischemic stroke in the young. Influenza-like illnesses (ILI) trigger ischemic strokes. We hypothesized that influenza and ILI are associated with CeAD.

In a case-crossover study within the New York State (NYS) Department of Health Statewide Planning and Research Cooperative System (2006-2014), we used ICD-9 codes to exclude major trauma and to define CeAD, influenza, and the Centers for Disease Control defined ILI. We estimated the association of ILI and influenza with CeAD by comparing their prevalence in intervals immediately prior (0-30,0-90,0-180, and 0-365 days) to CeAD (case period) to their prevalence exactly one and two years earlier (control periods). Conditional logistic regression models generated odds ratios and 95% confidence intervals (OR, 95% CI). Models were adjusted for NYS estimates of influenza prevalence rates.

Our sample included 3,610 cases of CeAD (mean age 52±16 years, 54.7% male, 6.2% Hispanic, 9.9% Black, 68.7% White). During case periods, 7.3% had one or more ILI. ILI was more likely within 90 days of CeAD compared to the same time interval one and two years before (0-15 days: adjusted OR 1.88, 95%CI 1.20-2.94; 0-30 days: adjusted OR 1.74, 95%CI 1.22-2.46; 0-90 days: adjusted OR 1.35, 95%CI 1.00-1.81). Influenza trended with CeAD (adjusted OR 1.86, 95%CI 0.37-9.24), but these results were not statistically significant, due to limited instances of confirmed influenza.

ILI may increase risk of CeAD for 15 days, and possibly up to three months.