Abstract TP263: Is Altitude Associated With Ischemic Stroke in the Young?

Abstract

Background: Stroke in the young (< 45 years old) is rare, yet may be increasing in prevalence due to the rise in traditional risk factors such as hypertension and smoking status. Whether altitude is a risk factor for stroke in the young has not been examined. At our high elevation state (Colorado), we report a high prevalence of stroke in the young. We hypothesized that the rate of stroke in the young was positively associated with state elevation. Methods: We conducted an ecologic study utilizing the most recent data from the Healthcare Cost and Utilization Project (HCUPnet- 2015), provided by the Agency for Healthcare Research and Quality, and U.S. Census data (2010). The proportion (%) of stroke admissions in the young within each state was identified from HCUPNet data using ICD9 diagnosis codes of 433-434. Prevalence rates (per 100,000 persons) of stroke in the young population within each state were calculated from US census data. Proportions and prevalence rates of stroke in the young were plotted against the average state elevation (feet above sea level) and examined with a generalized linear regression model. Results: HCUPNet data were available for 35 of 50 U.S. states. As shown in figure 1, high altitude states had the highest proportion of stroke admissions in young persons < 45 years, which was highest in Colorado (5.6%, altitude 6,800 feet) and lowest in Rhode Island (2.3%, altitude 200 feet). However, contrary to our hypothesis, high altitude states reported the lowest prevalence rate of stroke in the young (Figure 1, p=0.002). The rate of stroke was highest in South Carolina (16.5/100,000 young persons, altitude 43 feet) and lowest in Wyoming (4.6/100,000, altitude 6,700 feet). Conclusions: This hypothesis generating data does not appear to support an association between higher stroke prevalence rates in the young in high altitude states. Still, clinicians at higher altitude states should remain vigilant and suspect ischemic stroke in younger persons.