Abstract 11: Stroke in the Young: Preliminary Results for Temporal Trends in the Age of Stroke Incidence in a Large, Bi-Racial Population

Introduction: Previously, we reported that stroke incidence in the young (age < 55) significantly increased in both blacks and whites over four study periods between 1993 and 2010. Here we further describe this temporal trend, adding data from 2015. Methods: The Greater Cincinnati/Northern Kentucky region includes 2 southern Ohio and 3 contiguous Northern Kentucky counties (estimated population, 1.3 M). Our study determined first-ever hospital-ascertained strokes that occurred in the population from 7/1/93 to 6/30/94 and in calendar years 1999, 2005, 2010, and 2015 by screening ICD9 (and ICD10, in 2015) codes of all inpatient and emergency department visits. Cases were abstracted by study nurses and verified by study physicians. Results for 2015 are preliminary. The denominator for the calculation of incidence rates (in those aged ≥20 years) was extracted from the U.S. Census Bureau website (www.census.gov). Age- and race -specific incidence rates with 95% confidence intervals (CI) were calculated assuming a Poisson distribution. We tested for differences in age trends using Student’s t-test, X 2 , and Poisson regression as appropriate. Results: The mean± SD age of stroke was 71.3±13.6 in 1993-94, 70.9±14.4 in 1999, 68.4±15.5 in 2005, 68.5±15.6 in 2010, and 68.7±15.4 in 2015 (p<0.0001 for trend). The proportion of all strokes under age 55 went from 12% to 15% to 20% to 22%, then 18% in 1993-94, 1999, 2005, 2010, and 2015, respectively. Poisson regression showed a shift toward younger strokes across the five periods studied (p<0.0001). Age-specific stroke incidence rates by study period are presented in the Table. Discussion: The disturbing trend of increasing stroke in the young (age < 55) has leveled off slightly since 2010 but is still of great public health significance as younger strokes carry the potential for greater lifetime burden of disability. Further study is needed to determine the reasons for these results, including examination of race-specific trends.