Abstract 96: 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 three study periods between 1993 and 2005. Here we further describe this temporal trend, adding data from 2010. Methods: The Greater Cincinnati/Northern Kentucky region includes 2 southern Ohio counties and 3 contiguous Northern Kentucky counties (estimated population, 1.3 M). Our study determined first-ever hospital-ascertained strokes that occurred in the population between 7/1/93 and 6/30/94 and in calendar years 1999, 2005, and 2010 by screening ICD9 codes of all inpatient and emergency department visits. Cases were abstracted by study nurses and verified by study physicians. Results for 2010 are preliminary. The denominator for the calculation of incidence rates (in those aged ≥ 20years) was extracted from the U.S. Census Bureau website (www.census.gov). Age- and race-specific incidence rates and 95% confidence intervals (CI) were calculated assuming a Poisson distribution. We tested for differences in age trends using Student’s t-test, chi-square, and Poisson regression as appropriate. Results: The mean±SD age of onset was 71.3±13.6 in 1993-94, 70.9±14.4 in 1999, 68.4±15.5 in 2005 and 68.5±15.6 in 2010 (p<.0001 for trend). The proportion of all strokes under age 45 were 4.6%, 5.4%, 7.3%, and 6.1% in 1993-94, 1999, 2005, and 2010, respectively; Poisson regression showed a shift toward younger strokes across the four periods studied (p<.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) seems to have leveled off slightly in 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 trends.