Persistent ischemic stroke disparities despite declining incidence in Mexican Americans

Abstract

Objective: To determine trends in ischemic stroke incidence among Mexican Americans and non-Hispanic whites.

Methods: We performed population-based stroke surveillance from January 1, 2000 to December 31, 2010 in Corpus Christi, Texas. Ischemic stroke patients 45 years and older were ascertained from potential sources, and charts were abstracted. Neurologists validated cases based on source documentation blinded to ethnicity and age. Crude and age-, sex-, and ethnicity-adjusted annual incidence was calculated for first ever completed ischemic stroke. Poisson regression models were used to calculate adjusted ischemic stroke rates, rate ratios, and trends.

Results: There were 2,604 ischemic strokes in Mexican Americans and 2,042 in non-Hispanic whites. The rate ratios (Mexican American:non-Hispanic white) were 1.94 (95% confidence interval [CI] = 1.67-2.25), 1.50 (95% CI = 1.35-1.67), and 1.00 (95% CI = 0.90-1.11) among those aged 45 to 59, 60 to 74, and 75 years and older, respectively, and 1.34 (95% CI = 1.23-1.46) when adjusted for age. Ischemic stroke incidence declined during the study period by 35.9% (95% CI = 25.9-44.5). The decline was limited to those aged ≥60 years, and happened in both ethnic groups similarly (p > 0.10), implying that the disparities seen in the 45- to 74-year age group persist unabated.

Interpretation: Ischemic stroke incidence rates have declined dramatically in the past decade in both ethnic groups for those aged ≥60 years. However, the disparity between Mexican American and non-Hispanic white stroke rates persists in those <75 years of age. Although the decline in stroke is encouraging, additional prevention efforts targeting young Mexican Americans are warranted.

FIGURE 1

Age-, sex-, and ethnicity-adjusted completed ischemic stroke rates per 10,000 population, Nueces County, Texas, 2000–2010. See Supplementary Figure 1 for 95% confidence interval lines. [Color figure can be viewed in the online issue, which is available at www.annalsofneurology.org.]

FIGURE 2

Sex-adjusted first ever completed ischemic stroke rates per 10,000 population by ethnicity, Nueces County, Texas, 2000–2010: (A) age-adjusted; (B) 45- to 59-year-olds; (C) 60- to 74-year-olds; (D) subjects ≥75 years old. See Supplementary Figure 2 for 95% confidence interval lines. MA = Mexican American; NHW = non-Hispanic white. [Color figure can be viewed in the online issue, which is available at www.annalsofneurology.org.]