Ethnic Group Disparities in 10-Year Trends in Stroke Incidence and Vascular Risk Factors

Abstract

Data monitoring trends in stroke risk among different ethnic groups are lacking. Thus, we investigated trends in stroke incidence and modifiable stroke risk factors over a 10-year time period between different ethnic groups. Changes in stroke incidence were investigated with the South London Stroke Register (SLSR). The SLSR is a population-based stroke register, covering a multiethnic population of 271 817 inhabitants in South London with 63% white, 28% black, and 9% of other ethnic group (2001 Census). Between 1995 and 2004, 2874 patients with first-ever stroke of all age groups were included. Total stroke incidence decreased over the 10-year study period in men (incidence rate ratio 1995 to 1996 versus 2003 to 2004 [IRR] 0.82, 95% CI 0.69 to 0.97) and in women (IRR 0.76, 95% CI 0.64 to 0.90). A similar decline in total stroke incidence could be observed in whites for men and women (IRR 0.76, 95% CI 0.62 to 0.93 versus IRR 0.73, 95% CI 0.59 to 0.89, respectively); in blacks, total stroke incidence was reducing only in women (IRR 0.48, 95% CI 0.31 to 0.75). In whites, the prevalence of prior-to-stroke hypertension (P=0.0017), atrial fibrillation (P=0.0113), and smoking (P=0.0177) decreased; no statistically significant changes in prior-to-stroke risk factors were observed in blacks. Total stroke incidence was higher in blacks compared to whites (IRR 1.27, 95% CI 1.10 to 1.46 in men; IRR 1.29, 95% CI 1.11 to 1.50 in women), but the black-white gap reduced during the 10-year time period (IRR 1.43, 95% CI 1.13 to 1.82 in 1995 to 1996 to 1.18, 95% CI 0.93 to 1.49 in 2003 to 2004). Stroke incidence decreased over a 10-year time period. The greatest decline in incidence was observed in black women, but ethnic group disparities still exist, indicating a higher stroke risk in black people compared to white people. Advances in risk factor reduction observed in the white population were failed transferring to the black population.