Ethnic disparities in ischemic stroke, intracerebral hemorrhage, and subarachnoid hemorrhage incidence in the Netherlands

Abstract

Background and purpose: Data on the incidence of stroke subtypes among ethnic minority groups are limited. We assessed ethnic differences in the incidence of stroke subtypes in the Netherlands.

Methods: A Dutch nationwide register-based cohort study (n=7 423 174) was conducted between 1998 and 2010. We studied the following stroke subtypes: ischemic stroke, intracerebral hemorrhage, and subarachnoid hemorrhage. Cox proportional hazard models were used to estimate incidence differences between first-generation ethnic minorities and the Dutch majority population (ethnic Dutch).

Results: Compared with ethnic Dutch, Surinamese men and women had higher incidence rates of all stroke subtypes combined (adjusted hazard ratios, 1.43; 95% confidence interval, 1.35-1.50 and 1.34; 1.28-1.41), ischemic stroke (1.68; 1.57-1.81 and 1.57; 1.46-1.68), intracerebral hemorrhage (2.08; 1.82-2.39 and 1.74; 1.50-2.00), and subarachnoid hemorrhage (1.25; 0.92-1.69 and 1.26; 1.04-1.54). By contrast, Moroccan men and women had lower incidence rates of all stroke subtypes combined (0.42; 0.36-0.48 and 0.37; 0.30-0.46), ischemic stroke (0.35; 0.27-0.45 and 0.34; 0.24-0.49), intracerebral hemorrhage (0.61; 0.41-0.92 and 0.32; 0.16-0.72), and subarachnoid hemorrhage (0.42; 0.20-0.88 and 0.34; 0.17-0.68) compared with ethnic Dutch counterparts. The results varied by stroke subtype and sex for the other minority groups. For example, Turkish women had a reduced incidence of subarachnoid hemorrhage, whereas Turkish men had an increased incidence of ischemic stroke and intracerebral hemorrhage compared with ethnic Dutch.

Conclusions: Our findings suggest that Surinamese have an increased risk, whereas Moroccans have a reduced risk for all the various stroke subtypes. Among other ethnic minorities, the risk seems to depend on the stroke subtype and sex. These findings underscore the need to identify the root causes of these ethnic differences to assist primary and secondary prevention efforts.

Keywords: Netherlands; ethnicity; intracerebral hemorrhage; minority groups; minority health; stroke; subarachnoid hemorrhage.