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American Indians was greater than in Whites and generally less than in Blacks, before adjusting for the
presence of risk factors. Notably, they also found that post-stroke mortality was greater in American Indians
[23]
than in Black or White Americans . In a more recent study on the incidence of stroke in the Alaska Native
[24]
population, Boden-Albala et al. found that the overall annual age-standardised incidence of stroke was
similar to that of the annual incidence estimates for United States Whites, and lower or similar to other
ethnic minority groups in the United States. However, Alaskan Native people experienced greater rates of
stroke than United States Whites in all age groups except among those aged 20-24 years, when using data
[25]
from the Northeast Manhattan Study as a benchmark . Furthermore, substantial geographic heterogeneity
in incidence rates was noted. The incidence rates of stroke in Alaska Natives residing in the Northwestern
Arctic region were significantly greater than in the Kodiak and Interior regions. Rates of stroke in Alaskan
Natives were greater in men than in women, though women aged > 75 years had greater rates of
[24]
haemorrhagic stroke . In Canada, the age-standardised prevalence of stroke was 2-fold greater in Inuit
adults in northern Canada than in the general Canadian population, with disparities most notable in those
aged < 60 years . Greater incidence rates of stroke have also been reported in the Métis Peoples of Canada,
[26]
[27]
compared to others in the same region of Manitoba . Few data have been published on the incidence of
stroke in the Indigenous Peoples of South America . Saposnik et al. , in their systematic review of stroke
[28]
[28]
in South America found relatively low incidence rates in the Indigenous population, but these studies
comprised datasets from the 1980s to 1990s, and are likely to be outdated. In a 1-year follow-up of a cohort
of 1514 individuals conducted among the Chiquitano tribe from the southern Amazonas region in Bolivia,
[28]
the crude incidence of stroke was estimated to be 35 per 100,000 . Case numbers were small and age-
standardised incidence rates were not available; these relatively low crude rate estimates may have been
affected by selection bias as well as a younger age structure of this specific population, relative to the WHO
World Standard Population . There was no comparison with a non-Indigenous population in the same
[29]
region .
[30]
In Europe and Russia, disparities in the incidence of stroke between the Indigenous and non-Indigenous
populations are less clear. In Scandinavia, the incidence of stroke has been reported to be greater in the
Sami population compared with that in the non-Sami population of the same Nordic regions [31,32] , with
[32]
[32]
notable differences also reported between reindeer-herder and non-herder Sami people . Sjölander et al.
reported a greater incidence of stroke in the Sami population of Sweden overall, when compared with the
non-Sami population. However, reindeer-herding Sami men had a significantly lower age-adjusted
incidence of stroke, and reindeer-herding Sami women had a significantly greater incidence of stroke, when
compared to the non-Sami population. In particular, subarachnoid haemorrhage was significantly greater in
reindeer-herding Sami women than in non-Sami women with a standardised incidence ratio of 3.2. This
disparity was seen to a lesser extent in reindeer-herding Sami men (standardised incidence ratio of 1.4),
though with overlapping confidence intervals. Interestingly, reindeer-herding Sami women had a
significantly lower incidence of myocardial infarction than non-Sami women . In a study in Yakutia,
[32]
Russia, a region which is home to a significant proportion of Indigenous Peoples (including Yakuts, Evenks,
Evens, Dolgans, Yukagirs and Chukchi Peoples), there were no significant differences in the mean age of
incident stroke . Still, the proportion of haemorrhagic stroke was greater in the Indigenous patients (38%)
[33]
than in the Caucasian Russian patients with incident stroke (20.2%, P < 0.05) .
[32]
Risk factors for stroke in Indigenous Peoples
The major traditional modifiable risk factors for stroke are similar to coronary heart disease and peripheral
vascular disease. These include hypertension, hypercholesterolaemia and diabetes mellitus . Lifestyle
[34]
factors such as smoking, inadequate levels of physical activity, unhealthy diet and obesity are equally
[34]
important and often trend higher in Indigenous Peoples [5,35-38] . Age is the single most important risk factor
[39]
for stroke , yet Indigenous patients worldwide experience stroke approximately a decade younger than