The worldwide incidence and mortality rates for stroke decreased slightly from 1990 to 2019, but the overall numbers remain high—especially in high- and middle-income countries—according to a study published in an online issue of Neurology, the medical journal of the American Academy of Neurology (AAN). The study focused specifically on ischaemic stroke, which is caused by blood clots and makes up 85% of stroke cases.
“The decrease is likely due to better medical services available in high-income countries, which may offer earlier detection of stroke risk factors and better control of these risk factors,” said study author Liyuan Han (University of the Chinese Academy of Sciences, Ningbo, China). “But, even in these countries, the total number of people with strokes is increasing due to population growth and ageing, and worldwide stroke is the leading cause of death and a major cause of disability for adults.”
For the study, researchers analysed data from 1990 to 2019 from the Global Health Data Exchange. During that time, the average age-adjusted incidence rate of stroke decreased by 0.43%, from a rate of 105 strokes per 100,000 people to 95 strokes per 100,000 people. The rate was also higher in middle- and high-middle-income countries than in other areas.
At a regional level, the highest rates were in East Asia, with 144 per 100,000, and North Africa, the Middle East and Eastern Europe, with rates of 135 per 100,000. The lowest region was Australasia at 44 strokes per 100,000 people.
At a country level, the highest rates were in the United Arab Emirates at 208, Macedonia at 187 and Jordan at 181, while the lowest rates were in Ireland at 36, Nepal at 37 and Switzerland at 38 strokes per 100,000 people. Egypt (1.4%) and China (1.1%) had the most pronounced increases in stroke rates, the researchers also report.
Similarly to the stroke occurrence rate, the rate of death from stroke decreased slightly over the three decades assessed (1.6%)—but the overall numbers were high. The death rate decreased from 66 deaths per 100,000 people to 44 deaths per 100,000 people. The highest death rates were in Eastern Europe, with a rate of 100 per 100,000, as well as Central Asia at 79 and Central Europe at 67. The lowest rates were in high-income North America at 16, Australasia at 17 and high-income Asia Pacific at 18.
“Since ischaemic stroke is highly preventable, it is essential that more resources be devoted to prevention, especially in low- and middle-income countries where economic development is leading to changes in diet and lifestyle that may increase people’s risk factors for stroke,” said Han. “It has been estimated that at least half of all strokes may be preventable if effective changes were made to common lifestyle factors, such as high blood pressure, obesity, smoking and inactivity.”
A limitation of the study the researchers identified was that quality and accuracy of data from some underdeveloped countries cannot be guaranteed, as many did not have reliable information on deaths and strokes.