Although stroke is traditionally associated with older people, a major new study published in The Lancet this month reveals that it is increasingly affecting middle-aged and young people around the world.
The study, the Global and Regional Burden of Stroke in 1990-2000, collated data from around the world to calculate both regional and country-specific estimates of stroke. They included 119 studies in the research - 58 from high-income countries and 61 from middle-income and low-income countries.
The team of researchers, led by Prof. Valery Feigin, director of the National Institute for Stroke and Applied Neurosciences at AUT University in New Zealand, compared the results over time to build up a picture of the overall burden of stroke in all 21 regions of the world for the years 1990, 2005 and 2010.
Stroke can occur at any age and by far the majority occur in people aged over 65. But the research highlights that a growing number of children and young people are affected.
Researchers found that globally, more than 83,000 people aged 20 and younger suffer from stroke every year - that is 0.5% of the total number of people affected.
The study authors say:
"In 2010, 5.2 million (31%) strokes were in children (aged 20 years old and younger) and young and middle-aged adults (20-64 years), to which children and young and middle-aged adults from low-income and middle-income countries contributed almost 74,000 (89%) and 4 million (78%), respectively, of the burden."
And the researchers warn that without effective global preventive strategies, this figure will likely continue to rise.
Measuring the burden of stroke
But as stroke is one of the leading causes of serious long-term disability, the stroke burden also has a significant impact on disability-adjusted life-years of sufferers, as well as the economy.
The CDC estimates that the stroke burden costs the US $38.6 billion each year - a total including health care costs, medication and missed days from work.
As Prof. Feigin says:
"This is the first study to compare incidence and impacts of stroke between countries on a global scale. Now every country in the world has estimates of their stroke burden, based on the best available evidence.
The worldwide stroke burden is growing very fast and there is now an urgent need for culturally acceptable and affordable stroke prevention, management and rehabilitation strategies to be developed and implemented worldwide."
Significant differences in stroke burden worldwide
The study shows dramatic differences in stroke burden across the world and national income levels. Low- or middle-income countries experience up to 10 times as many stroke deaths, and illness and disability as high-income countries.
In high-income countries, age-standardized incidence of stroke decreased by 12% over the study period, with premature death rates and illness and disability rates also falling by 37% and 36% respectively.
These reductions may reflect improvements in education, the study authors explain, with more people following prevention and care advice (stopping smoking and controlling high blood pressure) as well as better diagnosis and acute stroke care.
Low- and middle-income countries, however, experienced an opposite trend. Stroke is associated with 46% more disability and illness, and a 42% higher mortality rate than high-income countries. The study authors say this could be down to a rise in the prevalence of risk factors - including unhealthy diets and obesity, high blood pressure, smoking and lack of physical activity.
The study comes as the American Stroke Association reminds us that October 29th, 2013 is World Stroke Day - a day to raise awareness of the impact of stroke.