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India has seen a staggering increase in the number of stroke cases in the last three decades, according to a new study published in the journal Lancet Neurology. The country recorded over 1.25 million new stroke cases in 2021 compared to 650,000 in 1990 — an increase of 51 per cent.
The prevalence of stroke in India has surged by 47 per cent, from 4.4 million in 1990 to 9.4 million in 2021, Valery Feigin, director of the National Institute for Stroke & Applied Neurosciences at Auckland University of Technology, New Zealand and a co-author of the study, told Down To Earth (DTE).
Globally, the number of people affected by strokes rose to 11.9 million in 2021, marking a 70 per cent increase since 1990. With 1.25 million new stroke cases, India made up 10 per cent of the global burden in 2021.
More than 75 per cent of stroke victims live in low- and middle-income countries (LMIC), the study highlighted.
“Environmental risk factors such as air pollution were responsible for a greater proportion of stroke burden in LMICs than in high-income countries,” read another related article published in the journal.
The absolute number of stroke cases linked to air pollution in LMICs was 20.5 million, compared to 1.46 million in high-income countries.
Previous research has indicated that air pollution can cause inflammation and oxidative stress, potentially influencing stroke incidence and progression.
“Given that ambient air pollution is reciprocally linked with ambient temperature and climate change, the importance of urgent climate actions and measures to reduce air pollution cannot be overestimated,” said Catherine O Johnson, lead research scientist at the Institute for Health Metrics and Evaluation.
The study suggested that rising stroke rates may be attributed to population growth, an ageing population and increased exposure to environmental and behavioural risk factors.
The findings are based on estimates of stroke incidence, prevalence, mortality and disability-adjusted life-year (DALY) counts, as well as age-standardised rates per 100,000 people per year for different types of stroke, including ischaemic stroke, intracerebral haemorrhage and subarachnoid haemorrhage, across 204 countries and territories from 1990 to 2021. The researchers also assessed key risk factors.
Globally, stroke-related deaths have declined by 44 per cent between 1990 and 2021, while DALYs due to stroke have risen by 32 per cent . Six clusters of risk factors were identified, including air pollution, tobacco use and dietary, behavioural, environmental and metabolic risks.
The global stroke burden linked to high body mass index increased by 88 per cent, while high temperatures rose by 72 per cent, high blood sugar by 32 per cent, consumption of sugar-sweetened drinks by 23 per cent, low physical activity by 11 per cent, high systolic blood pressure by 7 per cent and diets low in omega-6 polyunsaturated fatty acids by 5 per cent.
“The global growth of the number of people who develop stroke and die from or remain disabled by stroke is growing fast, strongly suggesting that currently used prevention strategies are not sufficiently effective,” Feigin said in a statement. He advocated for the adoption of new, evidence-based prevention strategies at both the population-wide and individual level to mitigate stroke risks globally.
Johnson stressed the importance of tackling obesity and metabolic syndromes, given the growing exposure to risk factors such as high blood sugar and diets rich in sugar-sweetened beverages. “Identifying sustainable ways to work with communities to take action to prevent and control modifiable risk factors for stroke is essential to address this growing crisis,” she added.
The study also emphasised the role of particulate matter air pollution in contributing to subarachnoid haemorrhage, on par with smoking. The related paper called for practical solutions, including enhanced surveillance, prevention measures, acute care and rehabilitation.
