New Delhi: As the world marks World Brain Stroke Day on Sunday, a lack of optimal data from the Southeast Asia region, including India, mars the fight against this deadly condition. According to a paper titled, ‘The burden, risk factors and unique etiologies of stroke in South-East Asia Region’, published in October 2023, the 11 countries comprising this block collectively account for as much as 40% of all the global brain stroke mortality. The paper was published in Lancet Regional Health – Southeast Asia.
Brain stroke occurs if blood supply to the brain is blocked due to clotting in the artery (known as ischemic stroke) or due to rupture of the artery (known as hemorrhagic stroke).
The highest incidence as well as prevalence was reported from India, with 1,291,245 cases and 9,650,716 cases respectively, said the paper, quoting Global Burden of Diseases (GBD), 2019. Prevalence is the proportion of the population who have developed a condition over a period of time. It consists of new as well as prevailing cases. On the other hand, incidence refers to the new cases that have come up over a time period (in the case of Global Burden of Diseases, the time period ranging from 1990 to 2019 was taken into account).
“Data on stroke prevalence is more readily available than on stroke incidence, reflecting the lack of population-based data in the region,” the paper says.
Asked whether the huge difference between the prevalence and incidence of cases in India was reflective of the fact that the country was missing out on several such cases, Jeyaraj D. Pandian, one of the lead authors, said, “It is possible”.
Pandian works with the neurology department at Ludhiana’s Christian Medical College.
Currently, India has two types of registries to monitor stroke cases – population-based registry and hospital-based registry. The former is considered a more rigorous exercise than the latter. This is because, in the case of a hospital-based registry, only those cases are taken into account which ultimately do land up in hospitals. But in the case of a population-based study, the data is collected from active cases from multiple sources like clinics, general practitioners, hospitals, nursing homes, diagnostic centres etc. A well-designed questionnaire is also used for what is known as ‘verbal autopsy’ from the family members of patients.
“Unlike hospital-based registry, population-based captures representative population [hence the need for it],” Pandian told The Wire. While there are hospital-based registries in at least 18 states of India, according to the Indian Council of Medical Research, there are only four population-based registries.
“We need to increase population-based registries on the line of such registries for cancer,” Pandian suggested. He added that unlike say Thailand or Bangladesh, India is such a vast country that it was impossible to extrapolate the data from one region to another.
“We need data from 6-7 states in the northern part of India itself to cover the entire region,” he said.
The paper also goes on to say: “Current data on stroke burden and risk factors is lacking, compelling an urgent need for high-quality hospital-level and population-level data in all South East Asia Region (SEAR) countries [including India].”
Though the highest prevalence and incidence were reported from India, the overall stroke-related mortality in the SEAR region was the highest in Indonesia followed by Myanmar and Bangladesh.
However, apart from the morbidity and mortality, there is another indicator that reflects how a condition is affecting people, in particular, and the country, in general. This is known as Disease Adjusted Life Years (DALYs). The DALYs, in effect, reflect how many years one has to live with the disease, thus not only affecting a person’s health but also their productivity.
Quoting the GBD study, the authors in this paper note that DALYs following stroke were the highest in India, followed by Indonesia and Bangladesh. The paper says high numbers of DALYs indicate a high burden of possibly more severe strokes and a lack of much-needed rehabilitation services.
“But also come to think of it this way. This figure [India recording highest DALYs] also means India is losing the largest in terms of productivity due to people getting strokes, in turn affecting the economy of the country too,” Pandian said.
Asked what could be one of the reasons for this, Pandian said somehow, Indians were getting brain strokes about 15 years earlier than their peers in the developed world. He attributed it to changes in lifestyles, dietary habits, high incidence of hypertension (high BP) and diabetes, exposure to pollution, smoking, low physical activity etc.
“Diabetes and hypertension are well established as culprits behind brain strokes,” he said. And, if there is a sudden and extreme fluctuation in blood pressure, the small artery can leak, leading to rupture, and this can very well cause brain haemorrhage, he explained.
Studies from India have reported hypertension prevalence of 19.9% population, the paper said.
About air pollution, he said that its role is more chronic in nature – stretched over a period of time, and it is a slow process. Once pollutants enter the bloodstream, they affect the arteries of the brain or their inner covering, at times damaging them. This leads to cholesterol deposition and clot formation.
“The sudden exposure to extremely high levels of pollution, especially after November, can be especially damaging,” he said.
Indoor air pollution, caused due to exposure to smoke from unclean sources of cooking, also exacerbates possibilities of a brain stroke, in a mechanism somewhat similar to air pollution.
On being asked whether genes and genetic predisposition also are important, he said though these factors could not be ruled out, there is a need for more compelling evidence to suggest their role, and more studies are needed in this regard.
Usually worldwide and in India too, the majority of brain stroke cases are ischemic, that is, caused by blood clotting. But Pandian said some of the north-eastern states and West Bengal appear to be the outliers as haemorrhagic cases are more prevalent. One of the possible reasons, he suggested, was high salt intake in these states. “In tea gardens, for example, people would have the habit of drinking tea mixed with salt to keep them hydrated for extraneous work,” he explained.
Certain practices, followed, especially, in southern India, make women after delivery vulnerable to strokes. Pandian explained that some pockets in this region have a habit of not giving water to the women till seven days after childbirth. This can lead to clot formation, he said.
“Pregnancy itself makes one a little more susceptible to clots, add to this the dehydration, and then, if at all one is genetically predisposed to strokes too…all these factors combined can make a woman very vulnerable to stroke,” the CMC neurologist explained.
TB meningitis, or what is known as brain TB in common parlance, can also lead to brain strokes. According to the paper, 15-60% of cases of TB meningitis report Ischemic strokes. “Tuberculosis (TB) remains a significant health problem in the SEAR. Two-thirds of the global caseload of TB is clustered in eight countries, and four of them (India, Indonesia, Pakistan, and Bangladesh) are in the SEAR,” the paper reads.
Dengue virus can also be one of the contributing factors. The paper says the specific causative mechanisms of stroke in dengue patients are poorly understood. Pandian said, empirically, if platelets are very low, it might lead to bleeding in various parts of the body, including the brain, and hence a stroke.
“But there is no cut-off of how low,” he said. Even some of the inflammatory response [immune system going into overdrive] to the dengue virus might lead to clot formation, Pandian explained.
As far as the common people are concerned, his prescription was simple, especially for those who suffer from hypertension and/or diabetes. “It is often seen people stop taking their medicines once these two parameters get to levels that they desire, and this is an invitation to many complications, including a stroke,” he said.
Sometimes these people suffer from a minor stroke – like numbness in one side of the body for 24 hours or less, he said, adding, that most of these strokes can be well taken care of, especially the ischemic ones and the patients land in hospitals in time. But when such minor strokes are ignored because of less enormity, they become fatal.