|Year : 2017 | Volume
| Issue : 1 | Page : 2-3
Climatic variations and stroke: Indian perspective
Telangana Neuro Centre, Warangal, Telangana, India
|Date of Web Publication||14-Mar-2017|
TNC Medical Foundation, Hanamkonda, Warangal, Telangana
Source of Support: None, Conflict of Interest: None
|How to cite this article:|
Chaudhary N. Climatic variations and stroke: Indian perspective. J Mahatma Gandhi Inst Med Sci 2017;22:2-3
Stroke is defined as focal neurological deficit resulting from diseases of cerebral vasculature and its contents. Among the developing countries, noncommunicable diseases (NCDs) are replacing the communicable diseases because of improved health-care services and emphasis on preventive medicine. Among the NCDs, neurological disorders form a significant proportion. The neuroepidemiology aids to assess the magnitude of the problem and guides the health needs at local, regional and national levels. This also quantifies the need of development of infrastructure along with provision of necessary resources and affordable care. The data from western countries cannot give a guideline for a country with a population >1.2 billion.
The origin of neuroepidemiology in India can be traced back to the 1960s when it was limited to epilepsy and stroke only. The expansion of neuroepidemiology was firmly rooted in the 1980s when community based studies for a spectrum of neurological disorders were initiated in Bangalore, Bombay, Delhi and Kashmir. Six studies were published between 1982 and 1995 covering the north, south and east zones of India including urban and rural population with a population size ranging from 17,000 to 100,000. The prevalence of neurological disorders was found to be 967-4070 with an average of 2394 per lakh population. The prevalence was greater in females (Bangalore and Malda),, and in the rural population (1.9:1 ratio).
Epidemiology of stroke is unique in nature because of its rapid rise in prevalence and incidence in India. The factors attributed are hypertension, diabetes mellitus, obesity, smoking, urbanization, stress and many unidentified social and cultural factors. The first large urban and rural population survey on stroke was conducted by Dr. Abraham in the late 1960s in Vellore. The last four decades have witnessed around 1700 research papers published in stroke. The crude prevalence rate of completed strokes varies from 52 to 472 per lakh person with the exception of the Parsi community who have very high rate of stroke at 842 [Table 1]. Higher prevalence rate was seen in urban population (153 per lakh) versus rural (93 per lakh). This regional variation may be due to degree and nature of risk factors. It is interesting to note that two surveys done in two different areas of Kolkata showed remarkable difference in crude prevalence rate, 147 in south Kolkata versus 487 in central Kolkata. This needs further exploration to identify the hidden risk factors by case control studies. The meta-analysis of studies conducted from 1980-2000 gave the average prevalence rate of 154 per lakh population whereas, between 2000 and 2015, it has increased from baseline 108 to 133 per lakh population.
|Table 1: Pattern of prevalence of stroke across rural and urban India,,|
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The overall incidence rate of stroke varies from region to region and the data are available only from few regions so far. The multi-center study “Indian collaborative acute stroke study” is on in seven cities of India and various other feasible studies are being done under the aegis of Indian Council of Medical Research. These two approaches will help develop national stroke registry. The last four decades of stroke related-papers published from India have revolved around the risk factors mentioned above. They have thrown light more on statistical data rather than the causative and risk factors. Of course, the therapeutic options have widened in its approach, but it is available only to the rich and elite of the urban population, beyond the reach of the poor and rural population. It is worth mentioning that around 30% of ischemic stroke in India are young (<45 years), which is two decades lower than the western counterparts. It is also a crude fact that with rising hypertension and diabetes, the stroke and cardiovascular disease will rise and the mortality will be at an alarming situation. The Government of India has launched the pilot phase of “National program for prevention and control of cancer, diabetes, cardiovascular diseases and stroke” in 100 districts. We hope that this initiative will help in decreasing the morbidity and mortality in stroke patients.
The relationship between the climate variation and stroke is a mixed bag. The average rainfall in a day and atmospheric pressure have failed to demonstrate the cause and effect relationship with stroke convincingly. On the other hand fall in the temperature below 9°C raises the prevalence of stroke three times (from 6 to 15 per day). There are scores of research papers from western and developed countries to substantiate this fact and some inconclusive pathomechanisms. There is a paucity of literature about the climate variation and stroke in India. It is common observation that elderly people die more frequently due to stroke during the winter season. Peninsular southern India due to lesser temperature variation will have a lower prevalence rate of stroke and death when compared to the sub-himalayan and central regions, where temperatures can drop below 0°C in the winter season. At the same time, the temperature may rise up to 50°C during summers in central and north India and humidity may reach 100% during rainy season. Effective prevention can be achieved in all parts of India against this climate invasion in the domain of stroke., Emerging and established comprehensive stroke centers in public or private sector can find out the exact pathophysiological correlation between climate and stroke supported by reputed medical research centers. This opens a new vista for research in the Indian sub-continent where stroke can also be analyzed from a new dimension such as climatic variations. However, the million dollar question is what insights can be gained from these studies and how they will make a difference in treatment of stroke , with a favourable outcome in future.
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