Key Points
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The South Asian region, which includes India, Pakistan, Sri Lanka and Bangladesh, has a high prevalence of stroke, especially in younger individuals, and short-term mortality from stroke is also high
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In addition to traditional risk factors for stroke, nontraditional factors including chewing tobacco are widespread in this region
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South Asia accounts for the largest proportion of the global burden of stroke in pregnancy and cerebral venous thrombosis
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Acute stroke care, including thrombolysis and stroke units, is limited in South Asia, and stroke prevention strategies are nonexistent at the national level
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Cost-effective interventions are needed owing to financial constraints
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Important areas of intervention include public awareness and physician training, as well as strong advocacy efforts and implementation research
Abstract
Three of the world's top 10 most populous countries are located in South Asia. The health-care problems of this region are different from those in the developed world, and the rapidly changing socioeconomic scenario, fast-increasing urbanization and longevity, changes in dietary patterns, and decrease in mortality from infectious diseases has made chronic illnesses of old age, such as coronary artery disease and stroke, an important area of focus. This article reviews stroke epidemiology and management issues in four South Asian countries: India, Pakistan, Sri Lanka and Bangladesh. The available literature is limited and mostly hospital-based, and differing study methodologies make direct comparisons difficult. The high prevalence of traditional risk factors, including hypertension, diabetes, dyslipidaemia and smoking, in these countries is alarming, and several nontraditional risk factors, such as water-pipe use, desi ghee, chewable tobacco, and infectious causes of stroke, are understudied. Access to tertiary stroke care is limited, and the use of tissue plasminogen activator is scarce. In addition, public and caregiver awareness of stroke risk factors and management is disappointing, and the interest of governments and policy makers in stroke is suboptimal. Interventions to reduce stroke burden and stroke-related mortality in South Asia should have a substantial impact at the global level.
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References
Feigin, V. L., Lawes, C. M., Bennett, D. A., Barker-Collo, S. L. & Parag, V. Worldwide stroke incidence and early case fatality reported in 56 population-based studies: a systematic review. Lancet Neurol. 8, 355–369 (2009).
Kulshreshtha, A., Anderson, L. M., Goyal, A. & Keenan, N. L. Stroke in South Asia: a systematic review of epidemiologic literature from 1980 to 2010. Neuroepidemiology 38, 123–129 (2012).
Hashmi, M., Khan, M. & Wasay, M. Growing burden of stroke in Pakistan: a review of progress and limitations. Int. J. Stroke 8, 575–581 (2013).
Razdan, S., Kaul, R. L., Motta, A. & Kaul, S. Cerebrovascular disease in rural Kashmir, India. Stroke 20, 1691–1693 (1989).
Dhamija, R. K. Long term outcome of stroke in rural communities. J. Assoc. Physicians India 47, 39 (1999).
Banerjee, T. K., Mukherjee, C. S. & Sarkhel, A. Stroke in the urban population of Calcutta—an epidemiological study. Neuroepidemiology 20, 201–207 (2001).
Bhattacharya, S., Saha, S. P., Basu, A. & Das, S. K. A 5 years prospective study of incidence, morbidity and mortality profile of stroke in a rural community of eastern India. J. Indian Med. Assoc. 103, 655–659 (2005).
Das, S. K. et al. A prospective community-based study of stroke in Kolkata, India. Stroke 38, 906–910 (2007).
Dalal, P. M., Bhattacharjee, M., Vairale, J. & Bhat, P. Mumbai stroke registry (2005–2006)—surveillance using WHO steps stroke instrument—challenges and opportunities. J. Assoc. Physicians India 56, 675–680 (2008).
Prasad, K., Vibha, D. & Meenakshi. Cerebrovascular disease in South Asia—Part I: a burning problem. JRSM Cardiovasc. Dis. 1, pii: cvd.2012.012025 (2012).
Farooq, M. U., Majid, A., Reeves, M. J. & Birbeck, G. L. The epidemiology of stroke in Pakistan: past, present, and future. Int. J. Stroke 4, 381–389 (2009).
Khatri, I. A. & Wasay, M. Can we stop the stroke epidemic in Pakistan? J. Coll. Physicians Surg. Pak. 21, 195–196 (2011).
Kamal, A. K. et al. The burden of stroke and transient ischemic attack in Pakistan: a community-based prevalence study. BMC Neurol. 9, 58 (2009).
Jafar, T. H. Blood pressure, diabetes, and increased dietary salt associated with stroke—results from a community-based study in Pakistan. J. Hum. Hypertens. 20, 83–85 (2006).
Gunaratne, P. S., Fernando, A. & Sharma, V. K. Development of stroke care in Sri Lanka. Int. J. Stroke 4, 38–39 (2009).
Mohammad, Q. D. et al. Prevalence of stroke above forty years. Mymensingh Med. J. 20, 640–644 (2011).
Das, S. K. et al. A prospective community-based study of stroke in Kolkata, India. Stroke 38, 906–910 (2007).
Dalal, P. M. et al. Population-based stroke survey in Mumbai, India: incidence and 28-day case fatality. Neuroepidemiology 31, 254–261 (2008).
Nagaraja, D. et al. Feasibility study of stroke surveillance: data from Bangalore, India. Indian J. Med. Res. 130, 396–403 (2009).
Kaul, S. et al. Subtypes of ischemic stroke in a metropolitan city of South India (one year data from a hospital based stroke registry). Neurol. India 50 (Suppl.), S8–S14 (2002).
Kaul, S. Stroke in India: are we different from the world? Pak. J. Neurol. Sci. 2, 158–164 (2007).
Dalal, P. M., Shah, P. M., Aiyar, R. R. & Kikani, B. J. Cerebrovascular diseases in west central India. A report on angiographic findings from a prospective study. Br. Med. J. 3, 769–774 (1968).
Padma, M. V., Gaikwad, S., Jain, S., Maheshwari, M. C. & Misra, N. K. Distribution of vascular lesions in ischaemic stroke: a magnetic resonance angiographic study. Natl Med. J. India 10, 217–220 (1997).
Syed, N. A. et al. Ischemic stroke subtypes in Pakistan: the Aga Khan University Stroke Data Bank. J. Pak. Med. Assoc. 53, 584–588 (2003).
Khealani, B. A. Hameed, B. & Mapari, U. U. Stroke in Pakistan. J. Pak. Med. Assoc. 58, 400–403 (2008).
Aquil, N., Begum, I., Ahmed, A., Vohra, E. A. & Soomro, B. A. Risk factors in various subtypes of ischemic stroke according to TOAST criteria. J. Coll. Physicians Surg. Pak. 21, 280–283 (2011).
Wasay, M. et al. Frequency and outcome of carotid atheromatous disease in patients with stroke in Pakistan. Stroke 40, 708–712 (2009).
Basharat, R. A., Yousuf, M., Iqbal, J. & Khan, M. M. Frequency of known risk factors for stroke in poor patients admitted to Lahore general hospital in 2000. Pak. J. Med. Sci. 18, 280–283 (2000).
Khan, M. et al. Stroke radiology and distinguishing characteristics of intracranial atherosclerotic disease in native South Asian Pakistanis. Int. J. Stroke 8 (Suppl. A100), 14–20 (2013).
Gunatilake, S. B., Jayasekera, B. A. & Premawardene, A. P. Stroke subtypes in Sri Lanka—a hospital based study. Ceylon Med. J. 46, 19–20 (2001).
Islam, M. N. et al. Burden of stroke in Bangladesh. Int. J. Stroke 8, 211–213 (2013).
Siddique, A. N., Nur, Z., Mahbub, S., Alam, B. & Miah, T. Clinical presentation and epidemiology of stroke: a study of 100 cases. J. Medicine 10, 86–89 (2009).
Miah, A. H. et al. Seasonal variation in types of stroke and its common risk factors. Mymensingh Med. J. 21, 13–20 (2012).
Khan, J. A. & Shah, M. A. Young stroke: clinical aspects. J. Coll. Physicians Surg. Pak. 10, 461–466 (2000).
Joshi, S. R. et al. Prevalence of diagnosed and undiagnosed diabetes and hypertension in India—results from the Screening India's Twin Epidemic (SITE) study. Diabetes Technol. Ther. 14, 8–15 (2012).
Zafar, A., Shahid, S. K., Siddiqui, M. & Khan, F. S. Pattern of stroke in type 2 diabetic subjects versus non diabetic subjects. J. Ayub Med. Coll. Abbottabad 19, 64–67 (2007).
Kamal, A. K. et al. The Karachi intracranial stenosis study (KISS) Protocol: an urban multicenter case–control investigation reporting the clinical, radiologic and biochemical associations of intracranial stenosis in Pakistan. BMC Neurol. 9, 31 (2009).
Srinivasan, K. Ischemic cerebrovascular disease in the young. Two common causes in India. Stroke 15, 733–735 (1984).
Lipska, K. et al. Risk factors for acute ischemic stroke in young adults in South India. J. Neurol. Neurosurg. Psychiatry 78, 959–963 (2007).
Razzaq, A. A., Khan, B. A. & Baig, S. M. Ischemic stroke in young adults of South Asia. J. Pak. Med. Assoc. 52, 417–422 (2002).
Christopher, R., Kailasanatha, K. M., Nagaraja, D. & Tripathi, M. Case–control study of serum lipoprotein(a) and apolipoproteins A-I and B in stroke in the young. Acta Neurol. Scand. 94, 127–130 (1996).
Nagaraja, D., Christopher, R. & Manjari, T. Anticardiolipin antibodies in ischemic stroke in the young: Indian experience. J. Neurol. Sci. 150, 137–142 (1997).
Vibha & Laskar, A. R. Women's health: beyond reproductive years. Indian J. Public Health 55, 247–251 (2011).
Wasay, M. et al. Ischemic stroke in young Asian women: risk factors, subtypes and outcome. Cerebrovasc. Dis. 30, 418–422 (2010).
Wasay, M. et al. Predictors of cerebral venous thrombosis and arterial ischemic stroke in young Asian women. J. Stroke Cerebrovasc. Dis. 21, 689–694 (2012).
Khan, M. et al. Pregnancy and puerperium-related strokes in Asian women. J. Stroke Cerebrovasc. Dis. 22, 1393–1398 (2013).
Mehndiratta, M. M., Aggarwal, P., Gupta, M., Puri, V. & Aggarwal, S. Stroke in 127 young people. Presented at the Lancet Stroke Conference, Montreal, 1998.
Kaul, S. Cerebrovascular disease in children. Indian Pediatr. 37, 159–171 (2000).
Murty, A. et al. Etiological spectrum and outcome of pediatric stroke at a tertiary referral center in South India. Presented at the Annual Conference of the Indian Academy of Neurology, Trichy, 2010.
Siddiqui, T. S., Rehman, A. & Ahmed, B. Etiology of strokes and hemiplegia in children presenting at Ayub Teaching Hospital, Abbottabad. J. Ayub Med. Coll. Abbottabad 18, 60–63 (2006).
Gupta, R. Trends in hypertension epidemiology in India. J. Hum. Hypertens. 18, 73–78 (2004).
Bhagyalaxmi, A., Atul, T. & Shikha, J. Prevalence of risk factors of non-communicable diseases in a District of Gujarat, India. J. Health Popul. Nutr. 31, 78–85 (2013).
Sridharan, S. E. et al. Incidence, types, risk factors, and outcome of stroke in a developing country the Trivandrum stroke registry. Stroke 40, 1212–1218 (2009).
Thakur, J. S., Garg, R., Narain, J. P. & Menabde, N. Tobacco use: a major risk factor for non communicable diseases in South-East Asia region. Indian J. Public Health 55, 155–160 (2011).
Sinha, D. N., Gupta, P. C., Ray, C. & Singh, P. K. Prevalence of smokeless tobacco use among adults in WHO South-East Asia. Indian J. Cancer 49, 342–346 (2012).
Mohan, V., Sandeep, S., Deepa, R., Shah, B. & Varghese, C. Epidemiology of type 2 diabetes: Indian scenario. Indian J. Med. Res. 125, 217–230 (2007).
Sharma, U. et al. Dyslipidemia and associated risk factors in a resettlement colony of Delhi. J. Clin. Lipidol. 7, 653–660 (2013).
Krishnan, M. N. Coronary heart disease and risk factors in India—on the brink of an epidemic? Indian Heart J. 64, 364–367 (2012).
Khealani, B. A. & Wasay, M. Burden of stroke in Pakistan. Int. J. Stroke 3, 293–296 (2008).
Jafar, T. H. et al. Ethnic subgroup differences in hypertension in Pakistan. J. Hypertens. 21, 905–912 (2003).
Alam, S. E. Prevalence and pattern of smoking in Pakistan. J. Pak. Med. Assoc. 48, 64–66 (1998).
Ahmad, K. et al. Prevalence and predictors of smoking in Pakistan: results of the National Health Survey of Pakistan. Eur. J. Cardiovasc. Prev. Rehabil. 12, 203–208 (2005).
Gilani, S. I. & Leon, D. A. Prevalence and sociodemographic determinants of tobacco use among adults in Pakistan: findings of a nationwide survey conducted in 2012. Popul. Health Metr. 11, 16 (2013).
Jafar, T. H. et al. Ethnic differences and determinants of diabetes and central obesity among South Asians of Pakistan. Diabet. Med. 21, 716–723 (2004).
Jafar, T. H., Jafary, F. H., Jessani, S. & Chaturvedi, N. Heart disease epidemic in Pakistan: women and men at equal risk. Am. Heart J. 150, 221–226 (2005).
Jafar, T. H., Chaturvedi, N. & Pappas, G. Prevalence of overweight and obesity and their association with hypertension and diabetes mellitus in an Indo-Asian population. CMAJ 175, 1071–1077 (2006).
Islam, A. K. & Majumder, A. A. Hypertension in Bangladesh: a review. Indian Heart J. 64, 319–323 (2012).
Hossain, A. M. et al. Analysis of sociodemographic and clinical factors associated with hospitalized stroke patients of Bangladesh. Faridpur Med. Coll. J. 6, 19–23 (2011).
Badiuzzaman, M. et al. Prevalence of modifiable risk factors among stroke patients in a tertiary care hospital in Dhaka. J. Med. 10 (Suppl. 1), S18–S21 (2009).
Global Tobacco Surveillance System. Global adult tobacco survey: Bangladesh report 2009. WHO [online], (2009).
Akhter, A. et al. Prevalence of diabetes mellitus and its associated risk indicators in a rural Bangladeshi population. The Open Diabetes Journal 4, 6–13 (2011).
Mostafa Zaman, M. et al. Plasma lipids in a rural population of Bangladesh. Eur. J. Cardiovasc. Prev. Rehabil. 13, 444–448 (2006).
Zaman, M. M. et al. Cardiovascular risk factors: distribution and prevalence in a rural population of Bangladesh. J. Cardiovasc. Risk 8, 103–108 (2001).
Wijewardene, K. et al. Prevalence of hypertension, diabetes and obesity: baseline findings of a population based survey in four provinces in Sri Lanka. Ceylon Med. J. 50, 62–70 (2005).
Mendis, S. & Ekanayake, E. M. Prevalence of coronary heart disease and cardiovascular risk factors in middle aged males in a defined population in central Sri Lanka. Int. J. Cardiol. 46, 135–142 (1994).
Somatunga, L. C. et al. Smokeless tobacco use in Sri Lanka. Indian J. Cancer 49, 357–363 (2012).
Katulanda, P., Jayawardena, M. A., Sheriff, M. H., Constantine, G. R. & Matthews, D. R. Prevalence of overweight and obesity in Sri Lankan adults. Obes. Rev. 11, 751–756 (2010).
Tennakoon, S. U., Kumar, B. N., Selmer, R., Mikram, M. J. & Meyer, H. E. Differences in predicted cardiovascular risk in Sinhalese and Tamils in Sri Lanka compared with Sri Lankans in Norway. Asia Pac. J. Public Health 25, 452–462 (2013).
Panicker, J. N. & Madhusudanan, S. Cerebral infarction in a young male following viper envenomation. J. Assoc. Physicians India 48, 744–745 (2000).
Gawarammana, I., Mendis, S. & Jeganathan, K. Acute ischemic strokes due to bites by Daboia russelii in Sri Lanka—first authenticated case series. Toxicon 54, 421–428 (2009).
Chakrabarti, S. D., Ganguly, R., Chatterjee, S. K. & Chakravarty, A. Is squatting a triggering factor for stroke in Indians? Acta Neurol. Scand. 105, 124–127 (2002).
Taqui, A. M. & Wasay, M. Cerebral infarction in tuberculous meningitis. Pak. J. Neurol. Sci. 6, 25–29 (2011).
Kaul, S. & Munshi, A. Genetics of ischemic stroke: Indian perspective. Neurol. India 60, 498–503 (2012).
Saleheen, D. et al. Association of phosphodiesterase 4D gene with ischemic stroke in a Pakistani population. Stroke 36, 2275–2277 (2005).
Munshi, A. et al. Association of SNP41, SNP56 and a novel SNP in PDE4D gene with stroke and its subtypes. Gene 506, 31–35 (2012).
Roy, S. et al. Association of E-selectin gene polymorphism (S128R) with ischemic stroke and stroke subtypes. Inflammation http://dx.doi.org/10.1007/s10753-013-9774–0.
Kalita, J. et al. ACE and ADD1 gene in extra and intracranial atherosclerosis in ischaemic stroke. Neurol. Res. 35, 429–434 (2013).
Marugan, M. M., Alagirisamy, R., Manokaran, S. & Balkrishnan, A. Paroxenase activity and PON1(Q/R192) gene polymorphism in ischemic stroke patient. IJLPR 2, 169–176 (2012).
Lath, R. et al. Decompressive surgery for severe cerebral venous sinus thrombosis. Neurol. India 58, 392–397 (2010).
Nagaraja, D. & Sarma, G. R. Treatment of cerebral sinus/venous thrombosis. Neurol. India 50, 114–116 (2002).
Kalita, J., Bandal, V., Misra, U. K. & Phadke, R. V. Cerebral venous sinus thrombosis in a tertiary care setting in India. QJM 99, 491–492 (2006).
Khealani, B. A. et al. Cerebral venous thrombosis: a descriptive multicenter study of patients in Pakistan and Middle East. Stroke 39, 2707–2711 (2008).
Narayan, D. et al. Risk factors, clinical profile, and long-term outcome of 428 patients of cerebral sinus venous thrombosis: insights from Nizam's Institute Venous Stroke Registry, Hyderabad (India). Neurol. India 60, 19–24 (2012).
Wasay, M. & Jabbar, A. Fight against chronic diseases (high blood pressure, stroke, diabetes and cancer) in Pakistan; cost-effective interventions. J. Pak. Med. Assoc. 59, 196–197 (2009).
Khealani, B. A., Javed, Z. F., Syed, N. A., Shafqat, S. & Wasay, M. Cost of acute stroke care at a tertiary care hospital in Karachi, Pakistan. J. Pak. Med. Assoc. 53, 552–555 (2003).
Misra, B. K., Purandare, H. R., Ved, R. & Ashok, P. P. Carotid endarterectomy: results and long-term follow-up of a single institution. Neurol. India 59, 390–396 (2011).
Khatri, I. A., Siddiqui, M., Khan, I., Nadeem, M. & Ahmad, A. Salvage decompressive craniectomy in malignant MCA infarcts—results of local experience at Shifa International Hospital, Islamabad, Pakistan. J. Pak. Med. Assoc. 58, 404–408 (2008).
Nizami, F. A. et al. Decompressive hemicraniectomy in supra-tentorial malignant infarcts. Surg. Neurol. Int. 3, 29 (2012).
Pandian, J. D., Liu, M., Misbach, J. & Venketasubramanian, N. Alternative therapies for stroke treatment in Asia. Int. J. Stroke 6, 541–543 (2011).
Khan, F. R. et al. Physiotherapy practice in stroke rehabilitation: a cross-sectional survey of physiotherapists in the state of Kerala, India. Top. Stroke Rehabil. 19, 405–410 (2012).
Kumar, H. & Gupta, N. Neurological disorders and barriers for neurological rehabilitation in rural areas in Uttar Pradesh: a cross-sectional study. J. Neurosci. Rural Pract. 3, 12–16 (2012).
Thomas, M. Community based rehabilitation in India—an emerging trend. Indian J. Pediatr. 59, 401–406 (1992).
Rathore, F. A., New, P. W. & Iftikhar, A. A report on disability and rehabilitation medicine in Pakistan: past, present, and future directions. Arch. Phys. Med. Rehabil. 92, 161–166 (2011).
Wijeratne, T. Neurorehabilitation in Sri Lanka: an emerging sub-specialty for neurology trainees. Int. J. Stroke 7, 163–164 (2012).
Islam, M. N. et al. Burden of stroke in Bangladesh. Int. J. Stroke 8, 211–213 (2013).
Maloni, P. K. et al. Perceptions of disability among mothers of children with disability in Bangladesh: implications for rehabilitation service delivery. Disabil. Rehabil. 32, 845–854 (2010).
Hankey, G. J. et al. Five-year survival after first-ever stroke and related prognostic factors in the Perth Community Stroke Study. Stroke 31, 2080–2086 (2000).
Bamford, J., Dennis, M., Sandercock, P., Burn, J. & Warlow, C. The frequency, causes and timing of death within 30 days of a first stroke: the Oxfordshire Community Stroke Project. J. Neurol. Neurosurg. Psychiatry 53, 824–829 (1990).
Murray, C. J. & Lopez, A. D. Global Comparative Assessments in the Health Sector: Disease Burden, Expenditures and Intervention Packages (WHO, 1994).
Biswas, M., Sen, S. & Simmons, J. Etiology and risk factors of ischemic stroke in Indian-American patients from a hospital-based registry in New Jersey. Neurol. Asia 14, 81–86 (2009).
Ray, B. K. et al. Early and delayed fatality of stroke in Kolkata, India: results from a 7-year longitudinal population-based study. J. Stroke Cerebrovasc. Dis. 22, 281–289 (2013).
Mateen, F. J., Carone, M., Alam, N., Streatfield, P. K. & Black, R. E. A population-based case–control study of 1250 stroke deaths in rural Bangladesh. Eur. J. Neurol. 19, 999–1006 (2012).
Das, K., Mandal, G. P., Dutta, A. K., Mukherjee, B. & Mukherjee, B. B. Awareness of warning symptoms and risk factors of stroke in the general population and in survivors of stroke. J. Neurosci. 14, 12–16 (2007).
Pandian, J. D. et al. Public awareness of warning symptoms, risk factors, and treatment of stroke in North West India. Stroke 36, 644–648 (2005).
Aly, Z. et al. Awareness of stroke risk factors, signs and treatment in a Pakistani population. J. Pak. Med. Assoc. 59, 495–499 (2009).
Srivastab, A. K. & Prasad, K. A study of factors delaying hospital arrival of patients with acute stroke. Neurol. India 49, 272–276 (2001).
Wasay, M. et al. Knowledge gaps in stroke care: results of a survey of family physicians in Pakistan. J. Stroke Cerebrovasc. Dis. 20, 282–286 (2011).
Prasad, K. et al. Stroke management. Ann. Indian Acad. Neurol. 14 (Suppl. 1), S82–S96 (2011).
Kamal, A. K. et al. Ischemic stroke care—official guidelines from the Pakistan Society of Neurology. Pak. J. Neurol. Sci. 5, 38–43 (2010).
Gunaratne, P. S. & Jeevatharan, H. World Stroke Day 2009, gold award winner. Int. J. Stroke 5, 323–324 (2010).
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Wasay, M., Khatri, I. & Kaul, S. Stroke in South Asian countries. Nat Rev Neurol 10, 135–143 (2014). https://doi.org/10.1038/nrneurol.2014.13
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