Characteristics of Cerebral Stroke in the Tibet Autonomous Region of China

Abstract

It is well known that cerebrovascular disease has become an important cause of adult death and disability. Strikingly, the Tibet Autonomous Region (TAR) ranks on the top in China for the incidence of stroke. To help explain this phenomenon, we have searched for and analyzed stroke-related literature for the TAR in the past 2 decades and have referenced reports from other regions at similar altitudes. This article focuses on epidemiology features, risk factors, and pathogenesis of stroke in the TAR in an effort to generate a better understanding of the characteristics of stroke in this region. The special plateau-related factors such as its high elevation, limited oxygen, the high incidence of hypertension, smoking, and the unique dietary habits of the region are correlated with the high incidence of stroke. In addition to these factors, the pathogenesis of stroke in this high-altitude area is also unique. However, there is no established explanation for the unique occurrence and high incidence of stroke in the TAR. Our study provides an important rationale not only for the clinic to prevent and treat this disease, but also for the government to develop appropriate health policies for the prevention of stroke in the TAR.

Stroke at Moderate and High Altitude

“…After identifying relevant articles that discussed stroke at high altitude, and cross referencing, we found one review (Ortiz-Prado and Dunn, 2011), eight case series (including pooled analysis) (Razdan et al, 1989;Jaillard et al, 1995;al Tahan et al, 1998;Jha et al, 2002;Niaz and Nayyar, 2003;Mahajan et al, 2004;Dhiman et al, 2018;Zhang et al, 2020), and seven case reports (Murdoch, 1995;Dietz and McKiel, 2000;Bandyopadhyay et al, 2002;Wilson et al, 2011;Chan et al, 2012;Yanamandra et al, 2014;Chandler and Mellor, 2016) that were considered appropriate for this review. Of the eight case series, four were from high altitude, including a pooled analysis (more than 2,500 m) ( Jaillard et al, 1995;Jha et al, 2002;Niaz and Nayyar, 2003;Zhang et al, 2020), and four were from moderate altitude (1,500-2,500 m) (Razdan et al, 1989;al Tahan et al, 1998;Mahajan et al, 2004;Dhiman et al, 2018). Additional literature review was done for the epidemiology, pathophysiology, and mechanisms of stroke at high altitude.…”

“…This increase was found particularly in younger age, mostly between 20 and 45 years. The stroke rates were found to be 10 times (Niaz and Nayyar, 2003) to 13 times (Razdan et al, 1989;Jaillard et al, 1995;al Tahan et al, 1998;Dietz and McKiel, 2000;Anand et al, 2001;Bandyopadhyay et al, 2002;Jha et al, 2002;Mahajan et al, 2004;Wilson et al, 2011;Chan et al, 2012;Yanamandra et al, 2014;Murdoch, 2015;Chandler and Mellor, 2016;Dhiman et al, 2018;Zhang et al, 2020) higher among people living at very high altitude and extremely high altitude.…”

“…The study from Cuzco City in Peru, located 3,400 m above sea level, found a crude prevalence of stroke of 6.47 per 1,000 population ( Jaillard et al, 1995). A recent study from the Tibet Autonomous Region reported an ageadjusted incidence of 4.5 per 1,000 compared with 2.36 per 1,000 in rest of the stroke belt of China and 1.1 per 1,000 in regions of China that are not considered as stroke belt (Zhang et al, 2020). Table 1 summarizes the demographic and clinical features of stroke at high altitude.…”

“…IS remains the predominant type of strokes; however, the incidence of hemorrhage may be comparatively higher at high altitudes. The study from Tibet Autonomous Region reported IS in 59% of patients and HS in 36% of patients (Zhang et al, 2020). In the study from Himachal Pradesh, for those patients in whom neuroimaging was available, 71.8% had IS, 27% had intracerebral hemorrhage (ICH), and 1 patient had subarachnoid hemorrhage (Mahajan et al, 2004).…”

Anterior Circulation Acute Ischemic Stroke in the Plateau of China: Risk Factors and Clinical Characteristics

“…An altitude above 1,500 m has an impact on human physiology. The unique climate, geographical environment, and customs have resulted in complex epidemiological features, pathogenic factors, and disease course characteristics ( 6 , 7 ). Although the country has the largest plateau globally and a resident population of about 12 million ( 8 ), stroke in highland areas has not been extensively studied, and no separate guidelines for prevention and treatment have been developed.…”