Background: Numerous studies on acute ischemic stroke (AIS) have been conducted at low-altitude regions, and the related findings have been used to guide clinical management. However, corresponding studies at high altitude are few. This study aimed to analyse the clinical characteristics of AIS patients at high-altitude regions through a hospital-based comparative study between Tibet and Beijing.Methods: This study included the diagnoses of AIS patients from People’s Hospital of Tibet Autonomous Region (PHOTAR) and Peking University First Hospital (PUFH) between 1 January 2014 and 31 December 2017, where data including patient demographics, treatment time, onset season, risk factors, infarction location, laboratory data, image examination results, treatments, and AIS subtype were collected and compared. Continuous and categorical variables were analysed with a two-sample t-test or Wilcoxon rank sum test and chi-square test, respectively. Significant risk factors were examined with binary logistic regression analysis.Results: In total, 236 and 1021 inpatients from PHOTAR and PUFH were included, respectively. The PHOTAR patients were younger than the PUFH patients (P<0.001). Young adult stroke, erythrocytosis, and hyperhomocysteinemia were more frequent in PHOTAR patients (all P<0.001). Other vascular risk factors, including hypertension, diabetes mellitus, hyperlipidaemia, and smoking and alcohol consumption history, were less prevalent in PHOTAR patients than in PUFH patients. The rate of intravenous thrombolysis and the rate of within intravenous thrombolysis window time were also lower in PHOTAR patients (both P<0.001). The PHOTAR group also tended to have anterior circulation infarction. Erythrocytosis and hyperhomocysteinemia were independent risk factors in PHOTAR, and young adults accounted for a larger proportion of stroke cases.Conclusion: In Tibet, AIS patients were relatively younger, and anterior circulation infarctions were more common. Erythrocytosis and hyperhomocysteinemia may contribute to these differences. Here, young adult stroke also accounted for a higher proportion, and this may be associated with erythrocytosis. Our findings present the first hospital-based comparative study in Tibet and may contribute to policies for stroke prevention in this region.

Background: Numerous studies of acute ischemic stroke (AIS) have been conducted at low altitude regions, and the related findings were used to instruct clinic management while corresponding studies at high altitude are few. This study aimed to analyse AIS clinic characteristics at high altitude regions by conducting a hospital-based comparative study between Tibet and Beijing. Methods: This study included the diagnoses of AIS patients from People’s Hospital of Tibet Autonomous Region (PHOTAR) and Peking University First Hospital (PUFH) between 1st January 2014, and 31st December 2017, where data including patient demographics, treatment time, onset season, risk factors, infarction location, laboratory data, image examination results, treatments, and AIS subtype were collected and compared. Continuous and categorical variables were analysed with a two-sample t-test or Wilcoxon rank sum test and chi-square test, respectively. Significant risk factors were examined with binary logistic regression analysis.Results: In total, 236 and 1021 inpatients from PHOTAR and PUFH were included, respectively. The PHOTAR patients were younger than the PUFH patients (P<0.001). Young adult stroke, erythrocytosis, and hyperhomocysteinemia were more frequent in PHOTAR patients (all P<0.001). Other vascular risk factors, including hypertension, diabetes mellitus, hyperlipidaemia, and smoking and alcohol consumption history, were less prevalent in PHOTAR patients than in PUFH patients. The rate of intravenous thrombolysis and the rate of within intravenous thrombolysis window time were also lower in PHOTAR patients (both P<0.001). PHOTAR groups also tended to have anterior circulation infarction. Erythrocytosis and hyperhomocysteinemia were independent risk factors in PHOTAR, and here young adults accounted for a larger proportion of stroke cases. Conclusion: In Tibet, the average age of AIS patients were less, and anterior circulation infarctions were also more common. Erythrocytosis and hyperhomocysteinemia may contribute to these differences. Here young adult stroke also accounted for a higher proportion, and this may be associated with erythrocytosis. Our findings present the first hospital-based comparative study in Tibet and may contribute to policies for stroke prevention in this region.

Background: Different physiological and pathological patterns have been found in the two sexes at high altitude. However, sex differences in brains remain unknown. Methods: T1-weighted MRI scanned in 61 Tibetan males and 68 Tibetan females aged 17-23, and Freesurfer was used to detect brain structures. Neuropsychological tests were also performed. Matched lowland Han subjects were controls. Results: Both Tibetan and Han males had larger global gray matter (GM) volume and white matter volume than females, while Tibetan but not Han female brains contained a larger proportion of GM than male brains. Tibetan females had significant smaller regional GM volume in the left rostral middle frontal gyrus, pars opercularis, and right caudal middle frontal gyrus, and moreover, GM volume in the left pars opercularis positively correlated with digit span score. However, Tibetans females had significantly thicker cortices in the left rostral middle frontal gyrus, left pars triangularis, right rostral middle frontal gyrus, and right pars triangularis than males and cortical thickness in these regions negatively correlated with altitude. In Tibetan females but not males, the negative correlation of cortical thickness with altitude has been testified by global analysis. Conversely, Han subjects showed discrepant sex differences in brains with Tibetans, showing larger regional GM volume and thicker cortices in different brain areas. Conclusion: A distinct pattern of sex differences exists between Tibetan and Han brains. Female brains may be more tolerable to hypoxia. Sex differences in the brains of Tibetans may be related to different neuropsychiatric performances in the two sexes.

Background: Lots of studies of acute ischemic stroke (AIS) had been conducted at low altitude regions, and related findings were used to instruct clinic management while corresponding studies at high altitude were few. This study aimed to analyse AIS clinic characteristics at high altitude regions by conducting a hospital-based comparative study between Tibet and Beijing. Methods: This study included the diagnoses of AIS patients from People’s Hospital of Tibet Autonomous Region (PHOTAR) and Peking University First Hospital (PUFH) between 1st January 2014, and 31st December 2017, where data including patient demographics, treatment time, onset season, risk factors, infarction location, laboratory data, image examination results, treatments, and AIS subtype were collected and compared. Continuous and categorical variables were analysed with a two-sample t-test or Wilcoxon rank sum test and chi-square test, respectively. Significant risk factors were examined with binary logistic regression analysis.Results: In total, 236 and 1021 inpatients from PHOTAR and PUFH were included, respectively. The PHOTAR patients were younger than the PUFH patients (P<0.001). Young adult stroke, erythrocytosis, and hyperhomocysteinemia were more frequent in PHOTAR patients (all P<0.001). Other vascular risk factors, including hypertension, diabetes mellitus, hyperlipidaemia, and smoking and alcohol consumption history, were less prevalent in PHOTAR patients than in PUFH patients. The rate of intravenous thrombolysis and the rate of within intravenous thrombolysis window time were also lower in PHOTAR patients (both P<0.001). PHOTAR groups also tended to have anterior circulation infarction. Erythrocytosis and hyperhomocysteinemia were independent risk factors in PHOTAR, and here young adults accounted for a larger proportion of stroke cases. Conclusion: In Tibet, the average age of AIS patients were less, and anterior circulation infarctions were also more common. Erythrocytosis and hyperhomocysteinemia may contribute to these differences. Here young adult stroke also accounted for a higher proportion, and this may be associated with erythrocytosis. Our findings present the first hospital-based comparative study in Tibet and may contribute to policies for stroke prevention in this region.

BackgroundLots of studies of acute ischemic stroke (AIS) had been conducted at low altitude regions, and related findings were used to instruct clinic management while corresponding studies at high altitude were few. This study aimed to analyse AIS clinic characteristics at high altitude regions by conducting a hospital-based comparative study between Tibet and Beijing.MethodsThis study included diagnoses of AIS patients from People’s Hospital of Tibet Autonomous Region (PHOTAR) and Peking University First Hospital (PUFH) between 1st January 2014, and 31st December 2017, where data including patient demographics, treatment time, onset season, risk factors, infarction location, laboratory data, image examination results, treatments, and AIS subtype were collected and compared. Continuous and categorical variables were analysed with a two-sample t-test or Wilcoxon rank sum test and chi-square test, respectively. Significant risk factors were examined with binary logistic regression analysis.ResultsIn total, 236 and 1021 inpatients from PHOTAR and PUFH were included, respectively. The PHOTAR patients were younger than the PUFH patients (P < 0.001). Young adult stroke, erythrocytosis, and hyperhomocysteinemia were more frequent in PHOTAR patients (all P < 0.001). Other vascular risk factors, including hypertension, diabetes mellitus, hyperlipidaemia, and smoking and alcohol consumption history, were less prevalent in PHOTAR patients than in PUFH patients. The rate of intravenous thrombolysis and intravenous thrombolysis window time were also lower in PHOTAR patients (both P < 0.001). PHOTAR groups also tended to have anterior circulation infarction. Erythrocytosis and hyperhomocysteinemia were independent risk factors in PHOTAR, and here young adults accounted for a larger proportion of stroke cases.ConclusionIn Tibet, the average age of AIS patients were less, and anterior circulation infarctions were also more common. Erythrocytosis and hyperhomocysteinemia may contribute to these differences. Here young adult stroke also accounted for a higher proportion, and this may be associated with erythrocytosis. Our findings present the first hospital-based comparative study in Tibet and may contribute to policies for stroke prevention in this region.