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Background: Numerous studies have shown that residential greenness positively correlates with enhanced health. Metabolic dysfunction-associated fatty liver disease (MAFLD) affects about a quarter of the population while lacking specific treatments. Given that the association between green space and MAFLD is still unknown, we explored the association between residential greenness and MAFLD as well as the potential mechanisms based on the baseline survey of the China Multi-Ethnic Cohort (CMEC). Methods: Residential greenness was expressed as normalized difference vegetation index (NDVI) and enhanced vegetation index (EVI). MAFLD was assessed through hepatic steatosis, the presence of overweight/obesity, type 2 diabetes mellitus, and evidence of metabolic dysregulation. We used logistic regression to examine the association between NDVI/EVI and the prevalence of MAFLD. Moreover, we utilized causal mediation analyses to explore the role of physical activity and ambient particulate matters (PM1, PM2.5, and PM10) on the association between residential greenness and MAFLD. Results: We included 72,368 participants from the CMEC and found that residential greenness was negatively associated with the prevalence of MAFLD. For an interquartile range (IQR) increase in NDVI500 m and EVI500 m, the odds ratio (OR) of MAFLD were 0.78 (95 %CI: 0.75, 0.81) and 0.81 (95 %CI: 0.78, 0.84), respectively. Greater association between residential greenness and MAFLD was observed among males. Air pollutants and physical activity could mediate a partial effect (8.5–22.9 %) of residential greenness on MAFLD. Conclusion: Higher residential greenness was associated with decreased risk of MAFLD. Moreover, the association was greater among males. The protective effects of residential greenness may be achieved by mitigating the hazardous effects of air pollutants and encouraging physical activity.

Abstract Background Obesity, diabetes, and hypertension, as three of the most prevalent chronic diseases, remain a daunting health challenge. However, to our knowledge, no study has made a thorough examination of the association between the three chronic diseases and daytime napping, a widely accepted behavior in many countries. This is especially necessary among Tibetan populations, whose lifestyles and health outcomes may be unique, yet patterns of chronic diseases and napping are under-examined. Thus, we sought to explore the aforementioned association in the Tibetan population of China. Methods A total of 2902 participants aged 45–79 in 2019 were included. Multivariate logistic regressions were conducted in 2020. The sex disparity was examined through interaction and stratified analyses. Results Hypertension (40.7%) was more prevalent than obesity (20.2%) and diabetes (21.6%). Comparing to non-nappers, those who napped were more likely to have any conditions (OR = 1.30, 95% CI = 1.04–1.62 for 1–59 min/day group and OR = 1.40, 95% CI = 1.10–1.80 for ≥60 min/day group). Participants who had 1–59 min/day of napping were more likely to develop obesity (OR = 1.37, 95% CI = 1.07–1.75), and ≥ 60 min/day of napping was associated with diabetes (OR = 1.33, 95% CI = 1.01–1.74). The interactions between napping and sex were not statistically significant in the models. Conclusions The study revealed napping was unfavorably associated with obesity, diabetes, and any conditions in Tibetan people living on the Tibetan Plateau. Future interventions regarding the three chronic diseases may pay more attention to napping. Trial registration Not applicable.

Abstract Background Self-rated health (SRH) has been frequently used in population health surveys. However, most of these studies only focus on specific factors that might directly affect SRH, so only partial or confounding information about the determinants of SRH is potentially obtained. Conducted in an older Tibetan population in a Chinese plateau area, the aim of our study is to assess interrelationships between various factors affecting SRH based on the conceptual framework for determinants of health. Methods Between May 2018 and September 2019, 2707 Tibetans aged 50 years or older were recruited as part of the China Multi-Ethnic Cohort Study (CMEC) from the Chengguan District of Lhasa city in Tibet. The information included SRH and variables based on the conceptual framework for determinants of health (i.e., socioeconomic status, health behaviors, physical health, mental health, and chronic diseases). Structural equation modeling (SEM) was used to estimate the direct and indirect effects of multiple factors in the conceptual framework. Results Among all participants, 5.54% rated their health excellent, 51.16% very good, 33.58% good, 9.12% fairly poor and 0.59% poor. Physical health (β = − 0.23, P

BackgroundThe association between habitual food intake in Tibet and metabolic syndrome (MetS) is largely unclear.ObjectiveTo examine the association between Tibetan habitual food intake and MetS among Tibetan adults.MethodsA population-based cross-sectional study, named the China Multi-Ethnic Cohort (CMEC) study, was conducted between 2018 and 2019. We used data from all Tibetans in the CMEC in the current study. The participants, 1,954 men and 3,060 women aged 18–79 years, were from Lhasa, Tibet Autonomous Region, Tibet. The habitual dietary intake was assessed using a food frequency questionnaire (FFQ). MetS was defined according to ATP III guidelines. Multivariate logistic regression was used to estimate the association between five Tibetan habitual foods and MetS.ResultsTsampa, butter tea, and Qing cha intake were associated with reduced prevalence of MetS. Compared with the lowest quartile of each food, odds ratios (ORs) and their 95% confidence intervals (95% CIs) of medium and high Tsampa intake were 0.59 (0.41–0.85) and 0.53 (0.36–0.77), ORs (95% CIs) of butter tea were 0.67 (0.52–0.88) and 0.61 (0.46–0.81), and Qing cha were 0.85 (0.71–1.03) and 0.75 (0.60–0.93), respectively. When exploring the joint effects of these three foods on MetS, the adjusted ORs and their 95% CIs were 0.65 (0.49–0.87) for the middle intake group and 0.59 (0.42–0.83) for the high intake group as compared with the never/rarely group (p = 0.022 for trend). Associations of MetS with Tibetan noodles and raw beef were not observed.ConclusionTsampa, butter tea, and Qing cha were negatively associated with MetS. The recommendation of increasing the intake of these foods may be beneficial for MetS prevention.

Background In Western developed countries, food-based dietary patterns have been associated with the risk of cardiometabolic diseases, but little is known about such associations in less developed ethnic minority regions (LEMRs), where the cardiometabolic disease burden is growing rapidly and food patterns differ substantially.Methods Between May 2018 and September 2019, we recruited 99556 participants aged 30-79 years from the China Multi-Ethnic Cohort (CMEC) Study. We measured habitual dietary intake with validated food frequency questionnaire (FFQ) and then calculated dietary pattern scores for two of the most studied a priori dietary patterns, i.e., Dietary Approaches to Stop Hypertension (DASH) and alternative Mediterranean (aMED) style diets, and three a posteriori dietary patterns. Four cardiometabolic risks, including hypertension, diabetes, dyslipidaemia and metabolic syndrome (MetS), were newly diagnosed by medical examination and blood tests. We estimated adjusted odds ratios (OR) relating various dietary pattern scores to cardiometabolic risks using marginal structural models under the guidance of directed acyclic graphs. For the above associations, we further calculated the proportion mediated by overweight (PM) using regression-based mediation analysis for better public health implications.Findings The final study sample consisted of 68834 participants. Among them, we newly diagnosed 12803 hypertension, 3527 diabetes, 16342 hyperlipidaemia, and 8198 MetS cases. Overall, all 5 dietary patterns showed considerable associations with risks of hypertension and MetS. Comparing the highest with the lowest quintiles, the DASH score showed the strongest inverse associations with risks of hypertension (OR=0.74, 95% CI:0.70-0.79; PM=10%) and MetS (OR=0.79, 95% CI:0.74-0.85; PM=35%); conversely, scores of the localized a posteriori Yunnan-Guizhou plateau dietary pattern in LEMRs showed the strongest positive associations with risks of hypertension (OR=1.44, 95% CI:1.35-1.52; PM=10%) and MetS (OR=1.35, 95% CI:1.26-1.46; PM=33%), with all P values for trend

Background: Exposure to a high-altitude environment is a risk factor for cerebral venous thrombosis (CVT) probably due to hypercoagulability. The study aims to explore the unique characteristics of CVT patients in high-altitude areas of China by comparing them with those in plain areas., Methods: We retrospectively included consecutive patients with CVT admitted to Tibet Autonomous Region People's Hospital (altitude 3650 m) and Peking Union Medical College Hospital (altitude 43.5 m) between January 2015 and December 2023. Patients from the plateau and the plain were considered two independent groups in this study. The risk factors, clinical and radiological presentations, treatment, and outcomes were analyzed and compared between the two groups., Results: A total of 169 patients with CVT were included in the study, 48 patients from plateau and 121 patients from plain. The median age was 27 and 34 years old, and women accounted for 66.7% and 54.5% respectively. Headache (91.7% vs. 71.1%, P = 0.004), altered consciousness (31.3% vs. 16.5%, P = 0.033), hemorrhage (41.7% vs. 19.0%, P = 0.002), and venous infarction (50.0% vs. 25.6%, P = 0.002) on imaging were more common in patients from plateau than those from plain. Pregnancy or puerperium was significantly more common in highland patients (25% vs. 5.8%, P < 0.001). The levels of D-Dimer (1.7 vs. 0.8 mg/L FEU, P = 0.01), fibrinogen (3.7 vs. 3.0 g/L, P < 0.001), hemoglobin (157 vs. 129 g/L, P = 0.01), white blood cells (9.6 vs. 7.5*10 12 /L, P < 0.001) and highly sensitive C-reactive protein (20.2 vs. 3.2 mg/L, P = 0.005) were remarkably higher in highland patients. The percentage of receiving anticoagulant therapy was lower in high-altitude patients (70.8% vs. 93.4%, P < 0.001). Favorable outcome at follow-up was observed in 81.4% of highland patients and 90.7% of lowland patients, with a median follow-up time of 330 days and 703 days respectively., Conclusions: The more severe clinical and imaging manifestations along with prominent inflammatory and hypercoagulable states were observed in plateau CVT patients, probably due to exposure to the hypoxic environment at high altitude. Pregnancy or puerperium were more common in highland patients. The overall prognosis of CVT patients from both groups were favorable., (© 2024. The Author(s).)

Introduction: Patients with clinically significant portal hypertension (CSPH) are recommended to be treated with non-selective beta-blockers (ie, carvedilol) to prevent the first hepatic decompensation event by the renewing Baveno VII consensus. CSPH is defined by hepatic venous pressure gradient (HVPG)≥10 mm Hg; however, the HVPG measurement is not widely adopted due to its invasiveness. Liver stiffness (LS)≥25 kPa can be used as a surrogate of HVPG≥10 mm Hg to rule in CSPH with 90% of the positive predicting value in majority aetiologies of patients. A compelling argument is existing for using LS≥25 kPa to diagnose CSPH and then to initiate carvedilol in patients with compensated cirrhosis, and about 5%-6% of patients under this diagnosis criteria may not be benefited from carvedilol and are at risk of lower heart rate and mean arterial pressure. Randomised controlled trial on the use of carvedilol to prevent liver decompensation in CSPH diagnosed by LS remains to elucidate. Therefore, we aimed to investigate if compensated cirrhosis patients with LS≥25 kPa may benefit from carvedilol therapy., Methods and Analysis: This study is a randomised, double-blind, placebo-controlled, multicentre trial. We will randomly assign 446 adult compensated cirrhosis patients with LS≥25 kPa and without any previous decompensated event and without high-risk gastro-oesophageal varices. Patients are randomly divided into two groups, with 223 subjects in group A and 223 subjects in group B. Group A is a carvedilol intervention group, while group B is a placebo group. All patients in both groups will receive aetiology therapies and are followed up at an interval of 6 months. The 3-year incidences of decompensated events of cirrhosis-related and liver-related death are the primary outcome. The secondary outcomes include development of each complication of portal hypertension individually (ascites, variceal bleeding or overt hepatic encephalopathy), development of spontaneous bacterial peritonitis and other bacterial infections, development of new varices, growth of small varices to large varices, delta changes in LS and spleen stiffness, change in hepatic dysfunction assessed by Child-Pugh and model for end-stage liver disease score, change in platelet count, development of hepatocellular carcinoma, development of portal vein thrombosis and adverse events with a 3-year follow-up. A predefined interim analysis will be performed to ensure that the calculation is reasonable., Ethics and Dissemination: The study protocol has been approved by the ethics committees of the Sixth People's Hospital of Shenyang (2023-05-003-01) and independent ethics committee for clinical research of Zhongda Hospital, affiliated to Southeast University (2023ZDSYLL433-P01). The results from this trial will be submitted for publication in peer-reviewed journals and will be presented at international conferences., Trial Registration Number: ChiCTR2300073864., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2024. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Objective: Health-related quality of life (HRQoL) was an important health outcome measure for evaluating an individual's overall health status. However, there was limited in the literature on HRQoL and its long-term changes of the Tibetan population. This study aimed to assess HRQoL of Tibetan and its changes over time, and explore the differences in HRQoL for residents at different altitudes., Design: Data for the cross-sectional study were extracted from the fifth and sixth waves of the National Health Services Surveys which were conducted in 2013 and 2018. A multistage stratified cluster random sampling strategy was used to select representative participants., Setting: Tibet Autonomous Region in China., Participants: This study recruited 14 752 participants in 2013 and 13 106 participants in 2018, and after excluding observations with missing values for key variables, 10 247 in 2013 and 6436 in 2018 were included in the study analysis., Primary and Secondary Outcome Measures: The EQ-5D-3L was used to measure participants' HRQoL., Results: The mean health state utility scores of the participants were 0.969±0.078 and 0.966±0.077 in 2013 and 2018, respectively. Pain/discomfort was the most frequently prevalent issue reported in 18.1% and 17.9% of the participants in 2013 and 2018, respectively. Tibetans living 3500-4000 m altitude had the best HRQoL. Age, sex, employment status, educational attainment, chronic disease and weekly physical exercise were influencing factors associated with HRQoL., Conclusions: The HRQoL of the Tibetan population was lower than the general Chinese population, and decreased over time between 5 years. There were differences in HRQoL among Tibetan at different altitudes, with residents living at 3500-4000 m having the best quality of life. More attention should be paid to those Tibetans who are older, female, unemployed and without formal education., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2023. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Background: Given the dramatic rise in population aging and widespread negative attitudes toward older people, it is necessary to understand the factors that affect age-related attitudes among young people in order to improve intergenerational solidarity and reduce ageism. The current study examined young people's contact with their grandparents and attitudes toward older people on both explicit and implicit levels., Method: The sample included 146 Chinese college students (M age = 21.50 yrs, SD = 2.23, 101 females). Participants completed a questionnaire concerning contact with their grandparents(contact quantity and contact quality), perceived typicality of their grandparents, intergroup anxiety, inclusion of other in the self, and explicit attitudes toward older people (aged 65 years or older) in general. Participants were also invited to complete a single-category implicit association test (SC-IAT) to assess their implicit attitudes toward older people., Results: The findings indicated that both quantity and quality of contact with grandparents predicted better explicit attitudes toward older people, and contact effects were stronger when one's grandparents were perceived as being typical of older adults. Contact quantity (not quality) was associated with more favorable implicit attitudes only when one's grandparents were perceived as highly typical older adults. Contact effects on explicit attitudes were mediated by intergroup anxiety and inclusion of other in the self., Conclusion: Our findings on the positive effects of contact with grandparents underscore the importance of promoting intergenerational contact within the family as a starting point to reduce prejudice toward older adults in age-segregated modern societies. Current results also provide insights on how to extend the benefits of grandparent-grandchild contact outside the family by promoting the perceived typicality of one's grandparents., (© 2023. BioMed Central Ltd., part of Springer Nature.)

Background: Providing equitable access to health care for all populations is an important sustainable development goal. China has made significant progress in achieving equity in healthcare utilization. However, research on equity in healthcare utilization in Tibet is sparse. This study aims to evaluate changes in income-related inequity in inpatient care utilization and unmet needs between 2013 and 2018 among the Tibetan population and identify the inequity source., Methods: Data for this cross-sectional study were obtained from the fifth and sixth waves of the National Health Services Survey in 2013 and 2018. After excluding observations with missing values for key variables, 11,092 and 10,397 respondents were included in this study, respectively. The outcome variables of interest were inpatient service utilization and unmet hospitalization needs. The concentration index and horizontal inequity index (HI) were used to assess income-related inequity. Non-linear decompositions were performed to identify the main contributors to inequity. In the decomposition method, need variables included sex, age, chronic diseases, and the EuroQol-Visual Analog Scale; non-need variables consisted of income, education, employment status, marital status, and health insurance schemes., Results: The probability of inpatient care utilization increased from 6.40% in 2013 to 8.50% in 2018. The HI for inpatient care utilization was 0.19 (P < 0.001) in 2013, whereas it decreased to 0.07 (P < 0.001) in 2018. The contribution of income to inequity in inpatient care utilization decreased from 87.09% in 2013 to 59.79% in 2018. As for unmet inpatient care needs, although its probability increased from 0.76 to 1.48%, the percentage of reasons for financial hardship decreased from 47.62 to 28.57%. The HI for unmet hospitalization need was - 0.07 in 2013 and - 0.05 in 2018, and neither was statistically significant. The New Rural Cooperative Medical Scheme made majority contributions to promote equity in unmet hospitalization need. Moreover, the female respondents reporting low EuroQol-Visual Analog Scale scores and patients with chronic disease were not only more likely to seek for inpatient care, but also have more unmet need than the reference groups., Conclusions: The inequity in inpatient care utilization in Tibet narrowed from 2013 to 2018, and there was no inequity in unmet hospitalization needs in 2013 and 2018. Income and the New Rural Cooperative Medical Scheme are the main drivers of equity promotion. To promote access to inpatient care utilization and decrease the probability of unmet hospitalization need in future, policymakers should target high-need residents in Tibet to improve accessibility, availability, and acceptability., (© 2023. The Author(s).)

Background: Studies of the impact of increased hemoglobin on spontaneous intracerebral hemorrhage (ICH) are limited. The present study aimed to explore the effect of increased hemoglobin on ICH., Methods: A retrospective single-center study using medical records from a database processed by univariate and multivariate analyses was performed in the People's Hospital of Tibet Autonomous Region in Lhasa, Tibet, China., Results: The mean hemoglobin level in 211 patients with ICH was 165.03 ± 34.12 g/l, and a median hematoma volume was 18.5 ml. Eighty-eight (41.7%) patients had large hematomas (supratentorial hematoma ≥ 30 ml; infratentorial hematoma ≥ 10 ml). No differences in ICH risk factors between the groups with different hemoglobin levels were detected. Increased hemoglobin was independently associated with large hematomas [odds ratio (OR) 1.013, P = 0.023]. Increased hemoglobin was independently associated with ICH with subarachnoid hemorrhage (OR 1.014, P = 0.016), which was more pronounced in men (OR 1.027, P = 0.002). Increased hemoglobin was independently associated with basal ganglia hemorrhage and lobar hemorrhage in men (OR 0.986, P = 0.022; OR 1.013, P = 0.044, respectively) but not in women (P > 0.1)., Conclusions: Increased hemoglobin was independently associated with large hemorrhage volume. Increased hemoglobin was independently associated with lobar hemorrhage in men and ICH with subarachnoid hemorrhage, which was more pronounced in men. Additional studies are needed to confirm our findings and explore potential mechanisms., (© 2021. The Author(s).)

After four decades of China's family planning policy, the shrinking family size and increasing life expectancy pose special challenges for the one-child generation in terms of providing care for aging parents. The current study explored young adults' responses to such pressure by examining their concerns about elder care, attitudes toward nursing homes, and living arrangement after marriage in a sample of 473 Chinese working young adults from six cities in China (46.9% males, M age = 25.1 years, 47.8% only children). Results showed that although most of the young adults reported to have thought about the issue of parents' elder care, the majority did not worry a lot about it. Only children expressed similar levels of worrying as those with siblings did. However, educational level, rather than sibling status, was systematically related to concerns about parents' elder care and attitudes toward nursing homes. People with higher education tended to worry less about elder care, and were less likely to consider placing parents in nursing homes as a violation of filial piety. Analyses of the married sub-sample ( n = 140) revealed that only children were more likely to co-reside with parents after marriage than those with siblings. And the main reason for co-residence was that the younger generation needed their parents' help for childcare, rather than to better take care of their parents. Implications for parents' elder care among Chinese only children were discussed., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Chen, Zhuoga and Deng.)

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, 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: Echinococcosis is a neglected zoonotic parasitic disease caused echinococcus parasitizes, poseing a significant economic burden on both humans and animals. There are limited studies on echinococcosis in China, especially Xizang Autonomous Region, although the area is endemic area for echinococcosis. The study aimed to provide information for strategic prevention against this disease., Methods: A cross-sectional survey was conducted among the residents in Xizang Autonomous Region, China to evaluate their knowledge, attitudes and practices on endemicity of echinococcosis. A face-to-face survey was conducted to collect the data using a well-designed questionnaire. The contents included basic personal information, knowledge, attitudes and practices about echinococcosis, personal hygiene and behavior habits, dog feeding and whether they had received the information on echinococcosis, and so on. We surveyed 840 persons in practice. All data analysis was performed using Epi Info 7.2., Results: Of the total particpants, 86.8% had a primary education level or below (including primary and illiterate), and even 45.0% were illiterate. Farmers and herdsmen represent the main occupations in this study. People who know all the echinococcosis-related knowledge in the questionnaire only accounted for 8.7% of the participants. However, none of the participants was aware of routes of echinococcosis infection in human or dogs. The data showed participants with higher educational background had the high awareness rate of echinococcosis-related knowledge or attitudes (chi-square for trend, χ 2  = 21.23, p<0.05 & χ 2  = 48.43, p<0.05). In addition, The percentage of the participant with awareness of echinococcosis-related practices was associated with their age and principle occupation (χ 2  = 52.72, p<0.05 & χ 2  = 20.63, p<0.05)., Conclusions: Xizang Autonomous Region is an epidemic area of Echinococcosis. The prevalence of the disease has been largely due to the lack of knowledge, awareness, and poor hygiene practice in local residences. Therefore, effective disease prevention education and awareness campaigns in community will be significantly helpful in prevention and control of echinococcosis.

Background and Purpose- Studies on the prevalence and risk factors of white matter lesions (WMLs) in Tibetans living at high altitudes are scarce. We conducted this study to determine the prevalence and risks of WMLs in Tibetan patients without or with nonacute stroke. Methods- We undertook a retrospective analysis of medical records of patients treated at the People's Hospital of Tibetan Autonomous Region and identified a total of 301 Tibetan patients without acute stroke. WML severity was graded by the Fazekas Scale. We assessed the overall and age-specific prevalence of WMLs and analyzed associations between WMLs and related factors with univariate and multivariate methods. Results- Of the 301 patients, 87 (28.9%) had peripheral vertigo, 83 (27.3%) had primary headache, 52 (17.3%) had a history of stroke, 36 (12.0%) had an anxiety disorder, 29 (9.6%) had epilepsy, 12 (4.0%) had infections of the central nervous system, and 3 (1.0%) had undetermined diseases. WMLs were present in 245 (81.4%) patients, and 54 (17.9%) were younger than 40 years. Univariate analysis showed that age, history of cerebral infarction, hypertension, the thickness of the common carotid artery intima, and plaque within the intracarotid artery were related risks for WMLs. Ordered logistic analysis showed that age, history of cerebral ischemic stroke, hypertension, male sex, and atrial fibrillation were associated with WML severity. Conclusions- Risk factors for WMLs appear similar for Tibetans residing at high altitudes and individuals living in the plains. Further investigations are needed to determine whether Tibetans residing at high altitudes have a higher burden of WMLs than inhabitants of the plains.

Background and Purpose: There have not been any new epidemiological studies related to stroke in Tibet for 20 years. This study aimed to collect stroke data from The City Staff Medical Insurance Registry in Lhasa, Tibet, to describe the incidence, clinical subtypes, and associated risk factors of stroke., Methods: We used retrospective, population-based descriptive analysis of all urban and rural workers in the City Staff Medical Insurance Registry who were admitted to designated hospitals from October 2006 to October 2008. Stroke was defined by the International Classification of Disease (ICD)-10 coded from hospital records., Results: Workers (81,298) were listed in the City Staff Medical Insurance Registry. Stroke patients (165) were included in the study, with 133 being first-ever patients. The age-standardized incidence rate was 88.725/100,000 per year (95% CI, 72.228-105.221), and mortality rate was 25.941/100,000 per year (95% CI, 16.416-35.466). The case fatality rate was 21.82%. Seventeen of the 133 patients (12.8%) were < 45 years of age. Stroke incidence rate was higher in ethnic Han patients than ethnic Tibetan patients. The most common subtype was cerebral infarction, and the most important risk factor was hypertension., Conclusions: Since the last study 20 years ago in Lhasa, stroke remains the primary fatal disease for the elderly, and its occurrence at younger ages is higher in Lhasa than in other areas of China. However, the annual incidence rate and mortality rate have decreased. The annual incidence rate is at a similar level to that in other parts of China. The primary subtype of stroke in Lhasa is cerebral ischemia.