A systematic review of the status and methodological considerations for estimating risk of first ever stroke in the general population.

AIMS: The methodological quality of development, validation, and modification of those models have not been evaluated via a thoroughly literature review. This study aims to describe the overall status and evaluate the methodological quality of risk prediction models for stroke incidence in the general population. METHODS: We searched the database of EMBASE and MEDLINE by the combination of subject words and key words to collect the research on stroke risk prediction model in the general population. The retrieval time was from the establishment of the database to September 2019. It should be mentioned that risk of bias for each model was assessed, and data on population characteristics and model performance was also extracted. RESULTS: The search screened 11,386 peer-reviewed publications and 57 citation searching, of which 48 were included in the review, describing the development of 51 prediction models, 47 external validation models, and 12 modification models. Among 51 development models, the predicted outcome concentrated on fatal or non-fatal stroke (n = 37, 73%). Thirty-nine development models (76%) were without internal validation. C-statistic or AUC was adopted for discrimination in 80% models, and Hosmer-Lemeshow test (n = 25, 49%) was also performed for calibration. Twenty-six development models (53%) were externally validated, among which only 2 (8%) were validated by independent researchers. Risk prediction performance was improved when models were modified by adding novel risk factors, such as the internal carotid artery plaque and intima-media thickness. CONCLUSION: Models for predicting stroke occurrence need further external validation, recalibration, or modification in different populations, to help interpret those models in the practice of stroke prevention.

Pre-hospital delay and its associated factors in first-ever stroke registered in communities from three cities in China.

This study aimed to explore pre-hospital delay and its associated factors in first-ever stroke registered in communities from three cities in China. The rates of delay greater than or equal to 2 hours were calculated and factors associated with delays were determined by non-conditional binary logistic regression, after adjusting for different explanatory factors. Among the 403 cases of stroke with an accurate documented time of prehospital delay, the median time (interquartile range) was 4.00 (1.50-14.00) hours. Among the 544 cases of stroke with an estimated time range of prehospital delay, 24.8% of patients were transferred to the emergency department or hospital within 2 hours, only 16.9% of patients with stroke were aware that the initial symptom represented a stroke, only 18.8% used the emergency medical service and one-third of the stroke cases were not identified by ambulance doctors. In the multivariate analyses, 8 variables or sub-variables were identified. In conclusion, prehospital delay of stroke was common in communities. Thus, intervention measures in communities should focus on education about the early identification of stroke and appropriate emergency medical service (EMS) use, as well as the development of organized stroke care.

[A cohort study on the relationship between cerebrovascular hemodynamic changing and risk of stroke].

OBJECTIVE: To study the role of cerebrovascular hemodynamic indexes (CVHI) changing in stroke and to provide reference for stroke prevention and risk factor study. METHODS: From 2003 to 2004, participants aged 40 years and above in two communities in Fengxian district were recruited by cluster sampling. Risk factors of stroke and CVHI were investigated and checked during baseline investigation. A total of 10 565 individuals completed the survey and met the inclusion criterion. After baseline investigation, the cohort was followed up for stroke occurrence. Relative risk (RR) of CVHI and common risk factors were estimated by cohort study design. RESULTS: Age of the cohort was (56.2 ± 11.4) years. 4444 (42.1%) were males and 6121 (57.9%) were females. Total follow-up duration was 67 885.7 person-years. A total of 195 stroke cases occurred and incidence density of stroke was 287.2 per 100 000 person-years. Stroke incidence in exposure groups of hypertension, heart disease and alcohol drinking was 3.47% (108/3118), 2.96% (21/710) and 2.50% (47/1882), respectively. The incidence in corresponding non-exposure group was 1.17% (87/7448), 1.77% (174/9855) and 1.70% (148/8683) respectively. There was significant difference between 2 groups (χ(2) value was 62.72, 4.56 and 4.94, respectively, P < 0.05). Stroke incidence in CVHI score < 25, 25 - 49, 50 - 74 and ≥ 75 groups was 9.12% (59/647), 5.68% (44/775), 2.52% (39/1545) and 0.72% (53/7403)(χ(2)trend = 273.57, P < 0.05), respectively. Incidence of stroke in 40 - 49, 50 - 59, 60 - 69, ≥ 70 years age group was 0.22% (8/3565), 1.28% (43/3357), 2.71% (50/1848) and 5.88% (94/1600) (χ(2)trend = 181.48, P < 0.05), respectively. Multiple Cox regression analysis indicated that RR (95%CI) value of hypertension and cigarette smoking was 1.40(1.02 - 1.92) and 1.59(1.19 - 2.12), respectively when comparing with non-exposure group. RR (95%CI) value in CVHI score < 25, 25 - 49 and 50 - 74 points group were 6.15 (4.08 - 9.26), 4.55 (2.98 - 6.96) and 2.68 (1.75 - 4.09), respectively when comparing with the score ≥ 75 points group. RR (95%CI) value in age 50 - 59, 60 - 69 and ≥ 70 years group was 4.61 (2.16 - 9.82), 7.81 (3.67 - 16.60) and 13.49(6.44 - 28.24), respectively when comparing with below 40 years group. CONCLUSION: CVHI score is the strong independent predictive factor and hypertension, cigarette smoking and age are the independent risk factors of stroke.

Public knowledge of stroke in Chinese urban residents: a community questionnaire study.

BACKGROUND AND PURPOSE: Intensive control of the risk factors of stroke and the pre-hospital delay after stroke onset both depend on the level of knowledge of stroke in the general population. Our primary objective was to assess the public knowledge about stroke among urban residents in four cities in China. METHODS: A semi-structured interview and questionnaire was delivered in a survey. Standardized risk factor and symptom statements were used to measure knowledge. The setting of two communities from four different cities of China was used to target a mix of social class and geography. Using systematic sampling and the household as a unit, at least 300 households were chosen in one community. Each household selected one person to fill in the self-designed questionnaire. Uniform training of community physicians was conducted before the survey, and the community physicians completed the survey by face to face indoor-investigation. RESULTS: Total integral questionnaires numbered 2519. The investigation showed that (1) hypertension was identified as a risk factor by nearly 90% of residents. Dyslipidemia, smoking, diabetes, and non-modifiable risk factors were identified by less than 65%; (2) medical therapy of hypertension and diabetes was known by nearly 80% of residents, and the awareness of lifestyle modification was less; (3) weakness or numbness were the most common symptoms identified by community residents (80.2%), and the awareness of other symptoms of stroke ranged from 58.2 to 71.2%; (4) the stroke knowledge score and education level were positively correlated (r(s) = 0.088, P<0.001), and age was negatively correlated (r(s) = -0.142, P<0.001); (5) 53.0% of residents would call an emergency medical system once stroke symptoms began; (6) the main sources of information about stroke were television (74.4%), doctors (63.2%) and newspapers (61.8%). CONCLUSION: At present, the urban community residents in China are lacking in knowledge about stroke. Going forward, we should strengthen health education through television, medical staff, newspapers, magazines. Targeted educational populations should be directed at those who are elderly, lower education, male and high risk.

[Study on over-weight, obesity and the exposure to stroke risk factors among 40 year olds and over in a community-based population].

OBJECTIVE: To describe the distribution of over weight and obesity to discover the level of exposure on risk factors of stroke among people aged 40 and over, in a community-based population. METHODS: From 2003 to 2004, people aged > or = 40 years in a community of Fengxian district in Shanghai were selected by cluster sampling. Out of 11,791 individuals who were selected, 10,565 met the inclusion criteria and responded to the investigation. By face to face interview, a cross-sectional survey was carried out, using a questionnaire for risk factors of stroke. Height, weight and blood pressures were measured and cerebrovascular hemodynamic parameters (CVHP) were checked. Age and gender distribution of over weight and obesity in the population were described. Using 60 year as cut-off point, participants were grouped into three: normal, over weight and obesity by body mass index. Level of stroke risk factor exposure between groups was compared and logistic regression model was used for multiple analyses. RESULTS: Proportions of over weight and obesity were 28.5 percent and 4.1 percent in male and 26.3 percent and 4.2 percent in female (P = 0.045). Systolic and diastolic blood pressure in over weight group were (132.5 +/- 19.4) mm Hg and (83.9 +/- 10.5) mm Hg (1 mm Hg = 0.133 kPa), which were higher than that in normal weight group and lower than that in obese group (P < 0.05). Exposure rate of heart disease, family history of stroke in < 60 year old group and diabetes in > or = 60 year group increased along with the increase of weight. Exposure rate of hypertension, abnormality of CVHP score in both age groups were also increased with the increase of weight. Data from multiple logistic regression indicated that hypertension, family history of stroke and heart disease, CVHP score below 75 points, sex and age were independent factors of over weight and obese. CONCLUSION: The prevalence of over weight or obesity in a community-based population among aged 40 years or over was around 30 percent. The overall exposure rate of stroke risk factors were increasing along with the increase of weight, especially for those in the middle age.

[Evaluation on the indirect economic burden of stroke using combination of disability-adjusted life years and human capital method].

OBJECTIVE: Using the indirect economic burden of stroke in a rural population to develop rational allocation of future health resources, in Hanzhong area. METHODS: Cluster sampling which involved 53 natural villages with a total number of 75,000 people selected from the 'stroke monitoring base' of rural population was adopted in this study in the Hanzhong area. All of the 164 stroke cases were studied through a self-designed questionnaire. In calculating disability-adjusted life years (DALYs), fixed value was used in accordance with the value of GBD. The disability assessment was simplified in DALYs calculation and modified Barthel's ADL was used in disability assessment of stroke patients. In indirect economic burden analysis, the human capital method combined with DALYs was adopted with the formula as: indirect economic burden = GNP per capita x DALYs x productivity weight. RESULTS: The total DALYs were 598.88, with an average DALY of stroke as 3.65 per case. The total indirect economic burden of stroke patients in rural areas was 1,993,977.8 RMB and the average of indirect economic burden of stroke was 12,158.4 RMB per case with the largest seen in the 45-59 age group, accounted for 74.4%. CONCLUSION: In our study, the use of method in combining the human capital with DALYs was the first time being adopted in calculation of the indirect economic burden of stroke in rural population in China. The burden seemed to be much lower than literature cited from other countries. It was reasonable to evaluate indirect economic burden of stroke using method in integrating DALYs with human capital, but it was difficult to calculate the DALYs.

[Baseline study and analysis on a stroke risk factor-related cohort in Fengxian county of Shanghai].

OBJECTIVE: To explore the exposed level of stroke risk factors in Fengxian county of Shanghai and the relationships between risk factors and stroke. METHODS: Community based populations including 10,565 individuals aged 40 years old and over were cluster sampled from Fengxian county in 2003 or 2004. Status of exposure on common risk factors such as hypertension, cardiovascular disease, diabetes, family history of stroke, cigarette smoking, alcohol intake were gathered while cerebral vascular hemodynamic index (CVHI) was examined, with CVHI score below 75 points as abnormal. During 2003 to 2006, 78 stroke cases occurred. The relationships between risk factors and stroke were analyzed by univariate and Cox proportional hazards regression models. RESULTS: Rates of exposure regarding hypertension, cardiovascular disease, diabetes, family history of stroke, obesity (BMI > or = 28 kg/m2), smoking, drinking and CVHI score abnormal were 21.14%, 6.72%, 1.88%, 5.63%, 4.17%, 34.96%, 17.81% and 29.43%, respectively. Data from Univariate analysis indicated that relative risk (95% CI) of above-mentioned risk factors were 2.76 (1.76-4.32), 2.19 (1.16-4.14), 1.52 (0.38-6.19), 1.58 (0.69-3.62), 1.24 (0.45-3.38), 1.75 (1.12-2.73), 2.10 (1.30-3.39) and 12.72 (7.02-23.06), respectively. Results from Cox proportional hazards regression models analysis showed that cigarette smoking, CVHI score abnormal were screened into equation. CONCLUSION: Among all the risk factors, rate of hypertension was the highest while hypertension, cardiovascular disease, cigarette smoking, alcohol intake and abnomal CVHI score had remarkable etiological correlations to stroke. Abnormal CVHI score, cigarette smoking seemed to be the independent forecasting factors related to stroke.

Evaluation of the relative risk of stroke in patients with hypertension using cerebrovascular hemodynamic accumulative score.

The relative risk (RR) of stroke in patients with hypertension was evaluated by using synthetic index of cerebrovascular hemodynamics. A total of 7,371 patients with hypertension with ages ≥40 years were selected from a population-based cohort study of the risk factors for stroke. The data on the baseline investigation of risk factors, the determination of cerebrovascular hemodynamic parameters (CVHP), and stroke follow-up were analyzed. The RR of stroke in patients with hypertension was evaluated by CVHP scores. Univariate analysis indicated that hypertension, complicated by other risk factors, had significant statistical association with the onset of stroke. RRs for stroke when hypertension complicated with decrease of hemodynamic scores, heart disease, cigarette smoking and alcohol consumption were 4.93 (95%CI, 3.26-7.45), 1.90 (95%CI, 1.36-2.66), 1.99 (95%CI, 1.42-2.79) and 1.73 (95%CI, 1.19-2.53) respectively. In multivariate analysis, hemodynamic score, age, sex, cigarette smoking, family history of stroke and systolic blood pressure were selected by the Cox regression for inclusion in the final analysis. Among them, the RR of hemodynamic score was highest. The analysis of dose-response relationships indicated that when the hemodynamic scores in patients with hypertension were lower than 75 points, the RR of stroke at 75, 60, 45, 30 and 15 points were 2.85, 4.43, 4.54, 5.40 and 9.88, respectively. The risk of stroke in patients with hypertension is closely associated with hemodynamic impairment and the hemodynamic score may be used for quantitative evaluation of relative risks of stroke.

[Baseline study on a stroke-related cohort in the rural community of Shanghai].

OBJECTIVE: To present data from a baseline investigation on stroke-related cohort population in rural area of Shanghai. METHODS: A cross-sectional study was carried out in a cluster sampling population aged 40 years and over. General information and data on common risk factors in the population were gathered and cerebral vascular hemodynamic indexes were checked. Hemodynamic score was estimated according to single indexes by unified methods. 5335 persons who had met the inclusion criteria were enlisted in the study. Exposure level of risk factors, prevalence of stroke, and hemodynamic indexes were analyzed and distributional characteristics were described. RESULTS: Exposure rate of hypertension, heart disease, diabetes, family history of hypertension, overweight or obesity in males were 31.74%, 6.09%, 1.16%, 3.22%, 17.64%, 29.68% and were 32.76%, 9.22%, 1.55%, 3.84%, 19.22%, 29.44% in female respectively. Standard prevalence of stroke was 1167.3/100000, which in male was significantly higher than that in female (P < 0.05). The change of cerebral vascular hemodynamic indexes was significantly associated with age. Hemodynamic score in 21.3% of the subjects was below 75 points. CONCLUSIONS: Among population of 40 years old and over in rural areas, hypertension was the principal risk factor regarding the rate of stroke. Prevalence of stroke in males was significantly higher than that in females. Abnormal rate of hemodynamic score was about 20% in this population.

[Analysis on direct economic burden of stroke in the rural population of Hanzhong, Shaanxi Province].

OBJECTIVE: To analyze the direct economic burden of stroke in rural areas of Hanzhong. METHODS: Plan on primary interview was made after the purpose of the study had been informed to the managers of the 'surveillance field base', heads and members of the monitor assistants and detailed information was collected in the fields. Every single patient of stroke was then interviewed by the above said interviewers,using a self-designed questionnaire. 164 patients with stroke were interviewed in 53 villages with 75,000 persons lived there. The main items involved in the questionnaire would include: costs for inpatient or outpatient, reaching-out fees, fee for accommodation during treatment as outpatient, costs for treatment at home, long term medicine, caregivers and funerals as well as average income. RESULTS: The median of annual direct economic burden was 3100 Yuan for each patient in Hanzhong rural area. There were no significant differences seen between males and females or among age groups (P > 0.05). The proportion of patients with medians of annual direct economic burden of: 1000 Yuan and below, 1001-5000 Yuan, 5001-10,000 Yuan, 10,001-20,000 Yuan and over 20,001 Yuan, were 29.2%, 36.0%, 18.3%, 9.8% and 6.0% respectively. The median of annual direct economic burden of first episode stroke was 5500 Yuan for each patient, and that of stroke was 1700 Yuan for each chronic patient. The direct economic burden of first episode was significantly higher than that of stroke (P < 0.01). The costs of hospitalization, accommodation of hospitalization and treatment at home of middle-aged patients were significant higher than that of old age patients (P < 0.05). CONCLUSION: In this study, the direct economic burden of stroke was 2.9 times of the annual personal average income, which was contrary to the reports from other countries. However, the State Health Bureau bore 87.1% of the direct economic burden for urban patients, but patients in the rural areas had to pay from their own pockets. The direct economic burden of stroke was heavy in Hanzhong rural region, which called for measures to be made to decrease the direct economic burden of stroke in the region.

[Effectiveness of Nao'an Capsule on stroke prevention among high risk population in Nanhui, Shanghai].

OBJECTIVE: To evaluate the effectiveness of stroke prevention among high risk population, using Nao'an Capsules. METHODS: Participants were selected from 696,558 residents in Nanhui, using county of Shanghai city. Individuals aged 35 years old and over with at least one risk factor exposure to stroke, received cerebral vascular hemodynamic examination. 18,271 cases meeting the criteria of cerebral vascular hemodynamic indexes accumulative score below 70 points were defined as individuals with high-risk and targets to receive intervention. According to the willingness of the participants, 10,313 cases received Nao'an Capsules for intensive intervention based on general intervention measures compared to 7958 cases only receiving general intervention. After the implementation of intervention, incidence and mortality rates of stroke and the effectiveness of three-year intervention were studied. RESULTS: Incidence of stroke in Nao'an Capsules group was significantly lower than that of the general intervention (P < 0.01) with 53.8% in males and 58.4% in females. The relative risk (RR) in two gender groups were 0.46 (0.33 - 0.64) and 0.39 (0.30 - 0.50) respectively. Multiple logistic regression analysis indicated that the history of hypertension, accumulative score of cerebral vascular hemodynamic indexes, age, gender and Nao'an Capsules intervention were the variables selected into the equation and significantly related to stroke. Among the variables, Nao'an Capsule was the strongest factor with a RR of 0.41. CONCLUSION: Incidence of stroke in Nao'an Capsule intervention group was significantly lower than that in the general intervention group after 3 years of intervention, suggesting that Nao'an Capsule intervention was the strongest factor affecting stroke occurrence in individuals at high-risk.

[Study on the application of the Chinese version of SF-36 scales and selection of interceptive cents for its grade range].

OBJECTIVE: To study the possibility of measuring quality of life by Medical Outcomes Study 36-Item Short-Form Health Survey scale and to subdivide grade range of Medical Outcomes Study 36-Item Short-From Health Survey (SF-36) total cents through a Quality of Life questionnaire among the elderly Chinese. METHODS: The quality of life of the 167 elderly Chinese in Suzhou was measured simultaneously by SF-36 and the Quality of Life questionnaire developed by Epidemiology Group of Geriatric Medicine Committee of China for the elderly. Validity and reliability were analyzed and subdivided the grade range of SF-36 total scores by Quality of Life questionnaire for the Chinese elderly. RESULTS: Eight common factors from factorial analysis were in accordance with their theoretical structure, and the cumulative contribution rates of the Quality of Life questionnaire for the elderly and SF-36 were 74.244% and 72.081%. The split-half reliability of the Quality of Life questionnaire for the elderly was 0.6676. The split-half reliability of SF-36 was 0.9384. In SF-36, the Cronbach's alpha coefficient of internal consistency reliability ranged from 0.81 to 0.89, which was satisfactory for group comparison except 0.63 for the social functioning and 0.42 for mental health scale and 0.69 for vitality scale. The Quality of Life questionnaire for old people seemed to have good validity and reliability but the SF-36 was better. The cent of the furthest truncation between the good quality of life and the medium one in the SF-36 was 117 with a Kappa value of 0.58. CONCLUSION: The SF-36 scale could be used for measuring and evaluating the quality of life for the Chinese elderly. The cent of the furthest truncation could provide reference to judge the level of the quality of life of the elderly.

Genetic susceptibility and environmental factors of esophageal cancer in Xi'an.

AIM: To analyse the role of genetic susceptibility and environmental factors in the process of esophageal cancer (EC) formation in Xi'an, China. METHODS: A hospital based case-control study, combined with molecular epidemiological method, was carried out. A total of 127 EC cases and 101 controls were interviewed with questionnaires containing demographic items, habit of tobacco smoking, alcohol drinking, and family history of EC. Polymorphism of CYP1A1 and GSTM1 of 127 EC cases and 101 controls were detected by PCR method. The interactions between genetic susceptibility and environmental factors were also discussed. RESULTS: Tobacco smoking, alcohol drinking and a family history of EC were risk factors for EC with an OR of 2.04(95% CI 1.15-3.60), 3.45(95% CI 1.74-6.91), 3.14 (95% CI 1.28-7.94), respectively. Individuals carrying CYP1A1 Val/Val genotype compared to those with CYP1A1 Ile/Ile genotype had an increased risk for EC (OR 3.35, 95% CI 1.49-7.61). GSTM1 deletion genotype was a risk factor for EC (OR1.81, 95% CI 1.03-3.18). Gene-environment interaction analysis showed that CYP1A1 Val/Val genotype, GSTM1 deletion genotype had synergetic interactions with tobacco smoking, alcohol drinking and family history of EC. CONCLUSION: Tobacco smoking, alcohol drinking and a family history of EC are risk factors for EC. CYP1A1 Val/Val and GSTM1 deletion genotypes are genetic susceptibility biomarkers for EC. There are synergic interactions between genetic susceptibility and environmental factors.

[The relationship between hypertension and cerebral hemodynamic scores of vascular function accumulative].

OBJECTIVE: To probe into the relationship between hypertension and hemodynamic score of cerebral vascular accumulative function by though studying the history of hypertension and level of blood pressure. METHODS: The database of blood pressure and cerebral vascular hemodynamic indexes (CVHI) were from baseline data and measurement in a cohort. 18,512 participants who met the included criteria were enlisted in the study. The function scores were estimated using uniform methods according to CVHI. Participants were grouped by age, years of having hypertension and level of blood pressure. Differences of the function score between different groups were compared. RESULTS: The function score in hypertension group was significantly lower than that of normal tension group, which decreased by 13.3 points. Within 5 years of hypertension history, the function score decreased as course of hypertension prolonged. The same trend was found between the score and level of both systolic and diastolic blood pressure. When systolic blood pressure elevated to 140 mmHg or diastolic blood pressure elevated to 95 mmHg, the function score was below 75 points. CONCLUSION: There were significant relationship between decrease of the function scores and medical history, course of hypertension as well as level of blood pressure.

[Principal component analysis and integral methods of cerebral vascular hemodynamic parameters].

OBJECTIVE: To establish a predicting model for stroke according to cerebral vascular hemodynamic indexes and major risk factors of stroke. METHODS: Participants selected from a stroke cohort with 25,355 population in China. The first step was to carry out principal component analysis using CVHI. Logistic regression with principal component and main risk factors of stroke were then served as independent variables and stroke come on as dependent variables. The predictive model was established according to coefficient of regression and probability of each participant was also estimated. Finally, ROC curve was protracted and predictive efficacy was measured. RESULTS: The accumulative contribution rates of four principal components were 58.1%, 79.4%, 88.4% and 94.6% respectively. Seven variables were being selected into the equation with the first to fourth principal component as history of hypertension, age and sex. Area under ROC curve was 0.855 and optimal cut-off point was probability over 0.05. Sensitivity, specificity and accuracy of stroke prediction were 80.7%, 78.5% and 78.5% respectively. CONCLUSION: The model established by principal component and regression could effectively predict the incidence of stroke coming on.

[Study on mortality, incidence and risk factors of stroke in a cohort of elderly in Xi'an, China].

OBJECTIVE: To prospectively study the relationship between risk factors and stroke incidence and mortality in the Chinese elderly. METHODS: An analytic study in a cohort population of 1,268 male retired cadres in a military setting. A health-screening program was carried out for all cadres aged 55 years or older in Xi'an in February 1987. Baseline data on smoking, cholesterol, triglyceride, blood pressure, body mass index (BMI), histories of hypertension, hyperlipidemia and coronary heart disease (CHD), stroke, diabetes and family histories of cardiovascular disease were investigated. Main outcome measures were stroke incidence, stroke and all-cause mortality. RESULTS: The cohort was followed up until June 30, 2001 and a total number of follow-up person-year was 15,546. During the follow-up period, there were 113 new stroke cases identified and the adjusted incidence was 727 per 100,000 person-year. Forty-five deaths were due to stroke and the adjusted mortality was 289 per 100,000 person-year. Using Cox model analysis, after adjustment on age, total cholesterol, triglyceride, smoking, drinking and physical exercise, we noticed that the systolic pressure, BMI, history of CHD and hyperlipidemia were independent risk factors for stroke incidence and morality. CONCLUSION: The incidence and mortality of stroke in this cohort were lower than those in the same age group of general population. Monitoring and controlling body mass index and blood pressure level seemed to be important factors for the prevention of stroke in the elderly.

[A cohort study on cerebral vascular hemodynamics accumulative score and risks of stroke].

OBJECTIVE: To estimate relative risk (RR) of cerebral vascular hemodynamics indexes (CVHI) accumulative score as well as some other risk factors of stroke. METHODS: A cohort study was carried out in 25 355 participants aged 35 and over in Northeast of China from 1994 to 2001. In the baseline survey, exposure rates of hypertension, diabetes, family history of stroke and hypertension, etc. were collected and CVHI was examined. CVHI accumulative score was synthesized according to contribution of single index. During the 7-year following up, 228 stroke cases were identified and stroke coming on was defined as the endpoint of observation. Uni-variable and multiple variables analysis were carried out for estimating RR of CVHI and other risk factors of stroke. RESULTS: Uni-variables analysis indicated that RR (95% confidence interval, CI) of Hypertension, heart diseases, diabetes, family history of hypertension and stroke, overweight or obesity, alcohol intake, cigarette smoking and CVHI < 75 scores were 3.23 (2.48 - 4.20), 2.53 (1.92 - 3.33), 2.38 (1.55 - 3.64), 1.32 (1.02 - 1.72), 1.82 (1.37 - 2.41), 1.62 (1.25 - 2.11), 1.48 (1.07 - 2.04), 1.76 (1.34 - 2.31) and 7.30 (5.43 - 9.80) respectively. Cox regression analysis showed that CVHI below 75 points, family history of stroke, cigarette smoking, heart disease, hypertension, age and sex were the factors being selected in equation. There was a significant dosage response between the decrease of CVHI score and the increase of stroke risk. RR of stroke reached 12.55 when CVHI below 75 points and history of hypertension appeared in the same individuals. CONCLUSION: Abnormality of CVHI score seemed to be the most important and independent factor among stroke risk factors. Decrease of CVHI score might serve as a marker of high risk and play important role in stroke, especially coexistence with hypertension.

[Study on a test of screening to predict stroke-using cerebral vascular hemodynamic indexes].

OBJECTIVE: To evaluate efficacy and optimal cut-off-point through cerebral vascular hemodynamic indexes (CVHI) examination to predict stroke. METHODS: A number of 20,333 people at 35 years old and over were checked by CVHI and accumulative score was calculated according to the value of detected indexes. Risk factors of stroke were investigated simultaneously. One hundred and sixty-eight patients with stroke occurred during 4-year following up. Typical syndromes and signs stroke were used as golden standard to evaluate screening efficacy of CVHI. RESULTS: Score of optimal cut-off-point of cerebral vascular hemodynamic indexes was under 75 in ROC curve analyses. Sensitivity, specificity, accuracy, positive and negative predictive values, positive and negative likelihood ratios as well as Youden's index for predicting stroke within 4 years after examination were found to be 87.50%, 67.70%, 67.86%, 2.21%, 99.85%, 2.71, 0.18 and 0.55 respectively. Sensitivity and positive predict values for predicting cerebral vascular thrombosis were superior to predicting cerebral hemorrhage. Positive predicting value in risk exposure population was higher than that of overall population. Coefficiency of variation of cerebral vascular hemodynamic examination was 4.03%. The agreement rate of examination between two physicians was 97.62% and Kappa value was 0.94. CONCLUSION: The score of optimal cut-off-point of cerebral vascular hemodynamic indexes examination was 75. Both Efficacy and reliability for predicting stroke seemed to be good, especially for predicting cerebral vascular thrombosis.

[A prospective study on smoking, quitting and mortality in a cohort of elderly in Xi'an, China].

OBJECTIVE: To prospective examine the relationship between smoking, quitting and mortality in older Chinese men by in Xi'an, China. METHODS: The design was a cohort analytic study. One thousand two hundred and sixty-eight retired male military veterans aged 60 or older were examined in 1987. At baseline, there were 388 never-smokers, 461 former smokers and 419 current smokers. Main outcome measure was all-cause and tobacco-associated mortality. RESULTS: Through 1999, 299 had died, 943 were alive and 26 lost. The mean follow-up time was 11 years and total person-year of follow-up was 14 163. After adjusting for age, blood pressure, body mass index, total cholesterol, triglycerides, alcohol intake, exercise and existing diseases, using Cox proportional hazard regression model, the relative risks (95% confidence intervals) for ever-smoking, deaths resulting from all causes, chronic obstructive pulmonary disease (COPD), lung cancer and coronary heart disease (CHD) were 1.34 (1.02 - 1.76), 3.23 (0.95 - 10.91), 2.31 (0.95 - 5.61) and 1.60 (0.81 - 3.19) respectively. The risks increased significantly with increasing amount and duration of smoking. Compared with current smokers, former smokers had lower risks of total mortality (excess risk reduction of 56%) and from CHD death (93%), but had higher risks for COPD death (excess risk increased 174%). CONCLUSIONS: Smoking is a major cause of death in older Chinese men and quitting can save lives. These results showing that higher risks of COPD death in former smokers with or without existing diagnosed COPD at baseline than those in current smokers could be explained by either the "healthy smoker effect" or the "ill quitter effect" or both. Early recognition of the significance of COPD symptoms followed by prompt quitting should be emphasized as strategies in the control of the growing tobacco epidemic.

Relationship of tobacco smoking CYP1A1 GSTM1 gene polymorphism and esophageal cancer in Xi'an.

AIM: To analyze the association of tobacco smoking polymorphism of CYP1A1 (7th exon) and GSTM1 genotype and esophageal cancer(EC) in Xi'an. METHODS: A hospital based case-control study, with molecular epidemiological method, was carried out. Polymorphism of CYP1A1 and GSTM1 of samples from 127 EC cases and 101 controls were detected by PCR method. RESULTS: There were no significant difference of age and gender between cases and controls. Tobacco smoking was the main risk factor OR=1.97;95% CI=1.12-3.48 for EC in Xi'an. The proportions of CYP1A1 Ile/Ile, Ile/Val and Val/Val gene types in cases and controls was 19.7% 45.7% 34.6% and 30.7%,47.5%, 21.8% respectively(P=0.049). Individuals with CYP1A1 Val/Val genotype compared to those with CYP1A1 Ile/Ile genotype had higher risk for EC increased (OR=2.48, 95%CI=1.12-5.54). The proportions of GSTM1 deletion genotype in cases and controls were 58.3% and 43.6%(OR=1.81, 95%CI=1.03-3.18, P=0.028). Analysis of gene-environment interaction showed that tobacco smoking and CYP1A1 Val/Val genotype; tobacco smoking and GSTM1 deletion genotype had synergism interaction respectively. Analysis of gene-gene interaction did not find synergistic interaction between these two genes. But in GSTM1 deletion group there was significant difference of distribution of CYP1A1 genotype between cases and controls (P=0.011). CONCLUSION: CYP1A1 Val/Val and GSTM1 deletion genotypes are genetic susceptibility biomarkers for EC. The risk increases, when person with CYP1A1 Val/Val and/or GSTM1 deletion genotype. And these two-metabolic enzymes seem to have interactions with tobacco smoking, in which the mechanism still needs further study.