高血压危险因素分类树分析

目的 探讨高血压的主要危险因素与高危人群，为高血压的防制提供理论依据。方法 采用以社区人群为基础的病例对照研究；以某工厂人群中筛检出的、未经药物系统治疗的l16名高血压患及136名血压正常健康为研究对象；运用分类树分析探讨高血压的主要危险因素与高危人群。结果 高血压的主要危险因素为：超重、中心型肥胖、饮酒、吸烟、高血脂症、年龄与性别。高血压主要高危人群为：(1)超重 中心型肥胖 饮酒；(2)超重 中心型肥胖 高年龄及其男性吸烟；(3)超重 高血脂症；(4)中心型肥胖 饮酒 吸烟。上述高危人群病例数占总病例数的82．76％。以学习集的分类结果为：灵敏度为82．76％，特异度为74．26％；以检验集的分类结果为：灵敏度为71．55％，特异度为61．03％。结论 对高血压不同高危人群应采取不同的防制措施；控制体重、饮酒、血脂水平、戒烟应为高血压一般人群防制的主要预防措施。     

早产危险因素的Logistic回归及分类树分析

目的应用分类树模型和Logistic回归模型进行对比分析,探索北京地区早产发生的影响因素。方法对北京地区5家妇幼保健院的1323例早产进行1：1病例对照研究,应用分类树模型和Logistic回归模型分析早产的影响因素。结果Logistic回归模型显示均衡饮食（OR=0．509）、产前检查（OR=0．233）、常住址为城镇（OR=0．555）是早产的保护性因素,受教育程度低（OR=1．674）、负性生活事件（OR=6．086）、性生活（OR=1．704）、前置胎盘（OR=11．834）、妊娠期糖尿病（OR=3．170）、妊娠期高血压疾病（OR：5．024）、早产史（OR=17．574）和胎膜早破（OR=4．083）是早产的危险因素。利用卡方自动交互检测法建立的分类树模型,共筛选出5个早产高危因素,其中胎膜早破是最重要的影响因素,其他包括妊娠期高血压疾病、膳食结构不均衡、无产前检查、文化程度低。结论孕期应进行定期的产前检查可及早发现高危妊娠,避免各种不良刺激,保持良好心态,积极预防胎膜早破。Logistic回归模型可以提供变量影响的定量解释,分类树模型可以更好地展现变量间的复杂相互作用。二者结合可更好地服务于流行病学的研究。     

应用分类树模型筛选恶性肿瘤危险因素的研究

目的介绍分类树模型筛选恶性肿瘤危险因素基本原理、运算法则和应用价值.方法以浙江省嘉善县乳腺癌现场调查数据为例,采用Exhaustive CHAID法建立分类树模型对调查结果进行危险因素筛选,使用错分概率Risk值和ROC曲线下面积对模型进行评价.结果分类树模型从全部105个候选变量中筛选出9个危险因素,其中职业是最重要的影响因素,工人、教师及退休人员的乳腺癌发生概率显著高于其他人员.另外,模型显示经常参加体育锻炼在不同人群中对乳腺癌的影响效果有所不同.模型错分概率Risk值为0.174,利用预测概率绘制的ROC曲线下面积为0.872,与0.5比较具有显著的统计学意义,模型拟合效果很好.结论分类树模型不仅可以有效挖掘筛选出主要的影响因素,还可以对研究变量科学定义分界点,展示变量间复杂的相互作用,在流行病学研究中具有较高的应用价值.     

山东省中西部农村居民高血压危险因素分类树分析

目的 探讨山东省中西部地区25岁以上农村常住居民高血压的危险因素及高危人群.方法 采用多阶段分层随机抽样的方法 ,对该地区调查对象进行问卷调查、体格检查以及实验室检测.应用分类树分析高血压人群的危险因素及高危人群.结果 高血压的主要危险因素为年龄、腹型肥胖、超重或肥胖、高血压家族史、血糖值较高等.高血压的高危人群主要为高年龄者;年龄较大且血糖值较高者;年龄较大且腹型肥胖或超重者;有高血压家族史且年龄较大者;有高血压家族史、腹型肥胖且年龄较大者.分类树模型学习集的灵敏度为71.87%,特异度为66.38%,总正确率为68.79%;检验集的灵敏度为70.70%,特异度为65.84%,总正确率为67.97%.结论 控制体重和血糖为一般人群的预防措施,不同高危人群应根据所具有的危险因素采取不同的防治措施.高血压的人群防治应将对一般人群的普遍预防和对高危人群的重点预防相结合.     

Exhaustive CHAID分类树与logistic回归在脑卒中危险因素中的应用

目的应用exhaustive CHAID分类树模型与logistic回归分析来分析北京社区居民脑卒中危险因素以及不同特征人群的重点干预因素,为加强北京市居民脑卒中的干预提供科学依据。方法于2007年6月至8月,采用整群抽样方法,对北京10 108名社区居民进行问卷调查、体格检查及检测空腹血糖、血脂。采用logistic回归与exhaustive CHAID分类树分析相结合来探讨影响北京市居民脑卒中的因素。结果 logistic回归分析和exhaustive CHAID分类树分析显示年龄、性别、踝臂指数(ABI)、高血压、腹型肥胖、高密度脂蛋白胆固醇、吸烟状况、工作强度为脑卒中的危险因素;Exhaustive CHAID分类树分析揭示老年者ABI贡献大,不容忽视中年者糖尿病。Logistic回归分析和exhaustive CHAID分类树分析的ROC曲线下面积分别为0.803和0.778,模型可靠。结论对脑卒中的防治,要在总体把握的情况下,对不同的高危人群应采取不同的防制措施。     

低血压患病及其危险因素的分类树研究

[目的]了解居民低血压患病情况,探讨低血压的危险因素。[方法]利用广东省 2002 年居民营养与健康状况调查数据,分析15 951名15岁以上常住居民低血压患病情况,应用分类树模型分析其危险因素。[结果]低血压的患病率为3 9%,女性及低年龄组人群患病率较高。低血压的分类树分析中,共有7个中间结、8个终结点。女性、白领、睡眠时间长是低血压的危险因素,高年龄组、独居、重度职业性体力活动、腰围粗、体重指数高、高盐摄入、血脂高是其保护因素。分类树模型的灵敏度与特异度在学习集分别为 93 4%和 77 1%,在检验集分别为 83 2%和 77 9%。[结论]女性及低年龄组人群是低血压的高发人群;女性、白领、睡眠时间长是低血压的危险因素。     

新生儿医院感染特点与相关因素的分类树分析

目的了解新生儿医院感染发生的特点,采用分类树模型分析新生儿医院感染的主要危险因素,识别高危人群,为临床采取针对性干预措施提供参考。方法收集2016年6月-2018年11月入住新生儿病房的5 303例患儿的个人信息和临床资料,包括性别、出生体质量、住院时间、器械使用、胃肠外营养和抗生素使用情况进行回顾性分析,了解感染现状,应用分类树模型分析医院感染危险因素。结果观察期间新生儿病房共收治5 303例新生儿,发生医院感染92例,98例次,医院感染率1.73%,感染例次率1.85%;医院感染部位以血液系统为主,占63.27%,以革兰阳性菌感染为主,占59.46%,表皮葡萄球菌是感染的主要病原菌;单因素分析和分类树模型分析结果显示,住院时间、出生体质量、有无使用器械是医院感染的主要危险因素,住院时间≥14d、出生体质量≤1 500g且使用器械的新生儿的医院感染率为27.48%,是医院感染的高危人群。结论低出生体质量、接受器械辅助治疗的新生儿,住院时间长,是新生儿病房医院感染的高危人群,应该被视为重点关注和保护的对象,加强该人群的管理对于减少新生儿医院感染具有重要意义。     

心脑血管疾病危险因素的Logistic回归分析

（目的）对非工业职业人群健康现状进行调查并对该部分职业人群心脑血管疾病患病情况及其危险因素进行分析。（方法）本文选择了金融、商业、干部三个非工业职业人群,主要分析了各职业人群心脑血管疾病患病率和标准化率,并应用Logistic回归进行了心脑血管疾病的危险因素分析。（结果）男性干部职业人群高血压和;冠心病患病率高于一般人群;女性高血压均高于一般人群。在三种非工业职业人群中,吸烟、饮酒、文化程度、工龄、家族史均与心肝离血管疾病的发生有关。（结论）职业因其工作环境、活动模式,其心脑血管疾病发病情况不同,呈现各自的职业特点。在非工业职业人群,为了降低心脑血管疾病的发病,应控制吸烟和饮酒。     

新加坡脑血管病死亡趋势

目的近25年来在新加坡脑血管疾病已成为占第三位的主要死因。此调查的目的在于检测新加坡近年来脑血管病死亡趋势，并调查人群中与之相应的中风危险因素的变化。方法根据新加坡出生和死亡登记及每年公布的出生、死亡报告。死亡病例使用国际疾病分类修订版8（1969～1978年）和9（1979年）。调查资料编码数包含在430～438之中。死亡率按全球标准人口构成进行年龄、性别标化，并按男、女进行分类。脑血管病危险因素模型来源于1970～1974年全国流行病学健康调查资料。结果每年脑血管病死亡绝对数从1970年的1041例上升到1994年的1692例。粗死亡率…     

多分类 logistic 回归在冠心病危险因素研究中的应用

目的：应用多分类logistic回归找出冠心病危险因素与冠状动脉病变程度间的关系,建立冠状动脉病变程度危险因素的“最优”回归方程。方法采取系统抽样的方法,对来自2005年1月至2009年12月期间山东省潍坊市某几所医院心血管内科初步诊断为冠心病并进行冠脉造影的患者病例,抽取256例作为多分类logistic回归分析的样本。冠心病组根据狭窄病变累及血管范围分为1支病变（单支病变组）、2支病变（双支病变组）和3支及以上病变（多支病变组）。通过多分类logistic回归方法分析冠心病与冠脉病变程度相关关系。结果以冠脉病变程度为因变量,各个因素为自变量。根据单因素分析的结果,从20个研究因素中筛选出8个有统计学意义的影响因素,经过数据相关性分析、共线性诊断及专业解释等,筛选出8个影响因素进入多分类logistic回归中,最后得到与冠脉病变程度有关的有统计学意义的影响因素6个,分别是年龄、合并疾病、心率、血糖、脂蛋白（a）;保护因素1个：X17（载脂蛋白A1）。根据筛选出的6个影响因素建立“最优”回归方程。结论应用多分类logistic回归找出与冠脉病变程度有关的危险因素,并定量分析出各危险因素在冠脉病变不同程度上的概率值。     

Lung cancer risk associated to exposure to radon and smoking in a case-control study of French uranium miners

A case-control study nested in the cohort of French uranium miners took smoking information into account in investigating the effect of radon exposure on lung cancer risk. This study included 100 miners who died of lung cancer and 500 controls matched for birth period and attained age. Data about radon exposure came from the cohort study, and smoking information was retrospectively determined from a questionnaire and occupational medical records. Smoking status (never vs. ever) was reconstructed for 62 cases and 320 controls. Statistical analyses used conditional logistic regression. The effect of radon exposure on lung cancer risk was assessed with a linear excess relative risk model, and smoking was considered as a multiplicative factor. Mean cumulative radon exposures were 114.75 and 70.84 Working Level Months (WLM) among exposed cases and controls, respectively. The crude excess risk of lung cancer per 100 WLM was 0.98 (95% CI: 0.18-3.08%). When adjusted for smoking, the excess risk was 0.85 per 100 WLM (95% CI: 0.12-2.79%), which is still statistically significant. The relative risk related to smoking was equal to 3.04 (95% CI: 1.20-7.70). This analysis shows a relative risk of lung cancer related to smoking similar to that estimated from previous miners' cohorts. After adjustment for smoking, the effect of radon exposure on lung cancer risk persists, and its estimated risk coefficient is close to that found in the French cohort without smoking information.     

Smoking and multiple sclerosis susceptibility

Smoking is one of the most established risk factors for multiple sclerosis (MS). The aim of this study was to investigate how age at smoking debut, duration, intensity and cumulative dose of smoking, and smoking cessation influence the association between smoking and MS risk. In two Swedish population-based case–control studies (7,883 cases, 9,264 controls), subjects with different smoking habits were compared regarding MS risk, by calculating odds ratios with 95 % confidence intervals. We observed a clear dose response association between cumulative dose of smoking and MS risk (p value for trend <10^?35). Both duration and intensity of smoking contributed independently to the increased risk of MS. However, the detrimental effect of smoking abates a decade after smoking cessation regardless of the cumulative dose of smoking. Age at smoking debut did not affect the association between smoking and MS. Smoking increases the risk of MS in a dose response manner. However, in contrary to several other risk factors for MS that seem to affect the risk only if the exposure takes place during a specific period in life, smoking affects MS risk regardless of age at exposure, and the detrimental effect slowly abates after smoking cessation.     

Change of exposure response over time and long-term risk of silicosis among a cohort of Chinese pottery workers

An analysis was conducted on a cohort of Chinese pottery workers to estimate the exposure-response relationship between respirable crystalline silica dust exposure and the incidence of radiographically diagnosed silicosis, and to estimate the long-term risk of developing silicosis until the age of 65. The cohort comprised 3,250 employees with a median follow-up duration of around 37 years. Incident cases of silicosis were identified via silicosis registries (Chinese X-ray stage I, similar to International Labor Organisation classification scheme profusion category 1/1). Individual exposure to respirable crystalline silica dust was estimated based on over 100,000 historical dust measurements. The association between dust exposure, incidence and long-time risk of silicosis was quantified by Poisson regression analysis adjusted for age and smoking. The risk of silicosis depended not only on the cumulative respirable crystalline silica dust exposures, but also on the time-dependent respirable crystalline silica dust exposure pattern (long-term average concentration, highest annual concentration ever experienced and time since first exposure). A long-term "excess" risk of silicosis of approximately 1.5/1,000 was estimated among workers with all annual respirable crystalline silica dust concentration estimates less than 0.1 mg/m(3), using the German measurement strategy. This study indicates the importance of proper consideration of exposure information in risk quantification in epidemiological studies.     

Risk assessment of the occupational contact with ammonium

The aim of the cohort retrospective study was to analyze and evaluate the influence of certain factors (age, profession, smoking) on the characteristics and the incidence rate of the upper respiratory tract diseases (URTDs) in the occupational contact with ammonium. Subjects were 180 men, divided into 3 professional groups. The average shift concentrations of ammonium were measured in the permanent work places and individually by personal passive dosemeters. The URTDs were classified into 15 groups according to localization and the stage of the inflammatory process. The relationships "time-response" and "dose (concentration)-response" were determined. The factor "cumulative exposure" was used in order to evaluate the actual noxious effect of NH3 on the mucose of the upper respiratory tract (URT). There was a statistically reliable difference found in the incidence rate of atrophic rhinitis, hypertrophic pharyngitis and laryngitis, and neoplasms of the URT in the workers with the highest cumulative exposure. For this group relative risk was 4.00, 2.22, 3.20 and 4.00, respectively, with 95% Cl. The "cumulative exposure" factor gives the best proofs for the toxic effect of ammonium and a possibility for assessment of the relative risk.     

1817名铸造厂工人缺血性心脏病的队列研究

目的研究铸造作业工人缺血性心脏病发病风险及其与铸造作业、矽尘累积接触量之间的剂量-反应关系,并对缺血性心脏病的发病风险进行预测。方法采用队列研究方法,选择某铸造厂1980年1月1日-1996年12月31日在册一年以上的铸造作业工人建立研究队列,观察终止日期为2009年12月31日。以浇注、配砂、清理、熔炼、天车、造型和制芯等工种工人作为铸造组,电工、钳工和检查工等辅助工作为对照组。使用SPSS软件Cox回归模型分析缺血性心脏病发病风险及其与铸造作业、矽尘累积接触量之间的剂量-反应关系,并使用logistic回归建立缺血性心脏病发病风险的预测模型。结果本研究共随访30年,1817人,45 553.05人年,缺血性心脏病156例,人-年发病率为342.46/10万,平均发病年龄51.46岁,发病工龄21.61年。男性、吸烟、饮酒、年龄和工龄分别都是缺血性心脏病发病的危险因素。缺血性心脏病发病风险与矽尘累积接触量呈正相关,调整吸烟的影响后,工人矽尘年累积接触量每增加1mg/m3,缺血性心脏病发病风险增加75.8%(RR=1.758,95%CI1.221～2.532)。铸造组工人缺血性心脏病发病风险显著增加,调整吸烟的影响后,与对照组工人相比,配砂工、清理工、熔炼工、造型工、制芯工分别增加1.048倍、1.395倍、70.4%、97.0%和1.270倍。根据预测模型,工人缺血性心脏病发病概率随日接触矽尘浓度的增加、接尘工龄的延长而增加。结论铸造作业工人面临较大的缺血性心脏病发病风险。不同工种工人缺血性心脏病发病风险不同,其中,配砂、清理、熔炼、造型、制芯工人较高。铸造作业、矽尘累积接触量是缺血性心脏病的独立危险因素。缺血性心脏病预测模型表明,发病概率与日接触矽尘浓度和接尘工龄呈明显的剂量-反应关系。     

Arsenic exposure, smoking, and lung cancer in smelter workers--a case-control study

A cohort of 3,916 Swedish copper smelter workers employed for at least 3 months between 1928 and 1967 was followed up through 1981. Arsenic exposure was estimated for different time periods at each workplace within the smelter. Detailed job records were linked to the exposure matrix, thus forming individual cumulative arsenic exposure measures for each smelter worker. Smoking history was collected for 107 lung cancer cases and 214 controls from the cohort. Lung cancer risks were positively related to cumulative arsenic exposure with smoking standardized relative risks ranging from 0.7 to 8.7 in different exposure groups. A negative confounding by smoking was suggested in the higher exposure categories. The interaction between arsenic and smoking for the risk of developing lung cancer was intermediate between additive and multiplicative and appeared less pronounced among heavy smokers.     

Lung cancer among workers in chromium chemical production

BACKGROUND: An elevated risk of lung cancer among workers in chromate production facilities has previously been reported. This excess risk is believed to be the result of exposure to hexavalent chromium. There have been mixed reports about whether trivalent chromium exposure is also associated with an excess lung cancer risk. Previous studies of measured hexavalent chromium exposure and lung cancer risk have not examined cigarette smoking as a risk factor. METHODS: A cohort of 2,357 workers first employed between 1950 and 1974 at a chromate production plant was identified. Vital status of the workers was followed until December 31, 1992. Work histories of cohort members were compiled from the beginning of employment through 1985, the year the plant closed. Annual average exposure estimates, based on historical exposure measurements, were made for each job title in the plant for the years 1950-1985. These exposure estimates were used to calculate the cumulative hexavalent chromium exposure of each member of the study population. Following closure of the plant, settled dust samples were collected and analyzed for hexavalent and trivalent chromium. The trivalent/hexavalent concentration ratios in each plant area were combined with historic air-sampling data to estimate cumulative trivalent chromium exposure for each individual in the study cohort. Smoking status (yes/no) as of the beginning of employment and clinical signs of potential chromium irritation were identified from company records. RESULTS: Cumulative hexavalent chromium exposure showed a strong dose-response relationship for lung cancer. Clinical signs of irritation, cumulative trivalent chromium exposure, and duration of work were not found to be associated with a risk of lung cancer when included in a proportional hazards model with cumulative hexavalent chromium exposure and smoking. Age-specific data on cumulative hexavalent chromium exposure, observed and expected numbers of lung cancer cases, and person-years of observation are provided. CONCLUSIONS: Cumulative hexavalent chromium exposure was associated with an increased lung cancer risk; cumulative trivalent chromium exposure was not. The excess risk of lung cancer associated with cumulative hexavalent chromium exposure was not confounded by smoking status. The current study offers the best quantitative evidence to date of the relationship between hexavalent chromium exposure and lung cancer. Am. J. Ind. Med. 38:115-126, 2000. Published 2000 Wiley-Liss, Inc.     

Occupational exposure to carcinogens and risk of lung cancer: results from The Netherlands cohort study.

OBJECTIVES: To investigate risk of lung cancers associated with common established carcinogenic occupational exposures (asbestos, paint dust, polycyclic aromatic hydrocarbons, and welding fumes) in a prospective cohort study among the general population, and to estimate the proportion of lung cancer cases attributable to these occupational exposures. METHODS: A prospective cohort study on diet, other lifestyle factors, job history, and cancer risk that started in 1986 in The Netherlands on 58,279 men, aged 55-69 years. Based on information about job history obtained from a self-administered questionnaire, case by case expert assessment was carried out to assign to each study subject a cumulative probability of occupational exposure for each carcinogenic exposure. For analysis, a case-cohort approach was used, in which the person-years at risk were estimated from a randomly selected subcohort (n = 1688). After 4.3 years of follow up, 524 lung cancer cases with complete job history were available. RESULTS: After adjustment for age, each of the other occupational exposures, and for smoking habits and intake of vitamin C, beta-carotene, and retinol, significant associations were found between risk of lung cancer and cumulative probability of occupational exposure to asbestos (relative risk (RR) highest/no exposure = 3.49, 95% confidence interval (95% CI) 1.69 to 7.18, trend P < 0.01 or paint dust (RR highest/no exposure = 2.48, 95% CI 0.88 to 6.97, trend P < 0.01). The population attributable risks (PARs) for the four exposures based on the multivariately adjusted RRs for ever exposed versus never exposed workers were calculated. The PAR of lifetime occupational exposure to asbestos was calculated to be 11.6%. CONCLUSIONS: This prospective cohort study among the general population showed that occupational exposure to asbestos or paint dust is associated with higher RRs for lung cancer. This study shows that after adjustment for smoking and diet about 11.6% of the cases of lung cancer in men is attributable to lifetime occupational exposure to asbestos.     

Lung cancer mortality at a UK tin smelter

BACKGROUND: An earlier study of mortality among male former employees at a tin smelter in Humberside, UK, had identified excess mortality from lung cancer, which appeared to be associated with occupational exposure. AIMS: The aim of the present study was to investigate the relationship between lung cancer mortality and quantitative measures of exposure. METHODS: Using available records of occupational hygiene measurements, we established exposure matrices for arsenic, cadmium, lead, antimony and polonium-210 ((210)Po), covering the main process areas of the smelter. We established work histories from personnel record cards for the previously defined cohort of 1462 male employees. Three different methods of extrapolation were used to assess exposures prior to 1972, when no measurement results were available. Lung cancer mortality was examined in relation to cumulative inhalation exposure by Poisson regression analysis. RESULTS: No significant associations could be found between lung cancer mortality and simple cumulative exposure to any of the substances studied. When cumulative exposures were weighted according to time since exposure and attained age, significant associations were found between lung cancer mortality and exposures to arsenic, lead and antimony. CONCLUSIONS: The excess of lung cancer mortality in the cohort can most plausibly be explained if arsenic is the principal occupational carcinogen (for which the excess relative risk diminishes with time since exposure and attained age) and if there is a contribution to excess mortality from an enhanced prevalence of smoking within the cohort. The implications of the dose-response for arsenic exposure for risk estimation merit further consideration.     

Environmental asbestos exposure in rural Turkey and risk of lung cancer

The aim of this study was to determine the risk of lung cancer in a cohort of villagers with environmental asbestos exposure. The study was carried out as a field-based epidemiological study. Information from 3143 individuals in 15 asbestos exposed villages and 2175 individuals in 12 control villages was obtained. Asbestos fiber type to which villagers were exposed mainly was tremolite or tremolite, actinolite, chrysotile mixtures. The cumulative fiber count of the villagers during their lifespan ranged from 0.19 to 4.61 fiber-years/ml. The annual average incidence ratio of lung cancer was 135.21/100,000 persons/year in men and 47.28 in women in the asbestos exposed villages. For the control villages, this ratio was 60.15/100,000 person/year in men and 15.06 in women. Being a male, advanced age, smoking and asbestos exposure were established to increase the risk of lung cancer. Environmental asbestos exposure in rural area is a risk factor for lung cancer independent of smoking.