Statistical Methods for Conditional Survival Analysis

We investigate the survival distribution of the patients who have survived over a certain time period. This is called a conditional survival distribution. In this paper, we show that one-sample estimation, two-sample comparison and regression analysis of conditional survival distributions can be conducted using the regular methods for unconditional survival distributions that are provided by the standard statistical software, such as SAS and SPSS. We conduct extensive simulations to evaluate the finite sample property of these conditional survival analysis methods. We illustrate these methods with real clinical data.     

对苯二胺对工人肺功能和健康相关生活质量的影响

目的分析对苯二胺职业接触人员的肺功能以及健康相关的生活质量情况。方法选取某染发剂生产企业中使用对苯二胺作为生产原料的染发剂生产车间的接触工人(100人)以及同一企业内不接触对苯二胺的工人(24人)作为主要对象,使用36项健康调查简表(SF-36)对工人的健康相关生活质量问卷进行调查,并进行职业健康检查,肺功能测试指标包括用力肺活量(FVC),1秒钟用力呼气量(FEV1.0),以及FEV1.0/FVC。结果调查工人中对苯二胺接触组和对照组的收缩压的差异有统计学意义(P<0.05)。接触组的各项肺功能指标FVC、FEV1.0、FEV1.0/FVC都低于对照组,差异有统计学意义(P<0.05),接触组躯体疼痛(P=0.002)、一般健康状况(P=0.029)、精力(P=0.038)、精神健康(P=0.003)在均低于对照组,差异有统计学意义。结论对苯二胺职业接触可能会对职业人群肺功能产生潜在危害,并影响工人的健康相关生活质量。     

煤矿开采行业工人下背痛与职业应激关联探讨

目的探讨煤矿开采行业工人下背痛与职业应激的关联性。方法2015年1月至2016年12月,选择山西省某大型煤矿开采企业某矿区的一线生产工人472名作为研究对象,采用问卷调查方法调查其基本信息、下背痛患病信息、职业应激水平,二分类Logistic回归法分析下背痛与职业应激的关系。结果研究对象472人中186人在过去一年内发生过下背痛,下背痛年患病率为39.41%。下背痛组的职业应激任务得分高于非下背痛组,差异有统计学意义(P<0.01)。二分类Logistic回归分析结果显示:年龄、婚姻情况、工龄、职业应激任务、劳动强度、工作中保持同一姿势、倒班可能是下背痛的危险因素(P<0.01),吸烟可能是下背痛的保护因素(P<0.01)。结论职业应激任务可能是煤矿开采工人发生下背痛的危险因素(P<0.01),合理分配工作任务、及时疏解煤矿开采工人的职业应激,可能是预防和控制下背痛的有效途径之一。     

互联网企业员工疲劳及影响因素研究

目的 了解互联网企业员工躯体疲劳和脑力疲劳现状,探究疲劳的影响因素。 方法 于2016年6月~9月,采用横断面研究方法对3省(市)35家互联网企业3 603名员工进行了问卷调查,分别采用疲劳量表-14与简明中文版职业应激量表、职业倦怠自评量表、工作相关肌肉骨骼疾患量表,分析互联网企业员工疲劳现况及影响因素,运用多因素Logistic二元回归模型,分析职业应激等因素对疲劳的影响。 结果 互联网企业员工躯体疲劳得分(4.53±2.56),脑力疲劳得分(2.37±1.64),总疲劳得分(6.90±3.55)。躯体疲劳与职业倦怠、肌肉骨骼疾患呈明显正相关(r=0.426、r=0.485,P<0.05),脑力疲劳与职业倦怠呈正相关(r=0.429,P<0.05)。JDC模式职业应激、ERI模式职业应激、职业倦怠、高度肌肉骨骼系统疾患为躯体疲劳发生的危险因素,OR值分别为1.58、1.72、4.08、5.91(P<0.05);上述影响因素同为脑力疲劳发生的危险因素,OR值分别1.73、1.37、2.61、2.08(P<0.05)。睡眠时间7 h以上是脑力疲劳、躯体疲劳发生的保护因素,OR值分别为0.61、0.62(P<0.05)。 结论 互联网企业员工疲劳现状不容乐观,企业关注员工职业心理健康、积极采取有效措施对缓解互联网企业员工疲劳至关重要。     

江苏省噪声作业工人职业体检异常情况分析

目的分析噪声作业工人疑似职业病和职业禁忌证的检出水平及其分布特征。方法依据GBZ 188-2014《职业健康监护技术规范》、GBZ 49-2014《职业性噪声聋的诊断》和GBZ/T 260-2014《职业禁忌证界定导则》,收集江苏省2015年1月1日至2015年12月31日重点职业病监测的149 271名噪声作业工人职业健康检查个案资料,对检查结果进行判定,计算出职业禁忌证和疑似职业性噪声聋检出率,分析检出率在不同性别、年龄、工龄、行业、企业规模等的分布特点。结果噪声作业工人职业禁忌证检出率为2.08%,疑似职业病检出率为2.03%。疑似职业性噪声聋检出率离岗时(2.13%)略高于在岗期间(2.03%)。职业禁忌证检出率在年龄≤20岁、41~50岁以及接触噪声工龄<1年组较高(分别为2.64%、2.48%、5.35%);疑似职业性噪声聋检出率;随年龄、工龄增长而升高(均P<0.05)。职业禁忌证检出率最高的行业是科学研究和技术服务行业(10.46%);疑似职业性噪声聋检出率最高的行业是交通运输、仓储和邮政业(5.88%)。职业禁忌证检出率最高的企业规模是中型企业(2.27%),最低的是微型企业(1.60%);疑似职业性噪声聋检出率最高的企业规模是大型企业(3.21%),最低的是微型企业(1.33%)。 结论应按规范加强噪声作业工人上岗前职业禁忌证以及在岗期间、离岗时疑似噪声聋的筛检。提高对非传统噪声行业噪声危害防治的重视程度和防治力度。     

Opportunities and obstacles in translating evidence to policy in occupational asthma

Purpose

Occupational asthma (OA), a common respiratory disorder in Western countries, is caused by exposures at the workplace. It is part of a broader definition of work-related asthma (WRA) that also includes pre-existing asthma aggravated by substances present in the workplace environment, and it is potentially preventable. The purpose of this paper is to illustrate preventive measures for occupational asthma by case studies.

Seropositivity in animals and risk of occupational brucellosis among abattoirs personnel associated with poor work practices and absence of safety policy in Egypt

Background Occupational hazards are the leading cause of morbidity and mortality among abattoirs personnel and animal workers. These hazards result from direct or indirect exposure to potential infection and several distressing events during routine procedures.

Objectives To serologically investigate the potential occupational brucellosis hazard at Egyptian abattoirs. To provide an insight on the needed biosafety practices that should be implemented to mitigate the spread of occupational brucellosis among abattoir workers.

Methods Two hundred and thirty (n = 230) blood samples were collected from animals in two Egyptian abattoirs. The rose Bengal test was used to evaluate the seroprevalence of Brucella in abattoir animals. A questionnaire was distributed among abattoir personnel to address biosafety gaps and deficiencies as a cause of occupational brucellosis.

Results The overall seroprevalence of Brucella using the rose Bengal test was 75.2% in the two targeted abattoirs. It was obvious that there are gaps of malpractices and inconvenient behavior among individuals of the targeted community.

Conclusions The current findings reveal the missing role of concerned authorities and lack of written safety policy. The data highlights the need for further research, including isolation and characterization of the causative agents, and reliable epidemiological studies.     

Regression analysis of interval‐censored failure time data with possibly crossing hazards

Interval‐censored failure time data occur in many areas, especially in medical follow‐up studies such as clinical trials, and in consequence, many methods have been developed for the problem. However, most of the existing approaches cannot deal with the situations where the hazard functions may cross each other. To address this, we develop a sieve maximum likelihood estimation procedure with the application of the short‐term and long‐term hazard ratio model. In the method, the I‐splines are used to approximate the underlying unknown function. An extensive simulation study was conducted for the assessment of the finite sample properties of the presented procedure and suggests that the method seems to work well for practical situations. The analysis of an motivated example is also provided.     

Effect of motorized scooters on physical performance and mobility: a randomized clinical trial

OBJECTIVE: To investigate the effects of providing a motorized scooter on physical performance and mobility. DESIGN: Randomized clinical trial comparing scooter users with usual care. SETTING: One academic and 1 Veterans Affairs medical center. PARTICIPANTS: Ambulatory, community-dwelling outpatients with rheumatoid arthritis or osteoarthritis of the knee. INTERVENTION: Provision of a motorized scooter for 3 months. MAIN OUTCOME MEASURES: Six-minute walk distance (6MWD) and mobility methods in diverse locations at baseline, 1 month, and 3 months, and accidents while using the scooter. RESULTS: The majority of scooter subjects (n=16/22 [72.7%]) used the scooter 4 or more days per week. The difference+/-standard deviation between the 2 groups in change in 6MWD over the study period was not statistically significant (scooter users, 16.9+/-73.0 m [55.5+/-239.6 ft]; usual care, 17.2+/-72.5 m [56.5+/-238.0 ft], P=.55). Four (18.1%) scooter users reported 9 accidents. Over the study period, the proportion of persons reporting use of a scooter (provided by the study or otherwise available) increased in the scooter-users group (eg, food stores, 16.7% to 52.6%; doctor's office, 0% to 35.7%) but not the usual-care group (food stores, 9.1% to 9.5%; doctor's office, 0% to 0%). CONCLUSIONS: Motorized scooters provided to ambulatory persons with arthritis were used intermittently. The greatest short-term risk from scooter usage appeared to be minor collisions.