2019-2020年中国40岁及以上人群二手烟暴露状况分析

目的 了解中国≥40岁人群二手烟的暴露情况，为控烟及慢性阻塞性肺疾病（COPD）的防控提供科学依据。方法 调查对象来源于2014-2015年和2019-2020年中国居民COPD监测在31个省（自治区、直辖市）125个监测点的≥40岁常住居民。采用多阶段分层整群随机抽样方法抽取调查对象，以面对面询问方式完成了74 559人的问卷调查，共64 142人纳入分析。采用复杂抽样加权方法描述我国≥40岁人群二手烟暴露率、各类场所接触二手烟的比例以及与每天吸烟者共同生活的比例，分析二手烟暴露和接触的影响因素，并与2014-2015年中国居民COPD监测中的二手烟暴露率和各类场所接触二手烟的比例进行比较。结果 2019-2020年，我国≥40岁人群二手烟暴露率为46.4%（95%CI：44.1%~48.8%），女性（47.2%，95%CI：44.8%~49.7%）高于男性（44.8%，95%CI：42.0%~47.6%），且随年龄增长而下降；职业为办事人员的二手烟暴露率最高。≥40岁人群在家中、工作场所、餐厅和公共交通工具接触二手烟的比例分别为24.3%（95%CI：22.2%~26.4%）、23.3%（95%CI：21.1%~25.5%）、6.6%（95%CI：5.3%~7.9%）和2.2%（95%CI：1.6%~2.7%）；文化程度越高的人群在家中接触二手烟的比例越低。在14岁及以前、14岁至调查时与每天吸烟者共同生活的比例分别为56.4%和59.2%。与2014-2015年相比，2019-2020年≥40岁人群二手烟暴露率有所升高，但差异无统计学意义（P=0.356）；≥40岁人群在家中接触二手烟的比例下降，而在工作场所接触二手烟的比例上升，其中农林牧渔水利业人群在工作场所接触二手烟的比例上升幅度最大。多因素分析显示，性别、年龄、职业和文化程度影响二手烟暴露风险及在不同场所接触二手烟的比例。结论 我国≥40岁人群的二手烟暴露率仍较高，工作场所和农林牧渔水利业的职业人群二手烟暴露水平上升，需加强对已有禁烟条例和法规的执行监督，不断推动国家公共场所禁烟立法并特别关注女性、文化程度较低、农林牧渔水利业人群的禁烟及二手烟暴露防护。     

2019-2020年中国40岁及以上人群肺功能检查状况分析

目的 了解我国≥40岁人群肺功能检查状况及其变化,为评价我国慢性阻塞性肺疾病（COPD）防控效果提供科学依据。方法 调查对象来自2014-2015年、2019-2020年中国居民COPD监测,该监测覆盖我国31个省（自治区、直辖市）,采用多阶段分层整群随机抽样方法,由经过培训的调查员面对面询问被调查者既往是否进行过肺功能检查。采用复杂抽样加权估计我国≥40岁人群肺功能检查状况及其95%CI,并比较两次监测调查对象的肺功能检查率。结果 共148 427人纳入分析,其中2014-2015年74 591人,2019-2020年73 836人。2019-2020年我国≥40岁居民肺功能检查率为6.7%（95%CI：5.2%~8.2%）,男性（8.1%,95%CI：6.7%~9.6%）高于女性（5.4%,95%CI：3.7%~7.0%）,城镇居民（8.3%,95%CI：6.1%~10.5%）高于乡村（4.4%,95%CI：3.8%~5.1%）;肺功能检查率随文化程度提升呈上升趋势;有慢性呼吸系统疾病史者肺功能检查率最高（21.2%,95%CI：16.8%~25.7%）,有呼吸道症状者次之（15.1%,95%CI：11.8%~18.4%）,慢性呼吸系统疾病名称知晓者高于不知晓者,曾经吸烟者高于现在吸烟和从不吸烟者,暴露于职业粉尘和/或有害气体者高于非暴露者,家庭使用污染燃料者低于未使用者（均P<0.05）。与2014-2015年相比,2019-2020年我国≥40岁居民肺功能检查率提高了1.9个百分点,不同特征人群的肺功能检查率均有所提高,有呼吸道症状者和有慢性呼吸系统疾病史者肺功能检查率分别提高了7.4个百分点和7.1个百分点（均P<0.05）。结论 我国2019-2020年肺功能检查率较2014-2015年有所提升,有慢性呼吸系统疾病史和呼吸道症状者提高幅度较大,但整体肺功能检查率仍处于较低水平。应进一步采取有效措施以提高肺功能检查率。     

2014年中国40岁及以上人群粉尘和/或有害气体暴露及其防护情况分析

目的 分析我国≥40岁人群粉尘和/或有害气体暴露的流行及其防护状况，为加强我国粉尘和有害气体暴露的职业防护提供依据。方法 资料来源于2014－2015年中国居民COPD监测，在31个省（自治区、直辖市）采用多阶段分层整群抽样，横断面调查125个监测点的≥40岁研究对象共75 107名，采用面对面询问调查方式收集相关信息，职业暴露定义为职业接触粉尘和/或有害气体累积超过1年。对样本进行复杂抽样加权估计暴露比例。结果 在纳入分析的71 061人中，粉尘和/或有害气体暴露率为46.3%，乡村（51.7%）高于城镇（40.3%）；西部地区人群的暴露率高于东、中部地区（P<0.001）；在不同文化程度人群中，小学及以下人群的暴露率最高（49.7%，P<0.001）。暴露人群采取防护措施比例总体为26.7%，东、中、西部地区暴露人群防护比例依次降低；城镇高于乡村；小学及以下文化程度的采取防护措施比例最低（20.7%）。在采取防护措施的人群中，经常防护者仅占50.7%。结论 我国人群粉尘和有害气体职业暴露率较高，采取防护措施比例较低，应当加强西部、乡村及文化程度较低人群的健康教育、职业防护和监管。     

1990-2014年中国40岁及以上人群慢性阻塞性肺疾病患病率Meta分析

目的 分析1990-2014年中国大陆地区≥40岁社区人群COPD患病率。方法 系统检索中国生物医学文献数据库、中文期刊全文数据库、万方电子期刊、PubMed、EBSCO等文献数据库,纳入1990-2014年公开发表的有关中国大陆地区居民COPD患病率的研究文献。采用Stata 12.0软件和Mantel-Haenszel固定效应和随机效应模型对结果进行合并分析。结果 共纳入30篇文献,中国≥40岁人群COPD患病率为9.9%(95%CI:8.8%～11.0%)。其中男性患病率为13.0%(95%CI:11.5%～14.4%),高于女性的5.8%(95%CI:4.9%～6.6%);COPD患病率随年龄增长而上升,由40～49岁的3.2%(95%CI:2.5%～3.9%)上升至≥70岁的20.3%(95%CI:18.2%～22.4%);不同区域、城乡人群间COPD患病率差异无统计学意义。结论 我国近20年≥40岁人群COPD患病率呈现缓慢上升趋势;不同研究在COPD诊断方法、诊断标准、样本构成等存在差异,使研究结果间存在显著的异质性差异。     

昼夜温差和相对湿度与汕头市居民急性心肌梗死之间的关联性分析

目的 分析汕头市气象条件对急性心肌梗死（AMI）患者死亡的影响和人群易感性，为当地医疗卫生系统提供防治AMI的科学依据。方法 收集2015年1月1日至2020年12月31日汕头市居民死因监测数据库中因AMI死亡的人群数据，利用分布滞后非线性模型分析昼夜温差和相对湿度对AMI死亡的影响及滞后效应。结果 研究期间汕头市因AMI死亡13 932人，男女性别比为1.3∶1，高昼夜温差暴露和低相对湿度暴露与AMI死亡之间存在显著关联，单日滞后效应均在滞后2 d时出现并达到最大（RR=1.019，95%CI：1.000~1.039；RR=1.018，95%CI：1.003~1.034）；累计滞后效应均在滞后0~14 d时达到最大（RR=1.199，95%CI：1.025~1.401；RR=1.279，95%CI：1.117~1.465）。≥75岁老年人和女性是高昼夜温差暴露和低相对湿度暴露条件下的易感人群。结论 昼夜温差和相对湿度与汕头市AMI死亡之间存在显著关联，其影响有明显的滞后性。女性和≥75岁老年人均为高昼夜温差和低相对湿度暴露条件下的易感人群。     

中国2013年成年人二手烟暴露水平及相关危害认知情况调查

目的 了解2013年我国成年人二手烟暴露水平及对二手烟暴露导致相关疾病的认知情况。方法 利用中国2013年慢性病及其危险因素监测样本人群,在302个监测点采用多阶段分层整群抽样方法,通过面对面询问的方式收集相关信息,共计调查179 570人,其中纳入有效样本量为176 179人。对样本进行复杂加权后,分析我国成年人二手烟暴露情况,以及对二手烟暴露导致相关疾病的知晓率。结果 调查人群经过复杂加权计算后,18岁以上人群二手烟暴露率为52.8%（95%CI：51.2%~54.4%）,且随年龄增大有下降趋势（χ²=515.8,P<0.000 1）,以商业服务职业人群最高（61.6%,95%CI：58.6%~64.5%）。二手烟暴露导致疾病知晓率为67.9%（95%CI：65.8%~69.9%）。城镇（77.0%,95%CI：75.0%~79.1%）高于乡村（60.0%,95%CI：57.7%~62.4%）,男性（69.8%,95%CI：67.8%~71.7%）高于女性（65.9%,95%CI：63.7%~68.1%）。对3种疾病的知晓率,城镇居民（49.8%,95%CI：47.3%~52.4%）高于乡村居民（37.9%,95%CI：35.4%~40.5%）;知晓二手烟暴露导致成年人肺部疾病的比率最高（88.5%,95%CI：87.5%~89.5%）,其次为儿童肺部疾病（70.0%,95%CI：68.1%~71.9%）,对二手烟暴露导致成年人心脏疾病的知晓率为最低（46.8%,95%CI：44.6%~49.1%）。结论 中国18岁以上成年人二手烟暴露水平较高,对二手烟暴露导致疾病尤其是成年人心脏疾病的知晓率较低。     

中国2019年HIV感染孕产妇所生儿童的失访状况及影响因素分析

目的 分析2019年中国HIV感染孕产妇所生儿童（HIV暴露儿童）的失访状况及影响因素。方法 资料来源于我国预防艾滋病、梅毒和乙型肝炎母婴传播管理信息系统2019年全国医疗机构报告的HIV感染孕产妇和HIV暴露儿童的基本信息和随访记录,HIV暴露儿童失访的定义为出生后满18月龄无法随访到且21月龄时仍未随访到的存活儿童。采用回顾性资料分析方法,HIV暴露儿童的失访影响因素分别采用χ²检验和logistic回归模型进行单因素和多因素分析。采用SPSS 25.0软件进行统计学分析。结果 在5 039例HIV感染孕产妇中,分娩的HIV暴露儿童5 035例,HIV暴露儿童的失访率为5.62%（283/5 035）。多因素logistic回归分析结果显示,孕产妇职业为农（牧、渔）民（aOR=0.34,95%CI：0.22~0.53）、婚姻状况为未婚（aOR=0.47,95%CI：0.24~0.93）、初婚（aOR=0.38,95%CI：0.22~0.67）、再婚（aOR=0.36,95%CI：0.20~0.67）与同居（aOR=0.47,95%CI：0.23~0.97）和本次妊娠前知晓自己感染HIV（aOR=0.53,95%CI：0.40~0.70）的HIV暴露儿童失访率较低;孕产妇为汉族（aOR=1.52,95%CI：1.09~2.13）、小学（aOR=2.06,95%CI：1.10~3.89）和初中文化程度（aOR=1.81,95%CI：1.03~3.17）、未抗病毒治疗（aOR=6.21,95%CI：4.32~8.93）和在乡（街道）级助产机构分娩（aOR=5.72,95%CI：1.61~20.27）的HIV暴露儿童失访率较高。结论 2019年我国HIV暴露儿童存在一定的失访,为进一步降低其失访率,提高妇女孕前HIV检测率和HIV感染孕产妇的抗病毒治疗率,对有效实施预防艾滋病母婴传播综合干预措施有重要意义。     

中国35岁及以上人群缺血性心血管病10年发病风险预测

目的 评估我国≥35岁人群缺血性心血管病10年发病风险。方法 2010年在全国31个省(自治区、直辖市)和新疆生产建设兵团的162个监测点,采用多阶段分层整群随机抽样方法,调查≥18岁成年人98712名,抽取其中≥35岁无缺血性心血管病史者共计67214人为调查对象,通过体格测量和相关指标实验室检测,以及面对面问卷调查收集吸烟情况,高血压、糖尿病和心血管病患病情况。采用国人缺血性心血管病10年发病危险度评估表预测缺血性心血管病10年发病风险。结果 我国≥35岁无缺血性心血管病史人群的缺血性心血管病10年发病风险预测得分为5.1(95%CI:4.9~5.2),平均危险度为4.2%(95%CI:4.0%~4.4%)。其中缺血性心血管病10年发病危险为高危者占8.5%(95%CI:7.8%~9.2%),男性(12.1%,95%CI:11.1%~13.0%)明显高于女性(4.9%,95%CI:4.4%~5.5%)(P<0.05),农村人群(8.8%,95%CI:7.8%~9.7%)高于城市人群(8.1%,95%CI:7.2%~8.9%)(P<0.05);10年发病风险为中危和低危者比例分别为19.1% (95%CI:18.2%~20.0%)和72.4%(95%CI:70.9%~73.9%)。随着教育水平提高或收入增加,缺血性心血管病10年发病风险为高危和中危者的比例均有所下降(P<0.05),而低危者的比例上升(P<0.05)。结论 我国≥35岁人群中有8.5%在未来10年发生缺血性心血管病的可能性超过10%,其中尤为应关注男性、农村、教育水平较低、收入较低人群。     

2019年中国40岁及以上女性家庭烹饪油烟暴露状况分析

目的 了解我国≥40岁女性家庭烹饪油烟的暴露现状及特征。方法 数据来源于2019-2020年中国居民慢性阻塞性肺疾病监测,采用多阶段分层整群随机抽样方法抽取全国31个省（自治区、直辖市）中125个监测县（区）的≥40岁常住居民,通过面对面询问调查收集人口统计学资料和家庭烹饪油烟暴露等相关信息。将家庭烹饪油烟暴露信息完整的女性37 164人作为研究对象,应用复杂加权分析方法,从烹饪时间、烹饪环境和自报烹饪油烟暴露分析不同特征女性家庭烹饪油烟暴露情况。结果 2019年我国≥40岁女性的每天做饭和经常做饭比例分别为83.9%（95%CI：82.1%~85.7%）和4.5%（95%CI：3.8%~5.2%）,其中每天做饭女性的日均做饭时长为1.8 h,日均做饭时长>2.0 h者占31.1%,做饭女性平均累计做饭年数为32.8年。做饭女性使用通风装置的比例为79.3%,厨房与起居室未分开的比例为3.2%。华南、西北地区女性厨房与起居室未分开比例分别为8.9%和7.2%,显著高于其他地区（P=0.036）。女性自报烹饪油烟暴露率为81.0%（95%CI：79.3%~82.7%）。乡村、年龄较大、文化程度较低、职业为农林牧渔水利业的女性,每天做饭比例、日均做饭时长、累计做饭年数、厨房与起居室未分开比例及自报烹饪油烟暴露率较高,做饭时使用通风装置的比例较低（均P<0.001）。结论 我国女性的家庭烹饪油烟暴露严重,仍有部分女性做饭时未采取任何通风措施,应重视女性尤其是社会经济地位较低女性的家庭烹饪油烟暴露及其健康危害。     

上海市2014-2020年流感发病强度的变化情况

目的 评估上海市2014-2020年流感监测网络的运行情况以及流感发病强度的变化。方法 基于上海市2014年1月1日至2020年12月31日的流感监测数据,对哨点医院流感样病例(ILI)缺报漏报和ILI标本采集情况进行评价,计算ILI就诊百分比(ILI%)、流感病毒检出阳性率和流感发病率,利用季节性自回归移动平均模型构建"反事实"情况下2020年流感发病强度的基线,以定量估计上海市2020年流感发病强度的相对变化。结果 2020年上海市ILI缺报漏报情况评价得分和ILI标本采集情况评价得分<5分的医院占比分别为9.68%和21.05%。上海市2014-2019年和2020年的ILI%分别为1.51%(95%CI:1.50%~1.51%)和2.31%(95%CI:2.30%~2.32%),流感病毒检出阳性率分别为24.27%(95%CI:24.02%~24.51%)和7.15%(95%CI:6.78%~7.54%),流感发病率分别为3.66‰(95%CI:3.62‰~3.70‰)和1.65‰(95%CI:1.57‰~1.74‰)。上海市2020年的ILI%升高了45.25%,流感病毒检出阳性率和流感发病率分别降低了78.45%和51.80%。结论 2020年上海市流感监测网络的运行情况发生改变,ILI%有所升高,流感病毒检出阳性率和流感发病率均有所降低,流感监测质量的改变是一个潜在的影响因素,未来仍需进一步加强流感监测的质量控制。     

Calcium intake in the elderly: validation of a dietary questionnaire

Epidemiological studies of calcium and osteoporosis have been hampered by the lack of a suitable tool for assessing calcium intake. This report describes a new frequency and amount questionnaire for measuring present and past calcium intake in the elderly. The validity of the questionnaire was tested against two commonly used standards of dietary assessment, five-day duplicate diets and seven-day weighed dietary inventories. The resulting correlation coefficients were, respectively, r = 0.76 and r = 0.69, while that for repeatability was r = 0.84. Furthermore, the questionnaire categorized subjects into thirds of the distribution of intake with almost no gross misclassification. It is suggested that the present findings may be extended to the majority of normal, healthy elderly subjects, implying wide application for the questionnaire in the assessment of calcium intake in the elderly.     

The occurrence of antimicrobial substances in toilet,sink and shower drainpipes of clinical units: A neglected source of antibiotic residues

Antibiotics represent one of the most important drug groups used in the management of bacterial infections in humans and animals. Due to the increasing problem of antibiotic resistance, assurance of the antibacterial effectiveness of these substances has moved into the focus of public health. The reduction in antibiotic residues in wastewater and the environment may play a decisive role in the development of increasing rates of antibiotic resistance. The present study examines the wastewater of 31 patient rooms of various German clinics for possible residues of antibiotics, as well as the wastewater of five private households as a reference.To the best of our knowledge, this study shows for the first time that in hospitals with high antibiotic consumption rates, residues of these drugs can be regularly detected in toilets, sink siphons and shower drains at concentrations ranging from 0.02?μg·L^?1 to a maximum of 79?mg·L^?1. After complete flushing of the wastewater siphons, antibiotics are no longer detectable, but after temporal stagnation, the concentration of the active substances in the water phases of respective siphons increases again, suggesting that antibiotics persist through the washing process in biofilms. This study demonstrates that clinical wastewater systems offer further possibilities for the optimization of antibiotic resistance surveillance.     

Self-reported health problems among Swedish miners one year after unemployment

Unemployment is considered to be a public health concern sincedeterioration in the health of the unemployed is often anticipated.However, for some groups, such as miners, unemployment mightimprove health due to a cessation of potentially harmful occupationalexposures. This study evaluates the health of 79 miners in oneSwedish iron-ore mine, and 226 age-matched controls from thegeneral population, during one year after the closure of themine. The participants received a questionnaire regarding medicalhistory and subjective symptoms at the beginning of the studyperiod, and after one year. Statistically significant negativeeffects on self-reported health attributable to unemploymentwere not found, although neuropsychiatric symptoms were morecommon among the unemployed miners. The miners reported a statisticallysignificant improvement in grip force (p=0.031). They had asignificantly higher prevalence of symptoms associated withmining related exposures when compared with the population controls;pain in the upper extremities [relative risk (RR)=2.27, 95%confidence interval (Cl)=1.44–3.59), back pain (RR=1.84;Cl=1.237–2.75), vasospastic disease of the fingers (RR=2.05;Cl=1.18–3.57) and obstructive respiratory symptoms (attacksof dyspnea and wheezing: RR=3.67; Cl=1.167–11.6).     

Excès de cas humains et animaux de tularémie en France au cours de l’hiver 2007–2008 : émergence ou phénomène isolé ?

Context

Tularemia is a zoonosis affecting humans and hares in France. We describe the results of surveillance in both species, in 2007 and 2008.

Methods

Human tularemia cases are mandatorily notifiable in France since 2003. In hares, surveillance relies on volunteer hunter associations in all districts of the country. Data from mandatory reports and volunteer surveillance in 2007/2008 were analyzed and compared with previous results.

Results

In 2007/2008, 144 cases were reported in humans and 117 cases in hares. This was a 100% increase compared to previous years. Human cases differed from those of previous years only by the frequency of contact with breeding animals. Human cases without any documented risk exposure were also more frequent.

Conclusion

An increase of tularemia cases occurred in 2007/2008 in both species. Complementary studies are needed to identify the species reservoir in France to understand the causes of this peak of cases.     

Occupational health hazards in mining: an overview

This review article outlines the physical, chemical, biological, ergonomic and psychosocial occupational health hazards of mining and associated metallurgical processes. Mining remains an important industrial sector in many parts of the world and although substantial progress has been made in the control of occupational health hazards, there remains room for further risk reduction. This applies particularly to traumatic injury hazards, ergonomic hazards and noise. Vigilance is also required to ensure exposures to coal dust and crystalline silica remain effectively controlled.     

Manufacture and use of nanomaterials: current status in the UK and global trends

This paper provides an overview of the production and use of nanomaterials (NMs), particularly in the UK. Currently, relatively few companies in the UK are identifiable as NM manufacturers, the main emphasis being the bulk markets in metals and metal oxides, and some niche markets such as carbon nanotubes and quantum dots. NM manufacturing in the UK does not reflect the global emphasis on fullerenes, nanotubes and fibres. Some assumptions have been made about the types of NM that are likely to be imported into the UK, which currently include fullerenes, modified fullerenes and other carbon-based NMs including nanotubes. Many university departments, spin-offs and private companies have developed processes for the manufacture of NMs but may only be producing small quantities for research and development (R&D) purposes. However, some have the potential to scale up to produce large quantities. The nanotechnology industry in the UK has strong R&D backup from universities and related institutions. This review has covered R&D trends at such institutions, and appropriate information has been added to a searchable database. While several companies are including NMs in their products, only a few (e.g. manufacturers of paints, coatings, cosmetics, catalysts, polymer composites) are using nanoparticles (NPs) in any significant quantities. However, this situation is likely to change rapidly. There is a need to collect more information about exposure to NPs in both manufacturing and user scenarios. As the market grows, and as manufacturers switch from the micro- to the nanoscale, the potential for exposure will increase. More research is required to quantify any risks to workers and consumers.     

深圳公立医院管理体制改革制度设计

深圳公立医院管理体制改革实行政事分开、管办分开,在理事会架构下按法定机构模式组建市医管中心,落实公立医院运营管理自主权.作者从当前公立医院管理体制的弊端入手,介绍了深圳市进行公立医院管理体制改革的基本思路及改革方案设计的主要举措,深入剖析了的改革方案的特点,并对改革效果进行了预测.     

Effects of nitrogen dioxide on red blood cells of rats: Changes in components of red cell membranes during in vivo exposure to NO2

Red cell membranes, prepared from red blood cells of rats exposed to 4, 10, or 20 ppm nitrogen dioxide (NO₂) for 1 to 10 days, were examined for evidence of changes in membrane components. Appreciable changes were not found in contents of phospholipid and cholesterol during exposure to 10 ppm NO₂. By contrast, protein content altered with the time of exposure. Moreover, changes in protein composition were observed by employing sodium dodecyl sulfate — polyacrylamide gel electrophoresis. Twenty-four-hour exposure to NO₂ at the concentration above 10 ppm resulted in a marked increase in the percentage of lysophosphatidylethanolamine (LysoPE) to the total phospholipids. The prolonged exposure to 10 ppm NO₂ gave rise to a further increase in LysoPE, whereas the percentage of phosphatidylethanolamine (PE) showed a gradual decrease. A 1-day exposure to 4.0 ppm NO₂ also caused an increase in sialic acid content and decreases in those of PE and hexose. In addition to contents of these components the percentage of LysoPE increased 5 days after exposure and the elevated values were maintained up to the end of exposure period. These results demonstrate that red blood cells in circulation exhibit different membrane properties in terms of lipid and carbohydrate composition during 10 days of exposure to 4.0 ppm NO₂.     

Investigating clusters in the workplace and beyond

Clusters of disease are common and occur in the workplace and in the general community. They often arouse considerable concern among the population. Investigations have sometimes lead to exciting new knowledge, but in general the investigation of clusters is difficult and often unrewarding, especially for community clusters. In the workplace, investigations are more likely to find associations and even new causes, but still many clusters remain enigmatic. Despite this, there are many reasons for investigating clusters, including allaying community concern and identifying uncontrolled exposures. A structure for investigating clusters in the workplace is suggested.