上海地区职业体检人群幽门螺杆菌感染与生活 方式的关系及危险因素研究

目的 调查上海地区职业体检人群中幽门螺杆菌（ Helicobacter pylori ,HP）感染现状,评价个人生活方式与HP感染的关系并对HP感染的可能危险因素进行探讨。为制定上海地区职业人群预防幽门螺杆菌感染策略提供参考依据。方法 采用整群抽样的方法选取2020年5月—2020年10月在华东疗养院进行HP检测的上海地区职业体检人群为研究对象,根据HP检测结果分为阳性组（1 045例）和阴性组（3 203例）,比较两组间体格检查、实验室检查及生活方式间的差异,并使用logistic回归探讨HP感染的危险因素。结果 本研究4 248例职业体检人群中,HP阳性检出率为24.6%,其中60~65岁年龄组HP感染率最低,仅为16.3%,各年龄组感染率不同（〖XC小五号.EPS;P〗=4.757, P ＜0.05）。有吸烟史（〖XC小五号.EPS;P〗=32.819 ,P ＜0.001）、饮酒史（〖XC小五号.EPS;P〗=8.499 ,P ＜0.05））的职业体检人群HP感染率显著高于未吸烟饮酒人群。HP感染阳性组中体质指数（BMI）( t =3.610, P ＜0.001)、收缩压( t =3.254, P ＜0.05)、舒张压( t =4.113, P ＜0.001)、空腹血糖( t =2.648, P ＜0.05)、胆固醇( t =2.112, P ＜0.05)等指标均高于阴性组。logistic回归显示,工作中的体力强度（ OR =1.206,95% CI :1.034~1.406）、经常请客应酬（ OR =1.161,95% CI :1.015~1.329）、吸烟史（ OR =1.236,95% CI :1.124~1.359）、体质指数（BMI）（ OR =1.026,95% CI :1.003~1.050）、空腹血糖（ OR =1.084,95% CI :1.012~1.161）是HP感染的危险因素,60~65岁年龄组（ OR =0.520,95% CI :0.332~0.814）、常吃水果（ OR =0.902,95% CI :0.818~0.994）是HP感染的保护因素。结论 上海职业体检人群HP阳性率24.6%明显低于我国平均水平;HP感染与生活方式存在密切联系。     

泸州地区体检在职人群血脂异常流行情况及危险因素分析

目的 了解泸州地区体检在职人群血脂异常的流行情况及危险因素分析,为制定相关疾病防控策略和措施提供依据。方法 采用方便抽样的方法调查对2020年6-12月泸州地区三家三甲医院18~60岁4878名健康体检在职人群,通过面对面问卷调查、体格检查和血生化检测收集资料,剔除不合格及关键变量缺失问卷,最终有4274名调查对象纳入研究分析中,使用非条件logistic回归进行危险因素分析。结果 调查发现,血脂异常的检出率为48.13%,其中高TG血症、高TC血症、高LDL-C血症、低HDL-C血症检出率分别为41.93%、18.88%、5.85%、1.39%,女性血脂异常及高TG血症、高TC血症、高LDL-C血症、低HDL-C血症检出率低于男性（χ2=541.00,P<0.001;χ2=55.30,P<0.001;χ2=534.32,P<0.001;χ2=34.61,P<0.001;χ2=23.13,P<0.001）,而年龄增高使血脂异常及各成分异常检出率增加（χ2=153.93,P<0.001;χ2=113.31,P<0.001;χ2=168.69,P<0.001;χ2=28.55,P<0.001）,吸烟主要导致血脂异常、高TG血症（OR=1.41,95%CI:1.19~1.66;OR=1.70,95%CI:1.44~2.00）,膳食情况一般或较差是血脂异常的危险因素（OR=1.28,95%CI:1.10~1.48;OR=2.36,95%CI:1.50~3.70）,中心性肥胖、超重、肥胖是血脂异常的危险因素（OR=1.66,95%CI:1.42~1.94;OR=4.06,95%CI:2.42~6.88;OR=5.56,95%CI:3.19~9.69）,吸烟、膳食情况较差、糖尿病、中心性肥胖是HDL-C降低的危险因素（OR=1.95,95%CI:1.08~3.50;OR=4.05,95%CI:1.17~9.24;OR=2.57,95%CI:1.39~4.77）。结论 泸州地区体检在职人群血脂异常程度高于全国平均水平,高TG血症和高TC血症是该地区体检在职人群血脂异常的主要形式,应该从加强运动、控制体重、良好的膳食情况等方面加强血脂异常的防控与管理。     

银川市学龄儿童青少年睡眠时间与血脂异常的关系

目的 了解银川市学龄儿童青少年睡眠时间的分布状况,并分析睡眠时间与血脂异常的关系。方法 采用现况研究,共抽取银川市1662名6~18岁学龄儿童青少年为研究对象,对其进行体格检查、问卷调查和实验室检测。结果 男、女各年龄组中随着年龄的增长睡眠时间<6.8h呈上升趋势,差异有统计学意义(男:〖XC小五号.EPS;P〗=213.019,女:〖XC小五号.EPS;P〗=269.115,均P<0.001)。睡眠时间<6.8h与7.9~9.0h相比,睡眠时间<6.8h的血脂异常检出率较高,且睡眠时间<6.8h的血脂异常检出率是7.9~9.0h的1.5(95%CI:1.0~2.2)倍,差异有统计学意义(〖XC小五号.EPS;P〗=4.094,P<0.05)。睡眠时间<6.8h的儿童青少年患血脂异常的风险是睡眠时间≥9h的2.31(95%CI:1.19~4.51)倍,差异有统计学意义(〖XC小五号.EPS;P〗=6.078,P<0.05);进一步调整年龄、性别和BMI后,上述现象依然存在,睡眠时间<6.8h的儿童青少年患血脂异常的风险是睡眠时间≥9h的2.00(95%CI:1.02~3.93)倍,差异有统计学意义(〖XC小五号.EPS;P〗=4.052,P<0.05)。结论 学龄儿童青少年睡眠时间不足随着年龄的增长呈上升的趋势,且睡眠时间不足与血脂代谢异常有关。     

单胎产妇妊娠期糖尿病发病情况及影响因素分析

目的 了解妊娠糖尿病（GDM）的发病情况，探讨其影响因素，为制定GDM的防控措施提供科学依据。方法 选取2015-2018年北京某地区分娩的5659例孕妇为研究对象，收集北京市妇幼保健信息系统中相关围产资料，采用SPSS 18.0统计软件进行〖XC小五号.EPS;P〗分析、多因素logistic回归分析GDM发病情况及影响因素。结果 研究对象共纳入5659人，其中GDM发病人数为858人，发病率为15.2%。不同户籍、年龄的孕妇GDM的发病率差异有统计学意义（〖XC小五号.EPS;P〗分别为26.66、76.0, P<0.01）。多因素分析结果显示，外地户籍是GDM发病的保护因素(OR=0.76,95%CI:0.64~0.90)；高龄(OR=1.72,95%CI:1.44~2.06)、孕前BMI超重(OR=1.96,95%CI:1.60~2.39)和肥胖(OR=3.41,95%CI:2.18~5.32)、有糖尿病家族史(OR=2.05,95%CI:1.42~2.96)、瘢痕子宫(OR=1.25,95%CI:1.03~1.52)、孕期甲状腺功能异常(OR=1.50,95%CI:1.22~1.84)、妊娠高血压疾病(OR=1.73,95%CI:1.17~2.57)均为GDM发病的危险因素（P<0.05)。结论 本地区GDM的发病率与相关研究报道结果不尽相同，它是多种因素作用的结果，做好孕前健康教育和孕中早发现、早干预，能降低GDM的发病率，改善母婴结局。     

2014-2018年珠海市梅毒感染情况分析

目的 了解珠海市梅毒感染状况和流行趋势，为制定梅毒防控措施提供参考依据。方法 通过实验室信息管理系统收集各医疗机构2014-2018年期间所有梅毒检测信息进行统计分析。结果 2014-2018年梅毒感染阳性5436例，总阳性率为0.75%，呈逐年降低趋势（〖XC小五号.EPS;P〗趋势=51.968，P<0.001），阳性者中1:8以下血清TRUST滴度占67.90%。男性阳性率（1.05%）高于女性（0.58%）(〖XC小五号.EPS;P〗=488.261，P<0.001)，男性1:8以下滴度占比（60.69%）低于女性（75.95%）(〖XC小五号.EPS;P〗=144.996，P <0.001)。≥60岁年龄段阳性率(1.13%)高于＜60岁年龄段阳性率（〖XC小五号.EPS;P〗=219.615，P<0.001），其1:8以下滴度占比(78.28%)较高。性病门诊阳性率最高（8.83%），其女性阳性率高于男性（〖XC小五号.EPS;P〗=203.592，P<0.001），且1:8以下滴度占比较低（60.46%）。结论 珠海市梅毒感染率呈缓慢降低趋势，男性高于女性，20～39岁为主要感染人群，老年人群不可忽视，性病门诊阳性率最高，住院阳性数占比较大，应进一步加强各人群梅毒筛查力度、规范诊疗、控制扩散。     

常州市职业作业人群血脂异常调查分析

目的 掌握目前常州市职业工作人群的血脂水平及血脂异常发生率,并分析其影响因素。 方法 选取2018年1月至2018年12月常州市疾病预防控制中心门诊部进行职业健康体检的5670 例体检者为研究对象并检测其血脂水平,采用多因素logistic回归研究性别、年龄、接触工龄、血压、心率以及职业有害因素对血脂异常的影响。 结果 常州市5670名职业作业体检者总胆固醇（TC）水平为（4.65±0.87）mmol/L、甘油三酯(TG) 水平为（1.03±0.78）mmol/L、高密度脂蛋白(HDL-C) 水平为（1.21±0.20）mmol/L、低密度脂蛋白（LDL-C）水平为（2.47±0.64）mmol/L,总血脂异常率为28.6%。多因素logistic回归结果显示,男性（OR=1.484,95%CI:1.275~1.728,P<0.001）、年龄（OR=1.135,95%CI:1.041~1.238,P=0.004）以及血压异常（OR=1.318,95%CI:1.144~1.519,P<0.001）都与血脂异常有关;在职业有害因素岗位类别方面,接触噪声作业人群（OR=1.433,95%CI:1.202~1.707,P<0.001）的血脂异常率要高于管理岗位,其他有害因素作业岗位人群与管理岗位人群相比,血脂异常率的差异均无统计学意义（P>0.05）。 结论 对50岁以上男性、血压异常者以及接触噪声作业等血脂异常高发职业作业人群,应加强对其血脂的定期监测,控制降低其血脂水平,从而预防和减少心血管疾病发生,延长其职业工作寿命。     

医院感染产ESBLs大肠埃希菌的耐药性及危险因素的logistic回归分析

目的 研究某三级甲等医院院内感染产超广谱β-内酰胺酶（ESBLs）大肠埃希菌的耐药性及危险因素，为临床合理使用抗菌药物及医院感染的防控提供依据。方法 采用回顾性病例对照研究，调查2016年1月1日至2018年12月31日期间全院检出产ESBLs大肠埃希菌院内感染患者共550例，对照组则为随机抽取同等数量同期分离的非医院感染产ESBLs大肠埃希菌病例，危险因素分析采用单因素〖XC小五号.EPS;P〗检验和多因素logistic回归分析。结果 共检出医院感染产ESBLs大肠埃希菌病例550例，其中男性325例，女性225例，平均年龄为59.30±20.71岁。耐药率除碳青霉烯类抗菌药物外，医院感染产ESBLs大肠埃希菌均高于对照组。产ESBLs大肠埃希菌医院感染的主要危险因素有:年龄（OR=1.163，95%CI:1.021~1.325，P<0.001）、住院天数（OR=1.789，95%CI:1.455~2.199，P<0.001）、手术（OR=4.436，95%CI:3.249~6.057，P<0.001）、基础疾病（OR=2.124，95%CI:1.562~2.888，P<0.001）和侵入性操作（OR=3.607，95%CI:2.667~4.879，P<0.001）。结论 除碳青霉烯类抗菌药物外，医院感染产ESBLs大肠埃希菌的耐药率均高于非医院感染产ESBLs大肠埃希菌；年龄、住院天数、手术、基础疾病和侵入性操是其主要危险因素。重点监测高危人群，规范抗菌药物的合理使用，将有利于指导院内感染该菌的预防与控制。     

海南地区健康人群的肾功能轻度下降与代谢综合征各组分及不同组合类型的相关性分析

目的 探讨健康人群的肾功能轻度下降与代谢综合征(Metabolic Syndrome,MetS)组分及不同组合类型的相关性。方法 选取肾功能轻度下降组5097例及随机匹配同期体检的肾功能正常组5204例为研究对象；慢性肾脏病流行病学协作公式(CKD-EPI公式)计算估计肾小球滤过率(estimate glomerular filtration rate,eGFR)评估肾功能；logistic多因素回归分析MetS各组分及不同组合与肾功能轻度下降的相关性。结果 该人群肾功能轻度下降组的MetS发生率(26.4%)高于正常组(22.4%)，差异有统计学意义（P＜0.05，〖XC小五号.EPS;P〗=28.711）；logistic多因素回归分析结果显示，校正年龄、性别、血尿酸、吸烟史、饮酒史后，MetS单组分与肾功能轻度下降有相关性的是腰围(OR=1.124，95%CI:1.012~1.249)、空腹血糖(OR=0.771，95%CI:0.701~0.848)和收缩压(OR=0.456，95%CI:0.392~0.529)；1~5个组分的Mets发生肾功能轻度下降的风险分别为1.235（95%CI:1.090~1.400）,1.379(95%CI:1.210~1.573),1.492(95%CI:1.292~1.723)，2.064(95%CI:1.710~2.490)，2.982(95%CI:2.056~4.326)；含有腹型肥胖、高血糖或高血压的MetS类型发生肾功能轻度下降的风险更高。结论 腰围、空腹血糖和收缩压是该人群肾功能轻度下降的独立危险因素，且含有这3个独立危险因素的MetS类型发生肾功能轻度下降的风险更高。     

苏北某市居民传染病健康素养水平与影响因素分析

目的 了解苏北某市居民传染病健康素养水平及影响因素,为提高居民应对烈性传染病的能力提供建议。方法 采用按规模大小成比例的概率抽样抽取苏北某市15~69岁居民为调查对象,使用统一编制的《全国居民健康素养监测调查问卷》进行调查。采用〖XC小五号.EPS;P〗检验、logistic回归、综合人群归因危险度及列线图等方法分析。结果 此次调查共抽取1975人,收回有效问卷1933份。居民传染病健康素养水平不合格人群比例为51.68%（95%CI=49.42%~53.93%）,文化程度小学及以下（72.78%）、年龄60~69岁（72.30%）占比较高,公务员/医务人员比例较低（31.73%）,差异有统计学意义（P<0.05）。Logistic回归分析显示,居民传染病健康素养水平的危险因素为:文化程度小学及以下（OR=3.775,95%CI=2.697~5.283）,小学以上大专以下（OR=1.611,95%CI=1.256~2.066）;职业农民/工人（OR=1.712,95%CI=1.070~2.737）,企业人员（OR=1.658,95%CI=1.008~2.730）;人均年收入<3000（OR=1.634,95%CI=1.196~2.234）;年龄60~69岁（OR=1.546,95%CI=1.023~2.336）;吸烟（OR=1.321,95%CI=1.060~1.646）。综合人群归因sPAR%为68.0%,其中文化程度（43.9%）PARc%最高,职业（36.9%）次之。列线图也显示了低文化程度是传染病健康素养水平预测的主要风险因素。结论 苏北某市超过半数居民传染病健康素养水平不合格,以农民、工人、低收入者为主,是健康教育工作的主要切入点。     

深圳市某中学一起流行性腮腺炎暴发疫情调查

目的 了解该起流行性腮腺炎疫情的流行特征和暴发原因,并分析接种含流腮成分疫苗的保护效果,为制定防控措施提供科学依据。方法 对病例进行个案调查,运用描述与分析流行病学方法分析疫情流行特征和相关因素。结果 本次疫情共发现病例99例,波及16个班级,总罹患率为6.96%(99/1423);疫情持续93天,共出现3次发病高峰和5-6代病例;病例主要集中在2楼,罹患率为22.82%(〖XC小五号.EPS;P〗=185.51,P<0.01),以初一年级发病为主,罹患率为11.58%(〖XC小五号.EPS;P〗=45.35,P<0.01);病例组参加“劳技中心”活动的比例高于对照组(〖XC小五号.EPS;P〗=16.35,P<0.01),OR值为4.38(95%CI:2.13~8.98);学生接种率为58.14%(425/731),接种过疫苗的学生罹患率低于未接种过的学生(〖XC小五号.EPS;P〗=13.16,P<0.01),疫苗保护率为49.08%;接种一剂次疫苗保护率为38.05%,接种两剂次疫苗保护率为67.23%;本次疫情的罹患率有随接种疫苗剂次增加而降低的线性趋势(〖XC小五号.EPS;P〗趋势=16.69,P<0.01)。结论 参加“劳技活动”是本次疫情暴发的主要危险因素,病例未及时隔离和流腮免疫空白是加速本次疫情扩散和蔓延的主要原因。     

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.