妊娠晚期缺铁性贫血现状调查及产前影响因素分析

目的 探讨妊娠晚期缺铁性贫血(IDA)现状及产前影响因素,为临床诊治提供参考依据。方法 纳入2017年2月—2020年2月96例在台州市立医院定期产检的妊娠晚期产妇为研究对象。随访并记录IDA发生率。采用Logistic多因素回归分析影响晚期妊娠产妇发生IDA的产前影响因素,并根据分析结果建立预测模型,验证其应用价值。结果 96例孕妇中16例发生IDA,发生率16.67%,记为观察组,其余80例为对照组。两组孕妇孕前体质指数(BMI)差异有统计学意义(P<0.05)。两组孕妇流产次数、不良饮食习惯及孕前月经量比较,差异均有统计学意义(均P<0.05)。Logistic多因素回归模型分析结果显示孕前BMI≥24 kg/m²(OR=0.695,95%CI=0.583～0.829)是IDA的保护因子(P<0.05),流产次数≥3次(OR=1.541,95%CI=1.286～1.847)、孕前月经量≥100 ml(OR=2.074,95%CI=1.429～3.010)及产检异常(OR=1.085,95%CI=1.032～1.985)是IDA的危险因素(P...     

定期产检对降低孕妇母婴并发症的临床价值

目的分析孕妇母婴并发症发生影响因素,评价定期产检在改善母婴预后中的应用价值。方法采用回顾性分析方法,以2011年1月-2015年5月,医院产科接待的4 889例孕妇作为研究对象,将其中母婴出现过不良妊娠结局的584例纳入病例组,其余4 305例纳入正常组,调取临床资料,进行回顾性分析。结果其中未按照要求进行产检者为3.44%(168/4 889),年龄(27.4±4.2)岁,同期按要求产检者(26.4±5.1)岁,差异无统计学意义(P0.05);正常组与病例组母年龄≥35岁、增补叶酸、孕期接触毒性与有害物质、接受免费产前检查、饲养宠物、定期产检比重,差异均有统计学意义(P0.05);密切接触宠物[OR=1.842,95%CI(3.671~11.528)]、母亲年龄[OR=2.476,95%CI(1.482~8.487)]、定期孕检[OR=0.914,95%CI(0.8571~1.487)]成为独立影响因素,其中定期孕检成为保护因素。结论本地区孕期定期产检率较高,定期产检确实可降低母儿并发症发生风险,改善预后。     

妊娠期缺铁性贫血发病的危险因素及对妊娠结局的影响

目的探讨妊娠期缺铁性贫血(IDA)发病的危险因素及对妊娠结局的影响。方法选取2018年1月-2019年6月台州市中心医院确诊的240例妊娠期IDA孕妇作为贫血组,随机选取480例未发生IDA的孕妇作为非贫血组,对所有孕妇进行随访调查;采用单因素比较法和多因素Logistic回归法分别筛选妊娠期IDA的危险因素,比较两组母婴妊娠结局的差异性。结果妊娠期IDA孕妇的危险因素包括高龄(OR=2.270)、农村地区(OR=3.161)、无规律产检(OR=4.371)、孕期素食为主(OR=3.442)及经常饮茶/咖啡(OR=4.768)等,而孕期营养指导(OR=0.485)、孕期补铁(OR=0.611)为保护因素。贫血组的妊娠期高血压疾病、胎儿窘迫、羊水异常、剖宫产、早产、产后出血及新生儿窒息等发生率均高于非贫血组(均P0.05)。结论影响妊娠期IDA孕妇发病的危险因素较多,且IDA对母婴妊娠结局影响较大,应做到早预防、早筛查、早诊断、早治疗,减少IDA的发生率,改善母婴妊娠结局。     

妊娠期糖尿病高龄孕妇并发子痫前期的相关因素分析

目的探讨妊娠期糖尿病(GDM)单胎妊娠高龄孕妇并发3种类型子痫前期(PE)(PE、早发型PE及重度PE)的相关因素。方法选择2018年1至12月在四川大学华西第二医院就诊的600例单胎妊娠高龄(≥35~39岁)孕妇纳入高龄组,年龄为(36.4±1.2)岁,其中GDM孕妇为200例,非GDM孕妇为400例。再按照与高龄组GDM与非GDM孕妇1∶1选取同期在本院就诊的600例单胎妊娠超高龄(≥40岁)孕妇纳入超高龄组,年龄为(40.9±1.2)岁,其中GDM孕妇为200例,非GDM孕妇为400例。本研究设定的可能影响孕妇发生PE的相关因素包括GDM、是否初产妇、人体质量指数(BMI)、文化程度、居住地及辅助生殖技术(ART)史,探讨这6种因素影响单胎妊娠高龄孕妇并发3种类型PE(PE、早发型PE及重度PE)的风险。采用t检验对年龄等进行组间比较,采用χ2检验对各组受试者中并发3种类型PE所占比例进行分析。对于2组孕妇并发3种类型PE影响因素的多因素非条件logistic回归模型进行分析。本研究遵循的程序符合2013年修订的《世界医学协会赫尔辛基宣言》要求。结果①高龄组和超高龄组中,GDM孕妇发生PE、早发型PE、重度PE所占比例均高于非GDM孕妇,其中高龄组GDM孕妇与非GDM孕妇并发PE者所占比例比较,差异有统计学意义(P<0.05)。超高龄组GDM孕妇与非GDM孕妇并发早发型PE、重度PE所占比例比较,差异亦有统计学意义(P<0.05)。②多因素非条件logistic回归分析结果显示,GDM是导致高龄组孕妇发生PE(OR=2.232,95%CI:1.080~4.613,P=0.030)的危险因素。GDM是导致超高龄组孕妇发生早发型PE(OR=3.456,95%CI:1.238~9.650,P=0.018)和重度PE(OR=2.236,95%CI:1.057~4.729,P=0.035)的危险因素。③控制混杂因素后,多因素非条件logistic回归分析结果显示,在高龄组中,GDM孕妇发生PE风险是非GDM孕妇的1.934倍(OR=1.934,95%CI:1.029~4.115,P=0.047);BMI≥24 kg/m2是导致高龄组GDM孕妇发生PE(OR=2.931,95%CI:1.332~6.449,P=0.008),早发型PE(OR=2.977,95%CI:1.105~8.019,P=0.031)和重度PE(OR=2.638,95%CI:1.093~6.365,P=0.031)的危险因素;居住地在乡村是导致其发生PE(OR=2.831,95%CI:1.042~7.686,P=0.041)和重度PE(OR=3.232,95%CI:1.088~9.603,P=0.035)的危险因素;文化程度高是高龄孕妇发生PE(OR=0.231,95%CI:0.071~0.749,P=0.015)和重度PE(OR=0.179,95%CI:0.048~0.673,P=0.011)的保护因素。在超高龄组中,GDM孕妇发生早发型PE、重度PE的风险,分别为非GDM孕妇的3.187倍(OR=3.187,95%CI:1.109~9.153,P=0.031)与2.3倍(OR=2.351,95%CI:1.043~5.302,P=0.039);BMI≥24 kg/m2是导致其发生PE(OR=2.654,95%CI:1.417~4.971,P=0.002)和重度PE(OR=3.418,95%CI:1.515~7.710,P=0.003)的危险因素;居住地在郊县是导致其发生PE(OR=2.374,95%CI:1.089~5.171,P=0.030)和重度PE(OR=5.303,95%CI:2.074~13.565,P<0.001)的危险因素;文化程度高是超高龄孕妇发生PE(OR=0.347,95%CI:0.135~0.892,P=0.028)和重度PE(OR=0.164,95%CI:0.047~0.574,P=0.005)的保护因素。结论GDM高龄孕妇的PE发病风险较非GDM高龄孕妇显著增高,GDM超高龄孕妇的早发型PE和重度PE发病风险较非GDM超高龄孕妇显著增加。BMI≥24 kg/m2、文化程度低、居住地在郊县和乡村,均是导致高龄及超高龄孕妇3种类型PE发生的危险因素。     

前置胎盘相关因素的病例对照及妊娠结局临床分析

目的探讨前置胎盘的相关因素及其对妊娠结局的影响。方法选择2012年1月—2015年10月住院待产的前置胎盘产妇79例为研究组,按照1∶2的比例匹配同期住院的158例健康产妇为对照组。对比两组相关因素的暴露情况及妊娠结局。计数资料采用χ~2检验,危险因素分析采用Logistic回归分析,P0.05为差异有统计学意义。结果年龄(OR=2.647,95%CI为1.707~4.105)、流产史(OR=3.245,95%CI为1.661~6.338)、剖宫产史(OR=3.500,95%CI为1.106~11.072)是前置胎盘发生的独立危险因素。文化程度(OR=0.653,95%CI为0.433~0.983)是保护因素。研究组的胎盘粘连植入、产后出血、低体重儿及早产儿发生率分别为11.39%、18.99%、22.78%和16.46%,均明显高于对照组的1.90%、5.70%、7.59%和5.70%,差异均有统计学意义(均P0.05)。结论孕产妇高龄、流产史和剖宫产史是前置胎盘的危险因素,文化程度是保护因素,前置胎盘孕妇的预后差。加强生殖健康宣教活动,减少非意愿妊娠和流产,严格控制剖宫产指征,可降低前置胎盘发生率,从而改善妊娠结局。     

早产儿发生低血糖的危险因素分析

目的 探究早产儿出生后发生低血糖的危险因素,为早产儿低血糖的预防和管理提供资料。方法 回顾536例胎龄<37周的早产儿临床资料,统计发生低血糖(血糖低于2.2 mol/L)的病例数,比较低血糖组和正常组的临床资料差异,运用Logistic回归模型分析早产儿发生低血糖的危险因素。结果 536例早产儿发生低血糖82例,发生率为15.3%。低血糖组早产儿的胎龄、出生体重低于正常组,小于胎龄儿(SGA)、剖宫产、出生体温<36.5℃、妊娠期甲状腺功能减退、妊娠期糖尿病、妊娠期高血压的比例高于正常组,差异均有统计学意义(P<0.05)。Logistic回归分析显示,SGA(OR=1.401)、妊娠期糖尿病(OR=2.746)、妊娠期高血压(OR=1.525)、出生低体温(OR=2.110)为早产儿低血糖的危险因素,阴道分娩(OR=0.596)为早产儿低血糖的保护因素,均P<0.05。结论 SGA、出生低体温、妊娠期高血压、妊娠期糖尿病可增加早产儿低血糖的发生风险,阴道分娩能够降低早产儿低血糖的发生风险。     

晚期妊娠合并心脏病发生心力衰竭相关危险因素研究

目的探讨导致合并心脏病的晚期妊娠女性发生心力衰竭的危险因素。方法选择2012年5月-2015年5月在首都医科大学附属安贞医院住院的合并心脏病的晚期妊娠孕妇中心力衰竭患者80例为研究组,随机选择同期住院的晚期妊娠期合并心脏病但未发生心力衰竭患者80例为对照组,采用单因素分析和多因素Logistic回归分析晚期妊娠合并心脏病发生心力衰竭的危险因素。结果单因素分析结果显示,孕期血压升高、贫血、低蛋白血症、肺动脉高压、定期产检、血浆BNP的异常升高、射血分数的下降两组患者差异有统计学意义(P0.05),产次、动脉血氧饱和度差异无统计学意义(P0.05)。多因素Logistic回归分析结果显示,孕期血压升高[OR=2.076,P=0.030]、贫血[OR=1.588,P=0.006]、低蛋白血症[OR=1.312,P=0.000]、中度肺动脉高压[OR=1.452,P=0.036]、重度肺动脉高压[OR=2.137,P=0.001],射血分数50%[OR=1.103,P=0.035]、孕期规律产检[OR=0.446,P=0.016]进入回归方程。结论孕期血压升高、贫血、低蛋白血症、中-重度肺动脉高压、射血分数50%为导致合并心脏病的晚期妊娠孕妇心力衰竭的危险因素,孕期规律产检为其保护性因素,孕期规律产检能有效控制这些危险因素可以改善妊娠合并心脏病患者的心功能,进而降低心力衰竭的发生率,改善整体患者的预后水平。     

孕前体质指数、孕期增重、年龄与妊娠期糖尿病发病风险的研究

目的探讨孕前体质指数、孕期增重、年龄与妊娠期糖尿病(Gestational diabetes mellitus,GDM)发病风险关系,为GDM的预防、诊治控制提供依据。方法选取2015-09/2016-09于新疆某妇幼保健院产检孕妇并确诊为GDM的孕妇496例为病例组,并随机抽取同期非妊娠期糖尿病孕妇366例作为对照组,比较不同孕前体质指数、孕期增重、不同年龄阶段孕妇妊娠期糖尿病发生情况。结果病例组孕前体质指数、孕期增重、平均年龄均高于对照组,差异有统计学意义(P0.05)。根据孕前体质指数对孕前体型分型分析,偏瘦、正常体重、超重、肥胖孕妇GDM逐级增加发生率增加,差异有统计学意义(P0.05),20~25岁孕妇GDM发生率46.4%,26~30岁之间孕妇GDM发生率52.4%,31~35岁孕妇GDM发生率59%,36岁以上孕妇GDM发生率74%,随年龄增加,GDM发生率增加,不同年龄阶段孕妇发病情况差异有统计学意义(P0.05)。回归分析显示,孕前体质指数大(OR=7.388,95%CI=1.045~52.244)、孕前腰围大(OR=4.054,95%CI=1.105~14.876)、年龄大(OR=3.596,95%CI=0.955~13.538)均增加孕妇发生GDM的风险。结论孕前体质指数、孕期增重、年龄是妊娠期糖尿病发病的危险因素。     

低出生体重与产前检查质量的回顾性分析

目的 探讨新生儿低出生体重(LBW)(出生体重＜2500 g)发生率与产前检查质量的关系.方法 采用Kessner's评定方法,对2008年1月至2009年12月在西安交通大学医学院第一附属医院产科产前检查的2964例单胎活产孕妇中,进行《产前检查问卷》调查.剔除缺项≥5项的问卷,共计回收有效问卷2928份,回收率为98.79％.对符合纳入标准的2928例单胎活产儿孕妇的产前检查质量进行评价.按照产前检查质量标准,将其分为充分组(n=1262)、居中组(n=1502)和不足组(n=164).采取回顾性分析方法于产后(2～7)d,依照《孕产妇产前检查手册》或门诊及住院病历记录3组孕妇的一般情况及其产前检查、孕期患病和分娩等情况.采用非条件logistic逐步回归分析法分析与LBW发生的相关危险因素及其与产前检查质量的关系(本研究遵循的程序符合本院人体试验委员会所制定的伦理学标准,得到该委员会批准,征得受试对象知情同意并与之签署临床研究知情同意书).3组孕妇孕前体重指数(BMI)、本次妊娠胎数比较,差异无统计学意义(P＞0.05).结果 LBW儿发生率在充分组、居中组和不足组分别为3.49％(44/1262),5.26％(79/1502)和19.51％ (32/164).产前检查不足组LBW儿发生率最高,与其他两组比较,差异有统计学意义(P＜0.01).LBW儿发生的相关危险因素包括:①孕妇年龄;②婚姻状况;③是否有妊娠合并症;④分娩地点;⑤孕期体重增加;⑥分娩孕周等,与产前检查质量密切相关(r=0.83,0.69,0.85,-0.68,-0.71,-0.74;P＜0.05).LBW儿发生与产次无相关性(r=0.26,P＞0.05).本组LBW儿与正常体重儿(≥2500 g)母亲的产前检查质量、年龄、婚姻状况、产次、是否有妊娠合并症、分娩地点、孕期体重增加、分娩孕周等比较,差异有统计学意义(x2=96.05,58.84,21.41,52.38,38.10,33.44,66.32,258.42;P＜0.05).与正常体重儿比较,LBW儿母亲孕期平均接受产前检查次数较少[(7.6±3.1)次vs.(5.4±2.9)次;t=9.16,P＜0.01];产前检查充分组较居中组LBW儿发生率低(OR=0.51,95％CI:0.35～0.72).调整孕妇年龄、孕期体重增加、妊娠并发症、产前检查医院类别及分娩孕周后,产前检查次数较少,仍是LBW儿发生的危险因素(OR=4.56,95％CI:3.02～6.84).结论 采用Kessner's评定方法评估产前检查质量相对客观准确,产前检查次数较少,是LBW儿发生的独立危险因素.     

妊娠期高血压疾病发病的危险因素分析

目的探讨妊娠期高血压疾病(HDCP)的危险因素,并分析HDCP对母婴妊娠结局的影响。方法选取130例确诊的HDCP孕妇为HDCP组,同时随机选取260例未发生HDCP的孕妇为非HDCP组,进行随访调查;采用单因素法和多因素Logistic回归法筛选影响HDCP发病的危险因素,比较两组母婴妊娠结局的差异。结果影响HDCP发病的危险因素包括高龄(OR=2.563)、孕前超重或肥胖(OR=3.550)、高血压疾病家族史(OR=4.088)、妊娠期糖尿病(OR=3.271)、孕期不良情绪(OR=4.216)、胰岛素抵抗(OR=4.865)以及无规律产检(OR=3.777)等。HDCP组的胎儿窘迫、子痫前期或子痫、胎盘早剥、剖宫产、产后出血、早产及新生儿窒息等发生率均高于非HDCP组(P0.05)。结论影响HDCP孕妇的危险因素较多,应针对这些高危因素早期采取干预措施,降低HDCP的发生率,控制血压,减少并发症,改善母婴妊娠结局。     

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.