浙江省城乡社区60岁以上老年人害怕跌倒而减少活动的流行特征及影响因素分析

目的 了解浙江省城乡社区60岁以上老年人害怕跌倒而减少活动的发生现状及其影响因素。方法 2013年10-12月由经过培训的调查员入户对1 972名60岁以上老年人进行问卷调查, 采用单因素和多因素logistic回归分析其影响因素。结果 因害怕跌倒而减少活动的老年人比例为43.15%(95%CI: 40.97%~45.34%), 其中男性和女性分别为41.79%(95%CI: 38.61%~44.98%)和44.36%(95%CI: 41.34%~47.38%), 不同性别的差异无统计学意义(χ²=1.32, P>0.05);60~、70~及≥80岁组因害怕跌倒而减少活动的比例分别为37.07%、44.87%和59.04%(趋势χ²=48.93, P<0.01)。过去12个月发生过跌倒老年人中, 因害怕跌倒而减少活动的比例为51.94%, 未曾发生过跌倒老年人中的比例为41.52%, 差异有统计学意义(χ²=11.56, P<0.01)。多因素logistic回归分析显示, 自评健康状况一般(OR=1.53)或不好(OR=1.69)、视力不良(相距1~5 m视物无困难: OR=1.95, <1 m才能辨认: OR=2.98)、听力不良(需大声交谈: OR=1.77)、经常使用辅具(OR=2.71)、年龄≥80岁(OR=1.56)、被诊断骨质疏松(OR=3.35)、被诊断眩晕症(OR=3.05)是老年人因害怕跌倒而减少活动的可疑危险因素, 而文化程度高(大学及以上: OR=0.54, 中学/中专: OR=0.54, 小学: OR=0.74)是保护因素。结论 浙江省城乡社区60岁以上老年人中害怕跌倒而减少活动的比例高。应针对患骨质疏松和眩晕症、视力和听力困难及自评健康状况差、经常使用辅具、文化程度低、高龄老年人开展健康教育, 鼓励其适当运动, 减少跌倒发生。     

PNPLA3、TM6SF2基因多态性及其与吸烟、饮酒交互作用对HBV相关肝癌的影响

目的 探讨PNPLA3、TM6SF2基因多态性及其与吸烟、饮酒交互作用对HBV相关肝癌（hepatitis B virus-associated hepatocellular carcinoma,HBV-HCC）的影响。方法 收集2010年1月至2014年3月HBV-HCC患者、慢性乙型肝炎（乙肝）患者（CHB）、肝硬化患者（LC）以及健康体检者的血液标本,应用飞行质谱技术检测patatin样磷脂酶域3（PNPLA3）基因位点rs738409和6号跨膜超家族成员2（TM6SF2）基因位点rs58542926的单核苷酸多态性（SNP）。利用在线SNP stats寻找基因多态性的最优赋值方法;检验SNP是否符合哈-温（H-W）遗传平衡定律;采用多分类logistic回归分析PNPLA3和TM6SF2多态性及吸烟、饮酒因素对HBV-HCC的影响,采用叉生分析和二分类logistic回归分析探讨基因-基因、基因-吸烟、饮酒交互作用对HBV-HCC的影响。结果 H-W遗传平衡检验结果显示,CHB组rs738409位点的基因型频率分布不符合H-W遗传平衡定律（χ²=11.980,P<0.005）,CHB组rs58542926位点、HBV-HCC组和LC组rs738409和rs58542926位点均符合H-W遗传平衡定律;调整年龄、性别的影响后,与健康体检者相比,HBV-HCC组rs58542926突变的OR=1.659,95% CI：1.026~2.684,P=0.039。与CHB组相比,HBV-HCC组饮酒的OR=1.680,95% CI：1.121~2.519,P=0.012。与LC组相比,HBV-HCC组饮酒与吸烟的OR值（95% CI）分别为1.539（1.071~2.213）和1.453（1.005~2.099）。交互作用分析显示,HBV-HCC组与CHB+LC组相比,rs738409与rs58542926交互作用的叉生分析相加模型OR=1.548（U=1.885,P=0.029）,logistic回归相乘模型OR=1.658（P=0.024）;饮酒与rs738409的交互作用叉生分析,饮酒且rs738409突变相加模型OR=1.811（U=1.965,P=0.024）,相乘模型无统计学意义;logistic回归相乘模型吸烟与饮酒的交互作用OR=1.756（P<0.001）。结论 TM6SF2基因突变、吸烟、饮酒是HBV-HCC的危险因素,PNPLA3与TM6SF2基因都突变、饮酒并且吸烟是HBV-HCC的危险因素。PNPLA3的单基因突变可以减弱饮酒对HBV-HCC的危害。     

成都市两城区部分成年男性吸烟者吸烟行为调查

目的 分析成都市成年男性吸烟者吸烟行为、吸烟量及其变化的影响因素。方法对成都市两城区320名成年男性吸烟者面对面问卷调查。采用描述性分析、t检验、χ²检验、单因素方差分析、Kruskal-Wails H秩和检验、累积比数logistic回归方法分析数据。结果 分析显示吸烟者更换卷烟后, 吸烟量增加(t=2.327, P=0.021), 焦油量降低(t=-11.251, P<0.001);累积比数logistic回归分析显示, 学历较低(OR=1.968, P=0.040)、收入较高(OR=2.053, P=0.043)、烟蒂较短(OR=2.366, P=0.010)、尼古丁高依赖(OR=7.143, P<0.001)者吸烟量更大。结论 更换卷烟的吸烟者更倾向选择低焦油卷烟;学历低、收入高、尼古丁高依赖的吸烟者是控烟健康教育、行为干预的重点人群。     

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。     

母亲MTHFR 677C/T多态性和孕期状况与子代发生先天性心脏病的相关性研究

目的 探讨母亲孕期MTHFR 677C/T多态性、孕期状况在子代先天性心脏病(CHD)发生中的相互关系。方法 采用病例对照研究,调查100对CHD胎儿和无CHD胎儿生物学母亲有关人口学、孕期环境相关情况、优生认知,并检测MTHFR 677C/T基因多态性以及血清同型半胱氨酸(HCY)、叶酸、VitB12水平,进行单因素和多因素非条件logistic回归分析。结果 病例组和对照组MTHFR 677C/T基因型和等位基因频率差异无统计学意义(χ²=1.08,P=0.582;χ²=0.53,P=0.468),血清HCY水平两组差异有统计学意义(t=-8.14,P=0.000)。单因素分析,14个因素有统计学意义(P<0.05);多因素logistic逐步回归分析,母亲教育程度(OR=3.386,95%CI:1.279~8.961)、家庭年收入(OR=8.699,95%CI:2.177~34.765)、患慢性病(OR=0.343,95%CI:0.134~0.881)、优生认知得分(OR=0.906,95%CI:0.836~0.981)、血清HCY水平(OR=1.734,95%CI:1.458~1.986)、异常生育史(OR=3.710,95%CI:1.217~11.308)等因素与子代CHD相关。结论 母亲MTHFR 677C/T多态性与子代CHD发生未发现关联;母亲教育程度低、家庭年收入低、异常生育史、优生认知得分低、血清HCY水平高可能增加子代CHD的发生危险。     

云南省7县结核分枝杆菌/HIV联合感染患者抗结核疗效影响因素分析

目的 分析结核分枝杆菌/HIV联合感染患者(TB/HIV)抗结核疗效的影响因素。方法 回顾性分析云南省7个中国全球基金结核病项目县2010年1月 1日至2012年6月30日登记管理的445例TB/HIV的抗结核治疗结果,通过问卷收集一般人口学特征、患者来源、治疗分类等因素,并作为分组变量进行单因素χ²检验。以抗结核治疗成功与否作为结局变量,采用多因素非条件logistic回归方法分析抗结核治疗效果的影响因素。结果 445例TB/HIV经标准化抗结核治疗,397例(89.21%)治疗成功,其中影响患者疗效的5个危险因素包括就诊时有>4个肺结核可疑症状(aOR=2.208)、在HIV/AIDS人群中主动筛查出的TB/HIV(aOR=5.856)、重症患者(aOR=4.607)、督导管理方式未采用全程督导(强化期督导方式aOR=4.129及全程管理方式aOR=8.090)和出现中断服药(aOR=21.517). 结论 通过加强主动筛查尽早发现TB/HIV,及时提供标准化抗结核治疗和全程督导的随访管理措施,能有效改善抗结核治疗效果。     

宫内发育迟缓影响因素的研究

目的 探讨宫内发育迟缓的影响因素。方法 采用整群抽样方法收集2008年4月至2011年3月湖南省浏阳市14个乡镇所有孕妇的孕产妇保健手册和分娩病历, 按照胎儿出生体重是否低于同孕龄胎儿体重的第10百分位数, 将6 105例单胎活产儿分为病例组和对照组, 采用单因素χ²检验和多因素非条件logistic回归分析胎儿宫内发育迟缓的影响因素。结果 共获得6 105例单胎妊娠的有效数据, 其中宫内发育迟缓528例(发生率为8.65%)。孕妇年龄<25岁(OR=1.268)、初产妇(OR=1.706)、初诊BMI<18.5 kg/m²(OR=1.709)、孕期体重增加不足(OR=1.576)以及患妊娠高血压综合征(OR=1.698)是宫内发育迟缓的危险因素。结论 孕妇年龄、产次、初诊BMI、孕期体重和妊娠高血压综合征与宫内发育迟缓有关。实时监测与控制体重及其变化, 加强妊娠高血压防治, 可能是预防宫内发育迟缓的重要措施。     

抗病毒治疗HIV感染者神经认知损伤与认知表现特征研究

目的 联合应用两种神经认知评价量表,探讨接受抗病毒治疗（ART）的HIV感染者神经认知损伤患病率、影响因素及其神经认知表现特征。方法 纳入浙江省台州市开展的HIV与衰老相关疾病前瞻性队列研究中2 250例接受ART的HIV感染者。使用中国版简易智能精神状态检查量表（MMSE）和国际HIV相关性痴呆量表（IHDS）评价其神经认知损伤情况,并对2个量表中的7个神经认知域进行聚类分析。结果 在接受ART的HIV感染者2 250例中,年龄集中在45~89岁（48.0%,1 080/2 250）,男性占79.2%（1 782/2 250）,小学及以下文化程度者占37.8%（852/2 250）。MMSE和IHDS判断的神经认知损伤的患病率分别为14.3%（321/2 250）和31.8%（716/2 250）。多因素logistic回归分析结果显示,HIV感染者MMSE判断的神经认知损伤危险因素包括60~89岁（aOR=2.63,95%CI：1.52~4.56）、抑郁症状（aOR=5.58,95%CI：4.20~7.40）和使用依非韦伦（EFV）治疗（aOR=2.86,95%CI：1.89~4.34）;男性（aOR=0.71,95%CI：0.51~1.00）、偏胖（aOR=0.63,95%CI：0.44~0.89）和文化程度较高（aOR=0.11,95%CI：0.05~0.25）为保护因素。IHDS判断的神经认知损伤危险因素包括60~89岁（aOR=3.10,95%CI：2.09~4.59）、抑郁症状（aOR=1.78,95%CI：1.44~2.20）和使用EFV治疗（aOR=1.79,95%CI：1.41~2.29）;男性（aOR=0.75,95%CI：0.58~0.97）、偏瘦（aOR=0.67,95%CI：0.47~0.96）、基线CD4⁺T淋巴细胞（CD4）计数≥350个/μl（aOR=0.69,95%CI：0.53~0.91）和文化程度较高（aOR=0.23,95%CI：0.14~0.39）是保护因素。HIV感染者的神经认知表现分为4种主要类型,在年龄、性别、文化程度、饮酒、抑郁症状、腰臀比、高血压病史、糖尿病病史、基线CD4计数和使用EFV治疗的差异有统计学意义（均P < 0.05）。结论 接受ART的HIV感染者神经认知表现分为4种类型,神经认知损伤患病率较高,需对不同类型者采取针对性的监测、预防与控制措施。     

HIV阳性男男性行为人群多性伴高危性行为状况及其影响因素分析

目的 调查HIV阳性MSM多性伴高危性行为状况,分析其影响因素。方法 通过"滚雪球"方法,在成都、重庆和广州市招募年龄≥18岁、经男男性行为感染HIV者为研究对象,取得知情同意后进行电子问卷调查,调查内容包括社会人口学特征、最近6个月的性伴和性行为状况、焦虑和抑郁症状评定等。采用χ²检验、t检验和非条件logistic回归的方法分别进行单因素和多因素分析。结果 501名HIV阳性MSM平均年龄(30.24±7.70)岁,最近6个月多性伴高危性行为报告率为17.4%(87/501)。多因素分析结果显示,最近6个月多性伴高危性行为的危险因素:婚姻状况为在婚(OR=1.93,95%CI:0.77~4.84)、离异或丧偶(OR=3.94,95%CI:1.66~9.36),有焦虑症状(OR=2.22,95%CI:1.16~4.27),有男性固定性伴(OR=5.04,95%CI:1.08~23.54)、男性偶然/商业性伴(OR=2.54,95%CI:1.34~4.80),高危性行为时饮酒(OR=3.00,95%CI:1.37~6.62)、性行为时使用Rush主要成分为(烷基亚硝酸盐)(OR=3.53,95%CI:1.72~7.23),将自己的HIV感染状况对男性固定性伴部分告知(OR=1.84,95%CI:0.78~4.33)、均未告知(OR=2.68,95%CI:1.25~5.73)和性感觉评分高者(OR=1.09,95%CI:1.03~1.15)。结论 HIV阳性MSM的多性伴高危性行为加速HIV的流行,因此,在发展针对该人群心理行为特征的高危性行为干预方法的同时,亟需建立有效遏制HIV经性传播的医学或生物学措施。     

陕西省新生儿体表先天畸形的影响因素分析

目的 探讨陕西省新生儿体表先天畸形的影响因素。方法 采用分层多阶段随机抽样方法,通过问卷调查2010-2013年陕西省孕满28周且结局明确的育龄妇女及其生育子女的相关信息,采用多因素logistic回归分析新生儿体表先天畸形的影响因素。结果 多因素logistic回归分析结果显示,妊娠期肝内胆汁淤积症（OR=21.76,95%CI：4.46～106.25）、不良孕产史（OR=11.88,95%CI：9.14～15.45）、家族出生缺陷史（OR=6.15,95%CI：2.66～14.23）、双胎（OR=5.74,95%CI：3.34～9.86）、母亲为工人（与其他职业比,OR=2.47,95%CI：1.30～4.68）或农民（与其他职业比,OR=1.91,95%CI：1.14～3.20）、产检<4次（与产检>7次者比,OR=1.84,95%CI：1.28～2.64）、职业危险暴露（OR=1.74,95%CI：1.26～2.42）、母亲来自关中地区（与陕北地区者比,OR=1.65,95%CI：1.20～2.28）、母亲居住农村（OR=1.75,95%CI：1.13～2.71）、围孕期使用药物（OR=1.64,95%CI：1.26～2.13）是体表先天畸形的危险因素,而母亲围孕期服用铁剂（OR=0.46,95%CI：0.21～0.99）是体表先天畸形的保护因素。结论 母亲来自关中地区、农村、农民或工人、不良孕产史、家族出生缺陷史、双胎、产检<4次、职业危险暴露、使用药物、妊娠期患肝内胆汁淤积症可能增加新生儿体表先天畸形的罹患风险。     

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.