河南省2008－2013年男男性行为人群艾滋病流行趋势分析

目的 分析河南省MSM人群HIV感染流行趋势,为河南省艾滋病防治政策与策略制定提供科学依据。方法 分析2008-2013年艾滋病病例报告系统中同性性传播HIV/AIDS病例的变化趋势,利用MSM人群艾滋病综合防治专项调查数据分析该人群HIV感染率及危险行为变化。结果 2008-2013年河南省同性性传播病例构成从1.3%上升到17.1%,呈现快速增长趋势;专项调查数据显示,MSM人群HIV感染率呈现快速上升趋势,从2008年的4.69%增至2013年的8.33%(趋势χ²=39.24,P<0.001).单因素分析结果显示,年龄(χ²=21.03,P<0.001)、文化程度(χ²=31.66,P<0.001)、职业(χ²=14.59,P=0.01)、最近1次肛交行为安全套使用情况(χ²=134.97,P<0.001)、最近6个月同性性行为安全套使用情况(χ²=97.15,P<0.001)、最近1年性病症状(χ²=67.21,P<0.001)以及梅毒感染(χ²=163.60,P<0.001)均为感染HIV的影响因素。多因素分析结果显示,年龄、性病症状史、感染梅毒与艾滋病防治知识不知晓为感染HIV的危险因素。结论 河南省MSM人群中HIV感染呈不断上升趋势,男男同性性传播已经成为主要感染途径,该人群不安全性行为普遍存在,亟需采取有效措施控制HIV在该人群中的传播。     

天津市2005-2017年医疗机构新报告HIV/AIDS特征分析

目的 分析天津市2005-2017年医疗机构新报告HIV/AIDS特征,为更好地在医疗机构中开展相关的艾滋病防治工作提供依据。方法 对新报告HIV/AIDS的流行病学调查及随访资料进行分析,同时回顾调查2005-2017年医疗机构新报告HIV/AIDS的科室来源及主要就诊疾病。结果 2005-2017年天津市医疗机构新报告HIV/AIDS 3 035例,医疗机构报告HIV/AIDS病例年均增长24.8%,其中49.2%（1 343/2 728）来源于住院病例,50.8%（1 385/2 728）来源于门诊病例,性病门诊就诊者检测在2011-2017年HIV阳性检出率呈现增长趋势（χ²=18.469,P=0.005）;医疗机构住院病例、门诊病例首次CD₄⁺T淋巴细胞计数（CD₄）（χ²=17.189,P=0.000）及新报告当年发生死亡比例（χ²=61.198,P=0.000）差异有统计学意义;二级医院与三级医院新报告HIV/AIDS首次CD₄值（χ²=16.751,P=0.000）及新报告当年发生死亡比例（χ²=18.926,P=0.000）差异有统计学意义;不同科室新报告HIV/AIDS首次CD₄值（χ²=37.620,P=0.000）及新报告当年发生死亡比例（χ²=95.489,P=0.000）差异有统计学意义。结论 2005-2017年天津市医疗机构门诊新报告HIV/AIDS较为及时,二级医院新报告HIV/AIDS比三级医院及时。在医疗机构重点科室门诊积极倡导医务人员中主动提供HIV检测服务,对于天津市艾滋病防治工作具有重要意义。     

新疆维吾尔自治区疏附县中小学生病毒性肝炎血清流行病学调查

目的 了解新疆维吾尔自治区（新疆）疏附县中小学生甲、乙、丙型病毒性肝炎流行情况及评估免疫接种效果。方法 2015年2-5月通过整群随机抽样方法对疏附县4个乡镇中小学生进行病毒性肝炎血清流行病学调查,检测HAV-IgG、HBsAg、HBsAb和HCV-IgG。结果 疏附县4 830名中小学生HAV-IgG阳性率为99.75%,男生为99.92%,女生为99.57%,差异有统计学意义（χ²=5.798,P=0.016）;HBsAg阳性率为3.02%,男生为3.55%,女生为2.47%,差异有统计学意义（χ²=4.782,P=0.029）;各年龄组的HBsAg阳性率差异有统计学意义（χ²=71.990,P=0.000）,农村地区（3.28%）高于城镇地区（1.61%）,差异有统计学意义（χ²=6.019,P=0.014）;HBsAb阳性率为38.84%,各年龄组的HBsAb阳性率差异有统计学意义（χ²=837.699,P=0.000）,城镇地区（42.36%）高于农村地区（38.20%）,差异有统计学意义（χ²=4.598,P=0.032）。HBsAg和HBsAb均为阴性的学生有2 815人,占总人数的58.28%。HCV-IgG阳性率为0.19%,阳性者均为维吾尔族农村学生。结论 疏附县中小学生甲型肝炎疫苗的免疫效果较好,处于乙型肝炎免疫空白状态的学生较多,丙型肝炎感染率较低,应及时对适龄儿童进行免疫接种和查漏补种。     

中国脊髓灰质炎网络实验室人员免疫接种状况及其影响因素分析

目的 调查中国省级脊髓灰质炎网络实验室人员免疫接种状况,分析其影响因素,为国家制定脊髓灰质炎网络实验室从业人员相关免疫策略提供参考。方法 2016年10－12月选取全国省级CDC脊髓灰质炎网络实验室全部从业人员为调查对象,采用问卷调查方式,收集该人群免疫接种状况,并利用SAS软件及趋势χ²检验和确切概率法进行免疫影响因素的统计学分析,以P<0.05为差异有统计学意义。结果 共调查77人,其中完成脊髓灰质炎基础免疫60人,17人（22%）基础免疫情况不详。从事脊髓灰质炎病毒工作后明确接种疫苗者为66人（86%）,接种信息记录不完整者为11人（14%）。影响免疫接种因素包括年龄（χ²=2.48,P<0.05）、职称（χ²=2.51,P<0.05）、工作时间（确切概率法计算：P<0.000 1）、学历（χ²=0.74,P=0.46）、性别（χ²=0.46,P=0.50）。结论 目前我国省级脊髓灰质炎网络实验室人员免疫接种情况较好,其中完成≥3剂次者占41%,且接种信息记录完整,应加强新入职实验室人员免疫接种。     

新疆维吾尔自治区夏尔西里自然保护区全沟硬蜱复合感染蜱媒病原研究

目的 了解新疆维吾尔自治区(新疆)夏尔西里自然保护区全沟硬蜱蜱媒病原复合感染情况。方法 2012年6月至2013年6月在新疆夏尔西里自然保护区采用布旗法采集全沟硬蜱,通过巢式PCR方法对蜱体内莱姆病伯氏疏螺旋体[Borrelia(B.) burgdorferi] 5S~23S rRNA 基因间隔区、无形体(Anaplasma)16S rRNA基因、斑点热立克次体(Rickettsia)ompA基因、Q热贝氏柯克斯体Coxiella(C.)burneti的com1基因、巴贝西原虫(Babesia)的Nss-rRNA基因进行扩增。结果 204只全沟硬蜱中104只蜱病原检测阳性,阳性率为50.98%,其中伯氏疏螺旋体阳性率为34.31%(n=70),斑点热立克次体阳性率为28.92%(n=59),嗜吞噬细胞无形体阳性率为9.31%(n=19),未检出Q热贝氏柯克斯体和巴贝西原虫。χ²检验显示,不同病原感染率差异有统计学意义(χ²=38.517,P=0.000)。204只蜱中有39只存在复合感染,复合感染率为19.12%(39/204),在病原检测阳性蜱中复合感染率为37.50%(39/104)。伯氏疏螺旋体与斑点热立克次体复合感染率为16.18%(n=33);伯氏疏螺旋体与嗜吞噬细胞无形体复合感染率为4.90%(n=10),斑点热立克次体与嗜吞噬细胞无形体复合感染率为2.94%(n=6),3种病原体复合感染率为2.45%(n=5)。经χ²检验,3种病原混合感染率差异有统计学意义(χ²=41.328,P=0.000)。结论 新疆夏尔西里自然保护区全沟硬蜱存在伯氏疏螺旋体、嗜吞噬细胞无形体、斑点热立克次体的自然感染,并存在2~3种病原的复合感染。     

山东省青岛市2006－2015年暗娼人群行为变化及流行因素研究

目的 分析山东省青岛市暗娼人群行为变化特征和艾滋病性病流行因素,为制订艾滋病防治对策和干预措施提供依据。方法 2006-2015年在哨点监测期4-7月按《全国艾滋病哨点监测实施方案》要求收集当地暗娼人口学特征及相关行为信息,并采集静脉血进行艾滋病、梅毒检测。结果 连续10年调查样本显示,年龄≥ 30岁、已婚/同居和应召暗娼所占比例呈增长趋势;梅毒感染率从2006年1.0%（4/420）上升至2015年13.3%（53/400）（趋势χ²=54.22,P<0.001）;吸食合成毒品率在12.0%（48/400）和55.5%（222/400）之间波动;最近1个月与客人发生性行为坚持安全套使用率呈下降趋势（趋势χ²=170.62,P<0.001）;艾滋病知识得分≥ 6（趋势χ²=152.96,P<0.001）和最近1年做过艾滋病检测比例（趋势χ²=114.87,P<0.001）呈上升趋势;2009-2015年分年度分层分析,吸食毒品与不吸食毒品的暗娼相比有更高的梅毒感染率和不安全性行为（P<0.05）,应召暗娼梅毒感染率高于场所招募暗娼（P<0.05）。结论 青岛地区暗娼人群梅毒感染率呈上升趋势,吸食合成毒品是影响青岛市性病艾滋病传播重要危险因素,建议加强对吸毒暗娼人群监测力度,开展有针对性干预措施。     

2003-2014年北京协和医院就诊患者HIV检测结果分析

目的 了解2003-2014年北京协和医院就诊患者HIV检测的感染状况及流行病学特征。方法 收集2003-2014年北京协和医院门诊与住院就诊患者的HIV检测结果,利用SPSS 19.0软件进行描述性统计分析。结果 2003-2014年共进行HIV筛查715 421人次,HIV初筛阳性1 012例（0.14%）,HIV确证阳性776例（0.11%）。HIV检测阳性率逐年升高（趋势χ²=66.83,P=0.000）,2012-2014年间增幅明显,2014年的HIV检测阳性率是2003年的3.40倍（2014年为0.17%,2003年为0.05%）。776例感染者中,男性631例（81.31%）,女性145例（18.69%）,2003-2014年间男性感染者构成比从50.00%升高到90.26%（趋势χ²=58.41,P=0.000）,年龄范围18～50岁（84.66%）,M为36岁（Q_R：27～43）。经性途径感染634例（81.70%）,且逐年增加（趋势χ²=126.38,P=0.000）,男男同性性行为感染从2003年的0.00%升高到2014年的53.90%（趋势χ²=11.96,P=0.001）。未婚感染者构成比从18.75%升高到42.21%（趋势χ²=43.74,P=0.000）。HIV筛查阳性的主要来源科室分别为内科（51.03%）、急诊（18.30%）、皮肤科（13.53%）。妇产科来源下降（2003年为18.75%,2014年为2.60%）,外科、五官科及口腔科、体检中心有所增加,分别从2003年的零检出到2014年的14例（9.10%）,11例（7.14%）,4例（2.60%）。结论 北京协和医院就诊患者的HIV/AIDS检测阳性率逐年升高,提示需要加强对大型综合医院就诊患者的检测。MSM作为重点人群,应加强艾滋病防控宣传和咨询检测。     

广州市2008－2015年注射吸毒人群HIV-1亚型分布特征及变化趋势

目的 了解2008-2015年广州市注射吸毒人群HIV感染者（IDU感染者）HIV-1亚型分布特征及变化趋势。方法 研究对象为2008-2015年确证的HIV-1感染者、注射吸毒途径感染、现住址为广州市。收集血清样本提取HIV-1 RNA,采用巢式PCR法扩增HIV-1 pol区基因片段,测序后构建系统进化树,确定HIV-1亚型,比较不同年份和不同特征样本的HIV-1亚型分布。结果 从517份血清样本中成功获得437份样本的pol区基因片段。437份样本的年龄（37.37±8.17）岁;外省户籍者占51.5%（225/437）,以广西壮族自治区户籍（广西籍）居多（54.2%,122/225）。HIV-1亚型分布以CRF07_BC（46.5%）、CRF01_AE（24.3%）和CRF08_BC（23.3%）为主。CRF07_BC和CRF08_BC在2008-2015年各年份构成比的差异有统计学意义（CRF07_BC：趋势χ²=19.703,P=0.006;CRF08_BC：趋势χ²=25.718,P=0.001）,其中CRF07_BC的构成比呈下降趋势（趋势χ²=15.139,P=0.000）,CRF08_BC的构成比呈上升趋势（趋势χ²=22.577,P=0.000）。广西籍IDU感染者中CRF08_BC亚型的构成比较高（蒙特卡罗模拟精确概率P=0.000,99% CI：0.000~0.000）。结论 2008-2015年广州市IDU感染者HIV-1亚型分布以CRF07_BC、CRF01_AE和CRF08_BC为主、多个亚型共存,CRF08_BC亚型的构成比呈上升趋势的特点。提示广西籍IDU感染者是广州市艾滋病防治重点人群,应加强干预。     

北京市18~65岁慢性病患者吸烟状态、戒烟态度及危险因素分析

目的 了解北京市18~65岁高血压、糖尿病、血脂异常、COPD、哮喘患者的吸烟状态、戒烟态度及危险因素。方法 数据来源于2014年北京市成人慢性病与危险因素监测,即在北京市16个区/县采用多阶段分层整群抽样方法抽取180个社区共19 815名调查对象,以其中18~65岁人群作为研究对象。结果 18 405例有效样本中,男性高血压、血脂异常患者现在吸烟比例均高于非患者（分别χ²=17.695,P<0.001;χ²=39.292,P<0.001）;女性高血压、COPD、哮喘患者现在吸烟者比例均高于非患者（分别χ²=6.649,P=0.010;χ²=6.276,P=0.012;χ²=8.245,P=0.004）。吸烟者中,高血压患者1年内想戒烟比例低于非高血压患者（χ²=20.487,P<0.001）,COPD患者1年内想戒烟比例高于非COPD患者（χ²=6.085,P=0.048）。男性中糖尿病（χ²=9.219,P=0.010）、血脂异常（χ²=13.513,P=0.001）患者中已戒烟者控制情况好于现在吸烟者。多因素logistic回归结果显示,吸烟是高血压（OR=1.17）、血脂异常（OR=1.25）、COPD（OR=1.78）、哮喘（OR=1.57）的影响因素。结论 北京市18~65岁居民中部分慢性病患者现在吸烟比例高且戒烟意愿低;吸烟是高血压、血脂异常、COPD、哮喘的危险因素。     

上海地区2015－2019年急性呼吸道感染病例中腺病毒感染情况分析

目的 研究2015-2019年上海地区急性呼吸道感染病例中腺病毒感染的流行病学特征和混合感染情况,为腺病毒的防控提供科学依据。方法 收集2015-2019年上海地区3家医院内的急性呼吸道感染病例,对纳入病例进行相关信息登记和采样,进行呼吸道病原体的多重PCR检测。结果 共纳入1 543例急性呼吸道感染病例,腺病毒阳性率2.92%（45/1 543）,流感样病例（ILI）和严重急性呼吸道感染病例（SARI）中的阳性率分别为2.74%（29/1 058）和3.30%（16/485）。ILI在2019年1-5月的阳性率5.43%（7/129）高于2015-2018年同期的0.52%~4.48%（Fisher精确检验值=8.92,P=0.036）。45例腺病毒阳性病例的发病时间主要分布在第一、二季度,合计占62.22%（28/45）,各季度发病阳性率的差异有统计学意义（χ²=12.52,P=0.006）,以第二季度的阳性率最高（6.03%）,高于其他季度的1.89%~2.93%。各年龄组间差异有统计学意义（χ²=16.94,P=0.001）,且随着年龄的增加阳性率有降低的趋势（χ²=10.16,P=0.001）,13~19岁组的阳性率（9.43%）高于其他年龄组（1.48%~4.81%）;学生组阳性率（12.07%）高于其他职业（2.61%）,差异有统计学意义（χ²=11.53,P=0.001）。45例腺病毒阳性病例中混合感染占31.11%（14/45）。ILI和SARI的混合感染率分别为34.48%（10/29）和25.00%（4/16）,14例混合感染病例中,腺病毒的主要混合感染病原是甲型流感病毒和冠状病毒。结论 上海地区急性呼吸道感染病例中存在一定比例的阳性病例,需进一步加强青少年人群中的腺病毒监测,重点是关注第二季度的学生等重点人群。     

The human drama of genetics: 'hard' and 'soft' media representations of inherited breast cancer

This paper examines media coverage of 'breast cancer genetics', and explores its implications for public understanding. We present a content analysis of coverage in British newspapers and look at a variety of popular forms, including women's magazines, television soap opera and radio drama. Genetic/inherited risk receives a great deal of coverage across a wide range of media formats and outlets. Much of this attention has focused on individuals from 'high risk families' and dilemmas around prophylactic mastectomies. Through examining media coverage, combined with interviews with media personnel and their sources, we show why this story proved so attractive to the media and highlight the different production values which influence coverage. Finally, we introduce preliminary findings from focus group discussions to demonstrate how such 'human interest' framing has engaged audience attention and influenced public understandings. The paper concludes by highlighting the implications for analysing, predicting, and engaging with, media representations of science.     

Worker education in the primary prevention of occupational dermatoses

This paper reports the evaluation of a skin care education programmeconducted on a fine chemicals manufacturing site where over1,000 employees are located. Approximately 60% are involvedin chemical manufacture. Over a 12 month period production staffreceived training in prevention of occupational dermatoses linkedto a site-wide poster initiative. The incidence of new casesof occupational dermatoses fell from 0.055 (70 cases in 1,277employees) to 0.021 (27 cases in 1,277 employees) before andafter the intervention respectively (p<0.0001). After otherfactors such as chemicals handled, observer bias and changesin reporting related to socioeconomic climate were taken intoaccount it is concluded that this study demonstrates the importanceof worker education as a tool for primary prevention of disease.Training materials such as video and poster presentations maybe effectively used in the chemical manufacturing industry asan adjunct to prevention and control of exposure to substanceshazardous to the skin. Such methods may also be used in otherindustries where there are significant risks of dermatoses.     

Regional Variation in Travel-related Illness acquired in Africa,March 1997–May 2011

To understand geographic variation in travel-related illness acquired in distinct African regions, we used the GeoSentinel Surveillance Network database to analyze records for 16,893 ill travelers returning from Africa over a 14-year period. Travelers to northern Africa most commonly reported gastrointestinal illnesses and dog bites. Febrile illnesses were more common in travelers returning from sub-Saharan countries. Eleven travelers died, 9 of malaria; these deaths occurred mainly among male business travelers to sub-Saharan Africa. The profile of illness varied substantially by region: malaria predominated in travelers returning from Central and Western Africa; schistosomiasis, strongyloidiasis, and dengue from Eastern and Western Africa; and loaisis from Central Africa. There were few reports of vaccine-preventable infections, HIV infection, and tuberculosis. Geographic profiling of illness acquired during travel to Africa guides targeted pretravel advice, expedites diagnosis in ill returning travelers, and may influence destination choices in tourism.     

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.     

The design of hazard risk assessment matrices for ranking occupational health risks and their application in mining and minerals processing

Two hazard risk assessment matrices for the ranking of occupational health risks are described. The qualitative matrix uses qualitative measures of probability and consequence to determine risk assessment codes for hazard-disease combinations. A walk-through survey of an underground metalliferous mine and concentrator is used to demonstrate how the qualitative matrix can be applied to determine priorities for the control of occupational health hazards. The semi-quantitative matrix uses attributable risk as a quantitative measure of probability and uses qualitative measures of consequence. A practical application of this matrix is the determination of occupational health priorities using existing epidemiological studies. Calculated attributable risks from epidemiological studies of hazard-disease combinations in mining and minerals processing are used as examples. These historic response data do not reflect the risks associated with current exposures. A method using current exposure data, known exposure-response relationships and the semi-quantitative matrix is proposed for more accurate and current risk rankings.     

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.     

The rise and fall in incidence of malignant mesothelioma from a British Naval Dockyard, 1979-1999

BACKGROUND: The incidence of malignant mesothelioma in Britain is predicted to rise over the next 15-25 years because of past failure to protect the workforce against inhalation of asbestos. In British Naval dockyards, alternative insulation materials and respiratory protection were introduced from the mid-1960s. Aims This study was carried out to investigate the effects of these control measures on mesothelioma deaths in dockyard workers. METHODS: Cases of mesothelioma of the pleura and peritoneum between 1979 and 1999 in workers from the Devonport Naval Dockyard, south-west England, were sought from coroners' and medico-legal records. RESULTS: Three hundred and one cases were identified, 7% peritoneal. The peak incidence occurred in 1991 with 25 cases per annum (quadratic model fit R(2) = 74.2%, P < 0.001) and we predict that by 2003 the incidence will fall to fewer than five cases per annum. The mean time between first exposure and presentation was 48.5 years [95% confidence interval (CI) = 47.3-49.8], but this was significantly shorter in the more heavily exposed trades, when compared with the less heavily exposed (42 years, 95% CI = 39.0-45.0, versus 49.5 years, 95% CI = 48.2-50.9). Those with higher exposure were also at significantly greater risk of peritoneal disease (P < 0.023, Fisher's exact test). CONCLUSION: The reduction in incidence of mesothelioma is greater than can be accounted for by reduction in numbers of dockyard workers over the last 50 years. Changes in insulation materials and improved industrial hygiene measures introduced into the Devonport Dockyard from the mid-1960s have resulted in an earlier decline in the incidence of malignant mesothelioma than that predicted for the British workforce as a whole.