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Reducing Participation Bias in Case-Control Studies: Type 1 Diabetes in Children and Stroke in Adults

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Open Journal of Epidemiology 2014年第3期4卷 129-134页

作者： Claire Keeble Stuart Barber Paul David Baxter Roger Charles parslow Graham Richard Law Department of Statistics University of Leeds Leeds UK Division of Epidemiology & Biostatistics University of Leeds Leeds UK

Background: Case-control studies have been used extensively in determining the aetiology of rare diseases. However, case-control studies often suffer from participation bias in the control group, resulting in biased odds ratios that cause problems with interpretation. Participation bias can be hard to detect and is often ignored. Methods: Population data can be used in place of the possibly biased control group, to investigate whether participation bias may have affected the results in previous studies, or in place of controls in future studies. We demonstrate this approach by reanalysing and comparing the results of two case-control studies: Type 1 diabetes in Yorkshire children and stroke in Indian adults. Findings: Using population data to represent the control groups reduced the width of the confidence intervals given in the original studies and confirmed the findings for the two diabetes risk factors used;caesarean birth (odds ratio (OR) = 2.12 (1.53, 2.95) compared with 1.84 (1.09, 3.10)) and amniocentesis (OR = 3.38 (2.09, 5.47) compared with 3.85 (1.34, 11.04)). The three stroke risk factors investigated were found to have increased odds ratios when using population data;hypertension (OR = 5.645 (5.639, 5.650) compared with 3.807 (2.114, 6.856)), diabetes (OR = 12.212 (12.200, 12.224) compared with 3.473 (1.757, 6.866)) and smoking (OR = 5.701 (5.696, 5.707) compared with 2.242 (1.255, 4.005)). Interpretation: Participation bias can greatly affect the results of a study and cause some potential risk factors to be over-or underestimated. This approach allows previous studies to be investigated for participation bias and presents an alternative to a control group in future studies, while improving precision.

关键词： Case-Control Diabetes Participation Bias Stroke Selection Bias

黑色页岩的经济潜景——萨斯喀彻温地区的Bakken地层

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国外铀金地质 1994年第1期11卷 3-19页

作者： G.R.parslow R.Karma 朱益平核工业北京地质研究院 100029

萨斯喀彻温地区的Bakken地层是由被一砂岩层分隔开的上下2层放射性黑色页岩组成。根据在石油测井中的γ射线特性曲线,其地层为Williston盆地地层学的最主要的标志层。记录了51个穿透Bakken地层的钴孔岩心,并对569个样品进行了地球化学... 详细信息

萨斯喀彻温地区的Bakken地层是由被一砂岩层分隔开的上下2层放射性黑色页岩组成。根据在石油测井中的γ射线特性曲线,其地层为Williston盆地地层学的最主要的标志层。记录了51个穿透Bakken地层的钴孔岩心,并对569个样品进行了地球化学研究。对500多个样品的主要元素在其中精选了一组微量元素(Ba、Cr、Nb、Ni、Pb、Rb、Sr、Th、U、V、Y、Zn、Zr)进行了“室内自检性”分析。此外,还对数目有限的样品(44个下层页岩,36个中间层砂岩,39个上层页岩)中的34种元素(Au、Ag、As、Ba、Br、Ca、Co、Cr、Cs、Fe、Hf、Hg、Ir、Mo、Na、Ni、Rb、Sb、Sc、Se、Sr、Ta、Th、U、W、Zn、La、Ce、Nd、Sm、Eu、Tb、Yb、Lu)用中子活化法(NAA)进行了批量分析。其结果表明,黑色页岩富含很多元素;特别是Bakken地层Zn含量非常高(可达5.5％),并且元素间的结合松散(即与粘土矿物和有机质关系密切),因此采用简单的冶金加工方法萃取Bakken地层中的多种矿产品是可行的。然而事实上,萨斯喀彻温地区的Bakken地层只因是隐伏露头(位于目前地表以下约500—2000m的深度),这样就为探“矿”带来了困准。另一方面,现存的、为采钾盐矿而建的矿井(用于开采下伏于Bakken地层的蒸发盐,因而穿透了Bakken地层)为开采含铀黑色页岩提供了廉价渠道。此外。

关键词：黑色页岩地层含铀页岩

基础铀矿勘探测量及其对早期识别潜在天然公害区的重要性:苏丹实例

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国外铀金地质 1992年第1期8卷 70-75页

作者： G.R.parslow B.Khalil A-R.K.Hassan 刘腾耀

1969年,在苏丹南科尔多凡省Kadugli西北约20km的Khor Berdab建成了一个小水坝。当时计划从水库到Kadugli镇铺设一条管道,以缓解那里的供水不足。此外。还预计水库能重蓄该区域的含水层,并且UNICEF计划在南科尔多凡钻约400口顶部带手泵... 详细信息

1969年,在苏丹南科尔多凡省Kadugli西北约20km的Khor Berdab建成了一个小水坝。当时计划从水库到Kadugli镇铺设一条管道,以缓解那里的供水不足。此外。还预计水库能重蓄该区域的含水层,并且UNICEF计划在南科尔多凡钻约400口顶部带手泵的水井(20—30m深),其中约200口井位于Miri湖(水库)和Kadugli附近。1982年,本文的一位作者***报道了使用手提式闪烁仪和采集土壤样品的野外工作,并确定了Miri湖横跨一条沥青铀矿矿化带(脉型),对健康造成了潜在的危害。1985年***做了进一步考查,***揭示在坝后面的泉水中以及Kadu-gli附近Hayat el Nar村的UNICEF井水中氡值约为3000脉冲/min,同时还指出井水中有380×10^(-9)的铀。做为IAEA TC项目SUD/3/003-1的一部分,1986年作者们再次考查了该地区,并使用四道伽玛能谱仪,以便更好地确定放射性带的范围和数值。典型的总道平均值为400脉冲/s,峰值为1200+脉冲/s,典型的剥谱后的铀、钍道计数很接近,平均为8脉冲/s,峰值为60+脉冲/s。1987年,本文的另一位作者***再次考查该地区,扩大了闪烁仪的测量范围,并采集了更多的样品,在1987年下半年和1988年上半年分析了这些样品中的主要元素和痕量元素。为了评价一些村镇井水中和水井周围,湖附近土壤中的氡值,***和***两位作者于1988年再次来到了该区。考查过的10个地点都有异常,水中氡的最高值超过8000脉冲/min。这一例证说明,把“早期”铀矿勘探测量数据归纳和并入其他机构(如WHO、UNICEF、NGO和Gov′t)的项目中是绝对必要的,这将有助于避免发生如 Miri湖周围的不幸情况。在这一干旱地区的村民们目前有充足的供水,但其中有许多被污染了。

关键词：铀矿床勘探测量苏丹

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睡眠中婴儿对低氧的初始通气反应的变异性

世界核心医学期刊文摘（儿科学分册） 2006年第12期2卷 55-56页

作者： Richardson H.L. parslow P.M. Walker A.M. R.S.C. Horne 王经纬 Ritchie Centre for Baby Health Research Monash Medical Centre246 Clayton RoadClaytonVic.3168Australia Dr.

Most of the available data on the hypoxic ventilatory response(HVR) in infants has been obtained in quiet sleep (QS),and only one study has made repeated tests in the same infant. We aimed to gain a more complete knowledge of the maturation and consistency of the initial phase of the HVR by performing multiple tests in both QS and active sleep (AS) over the first 6 mo of life in term infants. Fifteen healthy term infants were studied with daytime polysomnography longitudinally at 2-5 wk,2-3 mo,and 5-6 mo after birth. Each infant received multiple hypoxic(15%O2,balance N2) challenges (three or more) in bothAS and QS. In AS,infants consistently aroused to hypoxia; however,in QS,infants both aroused and failed to arouse. The initial phase of the HVR varied considerably between infants with the changes in ventilation/kg SD of inspired minute ventilation per kilogram of body weight ( /kg) being more variable during AS than QS at all three ages and overall decreasing with postnatal age in both sleep states. The variability between replicate VI·/kg measurements was also significantly greater in AS compared with QS at 2-5 wk postnatal age. There was no evidence of habituation to repeated hypoxic tests in either sleep *** study has demonstrated that the initial phase of the HVR is variable both between and within term infants in both AS and QS,with responses being markedly more variable during AS,and becoming more consistent with increasing postnatal *** performing only one test or by failing to account for arousal responses,previous studies may not have detected the natural variation of the infant HVR.

关键词：通气反应低氧睡眠状态初始反应多导睡眠图出生后自然变异变动性重复测定

英国接受重症监护的患儿中颅脑外伤的流行病学情况

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世界核心医学期刊文摘（儿科学分册） 2006年第4期2卷 11-11页

作者： parslow R.C. Morris K.P. Tasker R.C. 李开 Paediatric Epidemiology Group Centre for Epidemiology and Biostatistics University of Leeds 30 Hyde Terrace Leeds LS2 9JT United Kingdom

Aims: To describe the epidemiology of children with traumatic brain injury (TBI) admitted to paediatric intensive care units (PICUs) in the UK. Methods: Prospective collection of clinical and demographic information from paediatric and adult intensive care units in the UK and Eire between February 2001 and August 2003. Results: The UK prevalence rate for children (0- 14 years) admitted to intensive care with TBI between February 2001 and August 2003 was 5.6 per 100 000 population per year (95% Poisson exact confidence intervals 5.17 to 6.05). Children admitted to PICUs with TBI were more deprived than the population as a whole (mean Townsend score for TBI admissions 1.19 v 0). The commonest mechanism of injury was a pedestrian accident (36% ), most often occurring in children over 10. There was a significant summer peak in admissions in children under 10 years. Time of injury peaked in the late afternoon and early evening, a pattern that remained constant across the days of the week. Injuries involving motor vehicles have the highest mortality rates (23% of vehicle occupants, 12% of pedestrians) compared with cyclists (8% ) and falls (3% ). In two thirds of admissions (65% ) TBI was an isolated injury. Conclusions: TBI in children requiring intensive care is more common in those from poorer backgrounds who have been involved in accidents as pedestrians. The summer peak in injury occurrence for 0- 10 year olds and late afternoon timing give clear targets for community based injury prevention.

关键词：流行病学情况重症监护颅脑外伤统计学资料患儿家庭峰值时间 Townsend 安全预防措施住