• Assess the value of Q-statistics for studying clustering in residential histories of case-control studies. (confex.com)
  • Explain why residential histories may be important for studying cancer clusters. (confex.com)
  • The Centers for Disease Control and Prevention (CDC) continues to be aware of the need for response to public concern as well as to state and local agency concern about cancer clusters. (cdc.gov)
  • Response to cancer clusters is appropriate public health action, and the CDC will continue to provide assistance, facilitate communication among states, and foster the development of new approaches in cluster science. (cdc.gov)
  • More than a decade ago, the Centers for Disease Control and Prevention (CDC) recognized the need to develop operating procedures for response to public concern about disease clusters. (cdc.gov)
  • Clusters are recognized when meningococcal cases of the same phenotypic strain (markers: serogroup, serotype, and subtype) occur in spatial and temporal proximity. (cdc.gov)
  • A group of unrelated cases that occur in temporal and spatial proximity may be misinterpreted as a cluster or outbreak, but these cases would not justify additional public health measures, except perhaps to reassure the public. (cdc.gov)
  • In a real cluster, cases of the same strain occur in temporal and spatial proximity at a higher frequency than by chance. (cdc.gov)
  • Cluster tests work within a hypothesis testing framework that proceeds by calculating a statistic (e.g. clustering metric) to quantify a relevant aspect of spatial pattern in a health outcome (e.g. case/control location, disease incidence, or mortality rate). (biomedcentral.com)
  • The numerical value of this statistic is then compared to the distribution of that statistic's value under a null spatial model, providing a probabilistic assessment of how unlikely an observed cluster statistic is under the null hypothesis [ 15 ]. (biomedcentral.com)
  • Waller and Jacquez [ 16 ] formalized this approach by identifying five components of a spatial cluster test. (biomedcentral.com)
  • Few cancer clustering investigations have evaluated residential mobility even though exposure to environmental carcinogens may occur decades before a cancer diagnosis. (confex.com)
  • To date, most published disease cluster investigations use static geographies in which individuals are assumed to be sessile. (biomedcentral.com)
  • Recently developed Q-statistics can be used to investigate disease clusters based on mobility histories by quantifying space- and time-dependent nearest neighbor relationships. (confex.com)
  • Using case-control residential histories from 2378 participants in a US study and 6594 participants from a Danish study, we created a series of simulated clusters to examine Q-statistic performance and statistical significance. (confex.com)
  • This paper introduces a new approach for evaluating clustering in case-control data that accounts for residential histories. (biomedcentral.com)
  • Several of the methods so derived are applied to evaluate clustering of residential histories in a case-control study of bladder cancer in south eastern Michigan. (biomedcentral.com)
  • Statistically significant clustering of residential histories of cases was found but is likely due to delayed reporting of cases by one of the hospitals participating in the study. (biomedcentral.com)
  • Data with residential histories are preferable when causative exposures and disease latencies occur on a long enough time span that human mobility matters. (biomedcentral.com)
  • The methods presented in this paper build on this body of prior work to produce case-control cluster statistics for residential histories. (biomedcentral.com)
  • We then develop a suite of novel tests for evaluating local, global and focused clustering in residential histories using case-control data. (biomedcentral.com)
  • Finally, we illustrate several of the new techniques by quantifying local, global and focused clustering of residential histories in a case-control study of bladder cancer in Michigan. (biomedcentral.com)
  • 2016. pyJacqQ: Python implementation of Jacquez's Q-Statistics for space-time clustering of disease exposure in case-control studies. (asu.edu)
  • In a recent review of standard methods for evaluating exposure/hazards, disease mapping and clustering techniques, Bayesian approaches, Markov Chain Monte Carlo (MCMC) and geostatistical methods, Mather et al. (biomedcentral.com)
  • Outbreaks are recognized when place (e.g., an educational institution like a primary school), time (e.g., within 1 month), and conventional phenotypic markers (same serogroup, serotype, and subtype) make a connection likely (field cluster) or when an excess of incidence (e.g., 20x normal) is noticed in a retrospectively specified geographic or population area within a chosen period (community outbreak). (cdc.gov)
  • However, in the past 15 years, multiple cluster studies as well as scientific and technologic developments have affected cluster science and response (improvements in cancer registries, a federal initiative in environmental public health tracking, refinement of biomarker technology, cluster identification using geographic information systems software, and the emergence of the Internet). (cdc.gov)
  • BACKGROUND: Few studies have examined the development of geographic and socioeconomic inequalities in caries over time or have simultaneously assessed individual-level socioeconomic position (SEP) and neighborhood-level factors as a multi-layered phenomenon influencing caries inequalities. (bvsalud.org)
  • This study examined (i) the trends in geographic inequalities in caries among adolescents in Denmark and (ii) how the association between SEP and caries has progressed over time, when accounting for individual and neighborhood-level confounding factors. (bvsalud.org)
  • The incidence of such clusters was compared to the incidence that would be expected by chance by using space-time nearest-neighbor analysis of 4,887 confirmed invasive meningococcal cases identified in the 9-year surveillance period 1993-2001 in the Netherlands. (cdc.gov)
  • The objective of our study was to explore the phenomenon of meningococcal clustering in a more objective way by using a nearest-neighbor analysis in space and time that compares the actual occurrence of clusters with their background incidence. (cdc.gov)
  • Currently, to address both the needs of state health departments as well as public concern, the CDC now a ) provides a centralized, coordinated response system for cancer cluster inquiries, b ) supports an electronic cancer cluster listserver, c ) maintains an informative web page, and d ) provides support to states, ranging from laboratory analysis to epidemiologic assistance and expertise. (cdc.gov)
  • Disease clusters continue to concern the public, and public sentiment that environmental causes are responsible and must be investigated is widely prevalent. (cdc.gov)
  • Are bothersome clusters of veins becoming a growing concern? (manhattan-aesthetics.com)
  • the approaches vary among states as well as according to the nature of the cluster and the availability of case and comparison data. (cdc.gov)
  • We begin with a brief background on tests for disease clustering, followed by a summary of approaches to modeling human mobility. (biomedcentral.com)
  • This document has provided a framework that most state health departments have adopted, with modifications pertaining to their specific situations, available resources, and philosophy concerning disease clusters. (cdc.gov)
  • This approach has potential for identifying clustering in mobile populations but given differences in mobility patterns, future work is required to investigate generalizability of this rule set to other case-control datasets. (confex.com)
  • Discuss sensitivity of Q-statistics to key parameters, including cluster size, cluster density, population mobility, and choice of k-nearest neighbors. (confex.com)
  • and Qikt shows where and when local clustering takes place. (confex.com)
  • Results suggest the intersection of cases with significant clustering over their life course, Qik, with cases who are constituents of significant local clusters at given times, Qikt, allows us to identify simulated clusters. (confex.com)
  • Although many statistics have been proposed for assessing local, focused and global clustering in health outcomes, few, if any, exist for evaluating clusters when individuals are mobile. (biomedcentral.com)
  • Results: The accidents (0.318), placement position (0.235), time (0.198), roads (0.160), and population (0.079) were introduced as the main criteria in location road emergency stations. (ac.ir)
  • The precise mechanisms generating clusters or outbreaks puzzle public health workers, epidemiologists, and microbiologists ( 1 , 2 ). (cdc.gov)
  • In 1990 the CDC published the "Guidelines for Investigating Clusters of Health Events," in which a four-stage process was presented. (cdc.gov)
  • When two or more possibly related cases (secondary case or cluster) are identified, group contacts in an educational institution (daycare center or primary school) also receive prophylaxis with rifampicin. (cdc.gov)
  • Specifically, if three or more significant (Qik, p=0.001, Qikt, p=0.05) cases are detected in the same cluster region then it may be considered a true cluster. (confex.com)
  • Field clusters and community outbreaks are rarely seen in the Netherlands, possibly because of underreporting. (cdc.gov)
  • These statistics are calculated repeatedly through space and time and therefore face the problem of multiple testing in determining statistical significance. (confex.com)
  • Increasing relative socioeconomic inequalities in caries over time were observed with significant graded associations between SEP and caries despite adjustment for the various individual and neighborhood-level covariates and the effect of assessment year (e.g., 15-year-olds with parents having basic education had 1.91-fold [95% CI: 1.86-1.95] higher caries experience than those having parents with high education). (bvsalud.org)
  • A review of the literature on using GIS in the field of pre--hospital care has demonstrated that in these studies geographical accessibility to these services and the time of this accessibility has been most investigated [15-20]. (ac.ir)
  • Spider veins are usually harmless, though they can sometimes cause aching, burning, or pain, especially when you have remained standing for long periods of time. (manhattan-aesthetics.com)
  • Your vein specialist will customize a treatment plan to suit your short and long-term goals at the time of your initial consultation. (manhattan-aesthetics.com)
  • The states have the primary responsibility for response to cancer cluster concerns within their domain. (cdc.gov)
  • 1. Space-time analysis of testicular cancer clusters using residential histories: a case-control study in Denmark. (nih.gov)
  • 2. Space-time clustering of non-hodgkin lymphoma using residential histories in a Danish case-control study. (nih.gov)
  • 4. Investigation of spatio-temporal cancer clusters using residential histories in a case-control study of non-Hodgkin lymphoma in the United States. (nih.gov)
  • Our analyses illustrate its application as an alternative to other widely-used cluster methods when residential histories from epidemiological studies are available. (medscape.com)
  • The space-time SaTScan typically uses addresses at diagnosis to determine if cases are clustered, and so does not provide insight into timing of exposure and residential histories [ 33 ] that the GAM method provides in our current analyses. (medscape.com)
  • have developed a useful test for cluster detection that accounts for large residential histories, can accommodate various interpretations of time, and identifies which events are clustered. (medscape.com)
  • Our research group recently developed Q-statistics for evaluating space-time clustering in case-control studies with residential histories. (researchgate.net)
  • This technique relies on time-dependent nearest-neighbor relationships to examine clustering at any moment in the life-course of the residential histories of cases relative to that of controls. (researchgate.net)
  • 9. Space-time clustering analyses of testicular cancer amongst 15-24-year-olds in Northern England. (nih.gov)
  • No one method is ideal for every cluster investigation and each contributes different and important features to space-time analyses. (medscape.com)
  • [ 32 ] SaTScan is a widely-used and effective tool for cancer cluster analyses using registry-based data. (medscape.com)
  • Currently, to address both the needs of state health departments as well as public concern, the CDC now a ) provides a centralized, coordinated response system for cancer cluster inquiries, b ) supports an electronic cancer cluster listserver, c ) maintains an informative web page, and d ) provides support to states, ranging from laboratory analysis to epidemiologic assistance and expertise. (nih.gov)
  • This extension allows us to estimate space-time interaction as a function of spatial and temporal separation, and provides a useful reinterpretation of a popular test, due to Knox, for space-time interaction. (nih.gov)
  • The Knox method [ 25 , 26 ] defines pairs of events as being either close or not close in time or space. (medscape.com)
  • An advantage of the GAM method is that theoretical considerations of bias and variance are used to choose an optimal smoothing span, [ 17 ] whereas the Knox method uses arbitrary cutoff points to determine clustering. (medscape.com)
  • Clusters are recognized when meningococcal cases of the same phenotypic strain (markers: serogroup, serotype, and subtype) occur in spatial and temporal proximity. (cdc.gov)
  • The states have the primary responsibility for response to cancer cluster concerns within their domain. (nih.gov)
  • A group of unrelated cases that occur in temporal and spatial proximity may be misinterpreted as a cluster or outbreak, but these cases would not justify additional public health measures, except perhaps to reassure the public. (cdc.gov)
  • In a real cluster, cases of the same strain occur in temporal and spatial proximity at a higher frequency than by chance. (cdc.gov)
  • [ 35 ] Our spatial-temporal analysis combines the visualization of odds ratios while allowing for hypothesis-testing to determine clusters of significantly increased or decreased risk. (medscape.com)
  • In this paper, we extend this approach to illustrate how alternative temporal orientations (e.g., years prior to diagnosis/recruitment, participant's age, and calendar year) influence a spatial clustering pattern. (researchgate.net)
  • Maps of space-time clustering of bladder cancer cases are presented using different temporal orientations while accounting for covariates and known risk factors. (researchgate.net)
  • The GAM analysis uses one constant optimal smoothing span for space and another for time. (medscape.com)
  • Second-order analysis of spatial clustering. (nih.gov)
  • Gene clustering analysis of DNA microarray data]. (nih.gov)
  • GAM methods predict cancer risk based on the entire residential history, not just one time point, as well as duration of residence. (medscape.com)
  • The orientation of each state-based inquiry response and investigation plan is shaped by state philosophy and experience with previous clusters. (nih.gov)
  • We consider the problem of detecting and describing space-time interaction in point process data. (nih.gov)
  • the approaches vary among states as well as according to the nature of the cluster and the availability of case and comparison data. (nih.gov)
  • [ 34 ] The GAM method does not identify clusters of events but instead identifies areas of increased risk on a continuous risk map. (medscape.com)
  • In 1990 the CDC published the "Guidelines for Investigating Clusters of Health Events," in which a four-stage process was presented. (nih.gov)
  • The precise mechanisms generating clusters or outbreaks puzzle public health workers, epidemiologists, and microbiologists ( 1 , 2 ). (cdc.gov)
  • Response to cancer clusters is appropriate public health action, and the CDC will continue to provide assistance, facilitate communication among states, and foster the development of new approaches in cluster science. (nih.gov)
  • These developments have shaped the approach of the CDC National Center for Environmental Health (NCEH) for public health response to cancer clusters. (nih.gov)
  • A k nearest neighbour test for space-time interaction. (nih.gov)
  • [ 24 ] The GAM method visualizes breast cancer risk while adjusting for known confounders and testing for the statistical significance of location and time. (medscape.com)
  • Kulldorff's space-time SaTScan method detects cancer clusters of specified shape and provides center coordinates and relative risk measure for the mostly likely cluster. (medscape.com)
  • use an interesting three dimensional geovisualization method to display movement across time and space. (medscape.com)
  • This work proposes a space/time estimation method for atmospheric PM2.5 components by modelling the mass fraction at a selection of space/time locations where the component is measured and applying the model to the extensive PM2.5 monitoring network. (researchgate.net)
  • This systematic approach for evaluating space-time clustering has the potential to generate novel hypotheses about environmental risk factors and provides insights into empirical induction periods, age-specific susceptibility, and calendar year-specific effects. (researchgate.net)
  • Tests of clustering based on pattern-recognition procedures. (nih.gov)
  • Our results include space/time maps of atmospheric PAH concentrations in the New York area after 9/11. (researchgate.net)
  • While this ensures that mapped results are unaffected by the degree of smoothing, we ideally would use smoothing spans determined to be optimal in a combined time-space framework. (medscape.com)