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D Wartenberg

Publications and source records attributed to D Wartenberg.

At least 55 records · Page 3Linked to original sources
PubMed1992

A perceived cluster of amyotrophic lateral sclerosis cases in a Massachusetts community.

We investigated a report of a perceived cluster of amyotrophic lateral sclerosis (ALS) in Middleborough, Mass. Although an increase in ALS incidence was observed [2.51 deaths/100,000 person-years (p-y)], relative to the statewide rate over the years 1969-1985 (1.26/100,000 p-y), it was not statistically significant at the 95% confidence level. Problems in evaluating possible neurological disease clusters and their association with environmental exposures are presented.

Adult↗
PubMed1991

Defining exposure in case-control studies: a new approach.

Many epidemiologists conducting case-control studies choose to dichotomize their exposure data to make the analysis of the data easier and its presentation more straightforward. The choice of a specific rule for dichotomization can have a large effect on the outcome measure, the odds ratio, although this effect is rarely studied. The authors present a graphic approach for exploring this effect, the quantile-quantile (Q-Q) plot. By examining a Q-Q plot, an investigator simultaneously gains information about the distribution of exposures among cases, the distribution of exposures among controls, and odds ratios at all possible cutpoints and their standard errors. In addition, by finding the slope at each point along the Q-Q curve, it is possible to estimate the rate ratios for each possible value of exposure. The authors view the use of the Q-Q plot as an exploratory tool. It enables the investigator to become more familiar with the data and check for irregularities such as outliers, nonlinearities, or nonmonotonic dose-response curves, and idiosyncratic variations of the odds ratio. The authors present an example evaluating the risk of low birth weight as a function of mother's age for Boston births in 1984.

Adolescent↗
PubMed1991

Are non-whites at greater risk for occupational cancer?

All occupational cancer epidemiology articles that reported data on non-whites from four major journals were identified for the years 1984-1987. In addition to these 14 papers, four more papers were identified from computer searches, and another 13 were found by following up references from the original 14. Within these 31 papers, there were 36 analyzable cohorts (subgroups by job and sex). Five cohorts had elevated all-cancer mortality ratios in non-whites without an increase in whites. Sixteen cohorts showed elevated ratios in both racial groups, with 11 of the 16 having a higher non-white cancer mortality ratio than white cancer mortality ratio. For the 25 studies in which at least one racial group's cancer ratio was elevated, the non-white ratio exceeded the white ratio in 17 (68%). The overall paucity of articles on non-white cancer mortality, as well as the apparent trend toward increased occupational cancer mortality in non-whites, is discussed.

Bias↗
PubMed1991

Communicating to an alarmed community about cancer clusters: a fifty state survey.

A survey of all 50 U.S. states conducted in 1989 showed that 1,300-1,650 requests for cancer cluster investigations were received by state health departments. Most states responded with a three-stage process aimed at prioritizing clusters at each stage. Those situations deemed most serious were passed on to the next stage of evaluation. Thirty-eight of the 50 states said that communicating risk information to informants was a productive outcome, and 26 states sent materials to informants explaining the causes of cancer, clusters, how clusters are investigated, and other health education materials. Many states requested detailed information about reported clusters from informants. States with a major commitment to protecting public health and environment were more likely to provide information than states with weaker programs. Some officials discouraged people from pursuing their requests by trying to convince informants that a problem did not exist and by overwhelming them with questions and information. We recommend that health departments train their respondents in risk communications and establish an organizational climate that provides financial resources and institutional support appropriate to the complex task of communicating risk information to a public alarmed about a cancer cluster.

Cluster Analysis↗
PubMed1991

Newspaper coverage of cancer clusters.

This study reports an analysis of 176 newspaper articles about cancer clusters. The type of diseases, number of diseases, and status of ongoing health investigations were reported in the majority of articles. But background information such as, comparison of actual and expected number of cases, environmental causes and their confounders, and the existence of other clusters were not reported as often. Statements about risk were reported in most articles and, contrary to our expectations, were relatively balanced among risk asserting, risk denying, and mixed opinions. We noted a preponderance of risk asserting statements in the beginning of stories. Cluster stories cited an average of three sources, and two of these three sources were usually government officials. The remaining sources were divided among citizens, representatives of environmental advocacy groups and industry, and unaligned experts. Drawing on these data, we offer some suggestions to improve communication between scientists and journalists.

Environmental Pollution↗
PubMed1991

Estimating exposure using kriging: a simulation study.

Retrospective studies of disease often are limited by the resolution of the exposure measurements. For example, in a typical study of adverse health effects from contaminated groundwater, the number of wells sampled may range from only a few to as many as several dozen, while the number of cases and controls may be in the hundreds or more. To derive individual estimates of exposure for wells that were not sampled, investigators must extrapolate. In this study, we compare three methods of extrapolating from a limited number of observations to estimate individual exposures. Using two naive models of groundwater contamination, we compare nearest neighbor interpolation, inverse distance squared weighting, and kriging for estimating exposure based on a limited number of measurements. Our results show that although kriging is a statistically optimal method, it is not markedly better than simpler interpolation algorithms, though it is considerably more complex to use. Aberrant well measurements and discontinuities are problematic for all methods. We provide some guidance in interpolating data and outline a more comprehensive comparison of methodology.

Data Interpretation, Statistical↗
PubMed1991

The study of cancer in minorities.

Data inventories provide a concise reference base for researchers. The authors created a set of reference volumes listing databases used for studying cancer in New Jersey minorities. The process followed can be adapted for other disease outcomes or other regions.

Data Collection↗
PubMed1991

Temporal clustering of homicide among urban 15- to 24-year-old white and black Americans.

Temporal clustering of homicides among 15- to 24-year-old black and white Americans was studied in 22 heavily urbanized counties in the United States from 1979 through 1985. Thirty-eight million people, including 37% of black Americans and 14% of white Americans, lived in these densely developed countries. The pattern of white male homicide deaths was cyclical--that is, statistically significant excesses were observed on weekends and on national holidays. The pattern of black male homicide deaths was much less cyclical. But homicide deaths of black males were disproportionately likely to occur in a pattern of single days with multiple homicides as well as in periodic spikes, lasting less than a week, during which many homicides occurred. Implications for research and policy are discussed.

Adolescent↗
PubMed1990

Detecting disease clusters: the importance of statistical power.

A variety of methods and models have been proposed for the statistical analysis of disease excesses, yet rarely are these methods compared with respect to their ability to detect possible clusters. Evaluation of statistical power is one approach for comparing different methods. In this paper, the authors study the probability that a test will reject the null hypothesis, given that the null hypothesis is indeed false. They present a discussion of some considerations involved in power studies of cluster methods and review two methods for detecting space-time clusters of disease, one based on cell occupancy models and the other based on interevent distance comparisons. The authors compare these approaches with respect to: 1) the sensitivity to detect disease excesses (false negatives); 2) the likelihood of detecting clusters that do not exist (false positives); and 3) the structure of a cluster in a given investigation (the alternative hypothesis). The methods chosen, which are two of the most commonly used, are specific to different hypotheses. They both show low power for the small number of cases which are typical of citizen reports to health departments.

Clinical Protocols↗
PubMed1990

Understanding mass media coverage of disease clusters.

The responsibility of informing the general public about disease clusters belongs to health investigators. In the majority of instances the investigators must send their messages through the mass media. The authors analyzed nightly network television news coverage of disease clusters during the period 1978-1987, and newspaper coverage of four disease clusters. Formal content analysis of about 600 stories showed that the mass media focuses on human interest, conflicting information, blame, and political symbolism in their coverage of clustered health events. The authors offer suggestions to health practitioners about improving their communications with journalists.

Disease Outbreaks↗
PubMed1990

The fallacy of ranking possible carcinogen hazards using the TD50.

Ames et al. have proposed a new model for evaluating carcinogenic hazards in the environment. They advocate ranking possible carcinogens on the basis of the TD50, the estimated dose at which 50% of the test animals would get tumors, and extrapolating that ranking to all other doses. We argue that implicit in this methodology is a simplistic and inappropriate statistical model. All carcinogens are assumed to act similarly and to have dose-response curves of the same shape that differ only in the value of one parameter. We show by counterexample that the rank order of cancer potencies for two chemicals can change over a reasonable range of doses. Ames et al.'s use of these TD50 ranks to compare the hazards from low level exposures to contaminants in our food and environment is wholly inappropriate and inaccurate. Their dismissal of public health concern for environmental exposures, in general, based on these comparisons, is not supported by the data.

Animals↗
PubMed1989

An investigation of a reported cancer cluster in Randolph, Massachusetts.

An increasingly common public health problem is the perception that disease incidence has increased or a cluster of disease has occurred in a community. In most cases, the disease of concern is cancer and a local hazardous waste site or other environmental problem is involved. These problems can be difficult to investigate and public health officials are frequently criticized for their inability to address community concerns. This paper reports a case study of such a situation occurring in the Barlett-Green Acres (BGA) neighborhood of Randolph, Massachusetts. Study data were obtained by interviews in households of persons belonging to a list of alleged cancer cases initially supplied by residents and supplemented using records available in town and state public health offices. One objective of the investigation was to develop methods that may be of value in similar situations arising in other communities. From a list of names compiled prior to and during the investigation, 45 incident cases of cancer were identified and found suitable for analysis. An additional four cases were added from the Massachusetts Cancer Registry. The analysis showed the existence of a cancer cluster, but overall cancer incidence and mortality in the BGA neighborhood were not elevated. Residence history, disease site, and other features of the cancer cases were investigated using methods less sensitive to incomplete reporting than total incidence. No unusual features of the cancer data other than the initiating cluster were identified and no environmental hazard likely to impact the BGA neighborhood was discovered, hence we conclude that the most likely cause of the cancer cluster was random variation in cancer rates.

Adolescent↗
PubMed1989

A microcomputer-based vital records data base with interactive graphic assessment for states and localities.

Vital records data bases describe large populations over long periods of time, yet their organization and size often preclude or discourage their use. We constructed a microcomputer-based data base of all singleton births in Massachusetts, 1975-84. The original data were stored in 700,000 records, each 174 bytes long, occupying a total of over 120 megabytes (MB). By removing redundant information and unique identifiers, and packing the data, we store 21 fields of this information in a 16-byte record resulting in a data base of 11.1 MB, a saving of over 90 percent of disk space. By using programs written expressly for this data base, we can display a birth weight frequency plot of the entire data set in under 65 seconds on an IBM-compatible PC-AT. Comparable assessments in SAS-PC took over 105 minutes and in main frame SAS on an AS-9000 took over 37 CPU seconds. Implementing similar systems for state registries on births, deaths, cancers, and birth defects potentially offers investigators easy access to vast stores of information and would enable public health officials to produce timely reports, initiate a variety of surveillance activities, and respond rapidly to residents' inquiries about clusters and anomalous disease patterns.

Birth Certificates↗
PubMedDate not supplied

The inverse relationship between microvessel counts and tumor volume in breast cancer.

Angiogenesis has emerged as an indicator of metastatic potential in invasive breast cancer. Exponential tumor growth and the appearance of metastasis are observed as new microvessels form. We postulated that the relevance of angiogenesis would be enhanced if analyzed as a function of tumor volume rather than greatest diameter alone and that microvessel counts would proportionately increase as does volume. Since tumors are three-dimensional solids, volume was calculated using the formula for an ellipsoid, V = pi/6 (a x b x c). Sixty-four tumors < or = 2.5 cm were studied and analyzed in 5 mm incremental ranges. Mean microvessel counts did not vary significantly among these tumor size groups. However, analysis of microvessel counts as a function of tumor volume decreased from 947.1/cm3 (0-0.5 cm) to 18.1/cm3 (2.1-2.5 cm), a greater than 50-fold difference. High microvessel density in small cancers supports the notion of metastasis as an early event, making these small tumors perhaps ideal targets for antiangiogenic agents.

Breast Neoplasms↗