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D L Weed

Publications and source records attributed to D L Weed.

At least 19 recordsLinked to original sources
PubMed1998

Case-control studies of cancer screening: theory and practice.

This review summarizes methodologic theories for the design of cancer screening case-control studies and examines the methods applied in studies published in English from 1980 through 1996. In addition to summarizing state-of-the-art methodologic approaches, we identify areas where obvious gaps exist between theory and practice, and we recommend potential areas where theory and methodology may need further development. In particular, we focus on three major areas: 1) the selection of case and control subjects, 2) the definition of exposure (i.e., exposure to the screening test), and 3) bias. Each area is considered carefully by summarizing current theory, reviewing cancer screening applications, and linking recommended methodologic approaches to those used in practice to identify areas where inconsistencies exist. In general, we found methodologic theory and practice in this field of research to be consistent. However, discrepancies were identified in the area of exposure definition, including the use of screening frequency and the use of a detectable, curable preclinical phase for case subjects as the exposure measures. Even when recommended methods were followed, a number of difficulties arose in practice. Specific concerns included the ability to carry out the following: identifying all case subjects within a source population, defining eligibility criteria to ensure that case and control subjects had equal access to screening during the exposure period, distinguishing between symptomatic and diagnostic tests, and controlling for self-selection bias. Careful scrutiny is warranted in all aspects of the design of cancer screening case-control studies, and caution is advised in the interpretation of study results.

Case-Control Studies↗
PubMed1998

Review of epidemiologic studies of alcohol and prostate cancer: 1971-1996.

Prostate cancer is the most common cancer among American men, with few established risk factors. The association between prostate cancer and alcohol, a potentially modifiable risk factor, has been examined in numerous studies. We systematically reviewed the literature on alcohol and the incidence of prostate cancer by searching for published cohort and case-control studies using computerized databases, references, and experts, by evaluating studies for validity, and by summarizing the results and providing research recommendations. We found compelling evidence for no association between low-to-moderate alcohol consumption and prostate cancer. Most studies, however, did not assess the risk of heavy drinking, where there has been some suggestion of increased risk, or of lifetime patterns of drinking. None of the studies have used genetic markers, nor have they been conducted in populations with known familial risk. Further studies in some populations may be warranted.

Adult↗
PubMed1998

Quality of reviews in epidemiology.

OBJECTIVES: This study examined the quality of recent reviews in epidemiology. METHODS: All 1995 issues of 7 widely read epidemiology journals were searched to identify reviews. RESULTS: Twenty-nine reviews were identified. Methodology was not specified or incomplete for literature searches in 79% of reviews; the same was true for inclusion criteria in 83% and for combining studies in 62%. More than 60% of the reviews were not methodologically systematic. CONCLUSIONS: There is a need to improve the quality of review papers in epidemiology. If systematic methodology were followed more frequently, epidemiologic science and its application could be improved.

Epidemiology↗
PubMed1997

On the use of causal criteria.

BACKGROUND: Two recent accounts of the use of causal criteria make opposite claims: that criteria should be used more often to avoid bias in assessments of weak associations and, in direct contrast, that criteria are scientifically invalid. METHODS: A recent review of the current practice of causal inference in epidemiology, as well as some more theoretical concerns, reveals errors in the two claims. RESULTS: In practice, epidemiologists often use the criteria of consistency, strength, dose-response, and biological plausibility, but not often temporality, when judging weak associations. These criteria are used for causal assessments as well as for making public health recommendations. In theory, causal criteria can be used to either refute or predict causal effects. CONCLUSION: Research on causal inference methodology should be encouraged, including research on underlying theory, methodology, and additional systematic descriptions of how causal inference is practised. Specific research questions include: to what extent can consensus be achieved on definitions and accompanying rules of inference for criteria, the relationship of meta-analysis to the criterion of consistency, and the interrelationships of criteria such as consistency, strength of association, and biological plausibility.

Causality↗
PubMed1997

Lack of colon cancer coverage in seven women's magazines.

Women's magazines are an important source of health information. To evaluate the relevancy of articles in these publications to known disease risks, seven women's magazines were reviewed to assess their coverage of colon cancer, the third leading cause of cancer mortality in U.S. women. Specifically, the amount of coverage devoted to colon cancer as well as the presentation of issues in the prevention, risks, treatment, diagnosis and genetics of colon cancer were recorded. Twenty articles were published on colon cancer in these magazines during the years 1987-1995. Compared to five other cancers that also affect women, colon cancer was the focus of the fewest articles in the seven magazines analyzed.

Colonic Neoplasms↗
PubMed1997

The lifetime risk of developing prostate cancer in white and black men.

Two factors help explain increases in the lifetime risk of developing cancer: (a) decreasing overall mortality rates such that people are now living to older ages when cancer rates rise rapidly; and (b) increasing numbers of cancer cases discovered by new medical procedures, screening tests, and changes in the population risk factors. Prostate cancer lifetime risk estimates are particularly influenced by improved mortality rates and increased detection of asymptomatic disease. In this study, we report trends in lifetime risk estimates of developing prostate cancer in white and black men in the United States, from 1975 to 1993, and focus on the effects of changing mortality and screening. For the study period 1975-1977 to 1991-1993, the lifetime risk of developing invasive prostate cancer increased from 7.3 to 19.6% for whites and from 8.5 to 18.6% for blacks. When we recalculated these estimates using age-specific incidence trends from 1975 through 1989 (thereby controlling for the effect of prostate-specific antigen serum testing on prostate cancer incidence rates), the lifetime risk estimates in 1991-1993 fell to 13.8% for whites and 12.5% for blacks. When we made an additional assumption, basing lifetime risk estimates on higher 1975-1977 mortality rates, the lifetime risk estimates in 1991-1993 became 11.3% for whites and 11.8% for blacks. It is also shown that although mortality rates have improved for white and black men over the study period, they are much larger for blacks than whites in younger age groups, when the prevalence of prostate cancer is relatively low. As a result, fewer blacks survive to older ages when age-specific prostate cancer rates are large. It is of note that blacks have higher incidence rates for prostate cancer than do whites at every age-specific interval. Hence, increasing trends in lifetime risk of prostate cancer suggest, in large part, longer life expectancy and better detection methods.

Adult↗
PubMed1996

The practice of causal inference in cancer epidemiology.

Causal inference is an important link between the practice of cancer epidemiology and effective cancer prevention. Although many papers and epidemiology textbooks have vigorously debated theoretical issues in causal inference, almost no attention has been paid to the issue of how causal inference is practiced. In this paper, we review two series of review papers published between 1985 and 1994 to find answers to the following questions: which studies and prior review papers were cited, which causal criteria were used, and what causal conclusions and public health recommendations ensued. Fourteen published reviews on alcohol and breast cancer and 6 published reviews on vasectomy and prostate cancer were examined. For both series of reviews, nearly all available published studies were cited except for ecological studies and prior reviews. Sources of causal criteria were often not provided. When they appeared, all citations were either the 1964 Surgeon General's report or works of Austin Bradford Hill. Reviews often excluded and sometimes altered criteria without giving reasons for these changes. The criteria of consistency and strength of association were almost always used accompanied by dose-response and biological plausibility in a majority of reviews. The criterion of temporality, considered by many methodologists to be a necessary causal condition, was infrequently used. Confounding and bias were often added considerations. Public health recommendations were not discussed in nearly one-half of the reviews.

Breast Neoplasms↗
PubMed1995

Epidemiology, the humanities, and public health.

Epidemiologists may benefit from the disciplines of history, philosophy of science, ethics, literature, and art. Within these disciplines lie answers to the questions of who we are, what is right, how to think, and when to act. Studying and participating in the humanities may also help epidemiologists focus their professional concerns on the humanity their methods serve. A parallel phenomenon in the clinical sciences--medical humanities--provides support for the approach (and some lessons).

Epidemiology↗
PubMed1995

The association between alcohol and breast cancer: popular press coverage of research.

OBJECTIVES: This study was undertaken to examine popular press reports of the association between alcohol and breast cancer. METHODS: Articles from scientific journals and stories from newspapers and magazines published from January 1, 1985, to July 1, 1992, were retrieved from six on-line databases. Lay press stories were analyzed to determine which medical articles were publicized and what information was reported. RESULTS: Fifty-eight scientific articles on the relationship of alcohol and breast cancer were found, and 64 newspaper and 23 magazine stories were retrieved. The press cited 11 studies, 19% of those published during the study period. Three studies were featured in 77% of popular press stories. No scientific review articles were reported. Behavioral recommendations were given to the public in 63% of stories. CONCLUSIONS: The vast majority of scientific studies on alcohol and breast cancer were ignored in press reports. We encourage researchers and the popular press to give the public a broader understanding of public health issues.

Alcohol Drinking↗
PubMed1994

Science, ethics guidelines, and advocacy in epidemiology.

This article examines current ethics guidelines for recommendations on advocacy as an acceptable activity for epidemiologists. Three sets of guidelines, those produced by the Industrial Epidemiology Forum (IEF), the International Epidemiological Association (IEA), and the Council of International Organizations of Medical Sciences (CIOMS), appear to endorse the role of advocate, although there are differences in their recommendations. The IEF guidelines hint that advocacy is appropriate, the IEA guidelines recommend separating the roles of scientist and advocate, and the CIOMS guidelines recommend advocacy dependent on the quality of epidemiologic research and on causal interpretations of the data. Advocacy in the form of public health recommendations can be justified in terms of the principle of beneficence found in the guidelines, but is a central obligation only if the aims of the profession are enlarged to include not only the study of disease but also a commitment to disease prevention. An important issue in women's health--alcohol and breast cancer--provides an illustrative example.

Beneficence↗