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PubMedDate not supplied

The cancer non-epidemic of county 20: case study of an epidemiological mistake.

Two suburban communities in western Canada, with a combined population of 52,000, were affected by a false allegation of increased cancer risk. In 1986, a cancer research agency responded to community concern by conducting a study of cancer incidence (1979 to 1983) and reported elevation on the order of 125% of expected for most sites. Reanalysis of these data several months later revealed an error in the population figure used to calculate the rates. Correction brought the rates into line with Alberta as a whole and comparable to other communities surrounding Edmonton. National media reported the cancer excess but did not report the correction. A Joint Advisory Committee convened at the time by the Minister responsible was a valuable resource for public education. This case study may be useful in the instruction of students and as an example of clerical errors that can indirectly affect an otherwise useful study. Residents of two nearby communities in northern Alberta became concerned about an apparently elevated rate of cancer among adults in their area. Many speculated on an association with the concentration of refineries in eastern Edmonton and petrochemical facilities outside the city in one of the communities. In 1986, the responsible provincial agency conducted a preliminary study of cancer incidence in the area compared to Alberta as a whole. The findings were summarized in a draft document which became widely circulated, although it was never intended to be the definitive report. It was "leaked" from a high government office and became the basis for numerous news stories. A reanalysis of these data revealed that the population figure used to calculate the combined cancer rates for the two communities was valid only for one of them and not the two combined. Correction of this mistake brought the calculated rates into line with those for Alberta as a whole. The original error was shown to be one of interpreting a confusing set of tables that lacked specific instructions and is not likely to be repeated. The original study is now invalidated. Reference to its findings should be made only as it has affected recent local history and public concern. There is certainly no evidence for a serious chemical threat to the health of residents of the area today in the present study and no suggestion of an occupational or environmental factor at work in the past.

Air Pollutants↗
PubMed1989

The Journal of Family Practice 1974-1988. Window to an evolving academic discipline.

This paper examines the spontaneous evolution of original work in family practice as published in The Journal of Family Practice over the 15-year period since it began publication in 1974. An analysis was carried out by principal content and type of paper for the last five years in a manner comparable to an earlier analysis of the journal's first ten years of publication. Trends that emerge from this reanalysis provide a window to observe the further development of family medicine as a scientific and academic discipline. The last five years have seen a marked increase in clinical content of papers (from approximately 60 to 80 percent of published papers) together with continued emphasis on health services subjects. There has been a concurrent sharp increase in research papers, continued strong representation of case studies, and some decrease in both reviews and methods papers. Descriptive research continues to predominate among research papers. Although experimental research still represents only 5 percent of published papers, this percentage has more than doubled over the last five years. The reanalysis also revealed a substantial decline in the proportion of educational papers, as other journals in the field have assumed the primary role for this content area. It appears that the manuscript supply represented by original work in the field is still limited and that there is at present adequate or even surplus journal capacity for publication of work carried out in family practice settings. The quality and type of work continue to mature consistent with the needs of family medicine as a scientific and academic discipline.

Family Practice↗
PubMed1987

The importance of carotid artery plaque disruption and hemorrhage.

The event or mechanism that causes an asymptomatic atherosclerotic carotid artery to become symptomatic remains uncertain. Analysis of carotid endarterectomy surgical specimens from symptomatic patients has suggested that primary intraplaque hemorrhage is the most important initiating event. Reanalysis of several recent series of carotid endarterectomy specimens demonstrated that plaque disruption (ulceration) occurs as frequently as plaque hemorrhage, and that both processes are significantly more frequent in symptomatic as compared with asymptomatic endarterectomy specimens. A review of the coronary artery pathology literature reveals that plaque disruption is commonly present in patients with acute fatal myocardial infarction. It is widely asserted that coronary artery plaque disruption leads to luminal thrombosis and intraplaque hemorrhage. A similar sequence of events may occur in symptomatic carotid arteries.

Arteriosclerosis↗
PubMed1981

Stereoacuity norms in young children.

Stereoacuity was investigated in 3- to 5-year-old children and in adults by using four commercially available stereotests (the Frisby, Randot circles, Random-Dot E (RDE), and TNO tests) and by using an experimental stereotest. Comparative reanalysis was also made of data obtained from other studies of the RDE and Titmus circles tests. Stereoacuity norms are proposed for 3- to 5-year-old children for each of the commercially available tests. Factors influencing stereoacuity threshold differences among the different tests are discussed. The results on all tests are consistent with the hypothesis that binocular visual development is incomplete at 5 years of age.

Age Factors↗
PubMed2003

Urine testing for drugs of abuse: a survey of suburban parent-adolescent dyads.

BACKGROUND: The American Academy of Pediatrics is opposed to involuntary diagnostic testing for drugs of abuse. OBJECTIVE: To gather data about attitudes of parents and their teenagers about involuntary drug testing on parental request. DESIGN: Adolescents and their accompanying parents separately answered a printed survey in the offices of their private pediatrician. The survey posed 2 hypothetical questions about urine testing: (1) Do parents have the right to ask a teenager's physician to order a urine test for drugs of abuse without the teenager's knowledge-if the teenager has falling school grades, an uncooperative attitude, and major untruthfulness? (2) In such a case, should the teenager's physician obtain a urine test for drugs on parental request only, without the teenager's consent? RESULTS: A total of 393 paired evaluable surveys were collected: 77.6% from Virginia and 22.4% from Ohio. There were no significant differences in answers between the 2 study sites. Of the students, 85.8% had either an A or a B grade point average. Current marijuana use was unusually low in our teenaged respondents. Of the parents surveyed, 81.7% would want a physician to be able to perform a urine test for drugs of abuse for a problematic teenager without the young person's consent. The answers to the 2 questions about urine drug tests had poor kappa coefficients of agreement between teenagers and parents (0.04 and 0.09, respectively). Reanalysis, using the variables of age, grade point average, and frequency of marijuana smoking, showed little difference in agreement scores. CONCLUSIONS: In the 2 suburban pediatric practices surveyed, parental opinions and expectations were at variance with the American Academy of Pediatrics policy statement on nonconsensual urine drug testing in the presence of clinical problems. Pediatricians need to be conscious of this clinical-ethical dilemma, become familiar with the American Academy of Pediatrics policy on drug testing, and develop their own position and expertise in this area. The dyad method (parent-teenager survey) is novel and improved the methodology of our study. We surveyed middle-class suburban adolescents while previous studies of adolescents surveyed inner-city populations.

Adolescent↗
PubMed1978

Patterns of childhood social development in adult schizophrenics.

Previous analysis of teachers' comments in school records of schizophrenics showed progressive deviance in their childhood social behavior and sharp differences between the sexes. This report presents a replication of the longitudinal study and a reanalysis of the combined samples. The principal findings from the earlier study were confirmed: in the later school years, preschizophrenic girls were primarily introverted and preschizophrenic boys mainly disagreeable. In the new study, the preschizophrenic girls were also emotionally unstable, introverted, and passive from kindergarten through grade 6, suggesting in earlier history of social disengagement than was previously apparent, and the preschizophrenic boys were emotionally unstable in grades 7 through 12, confirming a nonsignificant trend in the original study. The boys were not behaviorally distinguishable from other boys in elementary grades, so the notion of progressive deviance appears more applicable in their case.

Adolescent↗
PubMed1980

Predicting the outcome of psychotherapy. findings of the Penn Psychotherapy Project.

Our study of predictability of outcomes of psychotherapy used predictions of two kinds: (1) direct predictions by patients, therapists, and clinical observers; and (2) predictive measures derived from the same sources. Seventy-three nonpsychotic patients were treated in psychoanalytically oriented psychotherapy (mean, 44 sessions). Two thirds of the therapists were residents in psychiatry; one third were more experienced. The two main composite outcome measures, measured at termination, were Raw Gain (residualized) and Rated Benefits, which intercorrelated at .76. Most patients improved and showed a considerable range of benefits. The clinical observers' direct predictions of Rated Benefits were highest (.27, P less than 905). The success of the predictive measures were generally insignificant, and the best of them were in the .2 to .3 range meaning that only 5% to 10% of the outcome variance was predicted. The Prognostic Index Interview variables did the best (eg, emotional freedom composite, .30; a crossvalidation for 30 patients was .39 (P less than .05). Neither the therapist measures nor the early psychotherapy session measures predicted significantly. Reanalysis of the similar Chicago Counseling Center study, in our terms, showed a similar low level of prediction success, eg, adequacy of functioning, marital status match, and length of treatment predicted significantly in both studies.

Adolescent↗
PubMed1991

Methodologic issues in maintenance therapy clinical trials.

In the early 1980s, the National Institute of Mental Health supported a multicenter, randomized, controlled, clinical trial on unipolar and bipolar disorder to evaluate the comparative efficacies of lithium carbonate, imipramine hydrochloride, a lithium-imipramine combination, and placebo in preventing the recurrence of affective disorders. The objective of this report is to present a reanalysis of the relative efficacies of these treatments in patients with unipolar disorder to focus attention on general issues related to the design and conduct of maintenance therapy trials. We show that the earlier conclusions of that study that imipramine and the combination therapy are more effective than lithium and placebo in preventing the recurrence of depression in unipolar patients can be accounted for by alternative explanations that are a consequence of the design of the study. Our findings have important implications for the design, conduct, and interpretation of results of maintenance therapy clinical trials in general.

Adult↗
PubMed1991

Conceptualization and rationale for consensus definitions of terms in major depressive disorder. Remission, recovery, relapse, and recurrence.

In 1988, the MacArthur Foundation Research Network on the Psychobiology of Depression convened a task force to examine the ways in which change points in the course of depressive illness had been described and the extent to which inconsistency in these descriptions might be impeding research on this disorder. We found considerable inconsistency across and even within research reports and concluded that research on depressive illness would be well served by greater consistency in the definition change points in the course of illness. We propose an internally consistent, empirically defined conceptual scheme for the terms remission, recovery, relapse, and recurrence. In addition, we propose tentative operational criteria for each term. Finally, we discuss ways to assess the usefulness of such operational criteria through reanalysis of existing data and the design and conduct of new experiments.

Depressive Disorder↗
PubMed1992

Motorcycle helmet-use laws and head injury prevention.

OBJECTIVE: To rebut criticism of a previous study of motorcycle helmet-use laws through reanalysis with improved measures of exposure, stratification for regional differences in crash risk, and addressing of total motorcycle-related mortality and the grounds for targeting motorcyclists for helmet-use laws. DESIGN: Death certificate-based correlational study of motorcycle-related deaths and motorcycle helmet-use laws. POPULATION STUDIED: United States resident deaths from 1979 through 1986. RESULTS: Regardless of the denominator used (resident population, motorcycle registrations, or motorcycle crashes), states with full helmet-use laws had consistently lower head injury-associated death rates than states without such laws, even when stratified by region. Total motorcycle-related mortality, however, was similar between law groups. On a registration or crash basis, motorcyclists who died in crashes had a fivefold to sixfold higher risk of head injury than those who died using any other type of motor vehicle. CONCLUSION: Full helmet-use laws were consistently associated with lower rates of head injury-associated death. While disagreement remains on the acceptability of the legislative approach, the scientific basis for motorcycle helmet-use laws as a head injury prevention tool appears sound.

Accidents, Traffic↗
PubMed2000

Craniofacial variation in Homo habilis: an analysis of the evidence for multiple species.

The question of heterogeneity in the Homo habilis sample continues to be controversial. Various lines of evidence have been used to reject the null hypothesis of intraspecific variation. This evidence derives from analyses of endocranial volume variation, probability estimates of sexual dimorphism, facial variation, cranial angles, CV analysis of craniofacial variation, the multivariate pattern of sexual dimorphism, the pattern of variability (CV) profiles, distance data using exact randomization methods, and various kinds of quantitative ordinations of fossils. Although consensus is lacking as to how the H. habilis sample is to be split, there is a growing perception that the degree of variation among the fossils is too great and the pattern of variation is too different to be explained by intraspecific variation. This has resulted in the recognition of new species such as "Homo rudolfensis." The present study critically examines the evidence commonly cited as the basis for recognizing multiple species in the extended H. habilis hypodigm. Reanalysis and reinterpretation of these data indicates that: (1) the degree of variation in the H. habilis sample is typical of modern hominoids, and (2) the pattern of variation among specimens of the H. habilis sample is consistent with intraspecific variation. Thus, at present, there is no sound basis to reject the null hypothesis of intraspecific variation as an adequate explanation of the morphological variation seen among specimens of the extended H. habilis sample. If multiple species are indeed represented, then their presence has not yet been satisfactorily demonstrated.

Animals↗
PubMed1998

Organization of the intrinsic connections of the monkey amygdaloid complex: projections originating in the lateral nucleus.

We have used the anterograde tracer, Phaseolus vulgaris-leucoagglutinin (PHA-L) to study the intrinsic projections of the lateral nucleus of the Macaca fascicularis monkey amygdaloid complex. A reanalysis of the monkey lateral nucleus indicated that there are at least four distinct cytoarchitectonic divisions: dorsal, dorsal intermediate, ventral intermediate, and ventral. The major projections within the lateral nucleus originate in the dorsal, dorsal intermediate, and ventral intermediate divisions and terminate in the ventral division. The ventral division also projects to itself but does not project significantly to the other divisions of the lateral nucleus. Thus, the ventral division appears to be a site of convergence for information entering all other portions of the lateral nucleus. There are substantial regional and topographic differences in the projections from each of the lateral nucleus divisions to other amygdaloid nuclei. The dorsal division projects to all divisions of the basal and accessory basal nuclei, to the periamygdaloid cortex, the nucleus of the lateral olfactory tract, the dorsal division of the amygdalohippocampal area, and the lateral capsular nuclei. The dorsal intermediate division projects to the intermediate and parvicellular divisions of the basal nucleus, to the parvicellular division of the accessory basal nucleus, and to the periamygdaloid cortex. The ventral intermediate division projects to the magnocellular division of the accessory basal nucleus and to the parvicellular division of the basal nucleus. The major projections from the ventral division are directed to the parvicellular division of the basal nucleus, the parvicellular division of the accessory basal nucleus, the medial nucleus, and the periamygdaloid cortex. Projections from all portions of the lateral nucleus to the central nucleus are generally very light. It appears, therefore, that each division of the lateral nucleus originates topographically organized projections to the other amygdaloid areas that terminate in distinct portions of the target regions. The topographic organization of intrinsic amygdaloid projections raises the possibility that serial and parallel sensory processing may take place within the amygdaloid complex.

Amygdala↗
PubMed1996

A population-based study of cancer risk in twins: relationships to birth order and sexes of the twin pair.

One thousand and sixty-three twins with cancer whose co-twin was born alive were identified among patients born since September 1939 with cancers incident in England and Wales during 1971-1984 at childhood and young adult ages. Site-specific risks of cancer were analysed in relation to birth order within the twinship and sexes of the twin pair, using adjusted national birth data to give control distributions of these variables. Risk of leukaemia was increased in first-born twins, risk of testicular cancer was increased in second-born twins with female co-twins but decreased in second-born twins with male co-twins and lung cancer risk was increased in first-born twins with same-sex co-twins. Cutaneous melanoma risk was increased in persons with opposite-sex co-twins, nervous system cancer risk was increased in females with opposite-sex co-twins and Hodgkin's disease risk was increased in persons with same-sex co-twins. For most of the findings, no previous comparable analyses are available, so interpretation of the results must be provisional until the analyses can be repeated on other data. The result for leukaemia would accord with previous suggestions that leukaemia may be of prenatal origin and may sometimes lead to intrauterine death. The Hodgkin's disease result would fit with theories of an infectious aetiology, and this view is strengthened by reanalysis of previous data on paralytic poliomyelitis in twins, which show a pattern similar to that for the Hodgkin's disease patients. Cancer risk in relation to birth order and sex of twins can give novel, objective data relating to prenatal and infectious disease aetiology of cancers.

Adult↗
PubMed1996

Statistical analysis of possible bias of clinical judgements due to observing an on-therapy marker variable.

In certain double-blind clinical trials there is the possibility that certain 'marker variables' observable during the trial may in part unblind the trial, even at a subliminal level. At issue is whether or not this potential unblinding biases the investigators' clinical efficacy assessments. This issue arose after the completion of three clinical trials that compared tretinoin emollient cream (TEC) 0.05 per cent to its vehicle in patients with photodamaged skin. The question raised was whether or not possible 'subliminal unblinding' of the investigators and patients, due to the cutaneous irritation associated with topical tretinoin, might have caused a treatment bias in the study. To address this issue, we undertook a reanalysis of these three clinical trials. In doing so, we develop in this paper a statistical modelling approach to address issues of possible bias introduced by the ability to observe such marker variables. The approach utilizes a linear discriminant analysis to introduce an auxiliary categorical variable for the efficacy analysis. A suitable categorical data model permits the estimation of relevant bias effects. We illustrate this approach with data from the three TEC 0.05 per cent trials.

Bias↗
PubMed2000

Expanded analysis of injury mortality among unionized construction workers.

BACKGROUND: To evaluate the utility of expanding the number and precision of injury categories used in previous occupational mortality studies, this study reanalyzed data from four previous studies of unionized construction workers (construction laborers, ironworkers, sheet metal workers, and operating engineers), by expanding the number of injury categories from 6 to 33. METHODS: Proportionate mortality ratios (PMRs) were computed using the distribution of deaths from the National Occupational Mortality Surveillance System, a mortality surveillance system from 28 states, as a comparison. A blue collar comparison group was also used in additional analyses to adjust for socioeconomic and other factors. RESULTS: This reanalysis identified significantly elevated PMRs in at least one of the four worker groups for falls, motor vehicle crashes, machinery incidents, electrocutions, being struck by falling objects, being struck by flying objects, explosions, suffocation, and water transport incidents. Limiting the comparison population to deaths among blue collar workers did not change the results substantially. CONCLUSIONS: This study demonstrates that increasing the precision of categories of death from injury routinely used in mortality studies will provide improved information to guide prevention. Am. J. Ind. Med. 37:364-373, 2000. Published 2000 Wiley-Liss, Inc.

Accidental Falls↗
PubMed2000

Comparative analysis of DNA flow cytometry and cytology of bladder washings: review of discordant cases.

DNA analysis is becoming an important diagnostic and prognostic adjunct test in urinary cytology. The aim of this study was to compare the results of DNA flow cytometry (FCM) with the cytologic diagnosis of bladder washings (BW). DNA ploidy was evaluated in 251 BW. In 65 cases, follow-up surgical biopsies were available. Cytology results were classified as positive and negative, and FCM results were categorized as diploid and aneuploid. Both tests were evaluated independently. Cases were defined as discordant if the cytology was negative and FCM was aneuploid, or if the cytology was positive and FCM was diploid. All discordant cases were reviewed, and positive predictive values (PPV) for FCM and cytology were calculated for cases with follow-up biopsy results. Cytologic evaluation classified 181 cases as negative, with 175 of them diploid and 6 aneuploid; and 70 as positive, with 53 of them diploid and 17 aneuploid. Overall, there were 59 discordant cases (23.5%, with a confidence limit of 18.2-28.8%). Of 6 aneuploid/cytology-negative cases, biopsies were available in 4 cases and showed one grade 1, two grade 2, and one grade 3 urothelial carcinoma (UC). Reanalysis of these 6 cytology specimens showed 1 case that should have been interpreted as positive (false negative), 4 true negatives, and 1 polyoma virus infection. Out of 53 diploid/cytology-positive cases, biopsies were available in 45 cases and showed nine grade 1, 14 grade 2, three grade 3 UCs, 11 UCs in situ, and eight negative biopsies. The PPV for cytology was 85%, and the PPV for FCM was 95%. We concluded that FCM, which requires a large number of cells, often cannot detect small aneuploid populations, which are present particularly in cases of UC in situ.

Adult↗
PubMed1999

Positron emission tomography correlations in and beyond medial temporal lobes.

This article discusses the potential usefulness of brain/ behavior correlational analyses in functional neuroimaging studies of memory, and how such analyses can illuminate the role of medial temporal lobes (MTL) and the hippocampus in episodic and declarative memory processes such as encoding and retrieval. Reanalysis of the results of four previously reported positron emission tomography (PET) studies yielded evidence of both positive and negative between-subjects correlations between recognition-memory accuracy and regional blood flow. The sites of these correlations were in MTL regions as well as in other cortical and subcortical areas, including frontal lobes (Brodmann areas 6, 9, 10, 11, and 47), temporal lobes (BAs 21, 22, and 38), insula, fusiform gyrus, and cuneus/precuneus. These findings were discussed with respect to issues such as localization of the correlation sites, the distinction between brain sites revealed by brain/cognition correlational analyses ("how" sites) and those yielded by cognitive subtraction methods ("what" sites), the tendency of the "how" sites in MTL to occur in the left hemisphere, the tendency of other "how" sites to occur in one or the other hemisphere, rather than bilaterally, and the meaning and "reality" of both brain/behavior correlations and task-related activations. Because of the known incidence of false-positives, all neuroimaging data, including those involving the localization of "what" and "how" memory sites in MTL and other brain regions, need to be interpreted cautiously, and findings of individual studies should not be overinterpreted.

Brain↗
PubMed1996

Impact of prenatal diagnosis on revised livebirth prevalence estimates of Down syndrome in the Lothian region of Scotland, 1978-1992.

Ramsay et al. [(1991) Biomed Pharmacother 45:267-272] reported on the livebirth prevalence of Down syndrome in the Lothian region of Scotland during 1978-1989. Their results suggested a temporal association between the events of Chernobyl in April 1986 and a significant-excess of cases in 1987. In the current study the data were extended for 3 years and reanalyzed, a major objective being to correct for the differential loss of fetuses with Down syndrome which occurs between prenatal diagnosis and birth. Other objectives were to estimate the prevalence reduction due to prenatal diagnosis, quinquennial maternal age-specific risk rates, and the level of ascertainment of cases. The reanalysis found a 12-year prevalence rate of 1.29 vs. the previous rate of 1.34, and a shift of the annual prevalence peak to 1988, with a reduced prevalence in 1987 compared to that found in the earlier study. The new results are less consistent in showing an association of Down syndrome clustering with the Chernobyl accident. For the 15-year study period, a 23% overall reduction in prevalence occurred due to prenatal diagnosis and elective abortion of affected fetuses, with a 50% reduction to women > or = 35 years of age. For 1988-1992, these reductions were 33% and 60%, which are among the highest reported in the literature for these time periods. The estimated quinquennial maternal risk rates were very similar to others already reported, and the data are consistent with a high level of case ascertainment. Since these women are approaching the upper limits of fetal detection through advanced maternal age alone, continued reduction in prevalence rates for Down syndrome through prenatal diagnosis and elective abortion will come mostly from increased use of other (chemical) screening techniques now available.

Adult↗