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PURPOSE: Autopsy studies can provide insight into disease trends and their determinants, including data on the prevalence of atherosclerosis. However, such studies are subject to autopsy bias, which limits their generalizability to the source population. The impact of this bias on autopsy based estimates of time trends in heart disease prevalence is unknown. To report on the trends over time in autopsy rates in Olmsted County, MN, to examine the association between clinical diagnoses of cardiovascular diseases (CVDs) and referral to autopsy and how this association may have changed over time. METHODS: We examined the trends in autopsy rates between 1979 and 1994 in Olmsted County, and the association between antemortem characteristics including cardiovascular diagnoses and autopsy referral. RESULTS: From 1979 to 1994, a total of 9110 residents died in Olmsted County. The average annual autopsy rate was 30%. Autopsy rates declined from 36% in 1979 to 23% in 1994, corresponding to an average decline of 0.6%/year (p < 0.01). Referral to autopsy was positively associated with younger age, male sex, in-hospital place of death, antemortem diagnoses of myocardial infarction (MI) or peripheral vascular disease (PVD), and earlier calendar period. There was no evidence of an interaction between calendar period and any of these predictor variables. Antemortem diagnosis of heart failure was associated with a decrease in the odds of referral to autopsy over time as compared to persons without such diagnosis. CONCLUSIONS: In Olmsted County, autopsy rates, although declining over time, have remained on average approximately 30%. Antemortem diagnoses of MI or PVD are associated with autopsy referral but this association did not change over time. While the greater decline overtime in the use of autopsy observed among decedents with an antemortem diagnosis of congestive heart failure (CHF) deserves further studies, the present findings reduce the concern for bias of time trends in the prevalence of atherosclerosis by changes in the clinical characteristics of decedents referred to autopsy.

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Controversy continues as to whether traumatic brain injury is a risk factor for Alzheimer's disease. The authors examined a related hypothesis that among persons with traumatic brain injury who develop Alzheimer's disease, time to onset of the disease is reduced. They used data on all documented episodes of traumatic brain injury that occurred from 1935 to 1984 among Olmsted County, Minnesota, residents. Community-based medical records were used to follow traumatic brain injury cases who were aged 40 years or older at last contact prior to June 1, 1988, for Alzheimer's disease until last contact, death, or June 1, 1988. The test of the hypothesis was restricted to those cases who developed Alzheimer's disease. The expected time to onset of Alzheimer's disease was derived from a life table constructed by using age-of-onset distributions within sex groups for a previously identified cohort of Rochester, Minnesota, Alzheimer's disease incidence cases without a history of head trauma. The authors found that of the 1,283 traumatic brain injury cases followed, 31 developed Alzheimer's disease, a number similar to that expected (standardized incidence ratio = 1.2, 95% confidence interval 0.8-1.7). However, the observed time from traumatic brain injury to Alzheimer's disease was less than the expected time to onset of Alzheimer's disease (median = 10 vs. 18 years, p = 0.015). The results suggest that traumatic brain injury reduces the time to onset of Alzheimer's disease among persons at risk of developing the disease.

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Our goal was to use cross-sectional national mortality data to provide a multivariable statistical analysis of the factors that contribute to the decision of whether an autopsy will be performed. The identification of determinants of the autopsy is an important prerequisite for finding cost-effective alternatives for arresting or reversing the decline of autopsy rates in the circumstances in which the autopsy can continue to make a crucial contribution to clinical medicine and public health. The source of the data was 1986 National Center for Health Statistics (Washington, DC) mortality data tapes for Kentucky, Maryland, Minnesota, and Washington for the 1986 calendar year. Separate multiple logistic regressions were conducted on these data on a state-by-state basis, with a total of 139,063 individual mortality records as the unit of analysis. The dependent variable in all models was autopsy (yes/no). Odds ratios for selected explanatory variables were estimated for all four states, and the relative contribution of each explanatory variable was studied in a detailed analysis of one state. In general, the following independent variables had a statistically significant positive relationship with whether an autopsy will be performed: male sex; nonwhite ethnicity; death due to ill-defined or unknown cause; death due to accident, suicide, or homicide; presence of a nationally recognized medical center in the county of death; and death occurring in a standard metropolitan statistical area. In general, the following independent variables had a statistically significant negative relationship with whether an autopsy will be performed: older age at death; higher income level of the decedent; death in a nursing home; death at home; and residency in the county of death. The two most important variables influencing the autopsy decision were age at death (especially old age) and death due to accident, homicide, or suicide.

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We have examined the relationship between mechanical injuries and the subsequent development of classic amyotrophic lateral sclerosis (ALS) through a critical review of the literature. Only prospective evaluation of a large cohort of trauma victims can provide an unbiased answer to this controversy. However, such an evaluation would be prohibitively expensive, and the results would not be available in our lifetime. The results of retrospective case-control studies are conflicting in part because of biases in the selection of patients and controls, poor definition of the nature and extent of the trauma and its chronological relationship to the onset of ALS, and a non-uniform approach to the collection of antecedent information. More rigorously designed studies show no association of ALS to antecedent trauma. The existing data thus do not suggest that mechanical trauma is a risk factor for ALS. Future case-control studies should conform to a standardized methodology. The critical analysis presented here of the research on the purported connection between mechanical injury and ALS may serve as a model for the evaluation of the role of trauma in other chronic diseases. Application of these methodological principles may bring increased scientific rigor to assessing the frequently litigated question of what constitutes a true trauma sequela.

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The importance of autopsy data in cancer epidemiological investigation is well appreciated by researchers at the Mayo Clinic. The Rochester Epidemiology Program Project is a complete population-based collection of morbidity and mortality data in Olmsted County, Minnesota (population, 100,000), funded by the National Institutes of Health since 1964. Comprehensive ascertainment of cancer in this community cohort has been augmented by initial diagnosis at autopsy for 12% of colorectal cancers, 35% of intracranial neoplasms, 45% of phaeochromocytomas and 37% of renal-cell carcinomas. These rates are in stark contrast to autopsy diagnoses in our cancer registry--usually less than 1%. The difference is attributable to the denominator in these comparisons, a concept of vital importance to the epidemiological interpretation of autopsy findings. Despite the enormous value of the autopsy in our research, social and economic factors diminished autoptic rates in Olmsted County from 63% in 1970 to 39% in 1984. These rates are well above that for the USA as a whole but parallel our national decline in frequency of autopsy. The major factors responsible for this reduction appear to be the increasing proportion of deaths in nursing homes and the advent of declining reimbursement in US health care.

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The existence of high quality, population-based, medical data facilitates the practice of modern epidemiology with its concomitant benefits for clinical practice and public health policy. Two exceptional examples of such databases are provided by Malmo, Sweden, and Olmsted County, Minnesota. This paper outlines briefly the similarities between these two geographic entities, and focuses, in particular, on the central role of the autopsy in Olmsted County. Changing temporal and spatial patterns of autopsy are reviewed as well as two important related issues: the role of consent and the medico-legal autopsy. The paper concludes with a summary of some of the more noteworthy contributions of autopsy-based epidemiological research in Olmsted County, and offers several recommendations for the establishment of a select network of special population-based study areas. These epidemiological "laboratories", through the interchange of data and tissue specimens, could make significant contributions to the study of diseases both nationally and internationally. Their interactive efforts and high quality data bases would help to increase the efficiency of the expenditure of scarce societal resources in epidemiology and health care.

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Maintenance of high autopsy rates is associated with specific benefits, especially for clinical practice and for clinical and epidemiologic research. We have compiled and evaluated (on the basis of related costs and benefits) a comprehensive list of recommendations to resurrect the autopsy and reestablish it as a central contributor to medical practice, teaching, and research.

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In this study, we examined in detail the patterns of autopsy rates for a half century (1935 through 1985) among residents of Olmsted County, Minnesota. The time trend of the autopsy in this community represents, in many respects, a microcosm of national trends. In the process of this analysis, we identified several medical and socioeconomic variables that may influence the rate of autopsy, including the age at death, physical location of death, gender, surgical procedures preceding death, immediate cause of death, and direct and indirect costs of the autopsy. In particular, the advancing mean age at death and the increase of the nursing home as a social phenomenon seem to have had a profound effect on autopsy rates both in Olmsted County and throughout the United States.

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This study outlines the role of autopsies in medical practice and health policy, details the nature and reason for declining rates, including those in Rochester, Minnesota, and suggests possible remedial measures to halt or reverse this trend. It is concluded that one of the principal impediments to reversing the declining rate of autopsies is what is referred to in Economics as "market failure." In particular, the nature of the spatial and temporal distribution of costs and benefits has precluded the existence of an incentive structure which can lead to a realization of the major net social benefits from the autopsy. Ultimately, it is only the explicit recognition by the medical profession, government agencies, corporate insurers, and the general public of the nature and significance of this market failure and foregone benefits which can lead to remediation.

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Extreme pollutant values are of great interest in water quality monitoring because of their frequent toxicological significance. The principal barrier to the detection of these values, however, is the cost of extensive and comprehensive monitoring. This paper demonstrates an efficient method to determine the maximum sample measurement from a finite set of sequential samples without explicitly testing them all. It is assumed that the process of sample measurement is distinct from collection and has higher costs. It is further assumed that the measurements have high positive autocorrelation.A methodology is presented based on a common industrial testing procedure referred to as composite sampling-the physical pooling or compositing of a set of sequential samples before measurement. A method known as primary first order compositing (PFOC) was found to be superior to the traditional technique of random sampling, particularly if small composite sizes are utilized.

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This paper compares the efficiencies of two sampling techniques for estimating a population mean and variance. One procedure, called grab sampling, consists of collecting and analyzing one sample per period. The second procedure, called composite sampling, collectsn samples per period which are then pooled and analyzed as a single sample. We review the well known fact that composite sampling provides a superior estimate of the mean. However, it is somewhat surprising that composite sampling does not always generate a more efficient estimate of the variance. For populations with platykurtic distributions, grab sampling gives a more efficient estimate of the variance, whereas composite sampling is better for leptokurtic distributions. These conditions on kurtosis can be related to peakedness and skewness. For example, a necessary condition for composite sampling to provide a more efficient estimate of the variance is that the population density function evaluated at the mean (i.e.f(µ)) be greater than[Formula: see text]. If[Formula: see text], then a grab sample is more efficient. In spite of this result, however, composite sampling does provide a smaller estimate of standard error than does grab sampling in the context of estimating population means.

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This paper makes an assessment of the impact of toxic chemical regulation in Canada. Ranges of costs and benefits, supplemented by survey information, analogous American data, interviews and case studies have been used to demonstrate the general usefulness of a cost-benefit framework for public sector decision-making even where information availability is constrained and complete analysis is not feasible. It is concluded that, with few exceptions, the impact of environmental regulation on chemical producers in Canada is neither excessive nor unduly onerous.

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This investigation is concerned with the development of a practical method for assessment of thought disorders. A review of eight major textbooks and four review articles revealed 37 different terms used to describe the components of thought disorders. Because of overlap of meanings or ambiguous usage, these terms were reduced to 17 discrete terms that could be operationally defined. Twenty-five psychiatrist were surveyed on the appropriateness of the definitions and their relevance to the concept of thought disorder. An average of 83 per cent agreement was obtained, and some of the definitions were modified as a result of the survey. Eight psychiatrists then applied this scale, titled the Thinking Dysfunction Rating Scale, to the evaluation of five videotaped patient interviews. Based on observation of all five patients, interjudge agreement was over 90 per cent for all items of the scale. Analysis of variance showed that the scale significantly discriminated among schizophrenics, patients with organic brain syndromes, psychotic depressives, geriatric depressives, and outpatients. The patterns of scores were found to vary among these five groups. The scale should be helpful for teaching purposes and as a checklist for routine clinical diagnosis.

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