Peter N. Nemetz

Recent trends in the prevalence of coronary disease: a population-based autopsy study of nonnatural deaths.

BACKGROUND Despite increases in obesity and diabetes mellitus, mortality caused by coronary disease continues to decline. Recent trends in coronary disease prevalence are unknown. METHODS There were 3237 deaths among Olmsted County, Minnesota, residents aged 16 through 64 years during the 1981-2004 period. Of the 515 due to accident, suicide, homicide, or a manner that could not be determined, 425 individuals (82%) had coronary anatomy graded. Pathology reports were reviewed for the grade of coronary disease (range, 0-5) assigned each of 4 arteries: left anterior descending (LAD), left circumflex (LCx), right coronary artery (RCA), and left main artery (LMA). High-grade disease was defined as more than a 75% reduction in cross-sectional luminal area (grade >or=4) in any of LAD, LCx, or RCA or more than 50% reduction (grade >or=3) in LMA. Evidence of any disease was defined as a grade higher than 0 in any artery. Calendar-year trends were analyzed as linear and nonlinear functions. RESULTS Over the full period (1981-2004), 8.2% of the 425 individuals had high-grade disease, and 83% had evidence of any disease. Age- and sex-adjusted regression analyses revealed temporal declines over the full period (1981-2004) for high-grade disease, any disease, and grade of coronary disease. Declines in the grade of coronary disease ended after 1995 (P <or= .01 for every artery) and possibly reversed after 2000 (P = .06 for LCx). CONCLUSIONS Declines in coronary disease prevalence overall (during 1981-2004) reinforce arguments that any increased prevalence resulting from improved survival among persons with disease was offset by reductions in disease incidence. Study findings suggest that declines in coronary disease prevalence have ended. The question of whether recent trends are attributable to increasing obesity and diabetes mellitus awaits further investigation.

Mechanical trauma as a risk factor in classic amyotrophic lateral sclerosis: Lack of epidemiologic evidence

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.

An Anatomy of the Autopsy, Olmsted County, 1935 Through 1985

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.

Resurrecting the Autopsy: Benefits and Recommendations

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.

Referral to Autopsy: Effect of Antemortem Cardiovascular Disease: A Population-Based Study in Olmsted County, Minnesota

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.

Efficient search procedures for extreme pollutant values.

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.

Japan's Energy Strategy at the Crossroads

HE WORLD OF ENERGY POLICY is characterized by sharp discontinuil ties and high stakes. Responses to energy supply uncertainties and the quest for energy security vary among nations, reflecting the different decision-making systems, resource profiles, and the values and perceptions of the future which are dominant in a country at a particular time. Indeed, the energy strategies of Japan reflect its unique social decisionmaking system and position as a major actor in world energy markets, with few natural resources except for a large population and a system disciplined to pursue national economic security objectives. The importance of Japan in the energy sphere, however, is not limited to the effects of its own consumption upon short-term supply and demand for different fuels. Japan has successfully changed technologies, which, in turn, has affected world demand patterns for energy, and influenced the longer-term development of certain important global energy resources such as coal. The attributes of Japans energy strategies in the past two decades provide an interesting model of response to a turbulent, complex environment. The Japanese model masterfully blends aggressive and defensive tactics, harmonizes competition with cooperation, and combines a longer-term assessment of domestic and international events with flexibility and a sensitive response to the current environment. In this article we analyze the development of Japanese energy policy and attempt to predict Japans future actions to secure its energy supply.

Contributions of Increasing Obesity and Diabetes to Slowing Decline in Subclinical Coronary Artery Disease

Background Our previous study of nonelderly adult decedents with nonnatural (accident, suicide, or homicide) cause of death (96% autopsy rate) between 1981 and 2004 revealed that the decline in subclinical coronary artery disease (CAD) ended in the mid‐1990s. The present study investigated the contributions of trends in obesity and diabetes mellitus to patterns of subclinical CAD and explored whether the end of the decline in CAD persisted. Methods and Results We reviewed provider‐linked medical records for all residents of Olmsted County, Minnesota, who died from nonnatural causes within the age range of 16 to 64 years between 1981 and 2009 and who had CAD graded at autopsy. We estimated trends in CAD risk factors including age, sex, systolic blood pressure, diabetes (qualifying fasting glucose or medication), body mass index, smoking, and diagnosed hyperlipidemia. Using multiple regression, we tested for significant associations between trends in CAD risk factors and CAD grade and assessed the contribution of trends in diabetes and obesity to CAD trends. The 545 autopsied decedents with recorded CAD grade exhibited significant declines between 1981 and 2009 in systolic blood pressure and smoking and significant increases in blood pressure medication, diabetes, and body mass index ≥30 kg/m2. An overall decline in CAD grade between 1981 and 2009 was nonlinear and ended in 1994. Trends in obesity and diabetes contributed to the end of CAD decline. Conclusions Despite continued reductions in smoking and blood pressure values, the previously observed end to the decline in subclinical CAD among nonelderly adult decedents was apparent through 2009, corresponding with increasing obesity and diabetes in that population.

Estimating means and variances: The comparative efficiency of composite and grab samples.

AbstractThis 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