Inquiry into diagnostic evidence supporting medical certifications of death

Evaluating the quality of evidence for diagnosing ischemic heart disease from verbal autopsy in Indonesia

BACKGROUND

Mortality and cause of death data are fundamental to health policy development. Civil Registration and Vital Statistics systems are the ideal data source, but the system is still under development in Indonesia. A national Sample Registration System (SRS) has provided nationally representative mortality data from 128 sub-districts since 2014. Verbal autopsy (VA) is used in the SRS to obtain causes of death. The quality of VA data must be evaluated as part of the SRS data quality assessment.

AIM

To assess the strength of evidence used in the assignment of Ischaemic Heart Disease (IHD) as causes of death from VA.

METHODS

The sample frame for this study is the 4,070 deaths that had IHD assigned as the underlying cause in the SRS 2016 database. From these, 400 cases were randomly selected. A data extraction form and data entry template were designed to collect relevant data about IHD from VA questionnaires. A standardised categorisation was designed to assess the strength of evidence used to infer IHD as a cause of death. A pilot test of 50 cases was carried out. IBM SPSS software was used in this study.

RESULTS

Strong evidence of IHD as a cause of death was assigned based on surgery for coronary heart disease, chest pain and two out of: sudden death, history of heart disease, medical diagnosis of heart disease, or terminal shortness of breath. More than half (53%) of the questionnaires contained strong evidence. For deaths outside health facilities, VA questionnaires for male deaths contained acceptable evidence in significantly higher proportions as compared to those for female deaths. (P < 0.001). Nearly half of all IHD deaths were concentrated in the 50-69 year age group (48.40%), and a further 36.10% were aged 70 years or more. Nearly two-thirds of the deceased were male (58.40%). Smoking behaviour was found in 44.11% of IHD deaths, but this figure was 73.82% among males.

CONCLUSION

More than half of the VA questionnaires from the study sample were found to contain strong evidence to infer IHD as the cause of death. Results from medical records such as electrocardiograms, coronary angiographies, and load tests could have improved the strength of evidence and contributed to IHD cause of death diagnosis.

Validation of verbal autopsy methods using hospital medical records: a case study in Vietnam

BACKGROUND

Information on causes of death (COD) is crucial for measuring the health outcomes of populations and progress towards the Sustainable Development Goals. In many countries such as Vietnam where the civil registration and vital statistics (CRVS) system is dysfunctional, information on vital events will continue to rely on verbal autopsy (VA) methods. This study assesses the validity of VA methods used in Vietnam, and provides recommendations on methods for implementing VA validation studies in Vietnam.

METHODS

This validation study was conducted on a sample of 670 deaths from a recent VA study in Quang Ninh province. The study covered 116 cases from this sample, which met three inclusion criteria: a) the death occurred within 30 days of discharge after last hospitalisation, and b) medical records (MRs) for the deceased were available from respective hospitals, and c) the medical record mentioned that the patient was terminally ill at discharge. For each death, the underlying cause of death (UCOD) identified from MRs was compared to the UCOD from VA. The validity of VA diagnoses for major causes of death was measured using sensitivity, specificity and positive predictive value (PPV).

RESULTS

The sensitivity of VA was at least 75% in identifying some leading CODs such as stroke, road traffic accidents and several site-specific cancers. However, sensitivity was less than 50% for other important causes including ischemic heart disease, chronic obstructive pulmonary diseases, and diabetes. Overall, there was 57% agreement between UCOD from VA and MR, which increased to 76% when multiple causes from VA were compared to UCOD from MR.

CONCLUSIONS

Our findings suggest that VA is a valid method to ascertain UCOD in contexts such as Vietnam. Furthermore, within cultural contexts in which patients prefer to die at home instead of a healthcare facility, using the available MRs as the gold standard may be meaningful to the extent that recall bias from the interval between last hospital discharge and death can be minimized. Therefore, future studies should evaluate validity of MRs as a gold standard for VA studies in contexts similar to the Vietnamese context.

Contributions of risk factors and medical care to cardiovascular mortality trends

Ischaemic heart disease, stroke, and other cardiovascular diseases (CVDs) lead to 17.5 million deaths worldwide per year. Taking into account population ageing, CVD death rates are decreasing steadily both in regions with reliable trend data and globally. The declines in high-income countries and some Latin American countries have been ongoing for decades without slowing. These positive trends have broadly coincided with, and benefited from, declines in smoking and physiological risk factors, such as blood pressure and serum cholesterol levels. These declines have also coincided with, and benefited from, improvements in medical care, including primary prevention, diagnosis, and treatment of acute CVDs, as well as post-hospital care, especially in the past 40 years. These variables, however, explain neither why the decline began when it did, nor the similarities and differences in the start time and rate of the decline between countries and sexes. In Russia and some other former Soviet countries, changes in volume and patterns of alcohol consumption have caused sharp rises in CVD mortality since the early 1990s. An important challenge in reaching firm conclusions about the drivers of these remarkable international trends is the paucity of time-trend data on CVD incidence, risk factors throughout the life-course, and clinical care.

Validation of cause-of-death statistics in urban China

BACKGROUND

National vital registration systems are the principal source of cause specific mortality statistics, and require periodic validation to guide use of their outputs for health policy and programme purposes, and epidemiological research. We report results from a validation of cause of death statistics from health facilities in urban China.

METHODS

2917 deaths from health facilities located in six cities in China constituted the study sample. A reference diagnosis of the underlying cause was derived for each death, based on expert review of available medical records, and compared with that filed at registration. Sensitivity, specificity and positive predictive value were computed for specific causes/cause categories according to the International Classification of Diseases (ICD), including analyses based on quality of evidence scores for each cause. Patterns of misclassification by the registration system were studied for individual causes of death.

RESULTS

The registration system had good sensitivity in diagnosing cerebrovascular disease and several site specific cancers (lung, liver, stomach, colorectal, breast and pancreas). Sensitivity was average (50-75%) for some major causes of adult death in China, namely ischaemic heart disease (IHD), chronic obstructive lung disease (COPD), diabetes, and liver and kidney diseases, with compensatory misclassification patterns observed between several of them. Sensitivity was particularly low for hypertensive disease.

CONCLUSIONS

Although diagnostic misclassification is not uncommon in urban death registration data, they appear to balance each other at the population level. Compensating misclassification errors suggest that caution is required when drawing conclusions about particular chronic causes of adult death in China. Investment is required to improve the quality of cause attribution for health facility deaths, and to assess the validity of cause attribution for home deaths. Periodic assessments of the quality of cause of death statistics will enhance their usability for health policy and epidemiological research.

The necessary role of the autopsy in cardiovascular epidemiology

The autopsy rate in the United States today is remarkably low, with proportionally fewer autopsies for natural causes of death. Consequently, most cardiovascular epidemiology studies do not use autopsy data and rely on death certificates, medical records, questionnaires, and family interviews as sources of mortality information. These practices introduce a high degree of variability and uncertainty regarding cause of death. This review illustrates the necessity for increased use of autopsies in cardiovascular epidemiology by critically evaluating other measures of cardiovascular disease (CVD) incidence. We evaluated the literature regarding CVD as cause of death and conducted discussions with cardiologists, pathologists, and epidemiologists. No attempt was made for meta-analysis. This review shows the limited reliability of death certificates, medical records, and interviews as sources of mortality statistics. In addition, the autopsy's role in clearly indicating the presence of CVD is illustrated. The autopsy used in conjunction with medical records is the only reliable means for establishing cause of death from CVD. There is an urgent need to reassess the current dependence of statistical mortality data on death certificates and other inadequate sources of CVD incidence. Death certificates, in general, are inadequately monitored for quality control and appropriate administrative oversight. With an increase in the number of hospitals performing no autopsies to investigate cause of death, a uniform national autopsy database is needed.

[Historical cohort study in the German rubber industry: goals, study design and data collection]

A historical cohort study is carried out to investigate occupational hazards in the German rubber industry since 1991. We present and discuss the study objectives and study design features such as cohort definition, assessment of occupational exposure and selection of the reference population. Cohort enumeration, assessment of vital status and cause of death ascertainment are described. With approximately 2,800 deaths throughout the observation period 1981 to 1991 it will be possible also to study the occupational etiology of rare diseases.

Use of multiple causes of death in the analysis of occupational cohorts--an example from the oil industry

OBJECTIVES

To examine the efficacy of routine examination of multiple causes of death occurring on death certificates in cohort studies, with an example from the oil industry.

METHODS

The underlying and multiple causes were coded for all notified deaths from a cohort of 35,000 men employed at eight oil refineries in the United Kingdom. Matrices of the frequencies of underlying causes by contributory causes were analysed for the total population and by subgroups defined by refinery, occupation, age, and calendar period of death.

RESULTS

Over 75% of the 10,128 certificates had two or more causes but this varied by disease. Many ratios of mentions of total to underlying causes were similar to those of England and Wales. Ratios for cancer of the larynx and pneumonia were lower, indicating possible over-reporting of these diseases as the underlying cause. Investigation of an excess of pneumonia deaths at one refinery indicated possible miscoding of the underlying cause or the wrong position of pneumonia on some certificates, particularly in combination with malignancy and stroke.

CONCLUSIONS

Routine analysis of multiple causes of death can provide useful additional information in cohort studies.

Arsenic in drinking water and mortality from vascular disease: an ecologic analysis in 30 counties in the United States

Chronic arsenic consumption can cause vascular diseases. Adverse vascular effects of arsenic in drinking water in the United States have not been studied. This study investigated the ecological relationship between the population-weighted mean arsenic concentration in public drinking water supplies and mortality from circulatory diseases in 30 U.S. counties from 1968 to 1984. Mean arsenic levels ranged from 5.4 to 91.5 micrograms/l. Standardized mortality ratios (SMRs) for diseases of arteries, arterioles, and capillaries (DAAC) (ICD 8th/9th revision, 440-448) for counties exceeding 20 micrograms/l were 1.9 (90% confidence interval [CI] = 1.7-2.1) for females and 1.6 (90% CI = 1.5-1.8) for males. The SMRs for the three subgroups of DAAC--arteriosclerosis, aortic aneurysm, and all other DAAC--tended to be elevated. With respect to the same arsenic group, the SMRs for congenital anomalies of the heart (ICD-8/9, 746/745-746) and circulatory system (ICD-8/9, 747) also tended to be elevated. Two competing interpretations emerge as possibilities: either there are spurious associations resulting from invalid outcome data or causal associations.

Mortality among female registered nurses and school teachers in British Columbia

The mortality profile of female nurses and teachers in British Columbia (BC) was examined using age-standardized proportional mortality ratios (PMRs) calculated for the period 1950-1984. Lowered overall mortality among nurses was seen for degenerative heart disease and for cerebrovascular accidents. Significantly elevated PMR values were observed for cancer of the breast and ovary in nurses of age 20-65 years. PMRs were significantly elevated for cancer of the pancreas and leukemia among those age 20 years and older. Elevated values were also observed for motor vehicle accidents and suicide among nurses in both age groups. Lower than expected mortality from degenerative heart disease and cerebrovascular accidents was seen in working age teachers (age 20-65 years). However, elevated PMRs were detected for carcinoma of the colon, breast, endometrium, brain, and melanoma. Among those 20 years and over, significantly elevated PMRs were also observed for cancers of the ovary and other digestive organs. Elevated PMRs were found for motor vehicle and aircraft accidents. Mortality from cirrhosis of the liver was lower than anticipated in both teachers and nurses. A number of significant PMRs declined when deaths of "homemakers" were withdrawn from the comparison group used to generate PMR values, suggesting that risk of death from various causes among women working outside the home differ from those seen in women who are predominantly in the home.

Cause-specific mortality: understanding uncertain tips of the disease iceberg

STUDY OBJECTIVE

To determine the extent to which individual diseases, when recorded as being present shortly before death, were certified as causes of death.

DESIGN

Retrospective cohort study in which the "subjects" were computerised linked records.

SETTING

Six districts in the Oxford Regional Health Authority area (covering a population of 1.9 million people).

SUBJECTS

Linked abstracts of hospital records and death certificates for people who died within four weeks and, for some diseases, within one year of hospital admission.

MAIN OUTCOME MEASURES

The percentage of people with each disease for whom the disease was recorded as the underlying cause of death, was recorded elsewhere on the death certificate, or was not certified as a cause of death at all.

RESULTS

Three broad patterns of certification are distinguished. Firstly, there were diseases that were usually recorded on death certificates when death occurred within four weeks of hospital care of them. Examples included lung cancer (on 91% of such death certificates), breast cancer (92%), leukaemia and lymphoma (90%), anterior horn cell disease (89%), multiple sclerosis (89%), myocardial infarction (90%), stroke (93%), aortic aneurysm (87%), and spina bifida (89%). These diseases were also usually certified as the underlying cause of death. Secondly, there were diseases which, when present within four weeks of death, were commonly recorded on death certificates but often not as the underlying cause of death. Examples included tuberculosis (on 76% of such certificates; underlying cause on 54%), thyroid disease (49%; 21%), diabetes mellitus (69%; 30%) and hypertension (43%; 22%). Thirdly, there were conditions which, when death occurred within four weeks of their treatment, were recorded on the death certificate in a minority of cases only. Examples of these included fractured neck of femur (on 25% of such certificates), asthma (37%), and anaemia (22%). Not surprisingly, there was "convergence" in certification practice towards the common cardiovascular and respiratory causes of death. There was also evidence that conditions regarded as avoidable causes of death may not have been certified when present at death in some patients.

CONCLUSION

When uses are made of mortality statistics alone, it is important to know which category of certification practice the disease of interest is likely to be in. Linkage between morbidity and mortality records, and multiple cause analysis of mortality, would considerably improve the ability to quantify mortality associated with individual diseases.

[Analysis of the reliability of the declaration of cancer as the basic cause of death in Salvador, Brazil]

The accuracy of the cancer mortality figures was determined by comparing the underlying causes of death as coded on death certificates with pathology reports and hospital diagnoses of a sample of 966 deaths of the total deaths occurring in Salvador during 1983. The death certificates were found to be accurate in 65% of 485 cancer deaths studied. Thirty-five histologically confirmed cancer deaths were found in a random sample of 481 deaths from other causes (460 stating other causes and 21 stating cancer sites that were not under study). This means that, approximately 700 more cancer deaths may be hidden among the remaining 10,098 death certificates.

Review of the validity of national coronary heart disease mortality rates

Epidemiologic studies of coronary heart disease are heavily dependent on national mortality rates. The diagnostic error for the coronary heart disease is substantial but unquantifiable and is conservatively at least +/- 30%. When this error is superimposed on innumerable errors and omissions in the compilation of monocausal mortality rates, the reliability of such vital statistics currently precludes their use for scientific purposes.

Estimating cancer mortality rates from SEER incidence and survival data

A method to estimate site-specific cancer mortality rates using Surveillance, Epidemiology, and End Results (SEER) Program incidence and survival data is proposed, calculated, and validated. This measure, the life table-derived mortality rate (LTM), is the sum of the product of the probability of being alive at the beginning of an interval times the probability of dying of the cancer of interest during the interval times the annual age-adjusted incidence rate for each year that data have been collected. When the LTM is compared to death certificate mortality rates (DCM) for organ sites with no known misclassification problems, the LTM was within 10 percent of the death certificate rates for 13 of 14 organ sites. In the sites that have problems with the death certificate rates, there were major disagreements between the LTM and DCM. The LTM was systematically lower than the DCM for sites if there was overreporting on the death certificates, and the LTM was higher than the DCM for sites if there was underreporting. The limitations and applications of the LTM are detailed.

Does screening for cervical cancer affect incidence and mortality trends? The Belgian experience

Age-specific mortality and morbidity for cervical cancer from 1956 to 1985 in Belgium show a slight decline for women aged 35-54, and a constant rate for other age groups. Population screening as done in Belgium between 1965 and 1980 failed to have any impact on these trends, which could be due to poor organization of screening or changing risk factors for cervical cancer in the population.

Dietary vitamin A and lung cancer: results of a case-control study among chemical workers

A nested case-control study conducted among a cohort of chemical manufacturing employees provided an opportunity to test the hypothesis that lung cancer risk is inversely related to dietary intake of vitamin A. Eligible for study were 308 former male employees who had died of lung cancer between 1940 and 1980. Two control groups, one a decedent and the other a "living" series, were individually matched to the cases one-for-one. Interviews were completed with 734 subjects or their next-of-kin and included a food frequency list. A vitamin A index was developed for each subject based on the frequency of consumption of 29 food items. After adjustment for a number of potentially confounding variables (e.g., smoking, educational level, and use of vitamin supplements), there was evidence that vitamin A intake was inversely associated with lung cancer risk. The effect was most pronounced in the comparisons with the "living" controls and appeared strongest among cigarette smokers. Subjects in the lowest tertile of vitamin A intake had approximately twice the risk of lung cancer as those in the highest. Analyses of an index of carotenoids and of individual food items suggested that plant sources of vitamin A may play a more important role in producing the effect than do animal sources.

Reliability of death certifications for different types of cancer. An autopsy survey

A series of 1000 cases was selected, on the basis of a clinical and/or post-mortem diagnosis of cancer, out of 4927 autopsies performed at the Institute of Pathologic Anatomy and Histopathology of Turin University. The comparison between clinical and post-mortem diagnoses pointed to an overall concordance with regard to the correct identification of a malignancy as the underlying cause of death of 75%; if the correct identification of type and primary site of the tumor was also taken into account, the concordance was only 56%. The rate of false-positive and false-negative diagnoses, the confirmation rate and sensitivity index of clinical diagnoses, and the error of estimate of the overall frequency of the different types of tumors were computed. Pancreas, liver and biliary tract tumors appear to be the most difficult to identify correctly during life; also lung, stomach and colorectal cancers, lymphomas and leukemias show fairly high rate of clinical errors. Breast cancer, tumors of the nervous system and colorectal cancers appear to be overnotified. These results seem to underscore the necessity of being very careful in drawing conclusions on the frequency and distribution of the different types of cancer on the basis of current mortality statistics.

The use of epidemiology, scientific data, and regulatory authority to determine risk factors in cancers of some organs of the digestive system. 5. Stomach cancer

In 1930, stomach cancer was the leading cause of death due to cancer among men in the United States. Among women it was the third leading cause of cancer deaths. Although it is well known that death rates for stomach cancer have diminished dramatically over the past 50 years, stomach cancer still has the third poorest 5-year relative survival rate of the different cancers, after pancreatic and lung cancer. Most evidence indicates that environmental factors play an important role in the development of stomach cancer. The remarkable decrease in stomach cancer mortality over the past 50 years and the results of a variety of migrant studies support this review. Several published case-control studies have shown positive associations with preserved meat and salted and pickled food in general. However, there are negative associations with vegetables, fruits and milk; vitamin C is implicated. Milk has both positive and negative associations. This points to the possibility of a carcinogen produced by traditional preservation methods such as salting and suggests that fresh vegetables and fruits and high intakes of vitamin C may reduce the risk. What specific role/s the diet plays in the incidence of stomach cancer remains to be seen. There is a need to elaborate the relationship of such factors as age, sex, migration, geography, environmental factors, and diet to the carcinogenic process that produces cancer of the stomach.

Health of the Chinese elderly in America

This article examines the mortality and morbidity patterns of Chinese elderly in America by using two established data sources: (1) the most recent vital statistics maintained by the National Center for Health Statistics, and (2) the cancer registry program called SEER (Surveillance, Epidemiology, and End Results) maintained by the National Cancer Institute at the National Institute of Health. The results suggest that Chinese Americans are relatively healthier than white Americans, the average age-adjusted death rate being lower for Chinese than for white Americans. Likewise, the age-specific death rates for all causes of death are lower for Chinese than for the majority white population. Details of statistics on rates of suicide, heart disease, neoplasms, and various forms of cancer are presented.

Exercise in coronary heart disease

Population levels of habitual activity have probably contributed to both the recent epidemic of cardiovascular disease and its waning. Evidence supporting the exercise hypothesis can be drawn from comparisons of individuals with differing levels of occupational and leisure activity. Both suggest that regular, endurance-type activity may halve the incidence of cardiac morbidity and mortality. This is an important prophylactic benefit, although Bradford Hill's criteria of a causal association have yet to be fully satisfied. Following the onset of clinical disease, both uncontrolled and randomised controlled trials suggest that progressive exercise rehabilitation improves prognosis by a useful 20 to 30%, but formal statistical proof is again difficult for technical reasons. Although over-enthusiastic vigorous physical activity can cause an immediate rise of cardiovascular events, this disadvantage is substantially outweighed by long term gains from regular physical activity. Classical epidemiology has proven its case by the experimental step of removing exposure to the causal agent. It is difficult to carry out such an analysis linking physical activity with the recent epidemic of ischaemic heart disease, although the recent waning of the disease may be attributed in part to an increase of habitual physical activity in many western nations. Evidence linking exercise to the prevention of clinical disease ('secondary prevention') is derived from large scale surveys of groups with supposed differences in occupational activity, athletic participation, active leisure pursuits or overall lifestyle. The majority of occupational comparisons have shown advantages to active workers in terms of deaths from cardiac disease, sudden death, cardiac morbidity, ECG abnormalities, and cardiac abnormalities at postmortem. However, concerns have been raised with regard to the accuracy of job classification, the intensity of occupational activity relative to active leisure, the adequacy of disease classification, and confounding influences due to differences of social class, stress and potential alienation. Studies comparing athletes and non-athletes have been faulted on grounds of initial selection for sport by body-build and uncertainties regarding continuing differences of endurance activity between recognised university athletes and their classmates. In general, no advantage of life expectancy has been seen in athletes, Karvonen and associates reported a 4 to 5 year advantage of longevity in Finnish cross-country skiing champions, although this might be attributable to other facets of their lifestyle.(ABSTRACT TRUNCATED AT 400 WORDS)

Disease competition as a factor in ecological studies of mortality: the case of urban centers

Disease competition is a condition in which death rates are not what would be expected from the combination of etiological factors present in a region. Four types of disease competition are described: error; dominant occupational-lifestyle etiology leading to dominant diseases; dominant lifestyle with a variety of disease outcomes; and protective effect. Three clues that disease competition exists are discussed. In order to assess the importance of disease competition, an analysis was made of the geographical distribution of male white mortality from 23 causes in the 73 most populous counties in the United States. The results showed evidence only of the dominant lifestyle type.

Making sense of mortality

This paper focuses upon the collection and processing of government mortality statistics, and especially upon the organisational and theoretical contexts within which such statistics are assembled. Two items of mortality data in particular are examined with a view to illustrating the broader issues: medical cause of death, and social class of deceased. Using a 10 per cent sample of 1981 Belfast death certificates as a base, the paper attempts to trace the specific stages through which the cause of death and social class data have to pass prior to their incorporation into mortality reports. The paper indicates that there are numerous grounds for believing that both kinds of data are flawed at their points of origin, and that the transformations which the data undergo during coding procedures leads to further distortions of our image of mortality and its social base. It is argued that these flaws and distortions are only partly due to technical and organisational shortcomings, and more likely due to weaknesses in the theoretical frameworks through which the data are sifted. The paper concludes by suggesting that the existing arrangements for registering deaths, dominated as they are by the principles of forensic medicine, are more properly viewed as a system for policing the dead, than as a mechanism for generating worthwhile data about diseases and their social distribution.

Validity of cause of death statements from relatives

In countries where death certificates are inaccessible for various reasons, cause of death statements made by relatives may gain greater importance. The validity of the cause of death of a deceased family member as stated by relatives compared to the underlying cause as stated on the death certificate has been examined in 310 cases. The sensitivity and the rate of confirmation are highest for neoplasms (both 89.6%). For cardiovascular diseases, the sensitivity (70%) is lower than the rate of confirmation (90%), indicating a certain amount of underreporting. The sensitivity is found to be lowest (50%) for diseases of the respiratory system. Violent deaths, on the other hand, were detected in 93.7%, although confirmed for only 75%. Closer relatives were able to report the cause of death more accurately. The time elapsed since the death of the family member, however, did not affect the recall of the relative. The concrete additional information from relatives, especially for cancer cases, is recommended in the absence of other data sources.

Multiple myeloma, leukemia, and cancer of the ovary in cosmetologists and hairdressers

In order to evaluate occupational mortality, age standardized proportional mortality ratios (PMR) were calculated for 160 female cosmetologists and hairdressers and 1,001 male barbers and hairdressers utilizing cause of death and occupation statements from British Columbia death registrations collected from 1950 to 1978. Female cosmetologists had elevated risks of death from multiple myeloma (PMR = 619, p = .03) and ovarian cancer (PMR = 204, p = .09). Male barbers and hairdressers had no corresponding elevated risk of myeloma but had a significantly high risk of death from leukemia (PMR = 188, p = .05). Further detailed studies of these occupations would be worthwhile to confirm and extend these findings.

Cancer mortality in metal workers

Age-standardized proportional mortality ratios (PMRs) were calculated for 10 036 metal workers in British Columbia with the use of information on cause of death and occupation recorded in death registrations from 1950 to 1978. Metal workers were found to have a significantly increased risk of death from lung cancer (PMR = 134). In addition, certain occupational groups of metal workers were found, for the first time, to be at increased risk of death from other types of cancer; these included leukemia (PMR = 356) and cancer of the rectum (PMR = 248) in metal mill workers, Hodgkin's disease in welders (PMR = 242) and multiple myeloma in machinists (PMR = 209).

Urbanization and cancer: changing mortality patterns?

"Analysis of the relationship between cancer rates and urbanization for United States counties for the period 1950-54 reveals the expected urban/rural differences for many digestive, urinary and respiratory organ cancers and for female breast cancer. Similar urban/rural differences existed in many other Western countries. By 1970-75, however, urban/rural differences in the United States had substantially narrowed." It is noted that "available data do not allow formal tests of the relationship between these changes and specific etiological factors, but the data suggest that the spatial convergence is related to the changing geography of such risk factors as smoking, alcohol consumption, manufacturing, and socioeconomic status and to the diminished size and role of the white foreign-born population, as well as to such confounding factors as medical practices and population migration."

[Quality of statistics on causes of death: current problems and perspectives]

Statistics of causes of death remain an important source of epidemiological data for the evaluation of various medical and health problems. The improvement of analytical techniques and, above all, the transformation of demographic and morbid structures of populations have prompted researchers in the field to give more importance to the quality of death certificates. After describing the data collection system presently used in Switzerland, the paper discusses various indirect estimations of the quality of Swiss data and reviews the corresponding international literature.

Coronary artery disease mortality in relatives of hypertriglyceridemic school children: the Muscatine study

From 2655 healthy school children participating in the 1973 and 1975 Muscatine Coronary Risk Factor School surveys, two groups of index cases were selected for a detailed family study of coronary mortality: a group with fasting triglyceride levels greater than the ninetieth percentile on both surveys (n = 75) and a group with triglyceride levels less than the tenth percentile on both surveys (n = 47). Coronary mortality in adult (age 30 years or older) first- and second-degree relatives was not different between the two groups. When the families of the high-triglyceride group was further subdivided based on the cholesterol percentile of the index child, greater coronary mortality was observed in the relatives of index cases with high cholesterol (higher than the seventy-fifth percentile). This study suggests that family members of children with elevated triglyceride and low cholesterol levels do not have excess coronary mortality.

A multiple cause of death analysis of hypertension-related mortality in North Carolina, 1968-1977

In this paper, records of all medical conditions on death certificates are used to evaluate hypertension-related mortality in North Carolina over the decade 1968-1977. Use of both an inclusive hypertension recode category and multiple cause data resulted in gains in information of over 750 per cent in all four race/sex groups compared to the commonly used underlying cause, hypertensive disease category. Race, sex and age specific 10-year trends in death rates for all mentions of hypertension are analyzed, with comparisons to underlying cause mortality from ischemic heart disease and stroke. Age-adjusted declines of 19 to 24 per cent between 1968 and 1977 were observed for all race/sex groups, although non-White declines occurred mainly at younger ages while White declines (especially White males) occurred mainly at older ages. The non-White excess of hypertension mentions (compared to Whites) increased for males and decreased for females. The decline in hypertension mentions, in spite of the increased awareness of hypertension as a public health problem which would make it more likely to be mentioned on death certificates, suggests that there was a real reduction in the contribution of hypertension to total mortality over the period.

A Note on the Changing Geography of Cancer Mortality within Metropolitan Regions of the United States

An investigation made of the geography of cancer mortality rates within the most populous metropolitan regions of the United States and the New Jersey-New York-Philadelphia metropolitan corridor shows that during the early 1950s, as expected, central city counties had substantially higher cancer mortality rates, especially respiratory and digestive, than did suburbs. Two decades later, differences between the central cities and the suburbs had narrowed and sometimes disappeared.

A note on the changing geography of cancer mortality within metropolitan regions of the United States

An investigation made of the geography of cancer mortality rates within the most populous metropolitan regions of the United States and the New Jersey-New York-Philadelphia metropolitan corridor shows that during the early 1950s, as expected, central city counties has substantially higher cancer mortality rates, especially respiratory and digestive, than did suburbs. Two decades later, differences between the central cities and the suburbs had narrowed and sometimes disappeared.

Accuracy of cancer death certificates and its effect on cancer mortality statistics

A study to determine the accuracy of cancer mortality data was done using cancer deaths occurring during 1970 and 1971 in eight of the nine areas included in the Third National Cancer Survey (TNCS). Death certificates with an underlying cause of death of cancer were compared to the hospital diagnosis for 48,826 resident cases of single primary cancers. The underlying cause of death as coded on the death certificate was found to be accurate for about 65 per cent of the cancer deaths in this study. Misclassification problems occurred for colorectal cancer, the second leading cause of death from cancer. Colon cancer was overreported and rectal cancer was under-reported on death certificates. Other misclassification problems were found for cancers of the uterus, brain, and buccal cavity including most of its sub-sites. Physicians tended to report a non-specific site of cancer on the death certificate rather than the specific site identified by the hospital diagnosis.

Respiratory disease mortality in New Mexico's American Indians and Hispanics

To determine the effect of ethnic group on respiratory disease occurrence, average annual sex, ethnic, and disease specific mortality rates for the period of 1969 to 1977 were calculated for New Mexico's American Indian, Hispanic, and Anglo populations. Incidence data were available for respiratory tract cancer. This study corroborates previous findings of reduced mortality from lung cancer in American Indians of both sexes and in Hispanic males. American Indian mortality from tuberculosis and from influenza and pneumonia was high. Hispanic males and American Indians of both sexes showed low mortality rates for chronic obstructive pulmonary disease (COPD). Differing cigarette usage is the most obvious explanation for the variations in COPD and lung cancer occurrence with ethnic group.

Childhood leukemias associated with fallout from nuclear testing

Continuing concern over the possible carcinogenic effects of low-level radiation prompted us to study the population of Utah because of its exposure to fallout from 26 nuclear tests between 1951 and 1958. Certain rural counties (high-fallout counties) received most of the fallout during that period. We reviewed all deaths from childhood (under 15 years of age) cancers occurring in the entire state between 1944 and 1975 and assigned them to a cohort of either high or low exposure, depending on whether 15 between 1951 and 1958. For reasons unknown, leukemia mortality among the low-exposure cohort in the high-fallout counties was about half that of the United States and the remainder of the state. Mortality increased by 2.44 times (95 per cent confidence, 1.18 to 5.02) to just slightly above that of the United States in the high-exposure cohort residing in the high-fallout counties, and was greatest in 10- to 14-year-old children. For other childhood cancers, no consistent pattern was found in relation to fallout exposure. The increase in leukemia deaths could be due to fallout or to some other unexplained factor.

Increased coronary mortality in relatives of hypercholesterolemic school children: the Muscatine study

From 2,874 school children participating in the 1971 and 1973 Muscatine Coronary Risk Factor Survey, we selected three groups of index cases for detailed family study: the HIGH group (n = 56), with cholesterol levels greater than the 95th percentile twice; the MIDDLE group (n = 46), cholesterol levels between the 5th and 95th percentile; and the LOW group (n = 46), cholesterol levels less than the 5th percentile twice. Coronary mortality determined from death certificates was increased in the young relatives (ages 30-59) of the HIGH group index cases, as follows: twofold excess in HIGH male relatives compared with the MIDDLE or LOW group (p less than 0.05); tenfold excess in the HIGH female relatives compared with the MIDDLE and LOW group combined (p less than 0.01). After correction for years at risk, there was an approximately twofold significantly-increased coronary mortality. Stroke mortality was higher, although not significantly, in the older relatives (ages greater than or equal to 60) of the HIGH index cases. Cancer mortality was not significantly different among the relatives of the three groups of index cases. This study indicates that school children's cholesterol levels cluster with those of their family members and that persistent hypercholesterolemia in children identifies families at risk for coronary artery disease.

[Mortality and incidence of malignant tumors in the Canton of Zürich]

Cancer mortality data of Switzerland and of the Canton of Zurich are being compared for the years 1969-1972. The pattern of distribution of the five most frequent cancer sites in Zurich compared to Switzerland shows a clear trend towards the American situation: increase of cancer of the colon, pancreas and lung, decrease of cancer of the stomach and esophagus. Incidence data of the first year of registration of the Zurich Tumor Registry are being discussed.

[Analysis of mortality, based on basic cause of death and on multiple causes]

Foram comentados alguns aspectos das estatísticas de mortalidade por causas básicas e por causas múltiplas. Utilizando uma amostra de óbitos ocorridos em hospitais e obtendo informações adicionais através dos prontuários médicos, foram refeitos os atestados comparando-os com os originais. Foi verificado que a causa básica está declarada incorretamente em 37,7% dos casos e que existem discordâncias que se compensam. O número médio de diagnósticos por atestados de óbito foi de 1,9, elevando-se para 2,9 quando se dispõem de informações adicionais. O número médio de diagnósticos adicionais que acompanhou a causa básica aumentou quanto mais longa foi a evolução da doença básica. A codificação de causas múltiplas tem como vantagens o reconhecimento de freqüências de doenças que raramente são consideradas básicas e as estatísticas de mortalidade por causas múltiplas não são afetadas pelas mudanças das regras de seleção da causa de morte.

Relationship between ventricular premature contractions on routine electrocardiography and subsequent sudden death from coronary heart disease

The association between ventricular premature contractions (VPC) on routine ECG and sudden death (SD) from coronary heart disease (CHD) during an ll-year period was examined in a historic prospective study of 1,214 white male factory workers, ages 35-69, in Canton, North Carolina. Prevalence of VPC was 92 (6.7%) increasing from 2% to 15% with age. Sixty of the 118 deaths were ascribed to CHD, 38 (63.3%) with 24-hour SD, and 27 (45%) with 1-hour SD. The relative risk of 1-hour SD for those with VPC was not increased (0.9); the risk of 24-hour SD was increased only minimally (1.3). Within the age band 50-59, the relative risk of 24-hour sudden death was 2.4 but the presence of other electrocardiographic abnormality carried the same increased risk. For the Canton population, using VPC on routine ECG as predictor of sudden death yielded no advantage over other ECG abnormalities.

Yellow fever vaccination, avian leukosis virus, and cancer risk in man

Comparison was made between 2659 veterans who died of cancer, during 1950 to 1954 or 1959 to 1963, and matched controls, based on the frequency of yellow fever immunization during World War II. The vaccine was produced from chick embryos that almost certainly contained avian leukosis-sarcoma viruses. Among the veterans, no relation was found between vaccination and leukemia, lymphoma, or other cancer.