Organic solvents and presenile dementia: a case referent study using death certificates.

Occupational exposure to organic solvents has been implicated in the development of "presenile dementia" in several studies. The death certificates of all men aged under 65 dying in England and Wales bearing presenile dementia as cause of death were collected for the years 1970-9 (n = 557): control death certificates were obtained, matched for age and sex. No significant differences were found between the groups as regards estimated occupational exposure to either organic solvents or lead.     

Occupation and five cancers: a case-control study using death certificates

A case-control approach has been used to examine mortality from five cancers--oesophagus, pancreas, cutaneous melanoma, kidney, and brain--among young and middle aged men resident in three English counties. The areas studied were chosen because they include major centres of chemical manufacture. By combining data from 20 years it was possible to look at local industries with greater statistical power than is possible using routine national statistics. Each case was matched with up to four controls of similar age who died in the same year from other causes. The occupations and industries recorded on death certificates were coded to standard classifications and risk estimates derived for each job category. Where positive associations were found the records of the cases concerned were examined in greater detail to see whether the risk was limited to specific combinations of occupation and industry. The most interesting findings to emerge were risks of brain cancer associated with the production of meat and fish products (relative risk (RR) = 9.7, 95% confidence interval (CI) 2.6-36.8) and with mineral oil refining (RR = 2.9, CI 1.2-7.0), and a cluster of four deaths from melanoma among refinery workers (RR = 16.0, CI CI 1.8-143.2). A job-exposure matrix was applied to the data but gave no strong indications of further disease associations. Local analyses of occupational mortality such as this can usefully supplement national statistics.     

Occupation and five cancers: a case-control study using death certificates.

A case-control approach has been used to examine mortality from five cancers--oesophagus, pancreas, cutaneous melanoma, kidney, and brain--among young and middle aged men resident in three English counties. The areas studied were chosen because they include major centres of chemical manufacture. By combining data from 20 years it was possible to look at local industries with greater statistical power than is possible using routine national statistics. Each case was matched with up to four controls of similar age who died in the same year from other causes. The occupations and industries recorded on death certificates were coded to standard classifications and risk estimates derived for each job category. Where positive associations were found the records of the cases concerned were examined in greater detail to see whether the risk was limited to specific combinations of occupation and industry. The most interesting findings to emerge were risks of brain cancer associated with the production of meat and fish products (relative risk (RR) = 9.7, 95% confidence interval (CI) 2.6-36.8) and with mineral oil refining (RR = 2.9, CI 1.2-7.0), and a cluster of four deaths from melanoma among refinery workers (RR = 16.0, CI CI 1.8-143.2). A job-exposure matrix was applied to the data but gave no strong indications of further disease associations. Local analyses of occupational mortality such as this can usefully supplement national statistics.     

Renal disease and occupational exposure to organic solvents: a case referent approach

Several recent studies have suggested that a relation may exist between exposure to occupational organic solvents and diseases of the kidney--particularly malignancy and glomerulonephritis. Two case referent studies were undertaken in the West Midlands to investigate these possibilities. In the case of renal cancer 54 live cases of biopsy proved adenocarcinoma of the kidney were compared with an equal number of community based healthy referents matched for age, sex, place of residence, and socioeconomic and ethnic grouping. For glomerulonephritis, 50 biopsy proved cases were matched in the same manner with 50 referents. Fourteen other patients were also reviewed who, on biopsy, proved not to have glomerulonephritis. For both sets of cases and their referents each individual was interviewed and a detailed account obtained of medical history and environmental exposures. Exposure to solvents was assessed independently and "blind" in a semiquantitative way by an experienced occupational hygienist. Past exposure was estimated for 10 different solvent types and 17 material types. No relation was found between exposure to solvents and renal cancer or glomerulonephritis. In the case of renal cancer the numbers studied only precluded a fourfold excess risk. For glomerulonephritis, the study, although methodologically superior to most other published studies and of similar size, was of similar power to the renal cancer investigation.     

Renal disease and occupational exposure to organic solvents: a case referent approach.

Several recent studies have suggested that a relation may exist between exposure to occupational organic solvents and diseases of the kidney--particularly malignancy and glomerulonephritis. Two case referent studies were undertaken in the West Midlands to investigate these possibilities. In the case of renal cancer 54 live cases of biopsy proved adenocarcinoma of the kidney were compared with an equal number of community based healthy referents matched for age, sex, place of residence, and socioeconomic and ethnic grouping. For glomerulonephritis, 50 biopsy proved cases were matched in the same manner with 50 referents. Fourteen other patients were also reviewed who, on biopsy, proved not to have glomerulonephritis. For both sets of cases and their referents each individual was interviewed and a detailed account obtained of medical history and environmental exposures. Exposure to solvents was assessed independently and "blind" in a semiquantitative way by an experienced occupational hygienist. Past exposure was estimated for 10 different solvent types and 17 material types. No relation was found between exposure to solvents and renal cancer or glomerulonephritis. In the case of renal cancer the numbers studied only precluded a fourfold excess risk. For glomerulonephritis, the study, although methodologically superior to most other published studies and of similar size, was of similar power to the renal cancer investigation.     

Using death certificates and medical examiner records for adolescent occupational fatality surveillance and research: a case study

Death certificates and medical examiner records have been useful yet imperfect data sources for work-related fatality research and surveillance among adult workers. It is unclear whether this holds for work-related fatalities among adolescent workers who suffer unique detection challenges in part because they are not often thought of as workers. This study investigated the utility of using these data sources for surveillance and research pertaining to adolescent work-related fatalities. Using the state of North Carolina as a case study, we analyzed data from the death certificates and medical examiner records of all work-related fatalities data among 11- to 17-year-olds between 1990-2008 (N = 31). We compared data sources on case identification, of completeness, and consistency information. Variables examined included those on the injury (e.g., means), occurrence (e.g., place), demographics, and employment (e.g., occupation). Medical examiner records (90%) were more likely than death certificates (71%) to identify adolescent work-related fatalities. Data completeness was generally high yet varied between sources. The most marked difference being that in medical examiner records, type of business/industry and occupation were complete in 72 and 67% of cases, respectively, while on the death certificates these fields were complete in 90 and 97% of cases, respectively. Taking the two sources together, each field was complete in upward of 94% of cases. Although completeness was high, data were not always of good quality and sometimes conflicted across sources. In many cases, the decedent's occupation was misclassified as "student" and their employer as "school" on the death certificate. Even though each source has its weaknesses, medical examiner records and death certificates, especially when used together, can be useful for conducting surveillance and research on adolescent work-related fatalities. However, extra care is needed by data recorders to ensure that occupation and employer are properly coded when dealing with adolescent worker deaths.     

Professional driving, smoking, and lung cancer: a case referent study

In a case referent study of about 600 cases of male lung cancer in northern Sweden the risk in professional drivers was specifically studied. Data concerning occupations, time and type of employment, and smoking habits were collected by questionnaires directed to close relatives. On average, professional drivers were heavier smokers and this was the chief cause of a slightly increased crude risk ratio in the study as a whole. Smoking drivers in an upper age group (70 and over) had a high relative risk of lung cancer, whereas in a lower age group (under 70) no significant increase was found. The relative risk in non-smoking drivers in the upper age group was moderately raised with borderline statistical significance. The high relative risk estimated for smoking drivers in the upper age group suggests a synergistic effect between smoking and occupational exposure.     

Professional driving, smoking, and lung cancer: a case referent study.

In a case referent study of about 600 cases of male lung cancer in northern Sweden the risk in professional drivers was specifically studied. Data concerning occupations, time and type of employment, and smoking habits were collected by questionnaires directed to close relatives. On average, professional drivers were heavier smokers and this was the chief cause of a slightly increased crude risk ratio in the study as a whole. Smoking drivers in an upper age group (70 and over) had a high relative risk of lung cancer, whereas in a lower age group (under 70) no significant increase was found. The relative risk in non-smoking drivers in the upper age group was moderately raised with borderline statistical significance. The high relative risk estimated for smoking drivers in the upper age group suggests a synergistic effect between smoking and occupational exposure.     

Use of death certificates to study ethnic-specific mortality

OBJECTIVES: The Hispanic population in the United States represents more than 40 million individuals, with Mexican Americans (MA) as the largest subgroup. To assess the utility of death certificates and medical records as the source of race/ethnicity data for epidemiologic studies, we compared self-reported race/ ethnicity to race/ethnicity recorded on death certificates and medical records in a bi-ethnic, non-immigrant U.S. community with a significant MA population. METHODS: This study utilized data collected from a subset of 1,856 participants of the Brain Attack Surveillance in Corpus Christi (BASIC) project. In-person interviews were conducted to determine self-reported race/ethnicity. Of those interviewed, 480 subsequently expired. Using self-reported race/ethnicity as the gold standard, we determined percent agreement, sensitivity, and specificity of the death certificate and medical record. RESULTS: Of the 480 subjects, 259 self-reported their race/ethnicity as non-Hispanic white (NHW), 195 self-reported as MA, and 26 self-reported as non-Hispanic black. Median age was 78.5 years and 55.8% were female. Percent agreement between self-reported race/ethnicity and race/ethnicity recorded on the death certificate and medical record was 97.1% and 96.3% respectively. Five percent of MAs were misclassified as NHW on their death certificates and 3% on their medical records. CONCLUSIONS: Results indicated that Hispanic designation recorded on death certificates and medical records in this community was largely consistent with that of self-report. This study suggests that vital statistics data in non-immigrant U.S. Hispanic communities can be used with confidence to investigate ethnic-specific aspects of disease and mortality. Similar studies in other multi-racial communities should be conducted to confirm and generalize these results.     

Death certification after a diagnosis of presenile dementia.

STUDY OBJECTIVES--To assess the value of death certification for the epidemiological study of dementia, the frequency with which the condition was recorded on death certificates of patients diagnosed with some form of dementia before the age of 65 years was studied. A further objective was to identify variables associated with failure to record dementia on the certificate. DESIGN--A cohort of patients with presenile dementia, differentiated by a clinical algorithm applied to hospital case records, was traced through the National Health Service Central Registry and details of certified causes of death were obtained. SETTING--The Northern Regional Health Authority in England. SUBJECTS--Prevalent cases of presenile dementia resident in the northern health region during 1986 traced up to April 1992. MEASUREMENTS AND MAIN RESULTS--The underlying cause of death was recorded as dementia or as Alzheimer's disease in 53% of cases of clinically diagnosed presenile Alzheimer's disease, 33% of cases of presenile vascular dementia, and 10% of cases of presenile dementia secondary to another neurological condition. Dementia or Alzheimer's disease was recorded in any part of the certificate in 75% of cases of Alzheimer's disease, 52% of vascular dementia, 33% of other dementias, and in 65% of cases overall. Dementia or a cerebral condition of a kind that can result in dementia was recorded in 80% of all cases. Failure to mention dementia was related to the clinical type of dementia, shorter duration of illness, and earlier period of study. CONCLUSIONS--The underlying cause of death seriously understates the frequency of dementia, but when the recording of other brain disease is taken into account the presence of potentially dementing brain disease is recorded much more frequently. It is suggested that coding chronic conditions present at death, such as dementia, in addition to those causing or contributing to death would improve the value of death certificates for epidemiological purposes.     

Recovering missing mesothelioma deaths in death certificates using hospital records

Background

In Brazil, underreporting of mesothelioma and cancer of the pleura (MCP) is suspected to be high. Records from death certificates (SIM) and hospital registers (SIH‐SUS) can be combined to recover missing data but only anonymous databases are available. This study shows how common data can be used for linkage and as an assessment of accuracy.

Methods

Mesothelioma (all sites, ICD‐10 codes C45.0‐C45.9) and cancer of the pleura (C38.4) were retrieved from both information systems and combined using a linkage algorithm. Accuracy was examined with non‐anonymous databases, limited to the state of São Paulo.

Results

We found 775 cases in death certificates and 283 in hospital registers. The linkage matched 57 cases, all accurately paired. Three cases, 0.4% in SIM and 1.3% in SIH‐SUS, could not be matched because of data inconsistencies.

Conclusions

A computer linkage can recover MCP cases from hospital records not found in death certificates in Brazil.

     

Review of death certificates to assess completeness of AIDS case reporting

To assess the level of reporting of acquired immunodeficiency syndrome (AIDS) cases, the authors reviewed death certificates for periods of 3 months during July through December 1985 in each of four cities: Washington, DC, New York City, Boston, and Chicago. Since reporting began in 1981, these cities have reported 38 percent of all AIDS cases in the United States. Death certificates were selected and matched to the AIDS surveillance registries in each city, and medical records of those not on the AIDS registry were reviewed to determine if AIDS had been diagnosed. The estimated completeness of AIDS case reporting to AIDS surveillance systems was high in all four cities (ranging from 83 percent to 100 percent). The unreported cases were similar to reported cases with respect to sex, race, risk factor, and specific diagnosis. Of the causes of death examined, AIDS, Pneumocystis carinii pneumonia, and Kaposi's sarcoma were predictive of AIDS as defined by the CDC case definition. However, 77 of 588 deaths (13 percent) attributed to 1 of these 3 causes occurred in cases that were presumptively AIDS but did not meet the diagnostic requirements to be classified as AIDS for reporting purposes. A review of death certificates provides an easy and rapid means of evaluating surveillance efforts and can be a useful adjunct to other methods of surveillance for AIDS.     

Adjusting for multiple-misclassified variables in a study using birth certificates

PurposeBirth certificates are a convenient source of population data for epidemiologic studies. It is well documented, however, that birth certificate data can be highly inaccurate. Nonetheless, studies based on birth certificates are routinely analyzed without accounting for sources of data errors. We focused on the association between maternal cigarette smoking and cleft lip and palate based on birth certificate data.MethodsWe adjusted odds ratio estimates simultaneously for exposure and outcome misclassification. We also calculated odds ratios adjusted for exposure misclassification only and outcome misclassification only.ResultsAdjustment for both maternal smoking during pregnancy and clefting resulted in adjusted odds ratios that ranged from less than 1.0 to much greater than the unadjusted estimate of 1.16, with most adjusted estimates outside of the 95% confidence limits (1.01, 1.33).ConclusionsBecause of the potentially large impact of birth certificate classification errors, we suggest that inferences from these or similar records employ quantitative methods for incorporating uncertainties caused by data errors.     

A comparative study of hospital fetal death records and Washington State fetal death certificates.

Hospital fetal death records were compared with Washington State fetal death certificates to ascertain the completeness of reporting. Washington State law requires reporting of all fetal deaths of 20 or more weeks gestation. For 16 hospitals reporting 603 fetal deaths, an additional 49 fetal deaths were identified in the mother's charts. The study documents underreporting, especially in the gestational ages closet to the 20-week age limitation where 71 per cent of the 48 unreported cases were 20 to 27 weeks gestation.     

Causes of death in Minamata disease: analysis of death certificates

Summary The causes of death in Minamata disease were analyzed and compared with those of control subjects. Of the 1422 Minamata disease patients in the Kumamoto Prefecture, 378 had died by the end of 1980. Of these 378, the first death occurred in 1954 with a peak incidence in 1956 when Minamata disease was officially reported for the first time. The number of deaths increased rapidly after 1972 with a second peak in 1976. The male: female ratio was 1.8: 1 and the mean age-at-death was 67.2 years (SD = ± 18.65). The mean age-at-death was younger in the cases of the initial outbreak than in those recently. There were, on the average, 2.8 causes of death per person. Of these cases, 157 (41.5%) had Minamata disease indicated on the death certificate, though 64 (16.9%) had Minamata disease coded as the underlying cause. Minamata disease and the noninflammatory diseases of the central nervous system (CNS) were the main underlying causes of death between 1954 and 1969, while, in the multiple cause data, pneumonia and non-ischemic heart disease were the most prevalent. Cerebrovascular diseases (18.0%) were the main underlying causes of death followed by malignant neoplasms (14.7%), cardiovascular diseases (14.1%) and Minamata disease (14.1%) in 1970 or later, while cardiovascular diseases (18.6%), Minamata disease (14.5%), cerebrovascular diseases (10.4%) and malignant neoplasms (7.1%) were the major multiple causes of death. As compared with the control, the proportions of deaths due to noninflammatory diseases of CNS and pneumonia were higher in the initial outbreak. Although the difference in the causes of death was less apparent recently, malignant neoplasms and hypertensive diseases tended to be lower. These results suggest that there is a need for a long-term follow-up of Minamata disease patients. The data also show the potential value of multiple causes of death coding in analyses of mortality.     

Risk factors in clinically diagnosed presenile dementia of the Alzheimer type: a case-control study in northern England.

STUDY OBJECTIVE--To investigate the relationship between presenile dementia of the Alzheimer type (PDAT) and family history, medical history, cigarette smoking, and exposure to aluminum. DESIGN--A case-control study in which 109 cases of clinically diagnosed PDAT and 109 controls matched for age and sex were compared for exposure to the risk factors. Odds ratios (ORs) were calculated using McNemar's test. SETTING--The northern health region of England. PATIENTS--Cases comprised those under 65 years diagnosed as having dementia by specialist services, who met clinical algorithm criteria for Alzheimer's disease (AD). Cases were confirmed at interview. MAIN RESULTS--Comparing cases with controls, (ORs) significantly greater than unity were obtained when there was a first degree relative with dementia (OR 2.5, 95% confidence interval 1.05, 6.56), any relative with dementia (OR 2.1, 95% CI 1.01, 4.55), and any relative aged less than 65 with dementia (OR 8.0, 95% CI 1.07, 348). Exposure to moderate levels of cigarette smoking (cumulative) was not significant; nor was exposure to aluminum in drinking water, diet, and medicinal sources. CONCLUSION--In this study of modest statistical power, a family history of dementia was confirmed as a risk factor in PDAT. No significant relationship between exposure to aluminium in water supplies, tea, and antacids was found. What is important, however, is the bioavailability of all dietary aluminium, determined by the concentrations of dissolved silicon in water: this requires further investigation.     

Esophageal cancer among Brazilian agricultural workers: case-control study based on death certificates

Several studies suggest that agricultural workers are at higher risk to develop and die by certain types of cancer. Esophageal cancer is not commonly listed among these types. However, some recent studies indicated that if there is an association between agricultural working and esophageal cancer, it s more likely to be observed among workers highly exposed to pesticides. In the present study, the magnitude of the association between agricultural working and esophageal cancer mortality was evaluated in a high pesticide use area in Brazil, through a death certificate-based case-control study. Cases were individuals from both genders, 30-59 years old, for whom basic cause of death was ascertained as cancer of the esophagus. For each case, one control was randomly selected from all possible controls for which the basic cause of death was ascertained as different from neoplasm and diseases of the digestive system. In addition, controls matched their cases by sex, age, year of death, and state of residence. Crude and adjusted odds ratios were then calculated to estimate the magnitude of the risk. Results showed that, in general, agricultural workers were at significantly higher risk to die by esophageal cancer, when compared to non-agricultural workers. Stratified analysis also revealed that the magnitude of such risk was slightly higher among illiterate agricultural workers, and simultaneous adjustment for several covariates showed that the risk was quantitatively higher among younger southern agricultural workers. These results suggest the esophageal cancer may be included among those types of cancer etiologically associated to agricultural working.