Contributing Cause Of Death Research Articles

Significance of inflammatory changes in the brainstem in forensic autopsy cases

Brain stem encephalitis is an uncommon disease. In order to assess the significance of inflammatory changes in the brain stem in a forensic autopsy material we reviewed the findings over a 12-year period. Between January 1st 1982–December 31st 1993, neuropathological examination of the brain was carried out in 29% of the autopsy cases from the Institute of Forensic Medicine, University of Oslo. Out of 4546 brains, 110 (2.2%) showed microglial nodules and perivascular lymphocytic cuffing in the lower brain stem. In 66 of the cases (60%), the abnormalities were limited to the nucleus and/or the spinal tract of the fifth cranial nerve. Only 16 of the 39 cases with more widespread changes, diagnosed as brain stem encephalitis, had a serious underlying or concomitant disease. Three particular cases of brain stem encephalitis are reported in more detail. In all three cases we suggest that the brain stem inflammatory changes may be either the direct or a contributory cause of death.

Reporting of dementia on death certificates: a community study.

To determine the extent to which conditions suggesting dementia are reported on death certificates of older adults and to identify the factors associated with reporting of dementia. A prospective epidemiological study in which community-dwelling subjects with and without dementia were identified and followed until death, after which their death certificates were examined. A total of 527 individuals who died during 8 years of follow-up of a population-based cohort of 1422 persons aged 65 and older at study entry. Demographic; study diagnoses, including Clinical Dementia Rating (CDR) Scale stages and diagnoses of Probable and Possible Alzheimer's disease (AD) by NINCDS-ADRDA criteria; disorders listed on death certificates as immediate, underlying, or contributory causes of death. Of 172 deceased subjects with study diagnoses of dementia, 30.2% had CDR = .5 and 69.8% had CDR > or = 1. Of 168 subjects in which dementia subtype could be diagnosed, Probable AD was diagnosed in 31.0% and Possible AD in 38.7%. On their death certificates, conditions indicating or suggesting dementia were reported in 23.8% of dementias overall; in 1.9% of those with CDR = .5 and 33.3% of those with CDR > or = 1; in 36.5% of those with Probable AD and 21.5% of those with Possible AD. In a multiple logistic regression model, variables associated independently with the reporting of dementia in demented individuals were: higher CDR stage of dementia (odds ratio (OR) 22.6; 95% confidence interval (CI), 2.9-174.7); likely etiology of dementia, Probable AD (OR = 3.5; CI, 1.1-10.6); and place of death, long-term care institution (OR = 3.8; 95% CI, 1.6-9.0). Although Alzheimer's disease is widely regarded as a leading cause of death, dementias are reported on the death certificates of only a quarter of demented individuals in the population at large. Reporting is more likely in those with more advanced dementia, with Probable Alzheimer's disease, and those who die in long-term care institutions.

Amyloidosis in a nationwide series of 1666 subjects with rheumatoid arthritis who died during 1989 in Finland.

Virtually all studies dealing with the occurrence of amyloidosis in subjects with rheumatoid arthritis (RA) have been based on selected series collected from university clinics. The purpose of the study was to obtain information on the true prevalence of amyloidosis and the role of amyloidosis as a cause of death. The study included all 1666 subjects (480 men and 1186 women) who had died in 1989 and had been entitled under the national sickness insurance scheme to receive specially reimbursed medication for RA. Amyloidosis was regarded as an immediate cause or an intervening antecedent cause of death in 64 cases (3.8%) and as a contributory cause of death in 33 cases (2%), corresponding to a prevalence of 5.8%. Amyloidosis had been diagnosed during life in 89 instances and was detected at autopsy in eight instances. Twenty-three (4.8%) of the subjects were men and 74 (6.2%) were women (P = 0.25). Compared with the remaining subjects in the study series, the lifespan of the subjects with amyloidosis was shortened by 7.7 yr. The prevalence of amyloidosis was lower than apparent from most earlier studies. Monitoring information derived from the Finnish sickness insurance system is a useful way of following trends in the occurrence of amyloidosis complicating RA.

Drug-related mortality in Denmark 1970-93

We analysed drug-related mortality in Denmark with respect to secular trends, gender, and regional variations, for the period 1970-93, for all deaths from poisoning and among drug addicts. The study was based on the Register of Causes of Death in Denmark and included 6,229 drug-related deaths, defined by specific combinations of manner of death, underlying cause of death, and contributory cause of death. The main outcome measure is age-specific mortality rate. A total of 63% of the drug-related deaths were registered as unnatural deaths. During the period studied, mortality increased for men in the 25 49 year age group and for women in all age groups over 25 years of age. For both men and women, the youngest birth cohorts from the mid-1950s and 1960s suffered much higher mortality than those born before 1950; however, the three youngest birth cohorts had almost the same mortality. During the entire period, mortality in the capital, Copenhagen, was much higher than in the provinces, but in the last years, a more favourable trend has been seen in Copenhagen.

Importance of heart failure as a cause of death. Changing contribution to overall mortality and coronary heart disease mortality in Scotland 1979-1992.

As heart failure is a syndrome arising from another condition, such as coronary heart disease, it is rarely officially coded as the underlying cause of death regardless of the cause recorded by the physician at the time of certification. We sought to assess the true contribution of heart failure to overall mortality and coronary heart disease mortality and to examine how this contribution has changed over time. We carried out a retrospective analysis of all death certificates in Scotland between 1979 and 1992 for which heart failure was coded as the underlying or a contributory cause of death. From a total of 833622 deaths in Scotland between 1979 and 1992, heart failure was coded as the underlying cause in only 1.5% (13695), but as a contributory cause in a further 14.3% (126073). In 1979, 28.5% of male and 40.4% of female deaths attributed to coronary heart disease (coded as the underlying cause of death) also had a coding for heart failure. In 1992 these percentages had risen significantly to 34.1% and 44.8%, respectively (both P<0.001). Mortality rates for heart failure as the underlying or contributory cause of death, standardized by age and sex, fell significantly over the period studied in all ages and in both sexes: by 31% in men and 41% in women <65 years and 15.8% in men and 5.1% in women > or =65 years, respectively (P<0.01 for all changes). Death from heart failure is substantially underestimated by official statistics. Furthermore, one third or more of deaths currently attributed to coronary heart disease may be related to heart failure and this proportion appears to be increasing. While the absolute numbers of deaths caused by heart failure remains constant, this study is the first to show that standardized mortality rates are declining.

Alcohol-related mortality by age and sex and its impact on life expectancy

The level of alcohol-related mortality has been estimated for several populations, but few studies have reported plausible results on the connection between alcohol-related mortality and age and sex. The Finnish death register includes information on both the underlying and contributory causes of death and it yields an individual-level estimate of the contribution of alcohol in mortality. The data for 1987–1993 are used to examine alcohol-related mortality by cause of death, age and sex and to estimate the impact of excessive alcohol use on life expectancy by sex. According to the results, 6% of all deaths were alcohol related. These deaths were responsible for a 2 year loss in life expectancy at age 15 years among men and 0.4 years among women, which explains at least one-fifth of the difference in life expectancies between the sexes. In the age group of 15–49 years, over 40% of all deaths among men and 15% among women were alcohol related. In this age group, over 50% of the mortality difference between the sexes results from alcohol-related deaths. The use of data on contributory causes of death, the organization of the Finnish death certification system and the relatively high proportion of alcohol-related deaths suggest that these data do not underestimate alcohol-related deaths to such an extent as has been the case in earlier studies using data from death certificates. This study shows that alcohol consumption is an important public health issue in Finland and a significant determinant of male premature mortality.

Suicides among physicians, engineers and teachers: the prevalence of reported depression, admissions to hospital and contributory causes of death.

The number of admissions to hospital, reported diagnoses, prevalence of reported depression and contributory causes of death among Finnish physicians, engineers and teachers who committed completed suicide between 1986 and 1993 were studied. The data for hospital admissions with diagnoses were obtained from the Finnish Hospital Discharge Register. Thin-layer chromatography was used to detect drugs in the liver, a dual-column gas chromatographic method was used for screening and quantification of drugs in the blood sample, and a head-space chromatographic method was used to measure blood alcohol levels. Physicians had more somatic diagnoses than the reference groups, and the prevalence of reported depression was higher among females than males. A minority of the depressed subjects had been admitted to hospital, although depression was observed to be the most prevalent contributory cause of death in all of the groups studied. The physicians used solid or liquid substances, especially barbiturates, as the main method of suicide. It is possible that depression in physicians, especially in male subjects, is undertreated in psychiatric hospitals.

Mortality in pediatric HIV: causes and contributing factors in the P2C2 study ♦ 732

A multicenter longitudinal study to assess the natural history of cardiac and pulmonary complications of vertically transmitted HIVenrolled 806 infants of HIV+ mothers. 205 were HIV+ at enrollment (I), 601 were enrolled prenatally or immediately postnatally; of this latter group 92 (15.3%) became HIV+ (IIa), 454 HIV- (IIb), and HIVstatus is unknown for 55 (IIi). There have been 105 deaths in study patients. Only 33/105 (31%) had autopsies. Because of the low autopsy rate and the need to determine cause of death in all, a multidisciplinary committee reviewed and categorized all deaths. Review is complete in 71/105 (68%). Nineteen deaths were in infants 5. Fifty-eight deaths were HIV related, 9 were not, in 4 there was insufficient information to categorize death. Of the 58 HIVrelated deaths, 8 were in infants 5. For the youngest, 6/8 had infectious deaths, 2/8 hemorrhagic. Contributing factors included chronic pulmonary disease and chronic cardiac disease in one each; none had MAI or encephalopathy. Of deaths between 1 and 5 years 18/34 were infectious, 6/34 wasting, 3/34 cardiac, 2 each pancreatitis, encephalopathy, and tumor (a third with malignancy had an infectious death), and 1 with DIC. Contributing factors included 20/34 chronic lung disease, 18/34 chronic cardiac disease (11 both), 13/34 MAI, 10/34 encephalopathy, and 24/34 wasting. Of the oldest (>5 years) 7/16 had infectious deaths, 4/16 cardiac, 3/16 wasting, 1/16 organ failure and 1/16 encephalopathy. Contributing factors included 8/16 chronic lung disease, 9/16 chronic cardiac disease (5/16 both), 8/16 MAI, 5/16 encephalopathy, 15/16 wasting. In conclusion, infectious deaths were common, 31/58 (53%), more so in younger children; non-infectious deaths included 7/58 (12%) cardiac, more frequent in older children. Wasting, MAI, and encephalopathy all increased with age as primary and contributory causes of death with wasting being nearly universal in older children. Evidence of chronic cardiac and pulmonary disease also increased with age; chronic cardiac disease was seen in 28/58 (48%) and 29/58(50%) had chronic lung disease.

Death certification in treated cases of presenile Alzheimer's disease and vascular dementia in Scotland.

although death certification data are commonly used in dementia epidemiology, their reliability has been questioned. death certificates were available from the Registrar General for Scotland for all patients with Alzheimer's disease/presenile dementia (AD PSD) or vascular dementia (VaD) who had died in Scotland up until 31 December 1994. Primary (immediate and underlying) and contributory causes of death were noted as well as place of death. Occupations of male patients were obtained from death certificates or from case notes and classified according to the Standard Occupational Classification. Bronchopneumonia was considered a non-specific cause of death and specific causes of death were classified as: cardiac disease, dementia, cerebrovascular disease, neoplasms, other vascular diseases and other diseases. Place of death was recorded as psychiatric hospital, district general hospital, nursing home or private residence. death certificates of 398 people who had been treated for AD PSD and 348 who had been treated for VaD were identified. Bronchopneumonia was the most common immediate cause of death in the AD PSD group (70.9%) but less so for the VaD group (51.7%). For both groups place of death was associated with significant differences in pneumonia being reported as the immediate cause of death as well as specific underlying and contributory causes of death. Dementia was recorded for 90.5% of AD PSD patients but for only 49.7% of the VaD group. Scottish death certificate data significantly underestimate the prevalence of presenile VaD. Changes in patterns of institutional care may affect dementia rates estimated from death certificate data.

AN AUDIT OF 319 DEATHS ACROSS FOUR GENERAL PRACTICES

SUMMARY Death is a major outcome measure, and the value of an audit of the preventable factors leading to individual deaths is accepted in secondary care. Although approximately 20 of a typical general practitioner's patients will die every year, audits of deaths in general practice are seldom published. This is probably partly due to the difficulties posed by comparability, partly due to the wide range of causes of such deaths and possible contributory factors, and partly due to confidentiality considerations. We describe an audit of all death occurring in our practices over a 12‐month period. Although cigarette smoking was considered to exceed all other contributory causes of death, preventable factors occurred in both primary and secondary care sufficiently often for important conclusions to be drawn. Comparison of causes of death between general practices is possible, and such enquiry can demonstrate important quality issues for both primary and secondary care.

Chronic mucus hypersecretion in COPD and death from pulmonary infection.

The association of chronic mucus hypersecretion and mortality is a matter of debate. We wished to determine whether the relationship between chronic mucus hypersecretion and chronic obstructive pulmonary disease (COPD)-related mortality could be explained by proneness to pulmonary infection. We followed 14,223 subjects of both sexes for 10-12 yrs. Cases where COPD was an underlying or contributory cause of death (n = 214) were included, and hospital records were obtained when possible (n = 101). From the presence of increased mucus, purulent mucus, fever, leucocytosis and infiltration on chest radiography, death was classified as either due to pulmonary infection (n = 38), other causes (n = 51), or unclassifiable (n = 12). Of subjects reporting chronic mucus hypersecretion at the initial examination, pulmonary infection was implicated in 54% of deaths, whereas this only occurred in 28% of subjects without chronic mucus hypersecretion. Controlling for covariates, in particular smoking habits, a Cox analysis showed a strong inverse relationship between ventilatory function and COPD-related mortality. Chronic mucus hypersecretion was found to be a significant predictor of COPD-related death with pulmonary infection implicated (relative risk (RR) 3.5) but not of death without pulmonary infection (RR 0.9). We consider that subjects with COPD and chronic mucus hypersecretion are more likely to die from pulmonary infections than subjects without chronic mucus hypersecretion. This may explain the excess mortality in subjects with COPD and chronic mucus hypersecretion found in previous studies.

Relationship of the type of tobacco and inhalation pattern to pulmonary and total mortality : Lange P, Nyboe J, Appleyard M, Jensen G, Schnohr P. Copenhagen City Heart Study, Rigshospitalet, Dept. 7123, Tagensvej 20, DK-2200 Copenhagen N. Eur Respir J 1992;5:1111–1117

Data from The Copenhagen City Heart Study, a prospective population study, were analysed to investigate the influence of the type of tobacco and inhalation on pulmonary and total mortality. The study sample comprised 6,511 men and 7,703 women, selected randomly after age-stratification from the general population. There were 2,986 plain cigarette smokers, 3,222 filter cigarette smokers, 1,578 smokers of cheroots/cigars, 433 male pipe smokers and 773 subjects smoking more than one type of tobacco. From 1976 until the end of 1989, 2,765 subjects died. Lung cancer was considered as main death cause in 268. Chronic obstructive pulmonary disease (COPD) was considered as the main cause in 94 cases and main or contributory cause of death in 195 cases (COPD related mortality). Current smokers had a higher risk of total mortality compared to lifetime nonsmokers: the relative risks (RR) ranged between 1.2 for male pipe smokers and 2.4 for female plain cigarette smokers. With regard to lung cancer mortality, the RR ranged between 4.1 for male pipe smokers and 7.9 for female plain cigarette smokers. Even higher RR values were estimated for COPD related mortality. In both sexes, the RR for the investigated end-points were lower in cheroot/cigar smokers and in pipe smokers than in cigarette smokers, but these differences were markedly diminished after an adjustment for the inhalation habit. The present study substantiates the view that tobacco smoking increases pulmonary and total mortality. The small differences between the various types of tobacco are probably caused by different inhalation patterns.

Cardiac tamponade caused by primary lung cancer and the management of pericardial effusion.

Between 1978 and 1990, 51 cases of pericardial effusion secondary to lung cancer were treated at the National Cancer Center Hospital by creating a pericardial window, using the subxiphoid approach, that was connected to a water-sealed drainage system. Most patients had advanced disease, such as distant metastasis (76%), pleural effusion (88%), and clinical Stage N2 or N3 disease (98%). Forty-five patients had cardiac tamponade, and six had no symptoms attributable to pericardial effusion. Cardiac tamponade was the initial manifestation of lung cancer in only 3 patients; it was a late manifestation in 48. Of those specimens that were examined cytologically, 92% had positive findings. The interval from creation of the pericardial window until removal of the drainage tube ranged from 4-135 days (median, 11 days). The interval was significantly longer in patients who previously had received thoracic radiation therapy (P < 0.05). The overall median survival was 80 days, and the 1-year survival rate was 10.5%. Postmortem examination showed that constrictive heart failure caused by pericardial lesions was the major contributory cause of death in 32% of patients. Using multivariate analysis, factors indicating a poor prognosis were: (1) the interval from the diagnosis of lung cancer to pericardial effusion development (P = 0.005) and (2) the absence of prior surgery (P = 0.007). The creation of a pericardial window effectively treated pericardial effusion in 85% of cases. However, the role of intrapericardial instillation of anticancer or sclerosing agents was unclear in this retrospective analysis.

Relationship of the type of tobacco and inhalation pattern to pulmonary and total mortality

Data from The Copenhagen City Heart Study, a prospective population study, were analysed to investigate the influence of the type of tobacco and inhalation on pulmonary and total mortality. The study sample comprised 6,511 men and 7,703 women, selected randomly after age-stratification from the general population. There were 2,986 plain cigarette smokers, 3,222 filter cigarette smokers, 1,578 smokers of cheroots/cigars, 433 male pipe smokers and 773 subjects smoking more than one type of tobacco. From 1976 until the end of 1989, 2,765 subjects died. Lung cancer was considered as main death cause in 268. Chronic obstructive pulmonary disease (COPD) was considered as the main cause in 94 cases and main or contributory cause of death in 195 cases (COPD related mortality). Current smokers had a higher risk of total mortality compared to lifetime nonsmokers: the relative risks (RR) ranged between 1.2 for male pipe smokers and 2.4 for female plain cigarette smokers. With regard to lung cancer mortality, the RR ranged between 4.1 for male pipe smokers and 7.9 for female plain cigarette smokers. Even higher RR values were estimated for COPD related mortality. In both sexes, the RR for the investigated end-points were lower in cheroot/cigar smokers and in pipe smokers than in cigarette smokers, but these differences were markedly diminished after an adjustment for the inhalation habit. The present study substantiates the view that tobacco smoking increases pulmonary and total mortality. The small differences between the various types of tobacco are probably caused by different inhalation patterns.

IgM-Antibodies againstT. PallidumDetected in Sera from Mothers of Stillborn Babies in Mozambique by the Solid-Phase Haemadsorption Assay (SPHA)

Serum samples taken at the delivery from 27 syphilitic mothers in Mozambique, 16 with stillborn babies and 11 with healthy babies were tested upon presence of IgM antibodies against T. pallidum by the solid-phase haemadsorption assay (SPHA). Fourteen out of the 16 serum samples from mothers with stillborn babies but only one out of the 11 samples from mothers with healthy babies were found positive by the SPHA test. Clinical signs indicative of syphilis are difficult to find in the Maputo area as there were more than 40,000 annual births and only five obstetricians when the study was carried out. It is believed that the findings may indicate those mothers who were serologically positive with the SPHA test had clinically active syphilis and that syphilis might be the cause or a contributory cause of death in 14 of the stillborn babies. The SPHA test was easy to perform and we recommend its adoption by laboratories with facilities to perform the TPHA test.

Certification of cause of death in French diabetic patients.

The aim was to assess the level of mortality related to diabetes in France. In other countries, an underrecording of diabetes on the death certificates of diabetic patients has been reported. Estimated death rate of diabetic patients was calculated using (a) the actual number of death certificates where diabetes was registered either as an underlying or as a contributory cause of death, and (b) estimates of the prevalence of diabetes in the population, by sex and age group, from which expected numbers of diabetic deaths were determined. Standardised mortality ratios were calculated using 1988 French mortality statistics as reference. The estimated standardised mortality ratio for diabetic subjects, with diabetes registered as the underlying cause, was 0.36. This standardised mortality ratio increased to 0.92 if both the underlying and contributory causes were considered. The estimated death rate, by sex and age group, implies that diabetes has a protective effect between the ages of 45 and 64 years, particularly in men. Evidence suggests that diabetes is completely omitted on the death certificates of many diabetic subjects, especially for those between the ages of 45 and 64 years. Using mortality statistics underestimates the prevalence of diabetes and its effects on public health. The difference in diabetes mortality between countries will not be reliable until there is a better registration of the causes of death in diabetic patients, and contributory as well as the underlying cause are coded and published.

Mortality from dementia among gastroduodenal ulcer patients.

The aim was to examine whether a high intake of aluminium containing antacids is a risk for Alzheimer's disease. The mortality from dementia (1970-87), coded from death certificates as underlying or contributory cause of death, was compared with national rates in a cohort of patients who had surgery for gastroduodenal ulcer disease between 1911 and 1978. Patient data were obtained from patient records from major hospitals in western Norway. 4179 patients were identified who met the study criteria, which included having had a documented stomach operation, having a reliably identifiable personal number, and being alive on Jan 1, 1970. The standardised mortality ratio for dementia was 1.10 (95% CI 0.85-1.40, n = 64) for all patients, while for patients operated on in the period 1967-78 it was 1.25 (95% CI 0.66-2.13, n = 13). As the majority of patients operated on after 1963 have probably been heavy consumers of aluminium containing antacids, the study provides meager evidence that a high intake of aluminium is an important risk factor for Alzheimer's disease, the major cause of dementia. However, the possibility of a raised mortality from Alzheimer's disease cannot be ruled out due to probable misclassification both in diagnosis and exposure. In addition, the observation period may have been too short to detect an effect since the latent period for Alzheimer's disease may be very long.

Initial evaluation and management of upper airway injuries in trauma patients

Study Objective: To examine and compare the mechanism of injury, diagnostic findings, initial methods of airway management, and outcome of patients who had upper airway injuries. Design: A retrospective review of hospital records. Setting: A large metropolitan, university-affiliated trauma center. Patients: Forty-six cases of upper airway injuries admitted between 1984 and 1988. Interventions: Diagnostic methods included clinical examination, cervical and thoracic radiographs, bronchoscopy and computerized tomographic (CT) scan. Therapeutic interventions ranged from conservative management with or without endotracheal intubation to operative reconstruction. Measurements and Main Results: Mechanism of injury was knife stab wound in 9 cases, gunshot wound in 17 cases, and blunt trauma in 20 cases. Location was the larynx in 13 cases, trachea in 24 cases, cricoid cartilage in 5 cases, and multiple sites in 4 cases. Diagnostic findings varied considerably according to the mechanism of injury, but radiographic evidence of soft tissue air and wounds opening into the airway were common findings. CT scan and bronchoscopy also were useful diagnostic tools. Overall mortality was 24%, which did not vary according to patient age or mechanism of injury. The airway injury itself was a primary or contributory cause of death in four cases, two of which were tracheal injuries and two injuries at the cricotracheal junction. Conclusions: In any patient with possible upper airway injury, plain radiographs of the chest and neck should be obtained to aid in the diagnosis. Elective intubation should be attempted only with a surgical team present and prepared for emergency tracheotomy. Fiber-optic bronchoscopy could be a valuable aid for both intubation and evaluation in such cases.

Relation of ventilatory impairment and of chronic mucus hypersecretion to mortality from obstructive lung disease and from all causes.

The relation of ventilatory impairment and chronic mucus hypersecretion to death from all causes and death from obstructive lung disease (chronic bronchitis, emphysema and asthma) was studied in 13,756 men and women randomly selected from the general population of the City of Copenhagen. During the 10 year follow up 2288 subjects died. In 164 subjects obstructive lung disease was considered to be an underlying or a contributory cause of death (obstructive lung disease related death); in 73 subjects it was considered to be the underlying cause of death (obstructive lung disease death). Forced expiratory volume in one second, expressed as a percentage of the predicted value (FEV1% pred), and the presence of chronic phlegm were used to characterise ventilatory function and chronic mucus hypersecretion respectively. For mortality analysis the proportional hazards regression model of Cox was used; it included age, sex, pack years, inhalation habit, body mass index, alcohol consumption, and the presence or absence of asthma, heart disease, and diabetes mellitus as confounding factors. By comparison with subjects with an FEV1 of 80% pred or more, subjects with an FEV1 below 40% pred had increased risk of dying from all causes (relative risk (RR) = 5.0 for women, 2.7 for men), a higher risk of obstructive lung disease related death (RR = 57 for women, 34 for men), and a higher risk of obstructive lung disease death (RR = 101 for women, 77 for men). Chronic mucus hypersecretion was associated with only a slightly higher risk of death from all causes (RR = 1.1 for women, 1.3 for men). The association between chronic mucus hypersecretion and obstructive lung disease death varied with the level of ventilatory function, being weak in subjects with normal ventilatory function (for an FEV1 of 80% pred the RR was 1.2), but more pronounced in subjects with reduced ventilatory function (for an FEV1 of 40% pred the RR was 4.2). A similar though statistically non-significant trend was observed with regard to obstructive lung disease related death. This study shows that impaired lung function is very strongly related to total mortality, obstructive lung disease related mortality, and obstructive lung disease mortality and suggests that chronic mucus hypersecretion, in those with impaired ventilatory function, is also a significant risk factor for death from obstructive lung disease.

Geographical associations between aluminium in drinking water and death rates with dementia (including Alzheimer's disease), Parkinson's disease and amyotrophic lateral sclerosis in Norway

Comparisons of maps and correlation and regression analysis indicate a geographical association between aluminium (Al) in drinking water and registered death rates with dementia (coded from death certificates as the underlying or a contributory cause of death) in Norway. High levels of Al in drinking water are in most cases related to acid precipitation. In general, correlations between aggregate environmental measurements and mortality are a weak source of evidence for risk factors for disease, however, and interpretations regarding cause-and-effect relationships should therefore be made with great care. The major uncertainty probably relates to the use of registered death rates with dementia as a measure of incidence rates of Alzheimer's disease. The dementia rates are correlated with population density, and it is possible that the association between AI and dementia might be due to differences in diagnosis and reporting of dementia. Thus, the present study can only be regarded as introductory, and further epidemiological studies are needed to help elucidate the role of AI in Alzheimer's disease. The results provide little evidence of an association between AI in drinking water and Parkinson's disease or amyotrophic lateral sclerosis.