Mortality in a cohort of men expressing the glucose-6-phosphate dehydrogenase deficiency

The objective of this study was to test the hypothesis of a lower mortality from cancer and cardiovascular diseases among men expressing glucose-6-phosphate dehydrogenase (G6PD) deficiency. We designed a mortality study based on death certificates from January 1, 1982 through December 31, 1992 in a cohort of G6PD-deficient men. Cohort members were 1,756 men, identified as expressing the G6PD-deficient phenotype during a 1981 population screening of the G6PD polymorphism. The setting was the island of Sardinia, Italy. Outcome measures were cause-specific standardized mortality ratios (SMRs), which were computed as 100 times the observed/expected ratio, with the general Sardinian male population as the reference. Deaths from all causes were significantly less than expected due to decreased SMRs for ischemic heart disease (SMR, 28; 95% confidence interval [CI], 10 to 62), cerebrovascular disease (SMR, 22; 95% CI, 6 to 55), and liver cirrhosis (SMR, 12; 95% CI, 0 to 66), which explained 95.6% of the deficit in total mortality. All cancer mortality was close to the expectation, with a significant increase in the SMR for non-Hodgkin's lymphoma (SMR, 545; 95% CI, 147 to 1,395). A decrease in mortality from cardiovascular diseases was one of the study hypotheses, based on an earlier human report and experimental evidence. However, selection bias is also a likely explanation. Further analytic studies are warranted to confirm whether subjects expressing the G6PD-deficient phenotype are protected against ischemic heart disease and cerebrovascular disease. This cohort study is consistent with more recent case-control studies in rejecting the hypothesis of a decreased cancer risk among G6PD-deficient subjects. The observed increase in mortality from non-Hodgkin's lymphoma and decrease in mortality from liver cirrhosis were not previously reported.     

Mortality among a cohort of electric utility workers, 1960-1991

Overall mortality trends among an electric utility workforce are examined. The study cohort (n = 40,335) included all workers with at least 1 year of work experience from 1960-1991; 3,753 deaths were observed in this cohort. Standardized mortality ratios (SMRs) and internal cohort analyses were used to assess mortality trends for the entire cohort and for specific occupational groups. Most SMRs were < or = 1.0 and were generally lower for noncancer (cardiovascular, COPD, and injuries) than for cancer mortality. Compared to office staff, rate ratios (RR) were higher for respiratory cancers for field staff [(RR = 2.3, 95% CI, 1.0-5.0) linecrew (RR = 2.2 95% CI, 1.5-3.1), and power plant occupations (RR = 2.4, 95% CI, 1.6-3.6)]. Nonmanagement occupations had rate ratios for motor vehicle injuries and all types of injuries, within a range of 2.5-4.7, with all lower CIs > 1.0. The healthy worker effect is an important factor in explaining the difference between SMR and internal cohort analyses results. The SMR results indicate that this workforce has lower rates for overall mortality, cardiovascular disease, cancer and nonintentional injury. A consistent finding in the internal cohort analyses that merits further research was higher mortality rates for respiratory cancer and injuries among nonoffice staff.     

Foetal rat pancreatic transplantation: posttransplantation development of foetal pancreatic iso- and allografts and suppression of rejection with mycophenolate mofetil (MMF) and cyclosporine based immunesuppression

CONTEXT: High-dose iodine 131 is the treatment of choice in the United States for most adults with hyperthyroid disease. Although there is little evidence to link therapeutic (131)I to the development of cancer, its extensive medical use indicates the need for additional evaluation. OBJECTIVE: To evaluate cancer mortality among hyperthyroid patients, particularly after (131)I treatment. DESIGN: A retrospective cohort study. SETTING: Twenty-five clinics in the United States and 1 clinic in England. PATIENTS: A total of 35 593 hyperthyroid patients treated between 1946 and 1964 in the original Cooperative Thyrotoxicosis Therapy Follow-up Study; 91 % had Graves disease, 79% were female, and 65% were treated with (131)I. MAIN OUTCOME MEASURE: Standardized cancer mortality ratios (SMRs) after 3 treatment modalities for hyperthyroidism. RESULTS: Of the study cohort, 50.5% had died by the end of follow-up in December 1990. The total number of cancer deaths was close to that expected based on mortality rates in the general population (2950 vs 2857.6), but there was a small excess of mortality from cancers of the lung, breast, kidney, and thyroid, and a deficit of deaths from cancers of the uterus and the prostate gland. Patients with toxic nodular goiter had an SMR of 1.16 (95% confidence interval [CI], 1.03-1.30). More than 1 year after treatment, an increased risk of cancer mortality was seen among patients treated exclusively with antithyroid drugs (SMR, 1.31; 95% CI, 1.06-1.60). Radioactive iodine was not linked to total cancer deaths (SMR, 1.02; 95% CI, 0.98-1.07) or to any specific cancer with the exception of thyroid cancer (SMR, 3.94; 95% CI, 2.52-5.86). CONCLUSIONS: Neither hyperthyroidism nor (131)I treatment resulted in a significantly increased risk of total cancer mortality. While there was an elevated risk of thyroid cancer mortality following (131)I treatment, in absolute terms the excess number of deaths was small, and the underlying thyroid disease appeared to play a role. Overall, (131)I appears to be a safe therapy for hyperthyroidism.     

Occupational low back pain: history and physical examination

The mortality experience of 7,119 workers who were employed at a Beaumont, Texas, refinery for at least 1 year between 1945 and 1987 was investigated. Mortality analyses based on standardized mortality ratios (SMRs) and 95% confidence intervals (95% CI) showed overall mortality was significantly lower than expected compared with the U.S. general population (SMR = 82, 95% CI = 79-86). Total cancer mortality was also lower than expected (SMR = 92, 95% CI = 84-100). Significant mortality deficits from several malignant and nonmalignant diseases were reported. A significant mortality increase in the broad category of lymphatic and hematopoietic cancers was found (SMR = 133, 95% CI = 103-170). This increase was attributed to a nonsignificant elevation in leukemia of all cell types combined (SMR = 139, 95% CI = 92-201) and a borderline significant increase in other lymphatic tissue cancer (SMR = 158, 95% CI = 101-235). The elevation in leukemia was confined to workers hired before 1950. Furthermore, the leukemia excess was shown to have peaked during the 1960s, with mortality no longer elevated post-1980. Analyses of cell type-specific leukemias showed a similar temporal pattern for acute myeloid leukemia (AML) which was not significantly elevated (SMR = 136, 95% CI = 59-268). Mortality from other leukemia cell types was similar to or lower than expected. Mortality from non-Hodgkin's lymphoma (NHL) (SMR = 140, 95% CI = 88-211) and multiple myeloma (MM) (SMR = 121, 95% CI = 55-230) were increased, but neither was statistically significant nor likely to be related to refinery employment. No death from asbestosis was reported, and mortality from mesothelioma and pulmonary fibrosis was lower than expected. Lung cancer mortality for the overall cohort was similar to expected. For the overall cohort, analyses by duration of employment and time since first employment showed no evidence of any trends for increasing cause-specific mortality. Separate analyses of male workers employed in operator jobs showed mortality patterns that were more favorable than those of the total cohort. Maintenance craftworkers showed statistically significant elevations in mortality for prostate cancer (SMR = 145, 95% CI = 107-194), leukemia (SMR = 179, 95% CI = 111-273), and other lymphatic tissue cancer (SMR = 233, 95% CI = 138-368). Detailed analyses indicated that, among maintenance craftworkers, mortality was elevated for AML, NHL, and MM, but none was significant. Furthermore, no upward trend by duration of maintenance jobs was observed. A small increase of lung cancer was observed among maintenance craftworkers (SMR = 120, 95% CI = 99-145), which was borderline significant. No relationship between lung cancer and duration of maintenance employment was found. In contrast, a deficit of pulmonary fibrosis was reported among maintenance craftworkers (SMR = 62, 95% CI = 17-159). These findings are discussed in conjunction with results from other refinery studies, and the limitations of the study are discussed.     

Mortality among coal miners with pneumoconiosis in Poland

A mortality cohort study was carried out on 7,065 coal miners with pneumoconiosis first diagnosed during the years of 1970-85. The cohort was selected from among subjects entered into the National Register of Occupational Diseases and followed up through to the end of 1991. The general male population of Poland was considered as a reference group. The PYRS-3 programme was used to identify, by means of standardized mortality ratios (SMRs), total and selected cause-specific mortality. An analysis revealed significantly elevated total mortality (SMR = 105; 95% confidence interval (CI): 100-110) in the whole cohort of coal miners. The risk of selected cause-specific mortality was significantly enhanced due to diseases of the respiratory system among which pneumoconiosis predominated (SMR = 383; 95% CI: 345-424). While mortality from all diseases of the circulatory system (SmR = 89; CI: 82-96), arterial hypertension (SMR = 63; 95% CI: 38-98), cerebrovascular diseases (SMR = 79; 95% CI: 62-99), atherosclerosis (SMR = 79; 95% CI: 66-93), and injury in poisoning (SMR = 50; 95% CI: 38-64) was significantly lower. The risk of death from malignant neoplasm of lung in the whole study population as well as in individual groups and categories of coal miners with pneumoconiosis, which varied in the risk of pneumoconiosis and the level of exposure to ionizing radiation, was not increased.     

Workplace risk factors for cancer in the German rubber industry: Part 2. Mortality from non-respiratory cancers

OBJECTIVES: To determine the mortality from non-respiratory cancers by work area among active and retired male workers of the German rubber industry. METHODS: A cohort of 11,633 male German workers was followed up for mortality from 1 January 1981 to 31 December 1991. Cohort members were active (n = 7536) or retired (n = 4127) on 1 January 1981 and had been employed for at least one year in one of five study plants producing tyres or technical rubber goods. Work histories were reconstructed from routinely documented "cost centre codes" and classified into six categories: I preparation of materials; II production of technical rubber goods; III production of tyres; IV storage and dispatch; V general service; VI others. Standardised mortality ratios (SMRs) and 95% confidence intervals (95% CIs), controlling for age and calendar year and stratified by work area (employment in respective work area for at least one year) and time related variables (year of hire, lagged years of employment in work area) were calculated from national mortality rates as the reference. RESULTS: Significant increases in mortality were found for pharyngeal cancer in work area IV (three deaths, SMR 486, 95% CI 101 to 1419), oesophageal cancer in work area III (11 deaths, SMR 227, 95% CI 114 to 407), and leukaemia in work areas I (11 deaths, SMR 216; 95% CI 108 to 387) and II (14 deaths, SMR 187; 95% CI 102 to 213). Furthermore, increased SMRs were found for stomach cancer in work area I (22 deaths, SMR 134; 95% CI 84 to 203), colon cancer in work area II (27 deaths, SMR 131, 95% CI 86 to 191), prostatic cancer in work area V (27 deaths, SMR 152, 95% CI 99 to 221), and bladder cancer in work areas IV (six deaths, SMR 253; 95% CI 93 to 551) and V (12 deaths, SMR 159, 95% CI 82 to 279). Mortality from cancer of the liver or gall bladder, pancreas and kidney, and from lymphomas was not substantially increased in any of the work areas. CONCLUSIONS: Mortality from cancer of several sites was associated with specific work areas. Some of these associations have been reported previously. Future analyses of our study will have to determine the role of specific exposures in the aetiology of these cancers.     

An evaluation of digital subtraction radiography for assessment of changes in position of the mandibular condyle

OBJECTIVES: This study evaluated the mortality experience of workers from the styrene-butadiene rubber industry. Concerns about a possible association of 1,3-butadiene and styrene with lymphohaematopoietic, gastrointestinal, and lung cancers prompted the investigation. METHODS: A retrospective follow up study was conducted of 15,649 men employed for at least one year at any of eight North American styrene-butadiene rubber plants. Analyses used standardised mortality ratios (SMRs) to compare styrene-butadiene rubber workers' cause specific mortalities (1943-91) with those of the United States and Ontario general populations. RESULTS: On average, there were 25 years of follow up per subject. The standardised mortality ratio (SMR) was 87 (95% confidence interval (95% CI) 85 to 90) for all causes of death combined and was 93 (95% CI 87 to 99) for all cancers. There was an excess of leukaemia (SMR 131, 95% CI 97 to 174), restricted to hourly workers (SMR 143, 95% CI 104 to 191). For causes of death other than leukaemia, SMRs were close to or below the null value of 100. Results by work area (process group) were unremarkable for non-Hodgkin's lymphoma, multiple myeloma, and stomach cancer. Maintenance workers had a slight increase in deaths from lung cancer, and certain subgroups of workers had more than expected deaths from cancer of the large intestine and the larynx. CONCLUSION: This study found an excess of leukaemia that is likely to be due to exposure to butadiene or to butadiene plus other chemicals. Deaths from non-Hodgkin's lymphoma, multiple myeloma, and stomach cancer did not seem to be related to occupational exposure. The excess deaths from lung cancer among maintenance workers may be due in part to confounding by smoking, which was not controlled for, and in part to an unidentified occupational exposure other than butadiene or styrene. Increases in cancer of the large intestine and larynx were based on small numbers, did not seem to be due to exposure to butadiene or styrene, and may be chance observations.     

Field studies and cost-effectiveness analysis of vaccination with Gavac against the cattle tick Boophilus microplus

This study presents findings from an updated retrospective cohort mortality study of male police officers from January 1, 1950 to December 31, 1990 (n = 2,593; 58,474 person-years; 98% follow-up). Significantly higher than expected mortality rates were found for all cause mortality (Standardized mortality ratio [SMR] = 110; 95% confidence interval [95% CI] = 1.04-1.17), all malignant neoplasms (SMR = 125; 95% CI = 1.10-1.41), cancer of the esophagus (SMR = 213; 95% CI = 1.01-3.91), cancer of the colon (SMR = 187; 95% CI = 1.29-2.59), cancer of the kidney (SMR = 2.08, 95% CI = 100-3.82), Hodgkin's disease (SMR = 313; 95% CI = 1.01-7.29), cirrhosis of the liver (SMR = 150; 95% CI = 1.00-2.16), and suicide (SMR = 153; 95% CI = 1.00-2.24). All accidents were significantly lower (SMR = 53; 95% CI = 0.34-0.79). Mortality by years of police service showed higher than expected rates for (1) all malignant neoplasms in the 1- to 9-years-of-service group; (2) all causes, bladder cancer, leukemia, and arteriosclerotic heart disease in the 10 to 19-year group; and (3) colon cancer and cirrhosis of the liver in the over 30 years of service group. Hypotheses for findings are discussed.     

Computerized tomography and magnetic resonance in the diagnosis of recurrent rectal neoplasms: comparison of reliability and errors of both methods

From two areas in the Province of Padova, we selected 2,283 male farmers who worked either in cattle raising or in crop/orchard cultivation. There were 422 cohort deaths from 1970 to 1992. Using the regional population as a reference, the standardized mortality ratio (SMR) was calculated, with 95% confidence intervals (CI) based on the Poisson distribution. Cancer mortality was significantly reduced among the 1,561 dairy farmers (SMR = 0.65; CI = 0.53-0.81); there was a significant decrease in lung cancer (SMR = 0.49; CI = 0.31-0.74), whereas a significant increase from brain tumors was found (SMR = 2.83; CI = 1.04-6.17). Neither overall cancer mortality nor the lung cancer SMR deviated significantly from unity for the 722 crop/orchard farmers. Among dairy farmers, moreover, lung cancer SMRs showed a significant downward trend across the quartiles of increasing length of work, 0.96 in the first quartile, and 0.48, 0.40, and 0.25 in the second, third, and fourth quartiles, respectively. Moreover, lung cancer risk decreased with increasing farm land area, with SMRs in the quartiles of 0.89, 0.37, 0.41 and 0.19. This decrease cannot be attributed to either a selection (healthy worker effect) or a confounding (lower percentage of smokers) bias. Nor was it due to an artifact introduced by differences in age distribution among the quartiles. Dairy farmers are known to be exposed to higher airborne endotoxin concentrations; reasonably, this cumulative exposure increases further with years of work and area of farm. Endotoxins may have protected the dairy farmers against lung cancer through the tumor necrosis factor produced by alveolar macrophages.     

Mortality and incidence of cancer among sewage workers: a retrospective cohort study

To study the incidence of and mortality from cancer among sewage workers a retrospective analysis was performed on a cohort of 656 men employed for at least one year at any one of 17 Swedish sewage plants during the years 1965-86. Assessment of exposure was done by classification of work tasks. Lower than expected total mortality (standardised mortality ratio (SMR) = 0.75, 95% confidence interval (95% CI) 0.58-0.97) and cardiovascular mortality (SMR = 0.61, 95% CI 0.39-0.91) was found. This was interpreted as a result of the healthy worker effect. For all cancers combined the mortality (SMR = 1.08, 95% CI 0.68-1.67) and morbidity (SMR = 1.02, 95% CI 0.72-1.38) were comparable with those of the general population. There were increased incidences for brain tumours (SMR = 2.19, 95% CI 0.45-6.39), gastric cancers (SMR = 2.73, 95% CI, 1.00-5.94), and renal cancers (SMR = 1.68, 95% CI = 0.35-4.90). For lung cancer the risk was reduced (SMR = 0.70, 95% CI 0.15-2.05). Allowance for a latency period of 10 years from the start of exposure did not change the pattern. Logistic modelling was used to search for exposure-response relations. In a logistic model with the confounder age forced in, renal cancer had a significant positive relation with a weighted sum of employment times, where the weights describe the classification of exposure. No exposure-response relations were found for brain tumors or gastric cancers. The increased risks are based on small numbers of cases. A future follow up will add more conclusive power to the study. Specific exposures need to be identified to allow for a better dose-response analysis.     

Occupational exposure to phenoxy herbicides and chlorophenols and cancer mortality in The Netherlands

As part of the "IARC International Register of Persons Exposed to Phenoxy Herbicides and Contaminants," a cohort of workers who manufacture and prepare chlorophenoxy herbicides was recruited in The Netherlands. The cohort comprised 2,310 workers from two plants, operated by different companies, who were followed during the periods 1955-1985 and 1965-1986, respectively. In 1963, there had been an industrial accident in one factory with concomitant release of dioxin into the environment. Loss to follow-up was 3%. Mortality data on 963 exposed and 1,111 nonexposed men were evaluated by external and internal comparison. Compared with national rates, total mortality (94 deaths, standardized mortality ratio [SMR] = 101; 95% confidence interval [CI], 82-124) and cancer mortality (31 deaths, SMR = 107; 95% CI, 73-152) for exposed workers were not significantly increased. A statistically insignificant increase was observed for non-Hodgkin's lymphoma (2 deaths, SMR = 299; 95% CI, 36-1,078). No cases of soft-tissue sarcoma were encountered. There was no increase in either total mortality (25 deaths, SMR = 111; 95% CI, 72-163) or cancer mortality (10 deaths, SMR = 137; 95% CI, 66-252) among the 139 workers probably exposed to dioxins during the 2,4,5-trichlorophenol production accident or the subsequent clean-up operations. Compared with nonexposed workers, exposed workers did not exhibit a higher total mortality (rate ratio [RR] = 1.28; 95% CI, 0.89-1.82). Mortality due to all cancers (RR = 1.7; 95% CI, 0.9-3.4) and respiratory cancer (RR = 1.7; 95% CI, 0.5-6.3) was insignificantly elevated. These findings suggest that the increases in cancer mortality among workers exposed to phenoxy herbicides and chlorophenols may be attributable to chance. Lack of power prevented evaluation with respect to specific cancers.     

Renal biopsy diagnosis in children presenting with haematuria

OBJECTIVES: This study considers the cause-specific mortality from cancer among art glass workers employed in 17 industrial facilities in Tuscany, Italy. METHODS: A cohort of 3390 workers, 3180 men and 210 women, employed at least 1 year, was taken from company payrolls. It was followed between the year each factory started operation, mostly the mid-1950s, and 31 December 1993. The cause-specific expected mortality from cancer was computed for men relative to Tuscany rates, specified for gender, 5-year age groups, and calendar year. Separate analyses were carried out for the job title of maker and former and for batch mixers. RESULTS: For 3180 men, the observed mortality was above the expected for larynx [standardized mortality ratio (SMR) 166, 90% confidence interval (90% CI) 90-282], lung (SMR 123, 90% CI 100-151), stomach (SMR 105, 90% CI76-142), and brain (SMR 150, 90%CI 71-282) cancer. Increases for these causes were also found for the makers and formers. Mortality from larynx and lung cancer increased with latency, and significantly increased SMR values were observed for > or =21 years since first exposure. The increasing pattern was also present after adjustment for smoking. CONCLUSIONS: The results showed consistently increased mortality from larynx and lung cancer in the overall cohort and among makers and formers. Stomach and brain cancer was also increased in the overall cohort and among the makers and formers.     

Does living near a constellation of petrochemical, steel, and other industries impair health?

OBJECTIVES: To investigate concern that local industrial air pollution in Teesside, England, was causing poor health, several areas there were compared with parts of the City of Sunderland. METHODS: Populations in similar social and economic circumstances but varying in their proximity to major industries were compared. Study populations lived in 27 housing estates in Teesside and Sunderland, north east England, with some data from subsets of estates. The estates were aggregated into zones (designated as A, B, and C in Teesside where A is closest to and C furthest from industry, and S in Sunderland). Zone S provided a reference area. The hypothesis was that a health gradient both within Teesside (A > B > C) and between Teesside and Sunderland (ABC > S) would indicate a possible health effect of local industrial air pollution. Data presented were: mortality (1981-91) from 27 housing estates; population self completion questionnaire survey data (1993, 9115 subjects) from 15 housing estates; and general practitioner (GP) consultation data (1989-94) from 2201 subjects in 12 Teesside estates. RESULTS: The populations in the four zones were comparable for indicators including smoking habits, residential histories, and unemployment. All cause and cause specific mortalities were high compared with England and Wales. Mortality in all Teesside zones (ABC) combined was mostly higher than in zone S. In people aged 0-64, lung cancer and respiratory disease showed gradients with highest mortality in areas closest to industry (A > B > C and ABC > S). The association was clearest for lung cancer in women (0-64 years old, trend across zones ABC, p = 0.07, directly standardised rate ratio relative to zone S was 169 (95% confidence interval (95% CI) 116-122)). There were no important, consistent gradients in the hypothesised direction between zones in consultation rates in general practice, and self reported respiratory and nonrespiratory health including asthma. CONCLUSIONS: There was no clear evidence that living close to industry was associated with morbidity, including asthma, or for most measures of mortality. For lung cancer in women the gradients indicated a health effect of local industrial air pollution. In the age group 0-64 observed gradients in lung cancer in men and mortality from respiratory disease in men and women were consistent with the study hypothesis, although not significant. The reasons for the different patterns at different ages, and between men and women, remain a puzzle.     

Stress and a glycinergic intervention interact in the modulation of MK-801-elicited mouse popping behavior

Cancer mortality in a population-based cohort of 10,322 parkinsonian patients (448 deaths observed during 1987 to 1994) was compared with that of the Italian province of Rome using the standardized mortality ratio (SMR). The overall cancer mortality risk was lower in this cohort than in the reference population (SMR, 56; 95% CI, 51 to 61). This reduction included most cancer sites as well as both smoking-related (SMR, 51; 95% CI, 42 to 60) and nonsmoking-related cancers (SMR, 58; 95% CI, 52 to 65). The observed reduction in cancer mortality risk in this cohort cannot be explained entirely by the hypothesis that smokers are less likely to develop PD.     

Dietary determinants of ischaemic heart disease in health conscious individuals

OBJECTIVE: To investigate dietary determinants of ischaemic heart disease (IHD) in health conscious individuals to explain the reduced risk in vegetarians, and to examine the relation between IHD and body mass index (BMI) within the normal range. DESIGN: Prospective observation of vegetarians, semi-vegetarians, and meat eaters for whom baseline dietary data, reported weight and height information, social class, and smoking habits were recorded. SUBJECTS: 10,802 men and women in the UK aged between 16 and 79, mean duration of follow up 13.3 years. MAIN OUTCOME MEASURES: Death rate rations for IHD and total mortality in relation to dietary and other characteristics recorded at recruitment (reference category death rate = 100). RESULTS: IHD mortality was less than half that expected from the experience reported for all of England and Wales. An increase in mortality for IHD was observed with increasing intakes of total and saturated animal fat and dietary cholesterol-death rate ratios in the third tertile compared with the first tertile: 329, 95% confidence interval (CI) 150 to 721; 277, 95% CI 125 to 613; 353, 95% CI 157 to 796, respectively. No protective effects were observed for dietary fibre, fish or alcohol. Within the study, death rate ratios were increased among those in the upper half of the normal BMI range (22.5 to < 25) and those who were overweight (BMI > or = 25) compared with those with BMI 20 to < 22.5. CONCLUSIONS: In these relatively health conscious individuals the deleterious effects of saturated animal fat and dietary cholesterol appear to be more important in the aetiology of IHD than the protective effect of dietary fibre. Reduced intakes of saturated animal fat and cholesterol may explain the lower rates of IHD among vegetarians compared with meat eaters. Increasing BMI within the normal range is associated with increased risk of IHD. The results have important public health implications.     

Socioeconomic status within social class and mortality: a prospective study in middle-aged British men

OBJECTIVE: It has been suggested that mortality differences between groups in society may be greater than are indicated by social class based on occupation. We have examined the relationship between social class and mortality using home and car ownership as additional indices of socioeconomic status within social class. DESIGN: A prospective study of a cohort of men representative of the social class distribution of middle-aged men in Great Britain. SETTING: One general practice in each of 24 towns in England, Wales and Scotland. SUBJECTS: Five years after the initial screening of 7735 men aged 40-59 years, 7262 men (94% of the original cohort) provided information on housing tenure and car ownership by completing a postal questionnaire. MAIN OUTCOME MEASURE: Deaths from all causes, cardiovascular, cancer and other non-cardiovascular causes during an average follow-up of 9.8 years (range 8.5-11.0 years) after the postal questionnaire. RESULTS: During the follow-up period there were 946 deaths from all causes among the 7262 men. The lowest mortality rates for all causes, cardiovascular, cancer and other non-cardiovascular causes were seen in non-manual social classes I and II. Manual social classes III and IV+V showed a significant 40% increase in risk of death compared to social classes I+II, even after adjustment for a wide range of risk factors (relative risk [RR] = 1.4, 95% confidence interval [CI]: 1.2-1.7 and RR = 1.4, 95% CI: 1.1-1.7 respectively). Within all social class groups, those owning both home and car showed lower rates than those who owned neither, even after adjustment for a wide range of risk factors and employment status. Compared with social classes I+II owning both home and car, all those not owning home and/or car, in each social group, showed a significant approximately twofold increase in risk of death. Adjusted RR for non-manual I+II = 2.1 (95% CI: 1.5-2.9), non-manual III RR = 2.0 (95% CI: 1.3-2.9), manual III RR = 1.8 (95% CI: 1.4-2.4) and manual IV+V RR = 1.8 (95% CI: 1.3-2.5). Similar relationships were seen in all major geographical regions of Great Britain. CONCLUSION: Mortality differences within society are greater than indicated by social class based on occupation alone. Irrespective of social class, men with greater material assets have lower rates of mortality from all causes than men less well endowed, independent of a wide range of lifestyle and biological factors. These findings suggest that mortality differences within our society are closely related to relative wealth.     

Lobar pneumonia: an occupational disease in welders

We have used data from three analyses of occupational mortality for England and Wales to investigate a suspected hazard of pneumonia in welders. Mortality from the disease was consistently raised in welders aged 15-64, with standardised mortality ratios of 184 (95% CI 150-224) in 1959-63 and 157 (121-200) in 1970-72. Analysis of data for 1979-80 and 1982-90 showed that the increased risk is attributable mainly to an excess of pneumococcal and unspecified lobar pneumonia (proportional mortality ratio 255, 95% CI 192-332). No excess occurred in men above retirement age (65). A possible explanation of these findings is that welding fume reversibly increases the susceptibility of the lung to pneumonic infection. The observation of a similar mortality pattern in moulders and coremakers points to the metallic component of the fume as a possible culprit, but ozone or oxides of nitrogen could also be implicated. There are grounds for lobar pneumonia to be considered an occupational disease in welders.     

Risk of gastric cancer in pneumoconiotic coal miners and the effect of respiratory impairment

OBJECTIVES: This study was carried out to investigate the mortality patterns in a group of 3790 coal miners. The study population had abnormal chest x ray films at a routine medical examination that was performed in the 1950s. METHODS: The total group of 3790 coal miners were followed up for mortality up to 1 January 1992. Causes of death, determined and coded at time of death, were traced with help from the Central Bureau of Statistics. RESULTS: Total mortality in this group of coal miners with abnormal chest x ray films was significantly higher than expected (SMR 127.1, 95% CI 122.5-131.6), mainly a reflection of the increase in mortality from non-malignant respiratory disease (SMR 411.0, 95% CI 382.3-441.3). Mortality from gastric cancer was also significantly increased (SMR 147.5, 95% CI 122.3-176.3). This risk of mortality from gastric cancer was confined to workers with no pneumoconiosis or only a mild form. Despite the strong relation to duration of employment and pneumoconiosis the group of workers with more severe manifestations of pneumoconiosis did not experience an excess in mortality from gastric cancer. CONCLUSION: This study confirms the earlier reported risk of gastric cancer in coal miners. Also it confirms the hypothesis that this risk of gastric cancer is limited to workers with a mild degree of pneumoconiosis or none. In workers with severe forms of pneumoconiosis the pulmonary clearance system is impaired in such a way that the inhaled coal dust does not reach the digestive tract.     

The Estonian study of Chernobyl cleanup workers: II. Incidence of cancer and mortality

A cohort of 4,742 men from Estonia who had participated in the cleanup activities in the Chernobyl area sometime between 1986 and 1991 and were followed through 1993 was analyzed with respect to the incidence of cancer and mortality. Incidence and mortality in the cleanup workers were assessed relative to national rates. No increases were found in all cancers (25 incident cases compared to 26.5 expected) or in leukemia (no cases observed, 1.0 expected). Incidence did not differ statistically significantly from expectation for any individual cancer site or type, though lung cancer and non-Hodgkin's lymphoma both occurred slightly more often than expected. A total of 144 deaths were observed [standardized mortality ratio (SMR) = 0.98; 95% confidence interval (CI) = 0.82-1.14] during an average of 6.5 years of follow-up. Twenty-eight deaths (19.4%) were suicides (SMR = 1.52; 95% CI = 1.01-2.19). Exposure to ionizing radiation while at Chernobyl has not caused a detectable increase in the incidence of cancer among cleanup workers from Estonia. At least for the short follow-up period, diseases directly attributable to radiation appear to be of relatively minor importance when compared with the substantial excess of deaths due to suicide.     

Mortality due to pancreatic and lymphopoietic cancers in chlorohydrin production workers

Men assigned to the chlorohydrin unit of Union Carbide's South Charleston plant in the Kanawha Valley of West Virginia were followed up for mortality from 1940 to the end of 1988. This 10 year update was conducted to verify previous findings of excesses of cancer among the 278 men assigned to the chlorohydrin unit, which primarily produced ethylene chlorohydrin from 1925 to 1957. This process produced ethylene dichloride and bischloroethyl ether as byproducts. Mean duration of assignment was 5.9 years and mean duration of follow up was 36.5 years. Standardised mortality ratios (SMRs) were calculated based on comparisons with the United States white male population. Duration-response trends were assessed by internal comparisons with two different groups of unexposed chemical workers in the Kanawha Valley. The evidence that the earlier finding of an excess of pancreatic cancer was work related is strengthened by the occurrence of two additional cases (0.9 expected). The SMR for pancreatic cancer was 492 (95% CI 158-1140), based on eight observed v 1.6 expected deaths. There were no additional deaths due to leukaemia, but the three to four-fold excess risk for lymphopoietic cancers persisted due to new cases of non-Hodgkin's lymphoma and a death from multiple myeloma. The SMR for lymphatic and haematopoietic cancers was 294 (eight observed v 2.7 expected; 95% CI 127-580). Pronounced increases in risk were seen for total cancer, pancreatic cancer, all lymphatic and haematopoietic cancers, and leukaemia with increasing durations of assignment to the chlorohydrin unit. Most of the cases were first assigned to the unit in the 1930s when chemical manufacturing was in its infancy and exposures were less controlled. These data are insufficient to identify conclusively the causative agent or agents. The weight of evidence, however, based on probable exposure, known toxicity of the chemicals, and animal responses suggest that high exposures to ethylene dichloride, perhaps in combination with other chlorinated hydrocarbons, is the most likely explanation.