Mortality among firefighters from three northwestern United States cities.

To explore whether exposure among firefighters to fire smoke could lead to an increased risk of cancer, lung disease, and heart disease, the mortality of 4546 firefighters who were employed by the cities of Seattle and Tacoma, WA and Portland, OR for at least one year between 1944 and 1979 were compared with United States national mortalities and with mortality of police officers from the same cities. Between 1945 and 1989, 1169 deaths occurred in the study population and 1162 death certificates (99%) were collected. Mortality due to all causes, ischaemic heart disease, and most other non-malignant diseases was less than expected based upon United States rates for white men. There was no excess risk of overall mortality from cancer but excesses of brain tumours (standardised mortality ratio (SMR) = 2.09, 95% confidence interval (95% CI) 1.3-3.2) and lymphatic and haematopoietic cancers (SMR = 1.31, 95% CI = 0.9-1.8) were found. Younger firefighters (< 40 years of age) appeared to have an excess risk of cancer (SMR = 1.45, 95% CI 0.8-2.39), primarily due to brain cancer (SMR = 3.75, 95% CI 1.2-8.7). The risk of lymphatic and haematopoietic cancers was greatest for men with at least 30 years of exposed employment (SMR = 2.05, 95% CI 1.1-3.6), especially for leukaemia (SMR = 2.60, 95% CI 1.0-5.4).     

Mortality in Florida professional firefighters, 1972 to 1999

BACKGROUND: Exposure to occupational hazards among firefighters may lead to increased mortality from cancer, lung, or heart disease. METHODS: Age- and gender-adjusted mortality rates of 34,796 male and 2,017 female Florida professional firefighters between 1972 and 1999 were compared with the Florida general population. RESULTS: One thousand four hundred eleven male and 38 female firefighter deaths with known causes were identified. In male firefighters, mortality due to all causes and most non-malignant diseases was significantly less than expected. There was no excess overall mortality from cancer, but excesses existed for male breast cancer [standardized mortality ratio (SMR = 7.41; 95% confidence interval (CI): 1.99-18.96) and thyroid cancer (SMR = 4.82; 95% CI: 1.30-12.34)]. Mortality from bladder cancer was increased and approached statistical significance (SMR = 1.79; 95% CI: 0.98-3.00). Firefighters certified between 1972 and 1976 had excess mortality from bladder cancer (SMR = 1.95; 95% CI: 1.04-3.33). Female firefighters had similar morality patterns to Florida women except for atherosclerotic heart disease (SMR = 3.85; 95% CI: 1.66-7.58). CONCLUSIONS: Excess mortality risk from bladder cancer may be related to occupational exposure during firefighting. The thyroid cancer and breast cancer risk in males, as well as the excess risk of cardiovascular disease mortality noted in females warrant further investigation.     

Lymphatic and haematopoietic cancer mortality in a population attending school adjacent to styrene-butadiene facilities, 1963-1993

STUDY OBJECTIVE: To evaluate the risk of mortality from lymphatic and haematopoietic cancers and other causes among students. DESIGN: The study used school records, yearbooks, and Texas Department of Health records for the school years 1963-64 to 1992-93 to construct a cohort of 15,403 students. Three mortality databases were searched to identify deaths, and mortality rates in the cohort were compared with mortality rates from the United States and Texas. Computed standardised mortality ratios and 95% confidence intervals were used. SETTING: Eastern Texas high school adjacent to facilities that have been producing synthetic styrene-butadiene since 1943. MAIN RESULTS: 338 deaths were identified. The all causes standardised mortality ratio was 0.84 (95% confidence intervals 0.74, 0.95) for men and 0.89 (0.73, 1.09) for women. The standardised mortality ratio for all lymphatic and haematopoietic cancers was 1.64 (95% confidence intervals 0.85, 2.87) for men and 0.47 (0.06, 1.70) for women. The slight male excess in lymphatic and haematopoietic cancers was stronger among men who attended school for two years or less. CONCLUSIONS: The overall mortality from lymphatic and haematopoietic cancer among the students was little different from that of the United States as a whole. A moderate excess for men, predominantly among the shorter-term students, was offset by a deficit among women. These variations are compatible with random fluctuations; the overall pattern is not indicative of an effect of environmental exposure sustained while attending the high school.     

Cohort mortality study of Philadelphia firefighters

BACKGROUND: Fire fighters are exposed to a wide variety of toxic chemicals. Previous studies have reported excess risk of some cancers but have been limited by small numbers or little information on employment characteristics. METHODS: We conducted a retrospective cohort mortality study among 7,789 Philadelphia firefighters employed between 1925 and 1986. For each cause of death, the standardized mortality ratios (SMRs) and 95% confidence intervals were estimated. We also compared mortality among groups of firefighters defined by the estimated number of career runs and potential for diesel exposure. RESULTS: In comparison with U.S. white men, the firefighters had similar mortality from all causes of death combined (SMR = 0.96) and all cancers (SMR = 1.10). There were statistically significant deficits of deaths from nervous system diseases (SMR = 0.47), cerebrovascular diseases (SMR = 0.83), respiratory diseases (SMR = 0.67), genitourinary diseases (SMR = 0.54), all accidents (SMR = 0.72), and suicide (SMR = 0.66). Statistically significant excess risks were observed for colon cancer (SMR = 1.51) and ischemic heart disease (SMR = 1.09). The risks of mortality from colon cancer (SMR = 1.68), kidney cancer (SMR = 2.20), non-Hodgkin's lymphoma (SMR = 1.72), multiple myeloma (SMR = 2.31), and benign neoplasms (SMR = 2.54) were increased among firefighters with at least 20 years of service. CONCLUSIONS: Our study found no significant increase in overall mortality among Philadelphia firefighters. However, we observed increased mortality for cancers of the colon and kidney, non-Hodgkin's lymphoma and multiple myeloma. There was insufficient follow-up since the introduction of diesel equipment to adequately assess risk.     

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.     

Cancer and other mortality patterns among United States furniture workers

Cause specific mortality was investigated among 36,622 members of a national furniture workers' union who were first employed in unionised shops between 1946 and 1962. Overall mortality for each race and sex group was less than expected when compared with United States death rates (white men SMR = 0.8, black men SMR = 0.7, white women SMR = 0.8, black women SMR = 0.5); however, raised risks were observed among white men employed in specific types of furniture industries and followed up for 20 or more years after first employment. Lymphatic and haematopoietic cancers were significantly raised (SMR = 1.8) among wood furniture workers followed up for at least 20 years due to excess deaths from leukaemia (SMR = 2.0) and non-Hodgkin's lymphoma (SMR = 2.0). Mortality from acute myeloid leukaemia was particularly high in this group (SMR = 4.7) based on six observed cases. Metal furniture workers followed up for at least 20 years experienced a significant excess of all cancers combined (SMR = 1.6), with non-significant increases in cancers of the lung, stomach, and colorectum. This group also had non-significant excesses of liver cirrhosis, arteriosclerotic heart disease, and cerebrovascular disease. Nasal cancer was not found to be significantly raised in this cohort, though the average follow up period may not have been sufficient to detect an excess risk for this uncommon tumour.     

Cancer and other mortality patterns among United States furniture workers.

Cause specific mortality was investigated among 36,622 members of a national furniture workers' union who were first employed in unionised shops between 1946 and 1962. Overall mortality for each race and sex group was less than expected when compared with United States death rates (white men SMR = 0.8, black men SMR = 0.7, white women SMR = 0.8, black women SMR = 0.5); however, raised risks were observed among white men employed in specific types of furniture industries and followed up for 20 or more years after first employment. Lymphatic and haematopoietic cancers were significantly raised (SMR = 1.8) among wood furniture workers followed up for at least 20 years due to excess deaths from leukaemia (SMR = 2.0) and non-Hodgkin's lymphoma (SMR = 2.0). Mortality from acute myeloid leukaemia was particularly high in this group (SMR = 4.7) based on six observed cases. Metal furniture workers followed up for at least 20 years experienced a significant excess of all cancers combined (SMR = 1.6), with non-significant increases in cancers of the lung, stomach, and colorectum. This group also had non-significant excesses of liver cirrhosis, arteriosclerotic heart disease, and cerebrovascular disease. Nasal cancer was not found to be significantly raised in this cohort, though the average follow up period may not have been sufficient to detect an excess risk for this uncommon tumour.     

Respiratory mortality among firefighters

Although firefighters have been shown in some studies to suffer chronic respiratory morbidity from their occupational exposures, an increased risk for dying from non-malignant respiratory diseases has not been documented in any previous retrospective cohort mortality study. In order to assess the possibility that an unusually strong "healthy worker effect" among firefighters might mask this increased risk, a mortality analysis of firefighters was carried out in three cities in relation to the United States population and also to a comparison cohort of police officers. The firefighters were employed between 1945 and 1980 and experienced 886 deaths by 1 January 1984; compared with the United States population they had a significantly reduced risk of dying from all causes (SMR = 82, 95% confidence interval, 77-87), and from non-malignant circulatory diseases (SMR = 81, 95% confidence interval 73-89), but no significant difference in risk of non-malignant respiratory diseases (SMR = 88, 95% confidence interval 66-117). Compared with police, the firefighters experienced a trend toward improved mortality outcomes for all causes investigated (SMR = 82), but they had an excess of deaths from non-malignant respiratory diseases (SMR = 141). The results indicate that firefighters are probably at increased risk for dying from non-malignant respiratory diseases; this increased risk may have been missed in previous studies because of the limitations of using a general reference population.     

Respiratory mortality among firefighters.

Although firefighters have been shown in some studies to suffer chronic respiratory morbidity from their occupational exposures, an increased risk for dying from non-malignant respiratory diseases has not been documented in any previous retrospective cohort mortality study. In order to assess the possibility that an unusually strong "healthy worker effect" among firefighters might mask this increased risk, a mortality analysis of firefighters was carried out in three cities in relation to the United States population and also to a comparison cohort of police officers. The firefighters were employed between 1945 and 1980 and experienced 886 deaths by 1 January 1984; compared with the United States population they had a significantly reduced risk of dying from all causes (SMR = 82, 95% confidence interval, 77-87), and from non-malignant circulatory diseases (SMR = 81, 95% confidence interval 73-89), but no significant difference in risk of non-malignant respiratory diseases (SMR = 88, 95% confidence interval 66-117). Compared with police, the firefighters experienced a trend toward improved mortality outcomes for all causes investigated (SMR = 82), but they had an excess of deaths from non-malignant respiratory diseases (SMR = 141). The results indicate that firefighters are probably at increased risk for dying from non-malignant respiratory diseases; this increased risk may have been missed in previous studies because of the limitations of using a general reference population.     

Update of the Texaco mortality study 1947-93: Part I. Analysis of overall patterns of mortality among refining, research, and petrochemical workers

OBJECTIVE: To update information on the workers of the Texaco mortality study to determine if the patterns of mortality have changed with 16 additional years of follow up. SUBJECTS AND METHODS: All workers were employed for > or = 5 years at company refineries, petrochemical plants, and research laboratories from 1947-93. The cohort now consists of 28,480 employees with an average of > or = 20 years of follow up. RESULTS: The overall mortality, and most cause specific mortalities were lower than or similar to those for the general population of the United States. For white men (86% of the cohort), there were 8873 observed deaths and 11,181 expected resulting in a significantly lower standardised mortality ratio (SMR) of 79. There were significant deficits for all the leading causes of death in the United States including all cancers, cancer of the lung, stroke, heart disease, respiratory disease, and accidents. Slightly increased mortality was found for cancer of the pancreas, cancer of the brain and central nervous system, leukaemia, and cancer of other lymphatic tissue. For cancer of the bone, the SMR was 162 (95% confidence interval (95% CI) 86 to 278), and for benign and unspecified neoplasms, it was 152 (95% CI 109 to 206). Overall mortality patterns for non-white men and women were similar to those for white men. Mortality patterns for white men were also examined by duration of employment, time first employed, location, and by job and process unit. There were significantly increased SMRs for brain cancer for those people employed as laboratory workers and on units with motor oil and for cancer of other lymphatic tissue for people employed on the fluid catalytic cracking unit. CONCLUSIONS: The results of the updated study showed a favourable mortality experience for employees in the Texaco mortality study compared with the United States population. There were a few increases found consistently including, but not limited to, brain cancer and cancer of other lymphatic tissue. These increases led to additional analyses that will be discussed in the accompanying paper.

 

     

A cohort mortality study of employees in the U.S. carbon black industry

OBJECTIVES: The objectives of this study are to evaluate historical mortality patterns, especially due to cancers, among employees of the U.S. carbon black industry and to address the methodological shortcomings of previous U.S. mortality studies. METHODS: We followed mortality of 5011 workers employed 1 year or more since the 1930s at 18 carbon black facilities through December 31, 2003. Age-, race-, sex-, and calendar year-adjusted standardized mortality ratios (SMRs) were calculated using state-specific mortality rates. RESULTS: Follow up was 96% complete. All-cause (SMR = 0.74, 95% confidence interval [CI] = 0.70-0.78) and all-cancer mortality (SMR = 0.83, 95% CI = 0.74-0.92) showed significant deficits. No excess was observed from lung (SMR = 0.97, 95% CI = 0.82-1.15) or bladder (SMR = 0.93, 95% CI = 0.47-1.87) cancers or from nonmalignant respiratory diseases (SMR = 0.99, 95% CI = 0.83-1.18). No trends were seen with duration of employment or time since hire for any cause of death. CONCLUSION: Employment in carbon black production in the United States seems not to be associated with increased mortality overall, cancer overall and, in particular, lung cancer. Further research, however, incorporating a detailed exposure assessment is needed to determine whether exposure to carbon black at high levels may be associated with an increased risk of cancer.     

Mortality and incidence of cancer in a cohort of Swedish chimney sweeps: an extended follow up study.

Despite 200 years of efforts to regulate safety in this occupation, chimney sweeps have increased mortality from cancer, ischaemic heart disease, and respiratory disease. Mortality and incidence of cancer were examined in a cohort of 5542 Swedish chimney sweeps employed through their national trade union at any time between 1918 and 1980. Previous studies of this cohort found increased risks of ischaemic heart disease, respiratory disease, accidental deaths, and various neoplasms. By increasing follow up, we sought to increase the power of the study and examine disease time trends. Mortality analysis was extended 7.5 years to cover the period 1951-90; cancer incidence analysis was extended six years to cover the period 1958-87. New findings include increased incidence and mortality of prostate cancer (SMR 169, 95% CI 106-256, 22 observed) and increased incidence of total haematolymphatic cancers (SIR 151, 95% CI 106-209, 36 observed). When only the most recent follow up period was analysed, previously observed risks persisted for total lung cancer (SIR 178, 95% CI 99-293), oat cell lung cancer (SIR 240, 95% CI 103-472), bladder cancer (SIR 247, 95% CI 131-422), and oesophageal cancer (Obs/Exp = 2/1.1). Mortality from ischaemic heart disease (SMR 98, 95% CI 76-123) and respiratory disease (SMR 111, 95% CI 56-199) declined during recent follow up, although significant excess mortality remained during analysis of the entire study period (ischaemic heart disease SMR 128, 95% CI 112-145; respiratory disease SMR 159, 95% CI 115-213). In analyses of the entire study period, risks of ischaemic heart disease and lung, bladder, and oesophageal cancer were adjusted for smoking; oesophageal cancer was also adjusted for use of alcohol. All risks remained significantly raised. Exposure-response analyses showed significant positive associations between duration of employment and risks for mortality from lung, oesophageal, and total cancer. Chimney sweeps remain at increased risk for cancers of the lung, oesophagus, and bladder. Our study supports a casual role for exposure to chimney soot, which contains carcinogens including polycyclic aromatic hydrocarbons. Extended follow up of this cohort now shows increased risks of prostate and haematolymphatic cancers.     

Haematopoietic cancer mortality among vehicle mechanics.

OBJECTIVE AND METHODS--This historical cohort study investigated causes of death among car and mobile equipment mechanics in the District of Columbia's Department of Public Works. Men who were employed for at least one year between 1977 and 1989 were eligible for inclusion in the cohort; follow up was up to the end of 1991. Three cases of leukaemia (index cases) had been reported among these workers before the inception of this study. This research was undertaken to estimate the relative risk of haematological cancer among mechanics working for the District of Columbia. RESULTS--Among the 335 male fleet maintenance workers, the all cause standardised mortality ratio (SMR) was 0.50 (33 observed deaths, 95% confidence interval (95% CI) 0.35-0.70), and the all cancer SMR was 0.55 (nine deaths, 95% CI 0.25-1.05). Three deaths from lymphatic and haematopoietic cancer were observed; the SMR was 3.63 (95% CI 0.75-10.63). In the subgroup with highest potential for exposure to fuels and solvents, the SMR for leukaemia and aleukaemia was 9.26 (two deaths, 95% CI 1.12-33.43), and the SMR for other lymphatic and haematopoietic neoplasms was 2.57 (one death from malignant lymphoma, 95% CI 0.06-14.27). All three lymphatic and haematopoietic cancer deaths were among car and mobile equipment mechanics (one was an index case). The two additional index cases were a fourth mechanic who died of leukaemia in 1992, after mortality follow up ended, and a fifth mechanic who was diagnosed with leukaemia in 1988 and is still alive. CONCLUSION--Many garage mechanics in this cohort regularly used petrol to clean parts and to wash their hands; some workers would occasionally siphon petrol by mouth. Benzene, a recognised cause of haematological cancer, is a component of petrol. Previous research indicates that garage mechanics may be at risk of leukaemia and other haematological cancers, presumably due to exposure to petrol; this study supports those findings.     

Mortality among Catholic nuns certified as radiologic technologists

BACKGROUND: Several studies have shown that Catholic nuns have a different mortality experience than women of similar age in the general population. We had a unique opportunity to evaluate mortality patterns of nuns identified in an occupational study of nearly 145,000 radiologic technologists (73% female). METHODS: A total of 1,103 women were classified as nuns based on their titles of "Sister" or "SR". Their mortality experience was compared to other female radiologic technologists and to U.S. white females. RESULTS: Five hundred eighty-three nuns (53%) were deceased as of January 1, 1995. Compared to other technologists, nuns were at significantly increased risk of dying from all causes (Standardized mortality ratio (SMR)=1.1; 95% Confidence interval (CI)=1.0-1.2, stomach cancer (SMR=2.7; 95% CI=1.2-5.4), diabetes (SMR=2.2; 95% CI=1.0-4.1), ischemic heart disease (SMR=1.2; 95% CI=1.1-1.4), all digestive diseases (SMR=2.0; 95% CI=1.3-3.0), and gastric and duodenal ulcers (SMR=8.3; 95% CI=2.3-21.3). In contrast, we observed a significant deficit in lung cancer (SMR=0.5; 95% CI=0.2-0.9), no deaths from cervical cancer, and a breast cancer risk 10% lower than expected (SMR=0.9; 95% CI=0.6-1.3). When compared to U.S. females, nuns experienced significantly reduced mortality from all causes (SMR=0.8; 95% CI=0.7-0.9), cervical cancer (SMR=0.0; 95% CI=0.0-0.7), all endocrine, metabolic and nutritional diseases (SMR=0.5; 95% CI=0.3-0.9), all circulatory diseases (SMR=0.7; 95% CI=0.7-0.8) including ischemic heart disease and cerebrovascular disease, and all respiratory diseases (SMR=0.5; 95% CI=0.3-0.8), and a nearly significant deficit of diabetes (SMR=0.6; 95% CI=0.3-1.0). In contrast, nuns had an almost 3-fold greater risk of tuberculosis (SMR=2.9; 95% CI=1.4-5.3) and a 20% excess of breast cancer (SMR=1. 2; 95% CI=0.8-1.7). The breast cancer excess was concentrated among nuns first certified before 1940 (SMR=2.0; CI=1.3-3.0), when radiation doses were possibly the highest, but the risk did not increase with increasing length of certification. CONCLUSIONS: Compared with the general population, the mortality experience of nuns was favorable and reflected the "healthy worker effect" commonly seen in occupational studies. Patterns observed for breast and cervical cancer possibly indicate differences in reproductive and sexual activities associated with belonging to a religious order. The possibility of a radiation-related excess for breast cancer among nuns certified before 1940 cannot be completely discounted, although there was no dose-response relationship with a surrogate measure of exposure (number of years certified). When their mortality experience was compared with other radiologic technologists, the influence of lifestyle factors was not apparent. Am. J. Ind. Med. 37:339-348, 2000. Published 2000 Wiley-Liss, Inc. dagger     

Mortality in a historical cohort of bus drivers

In an attempt to address previously reported excesses of ischaemic heart disease (IHD), lung cancer and bladder cancer among professional drivers, the mortality (SMR) of 2134 Montreal city bus drivers employed for at least five years as of January 1962 and followed until 31 December 1985 was compared with that of the male population of greater Montreal. The vital status of 94% of the cohort was ascertained. The number of deaths observed was 804. The overall mortality was somewhat lower than expected (SMR = 97). A small, non-significant excess mortality was found for ischaemic heart disease (IHD) (O/E = 313/295, SMR = 106, 95% CI: 95-118) and circulatory system diseases (O/E = 441/405, SMR = 109, 95% CI: 99-119). However, no excesses were observed for lung cancer (O/E = 78/84.4, SMR = 92, 95% CI: 73-114) or bladder cancer (O/E = 4/7.4, SMR = 54, 95% CI: 15-138). These results are compatible with other studies which have found a small risk of IHD for bus drivers.     

Mortality from cancer and other causes among airline cabin attendants in Germany, 1960-1997

Airline cabin attendants are exposed to several potential occupational hazards, including cosmic radiation. Little is known about the mortality pattern and cancer risk of these persons. The authors conducted a historical cohort study among cabin attendants who had been employed by two German airlines in 1953 or later. Mortality follow-up was completed through December 31, 1997. The authors computed standardized mortality ratios (SMRs) for specific causes of death using German population rates. The effect of duration of employment was evaluated with Poisson regression. The cohort included 16,014 women and 4,537 men (approximately 250,000 person-years of follow-up). Among women, the total number of deaths (n = 141) was lower than expected (SMR = 0.79, 95% confidence interval (CI): 0.67, 0.94). The SMR for all cancers (n = 44) was 0.79 (95% CI: 0.54, 1.17), and the SMR for breast cancer (n = 19) was 1.28 (95% CI: 0.72, 2.20). The SMR did not increase with duration of employment. Among men, 170 deaths were observed (SMR = 1.10, 95% CI: 0.94, 1.28). The SMR for all cancers (n = 21) was 0.71 (95% CI: 0.41, 1.18). The authors found a high number of deaths from acquired immunodeficiency syndrome (SMR = 40; 95% CI: 28.9, 55.8) and from aircraft accidents among the men. In this cohort, ionizing radiation probably contributed less to the small excess in breast cancer mortality than reproductive risk factors. Occupational causes seem not to contribute strongly to the mortality of airline cabin attendants.     

A cohort study on the mortality of firefighters.

This study was set up to investigate the effect of exposure to combustion effluents on the chronic health of firefighters. A cohort of firefighters was followed up through 10 years with regard to cause specific mortality. Comparisons were made with another cohort of civil servants and salaried employees in physically demanding jobs. After a latency of five years, an excess mortality from cancer was seen for persons aged 30 to 74 (standardised mortality ratio (SMR) 173, 95% confidence interval (95% CI) 104-270). A significant increase in lung cancer was seen in the group aged 60 to 74 (SMR 317, 95% CI 117-691), whereas non-pulmonary cancer was significantly increased in the group aged 30 to 49 (SMR 575, 95% CI 187-1341). It is concluded that inhalation of carcinogenic and toxic compounds during firefighting may constitute an occupational cancer risk. An extended use of respiratory protective equipment is advocated.     

A cohort study on the mortality of firefighters

This study was set up to investigate the effect of exposure to combustion effluents on the chronic health of firefighters. A cohort of firefighters was followed up through 10 years with regard to cause specific mortality. Comparisons were made with another cohort of civil servants and salaried employees in physically demanding jobs. After a latency of five years, an excess mortality from cancer was seen for persons aged 30 to 74 (standardised mortality ratio (SMR) 173, 95% confidence interval (95% CI) 104-270). A significant increase in lung cancer was seen in the group aged 60 to 74 (SMR 317, 95% CI 117-691), whereas non-pulmonary cancer was significantly increased in the group aged 30 to 49 (SMR 575, 95% CI 187-1341). It is concluded that inhalation of carcinogenic and toxic compounds during firefighting may constitute an occupational cancer risk. An extended use of respiratory protective equipment is advocated.     

Mortality among workers exposed to polychlorinated biphenyls (PCBs) in an electrical capacitor manufacturing plant in Indiana: an update

An Indiana capacitor-manufacturing cohort (n=3,569) was exposed to polychlorinated biphenyls (PCBs) from 1957 to 1977. The original study of mortality through 1984 found excess melanoma and brain cancer; other studies of PCB-exposed individuals have found excess non-Hodgkin lymphoma and rectal, liver, biliary tract, and gallbladder cancer. Mortality was updated through 1998. Analyses have included standardized mortality ratios (SMRs) and 95% confidence intervals (CIs) using rates for Indiana and the United States, standardized rate ratios (SRRs), and Poisson regression rate ratios (RRs). Estimated cumulative exposure calculations used a new job-exposure matrix. Mortality overall was reduced (547 deaths; SMR, 0.81; 95% CI, 0.7-0.9). Non-Hodgkin lymphoma mortality was elevated (9 deaths; SMR, 1.23; 95% CI, 0.6-2.3). Melanoma remained in excess (9 deaths; SMR, 2.43; 95% CI, 1.1-4.6), especially in the lowest tertile of estimated cumulative exposure (5 deaths; SMR, 3.72; 95% CI, 1.2-8.7). Seven of the 12 brain cancer deaths (SMR, 1.91; 95% CI, 1.0-3.3) occurred after the original study. Brain cancer mortality increased with exposure (in the highest tertile, 5 deaths; SMR, 2.71; 95% CI, 0.9-6.3); the SRR dose-response trend was significant (p=0.016). Among those working >or= 90 days, both melanoma (8 deaths; SMR, 2.66; 95% CI, 1.1-5.2) and brain cancer (11 deaths; SMR, 2.12; 95% CI, 1.1-3.8) were elevated, especially for women: melanoma, 3 deaths (SMR, 5.99; 95% CI, 1.2-17.5); brain cancer, 3 deaths (SMR, 2.87; 95% CI, 0.6-8.4). These findings of excess melanoma and brain cancer mortality confirm results of the original study. Melanoma mortality was not associated with estimated cumulative exposure. Brain cancer mortality did not demonstrate a clear dose-response relationship with estimated cumulative exposure.     

Mortality and cancer morbidity in workers exposed to low levels of vinyl chloride monomer at a polyvinyl chloride processing plant

To study whether exposure to low levels of vinyl chloride monomer (VCM) causes increased risk for cancer morbidity and death from ischemic heart disease, a cohort study was performed among 2,031 male workers at a polyvinyl chloride (PVC) processing plant who had been employed for at least 3 months during the period 1945-1980. An almost significantly increased total mortality (SMR = 116, 95% CI 99-136) was found. Deaths caused by violence or intoxication were significantly increased (SMR = 153, 95% CI 109-213), but not deaths from ischemic heart disease (SMR = 100, 95% CI 73-135). A significant increase in total cancer morbidity was observed (SMR = 128, 95% CI 101-161). Respiratory cancers were significantly increased (SMR = 213, 95% CI 127-346). Furthermore, six brain tumors (vs. 2.6 expected) were observed. This increase, however, was not significant (SMR = 229, 95% CI 84-498). No liver hemangiosarcoma was observed. Applying a latency period of greater than or equal to 10 years from start of employment did not change the risk patterns. There were no significant exposure-response associations between exposure estimates for VCM, asbestos, and plasticizers and cancer morbidity.