Mortality of UK oil refinery and petroleum distribution workers, 1951-2003

BACKGROUND: The health of UK petroleum industry workers has been monitored for many years. AIM: To identify any long-term adverse health outcomes from occupational exposures in this industry. METHODS: The mortality (1951-2003) and cancer morbidity (1971-2003) experienced by cohorts of 28,555 oil refinery workers and 16,477 petroleum distribution workers has been investigated. Study subjects were all those males first employed in the period 1946-74 at one of eight UK oil refineries or 476 UK petroleum distribution centres; all subjects had a minimum of 12 months employment with some employment after 1 January 1951. Observed numbers of cause-specific deaths and site-specific cancer registrations were compared with expectations based on national mortality and cancer incidence rates. RESULTS: Standardized mortality ratios (SMRs) were significantly <100 for all causes both in oil refinery workers (Obs 11,156, SMR 89) and in petroleum distribution workers (Obs 7320, SMR 96). Significantly elevated SMRs were shown in oil refinery workers for cancer of the pleura (mesothelioma) (Obs 64, SMR 261) and melanoma (Obs 48, SMR 168). Significantly elevated SMRs were not found in petroleum distribution workers for any site of cancer. Significantly elevated standardized registration ratios (SRRs) were only shown in oil refinery workers and for cancer of the pleura (mesothelioma) (Obs 115, SMR 274), melanoma (Obs 85, SMR 129) and other skin cancer (Obs 983, SRR 117). CONCLUSIONS: The only findings that showed clear evidence of an occupational cancer hazard were those for mesothelioma in oil refinery workers.     

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.     

Investigation of cancer incidence and mortality at a Scottish semiconductor manufacturing facility

BACKGROUND: We became aware of concern about cancer at a Scottish semiconductor manufacturing facility in 1998. Aim To compare cancer experience among current and former workers at the facility, with an appropriate comparison population, making use of any readily available exposure information. METHOD: We obtained personnel and employment episode information from four sources within the company. Workers were flagged for death and cancer registrations at the National Health Service Central Register in Edinburgh. We constructed standardized registration and mortality ratios (SRRs and SMRs), using Scotland as the comparison, with and without an adjustment for deprivation. RESULTS: The main mortality analysis included 4388 workers, with a mean length of follow-up of 12.5 years. Overall mortality was substantially below that expected for men, and for women was slightly below expected. Total cancer registrations were close to expected levels for men and women. Four cancers produced noteworthy findings: malignant neoplasm of the trachea, bronchus and lung in women-deprivation adjusted SRR [95% confidence interval (CI), number of cases] 273 (136-488, 11 cases); malignant neoplasm of the stomach in women-adjusted SRR 438 (90-1281, three cases); and malignant neoplasm of the female breast-adjusted SRR 134 (82-206, 20 cases). The unadjusted SMR for male brain cancer was 401 (83-1172, three cases) and there was an additional non-fatal case. CONCLUSION: These findings, particularly those relating to lung cancer, though inconclusive, point to the possibility of a work-related risk of cancer that justifies further investigation.     

Cohort mortality study of rubber and plastics product makers in Italy

A retrospective cohort mortality study was carried Out in 20industrial factories in the Local Health Unit Bologna Sud (EmiliaRomagna, Italy), where different rubber and plastics productswere manufactured. The cohort consisted of 925 subjects (578males and 347 females) employed for at least six months continuously;follow-up was between the beginning of operation of each factory,ranging between mid fifties and mid seventies, and 31 December1989. For those exposed more than one year cause specific StandardizedMortality Ratios (SMRs) were computed using regional rates forcomparison, 90% confidence intervals (Cl) were calculated assumingthe Poisson distribution. Among the 748 subjects employed formore than one year (457 males and 291 females) there were nolost to follow-up, 54 individuals were dead (41 males and 13females) and for three subjects the cause of death was unknown.The results showed that all causes mortality was above expectancyin the total cohort (SMR=123; 54 Obs; 90% Cl=97–154),among males (SMR=117; 41 Obs; 90% Cl=89–152) and females(SMR=143; 13 Obs; 90% Cl=85–228). Increased mortalityfor all malignant tumours was observed in the total cohort (SMR=150;25 Obs; 90% Cl=104–209) and for both genders. All ninelung cancer cases were observed among males, the SMR was equalto 218 and was statistically significant; seven cases occurredat duration of exposure less than 10 years and six at latencyup to 20 years. The interpretation in terms of causality ofthe present investigation is limited by the small number ofobservations and by exposure definition solely in terms of employmentin the study factories; nonetheless the results are indicatingthe existence, in this group of rubber and plastics productmakers, of an adverse health effect which deserve further investigation.     

The suicide mortality of working physicians and dentists

BACKGROUND: Some studies have shown that physicians and dentists have elevated risks of suicide, while other studies have not. AIMS: Using all deaths and corresponding census data in 26 US states, we examine the suicide risk for working physicians and dentists. METHODS: Death and census data for working people were obtained from 1984 through 1992. Directly age-standardized suicide rate ratios (SRRs) were calculated for white male and white female physicians and white male dentists. RESULTS: For white female physicians, the suicide rate was elevated compared to the working US population (SRR = 2.39, 95% CI = 1.52-3.77). For white male physicians and dentists, the overall suicide rates were reduced (SRR = 0.80, 95% CI = 0.53-1.20 and 0.68, 95% CI = 0.52-0.89, respectively). For older white male physicians and dentists, however, observed suicide rates were elevated. CONCLUSIONS: White female physicians have an elevated suicide rate. Only older white male physicians and dentists have elevated suicide rates, which partially explains the varied conclusions in the literature.     

Mortality and cancer morbidity of production workers in the United Kingdom flexible polyurethane foam industry.

OBJECTIVE--To describe cause specific mortality and site specific cancer morbidity among workers employed in factories that produce polyurethane foams, and to determine if any part of the experience may be due to occupation, and in particular to exposure to diisocyanates. DESIGN--Historical prospective cohort study. SETTING--11 factories in England and Wales. SUBJECTS--8288 male and female production employees with some employment in the period 1958-79, and with a minimum period of employment of six months. MAIN OUTCOME MEASURES--Observed and expected numbers of deaths for the period 1958-88, and corresponding figures for cancer registrations for the period 1971-86. RESULTS--Compared with the general population of England and Wales, standardised mortality ratios (SMRs) for all causes and all neoplasms were 97 (observed deaths (Obs) 816) and 88 (Obs 221) respectively. Statistically significant excesses were found among women for cancer of the pancreas (expected deaths (Exp) 2.2, Obs 6, SMR 271, 95% CI 100-595) and cancer of the lung (Exp 9.1, Obs 16, SMR 176, 95% CI 100-285). Similar excesses were not found among male employees, and the SMRs for cancers of the lung and pancreas among the total study population were 100 (Obs 81) and 136 (Obs 14) respectively. Overall incidence of cancer was also below expectation (SRR 94, Obs 277), although statistically significant excesses among women were found for cancers of the larynx and kidney, based on three and four cases respectively. Incident cancers of the lung and pancreas among women were also in excess, although these findings were not independent of the findings for mortality. Poison regression did not indicate that ever having been employed in jobs attracting either higher or lower exposure to isocyanates was a risk factor for the mentioned cancers. A nested case-control design was used to investigate any associations with nine other occupational exposures. No statistically significant association was found. CONCLUSIONS--In general, cancer rates in this population were lower than those for the general population. All increased cancer rates among women occurred at sites of cancer known to be related to cigarette smoking, and these excesses are probably due to a combination of cigarette smoking, chance, and factors unrelated to the industry under study.     

Mortality of iron-steel workers in Anshan, China: a retrospective cohort study

Foundry workers have increased mortality and morbidity risks from numerous causes, including various cancers. A retrospective Chinese iron-steel cohort study was conducted to examine the mortality effects of exposure to foundry work. Standardized mortality ratios (SMRs) and standardized rate ratios (SRRs) were calculated to evaluate mortality risks among male workers with exposure to 15 hazardous factors, adjusting for confounders. During 14 years of follow-up, 13,363 of 121,846 male workers died. SMR analysis showed a healthy-worker effect in comparison with the general population. SRR analysis showed increased risks for all causes, all neoplasms, and others among the exposed workers compared with non-exposed blue-collar workers. Combined exposure to polycyclic aromatic hydrocarbons and two or more dusts increased the risks of lung cancer (SRR = 654; 95% CI: 113-3,780) and other malignancies. Foundry work has adverse health effects, including carcinogenic risks.     

Cohort study of art glass workers in Tuscany, Italy: mortality from non-malignant diseases

This investigation studies cause-specific mortality of art glass workers employed in 17 industrial facilities in Tuscany, Italy. A cohort of 3,390 workers employed for at least 1 year was enumerated from company payrolls. Follow-up was between the start of employment in each factory and 31 December 1993. The cause-specific expected mortality was computed relative to Tuscany rates and specified for gender, 5-year age groups and calendar year. Separate analyses were carried out for the jobs of makers and formers and for batch mixers. Among males (3, 180 individuals) observed mortality for non-cancer causes was higher than expected for hypertensive disease [standardized mortality ratio (SMR) = 178, 90% confidence interval (90% CI) = 96-301], pneumoconiosis (SMR = 200, 90% CI = 94-376) and diseases of the genitourinary system (SMR = 169, 90% CI = 95-279). Increases for the above causes were shown also among makers and formers: hypertensive disease (SMR = 182, 90% CI = 85-341), pneumoconiosis (SMR = 250, 90% CI = 109-493) and diseases of the genitourinary system (SMR = 224, 90% CI = 121-380). For batch mixers an increase was present for cerebrovascular disease. The observed mortality for cancer causes was above the expected for cancers of the larynx, lung, stomach and brain. This study points to the existence for Tuscan glass workers of health effects in addition to cancer; previously observed carcinogenic effects were also confirmed.     

A cohort mortality and cancer incidence survey of recent entrants (1982-91) to the UK rubber industry: findings for 1983-2004

AIM: To monitor the occurrence of cancer in a recently defined cohort of UK rubber workers. METHODS: A cohort of 8651 male and female workers from 41 UK rubber factories has been enumerated. All employees had a minimum of 12 months employment and were first employed at one of the participating factories in the period 1982-91. Mortality and cancer incidence data for the period 1983-2004 were compared with expected values based on appropriate national rates. RESULTS: Mortality from lung cancer was close to expectation for males [observed 22, standardized mortality ratio (SMR) 93] and females (observed 2, SMR 70). Mortality from stomach cancer was also unexceptional in males (observed 4, SMR 86) and females (observed 0, SMR 0). Although based on small numbers, significantly elevated mortality was shown for multiple myeloma in males (observed 5, SMR 385) and females (observed 2, SMR 952). All seven of these latter deaths occurred in workers from the general rubber goods (GRG) sector. CONCLUSIONS: The findings should be treated with caution as they relate to a relatively early period of follow-up. Nevertheless, they hold out the prospect that the elevated SMRs for stomach and lung cancers reported for historical cohorts of UK rubber workers will not be present in more recent cohorts. The elevated occurrence of multiple myeloma may represent no more than a chance finding. Alternatively, these findings may reflect the presence of an unrecognized occupational cancer hazard in parts of the GRG sector of the UK rubber industry.     

Mortality of iron and steel workers in Korea

BACKGROUND: The mortality experience of iron and steel workers from modern plants in developing countries has not been extensively described. METHODS: Mortality at two Korean iron and steel manufacturing complexes was analyzed using Poisson regression methods with both direct and indirect standardization. Work histories were linked with a national mortality registry. Workers (44,974) hired beginning in 1968 were followed from 1992 to 2001. RESULTS: The 806 deaths observed during 10 years of follow-up comprised 2% of the population at risk and represented a large healthy worker effect (HWE) for all causes (SMR = 0.59, 95% CI = 0.55-0.63) and for cancer (SMR = 0.79, 95% CI = 0.70-0.90). Mortality at subsidiaries was considerably higher than at the parent plants (SRR = 1.71, 95% CI = 1.47-1.99). Relative mortality rates declined with employment duration: > 20 years had significantly reduced mortality (SRR = 0.59, 95% CI = 0.43-0.82) compared to duration < 1 year (test for trend: P = 0.0006). Fatal injury deaths in the first year were highly elevated (SMR = 3.10, 95% CI = 2.17-4.26) declining to less than that expected after 5 years. Cancer mortality was elevated in stainless steel production (SRR = 3.26, 95% CI = 1.37-6.49) and overall mortality was elevated for work in plant maintenance departments (SRR = 1.17, 95% CI = 1.00-1.37), particularly for fatal injuries (SRR = 1.67, 95% CI = 1.29-2.14). All-cause mortality increased with employment duration in the steel-production departments, as did fatal injuries in material handling/construction. CONCLUSIONS: This steelworker cohort exhibits excess mortality in some process areas. More detailed retrospective exposure assessment and future follow-up of this cohort will better define health risks in the modern iron and steel manufacturing.     

Cancer mortality among shoe manufacturing workers: an analysis of two cohorts.

OBJECTIVES: To examine the cancer risk of shoe manufacturing workers and evaluate whether the risk was associated with exposure to leather dust and solvents. METHODS: Data from two historical cohort studies of shoe workers were expanded and analysed in parallel. A total of 4215 shoemakers from England contributing 103 726 person-years at risk and 2008 shoemakers from Florence, Italy, contributing 54,395 person-years at risk were included in the analysis. Exposure to leather dusts and solvents from glues was evaluated on the basis of job title information. Standardised mortality ratios (SMR) were calculated as ratios of observed deaths (Obs) over expected derived from national mortalities. RESULTS: Overall mortality was lower than expected in both cohorts (English cohort: Obs 3314, SMR 81, 95% confidence interval (95% CI) 78-84; Florence cohort: Obs 333, SMR 87, 95% CI 78-97). An increased risk of nasal cancer was found (English cohort: Obs 12, SMR 741; Florence cohort: Obs 1, SMR 909). 10 of the 13 cases occurred among English workers employed in the manufacture of welted boots (SMR 926, 95% CI 444-1703), a sector of the industry thought to have had the highest exposure to leather dust. Mortality from leukaemia was not increased in the English cohort (Obs 16, SMR 89), but was increased in the Florence cohort (Obs 8, SMR 214, 95% CI 92-421); and the highest risk was found among shoe workers in Florence who were first exposed between 1950 and 1959 when exposure to benzene was substantial (Obs 3, SMR 536, 95% CI 111-1566). Some evidence for an excess risk of stomach, bladder, and kidney cancer, as well as multiple myeloma and non-Hodgkin's lymphoma was also found in the Florence cohort only among workers employed in jobs with the highest exposure to solvents. CONCLUSIONS: These findings confirm the associations between exposure to leather dust and nasal cancer and between exposure to benzene and leukaemia in the shoe manufacturing industry and suggest that the risk of other cancers may be increased among workers exposed to solvents or glues.     

An epidemiological study of workers exposed to vinyl chloride in the plants of Ferrara, Rosignano and Ravenna

The aim of the present study is to investigate cause-specific mortality among male workers employed in vinyl chloride manufacture and polymerization in three Italian plants located in Ferrara, Rosignano and Ravenna. The cohorts include all workers hired between start of operation and, respectively 1985, 1978 and 1985, amounting to 418, 206 and 635 subjects followed up for mortality until 1996 (Ferrara and Rosignano) and 1997 (Ravenna). Cause specific SMRs (Standardized mortality ratios) were computed. Expected figures were obtained from mortality rates for the population resident in the region where the plant was located, for each SMR value a 90% confidence interval (CI) was calculated on the assumption of a Poisson distribution. The study detected an increased mortality for primary liver cancer in all three plants; SMR values were 444 in Ferrara (4 Obs. 90% CI 160-1069), 200 in Rosignano (1 Obs. 90% CI 10-869) and 375 in Ravenna (3 Obs. 90% CI 110-1038). In the pooled cohort liver cancer SMR was equal to 364 (8 Obs. 90% CI 108-390). In one plant, Ferrara, observed mortality was above the expected for lung cancer, SMR = 146 (14 Obs. 90% CI 89-229) and for larynx cancer, SMR = 500 (4 Obs. 90% CI 174-1167). One death from pleural cancer was observed in Rosignano (SMR = 1000 90% CI 47-4331). A non significant increase was detected for liver cirrhosis, in Ferrara (SMR 108, 6 Obs. 90% CI 73-332) and Rosignano (SMR 129, 3 Obs. 90% CI 35-332). The study results are confirming the carcinogenic action of vinyl chloride on the liver, they are pointing to its possible role in lung cancer development, as already shown for workers employed in Porto Marghera; an increased risk for larynx cancer is also shown.     

Mortality among workers in an Italian cigarette factory

A cohort study was conducted to evaluate the mortality pattern among female and male workers in a cigarette factory. The study followed 972 female workers and 761 male workers with at least 6 months of cumulative employment from 1 January 1962 through 1 July 1996. Among women, mortality from all causes of death [standardized mortality ratio (SMR) = 0.9; 95% confidence interval (CI) = 0.8-1.1] and mortality from all malignant neoplasms (SMR = 1.1; CI = 0.9-1.3) were consistent with reference rates. Male workers had a significantly reduced overall mortality (SMR = 0.8; CI = 0.7-0.9), while mortality from all malignant neoplasms was as expected (SMR = 0.9; CI = 0.7-1.0). Among female workers the frequencies of deaths from diseases of nervous system (SMR = 2.0; CI = 1.1-3.4) and from non-Hodgkin's lymphoma (NHL) (SMR = 2.7; CI = 1.0-5.6) were elevated at a statistically significant level. No association between duration of employment and diseases of nervous system was observed. A higher risk for NHL, based on three deaths, was reported among female workers with 15 or more years of employment (SMR = 8.1; CI = 2.2-21.0). Although based on small numbers, the excess of NHL here reported suggests that potential exposure to foliar residues of pesticides should be thoroughly considered in tobacco manufacturing.     

Cancer incidence in an occupational cohort exposed to bitumen fumes

This study was conducted to investigate whether bitumen fumes should be considered carcinogenic to human beings. A historical cohort of heavily exposed mastic asphalt workers was followed from 1959 through 1984 (inclusive) with regard to cancer incidence. A total of 679 Danish men were included in the study cohort. Among these, 75 new cases of cancer were observed within the period studied. The cancer incidence observed among the group significantly exceeded that of the total Danish male population, the standardized morbidity ratio (SMR) being 195 (95% confidence interval (95% CI) 153-244). Significant increases were seen for cancer of the mouth (SMR 1111, 95% CI 135-4014), the esophagus (SMR 698, 95% CI 144-2039), the rectum (SMR 318, 95% CI 128-656), and the lung (SMR 344, 95% CI 227-501). It is suggested that exposure to cracking products in the fumes of heated bitumen has contributed to the elevated cancer incidence observed.     

Simian virus 40 and mesothelioma in Great Britain

BACKGROUND: Simian virus 40 (SV40) is a DNA virus that has been shown capable of infecting and transforming cells in various species. Laboratory studies have suggested that inoculation with SV40 is associated with various types of cancer, including mesothelioma. AIMS: To test the hypothesis, via an ecological analysis, that exposure to SV40 via contaminated polio vaccines is a risk factor for mesothelioma in humans. METHODS: Mesothelioma mortality rates in Great Britain for two birth cohorts likely to have been exposed to SV40 via poliovirus vaccination were compared with a birth cohort likely to be largely unexposed. RESULTS: There was some evidence for both males (P < 0.05) and females (P < 0.05) that the mesothelioma mortality rates were higher in the first exposed cohort: rate ratio (RR) = 2.4 [95% CI (confidence interval) 1.2-5.0] and RR = 3.7 (95% CI 1.0-14). However, in the second exposed cohort, mortality rates were elevated in females only, and the evidence was slightly less convincing (P = 0.055). CONCLUSION: Although the results for females show a reduction in the mesothelioma mortality rate coinciding with the introduction of the SV40-free Sabin polio vaccine, the absence of a similar result in males and of a priori biological evidence of a sex-specific SV40 effect, makes chance the most plausible interpretation of these findings.     

Mortality of workers at a nickel carbonyl refinery, 1958-2000

Background: Excess risks of respiratory cancer have been shown in some groups of nickel exposed workers. It is clear, however, that not all forms of nickel exposure are implicated in these excess risks.

Aim: To determine whether occupational exposures received in a modern nickel carbonyl refinery lead to increased risks of cancer, in particular nasal cancer and lung cancer.

Methods: The mortality experienced by a cohort of 812 workers employed at a nickel refinery was investigated. Study subjects were all male workforce employees first employed in the period 1953–92 who had at least five years' employment with the company. Observed numbers of cause specific deaths were compared with expectations based on national mortality rates; SMRs were also calculated by period from commencing employment, year of commencing employment, and type of work.

Results: Overall, standardised mortality ratios (SMRs) were close to 100 for all causes (Obs 191, SMR 96, 95% CI 83 to 111), all neoplasms (Obs 63, SMR 104, 95% CI 80 to 133), non-malignant diseases of the respiratory system (Obs 18, SMR 97, 95% CI 57 to 153), and diseases of the circulatory system (Obs 85, SMR 94, 95% CI 75 to 116). There were no significantly increased SMRs for any site of cancer. There was a non-significant excess for lung cancer (Obs 28, Exp 20.17, SMR 139, 95% CI 92 to 201), and in subgroup analyses a significantly increased SMR of 231 (Obs 9) was found for those 142 workers with at least five years' employment in the feed handling and nickel extraction departments. In the total cohort there was a single death from nasal cancer (Exp 0.10).

Conclusions: The non-significant excess of lung cancer deaths may well be a chance finding, but in light of previous studies some role for nickel exposures cannot be excluded.

     

Mortality due to asbestos-related causes among railway carriage construction and repair workers

The objective of this study was to further clarify the cancer risk associated with asbestos exposure in railway carriage construction and repair. The cohort included 734 subjects employed between 1 January 1945 and 31 December 1969. Vital status was ascertained at 31 December 1997. Mortality was investigated in the time span 1970-97. Forty-two subjects (6%) were lost to follow-up and eight causes of death (4%) could not be ascertained. The overall mortality was not above the expected value. Among neoplastic diseases, excesses were observed for lung ?tandardized mortality ratio (SMR) = 124; 90% confidence interval (CI) = 87-172; 26 obs), pleura (SMR = 1,327; CI = 523-2,790; 5 obs), larynx (SMR = 240; CI = 95-505; 5 obs), liver (SMR = 241; CI = 126-420; 9 obs), pancreas (SMR = 224; CI = 98-443; 6 obs) and multiple myeloma (SMR = 429; CI = 117-1,109; 3 obs). The observed excess of lung and pleural neoplasms can be causally related to asbestos exposure in the manufacture of railway carriages. A causal role of asbestos exposure in the raised SMRs from laryngeal and pancreatic neoplasms and multiple myeloma cannot be conclusively proven.     

Mortality and cancer incidence in a cohort of registered nurses from British Columbia, Canada

BACKGROUND: A retrospective cohort study of provincial registered nurses (RNs) from British Columbia, Canada was undertaken to determine risks of mortality and cancer incidence; in particular for breast cancer and leukemia. METHODS: Cohort records of RNs from 1974 to 2000 were linked to Canadian death and cancer registries. Analyses included standardized mortality (SMR) and incidence ratios (SIR) as well as relative risks for internal comparisons. RESULTS: There were 58,125 RNs in the cohort (96.7% females). The SMR for all causes of mortality for female RNs was low, at 0.61 (95% CI, 0.58-0.64). The only elevated SIR for female RNs was for malignant melanoma (1.27; 95% CI, 1.10-1.46). Ever working in a hospital, medical surgical specialties or maternal/pediatrics showed some elevated cancer risks. CONCLUSIONS: Low SMRs for the female RN cohort suggest healthful lifestyles and a healthy worker effect. Length of employment as a nurse, in hospitals and in specific fields was associated with some increased risks of cancer.     

Extended mortality follow-up among men and women in a U.S. furniture workers union

The addition of 5 years of follow-up and over 411,000 person-years of observation to a cohort of 34,081 men and women employed in U.S. furniture and other related industries allowed the investigation of mortality patterns among women and minority races in addition to white men. A significant excess of pleural mesotheliomas occurred among white men (standardized mortality ratio [SMR] = 3.7, 95% confidence interval [CI] = 1.2–8.7) but could not be linked to a particular type of furniture manufacturing. SMRs for myeloid leukemia and chronic nephritis were elevated among white men employed in the wood furniture industry but were not statistically significant. Males in the black/ other race categories in wood furniture plants showed nonsignificant mortality excesses for infectious diseases and cancers of the prostate and colon and rectum. Among white women employed in wood furniture plants, mortality was elevated for cancers of the pancreas and lung during the most recent follow-up period. In metal furniture plants, mortality was raised among men in both race groups for kidney cancer (black/other SMR = 8.0, 95% CI = 1.6–23.2; white SMR = 2.1, 95% CI = 0.4–6.2) and diabetes mellitus (black/other SMR = 2.2, 95% CI = 0.6–5.6; white SMR = 1.8, 95% CI = 0.7–3.9). Stomach cancer mortality was significantly elevated (SMR = 3.3, 95% CI = 1.3–6.8) among white men in metal furniture plants and was of the same magnitude over both the previous and the most recent follow-up periods. Among those working with textiles, SMRs were significantly elevated for leukemia (SMR = 6.1, 95% CI = 1.2–7.8) and cancers of the colon and rectum (SMR = 3.2, 95% CI = 1.3–4.5) for white women. Lung cancer mortality was increased for white men and women in textile operations, but SMRs were not statistically significant. SMRs for a number of other causes of death that were elevated at the end of the earlier follow-up period were not increased during the new follow-up period. © 1994 Wiley-Liss, Inc.