Retrospective cohort study of workers of a synthetic textiles plant in quebec: II. Colorectal cancer mortality and incidence

This paper describes standard mortality and nested case-control analyses of colorectal cancer for a cohort of synthetic textiles workers in which a cluster of five cases was observed previously. The cohort consisted of 7,487 men and 2,724 women who had more than 1 year's experience at the plant and who were either working in 1947 or were newly employed between 1947 and 1977. The Standardized Mortality Ratio (SMR) for colorectal cancer for men was 0.69 (95% confidence interval (CI): 0.52-0.92; 50 deaths) and for women it was 1.02 (95% CI: 0.57-1.69; 15 deaths). Among men only there was a suggestion that risks increased according to the length of service at the plant. In the nested case-control study, incident cases as well as deceased cases were included. A variety of analyses were carried out according to duration of employment in the processing units. For men the risk of colon cancer increased with duration of employment in the polypropylene and cellulose triacetate extrusion unit (unadjusted odds ratio (OR) for ≤5 years duration = 5.52; 95% CI: 1.12-27,26; 4 exposed cases). It was not possible, however, to provide an independent confirmation of this putative association because the case series included three of the original five cases. There was some evidence of increased risks in the cellulose acetate fiber manufacturing unit and in the dyeing and finishing unit, but the data were compatible with the null hypothesis of no effect. No associations were observed for employment in any of the other processing unit.     

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.     

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 study of workers compensated for asbestosis in Poland, 1970-1997

The aim of the study was to assess the risk of asbestos-related malignancies among persons with diagnosed asbestosis. The study covered a cohort composed of 907 men and 490 women afflicted by asbestosis, diagnosed is 1970-1997. The follow-up of the cohort continued until 31 December 1999. In all, 421 deaths were registered and causes of death were retrieved for 93.3% of the deceased. A significantly increased mortality was observed both in the male 1300 deaths; SMR = 127; 95%CI: 113-142) and female (121 deaths, SMR = 150; 95%CI: 124-179) cohorts. The elevated number of deaths in the male and female cohorts were noted mainly due to respiratory diseases (men: 42 deaths; SMR = 344; 95%CI: 248-465; women: 20 deaths, SMR = 789; 95%CI: 482-1219) malignant neoplasms (men: 91 deaths, SMR = 146; 95%CI: 118-179; women: 34 deaths, SMR = 159; 95%CI: 110-222), including lung cancer (men: 39 deaths, SMR = 168; 95% CI: 119-230; women: 13 deaths, SMR = 621; 95%CI: 331-1062) and pleural mesothelioma (men: 3 deaths, SMR = 2680; 95%CI: 553-7832; women: 3 deaths, SMR = 7207; 95%CI: 1031-14612). Taking into account a cumulative dose of fibers, it was found that a significantly increased mortality from lung cancer and pleural mesothelioma applied to persons exposed to a dose above 25 f-y/ml. The results indicate that persons with asbestosis are at higher risk of developing malignant neoplasms, especially lung cancer and mesothelioma.     

Mortality among Rocketdyne workers who tested rocket engines, 1948-1999

OBJECTIVE: The objective of this study was to evaluate potential health risks associated with testing rocket engines. METHODS: A retrospective cohort mortality study was conducted of 8372 Rocketdyne workers employed 1948 to 1999 at the Santa Susana Field Laboratory (SSFL). Standardized mortality ratios (SMRs) and 95% confidence intervals (CIs) were calculated for all workers, including those employed at specific test areas where particular fuels, solvents, and chemicals were used. Dose-response trends were evaluated using Cox proportional hazards models. RESULTS: SMRs for all cancers were close to population expectations among SSFL workers overall (SMR = 0.89; CI = 0.82-0.96) and test stand mechanics in particular (n = 1651; SMR = 1.00; CI = 0.86-1.16), including those likely exposed to hydrazines (n = 315; SMR = 1.09; CI = 0.75-1.52) or trichloroethylene (TCE) (n = 1111; SMR = 1.00; CI = 0.83-1.19). Nonsignificant associations were seen between kidney cancer and TCE, lung cancer and hydrazines, and stomach cancer and years worked as a test stand mechanic. No trends over exposure categories were statistically significant. CONCLUSION: Work at the SSFL rocket engine test facility or as a test stand mechanic was not associated with a significant increase in cancer mortality overall or for any specific cancer.     

The Drake Health Registry Study: cause-specific mortality experience of workers potentially exposed to beta-naphthylamine

OBJECTIVE: To examine the cause-specific mortality experience of an occupational cohort with probable past exposure to beta-naphythylamine (BNA). METHODS: Subjects were 374 male and 26 female workers employed at a Pennsylvania chemical plant that produced or used beta-naphthylamine (BNA) between 1940 and 1981. Vital status through 1998 was determined for 97.5% of the cohort and cause of death for 100% of 79 deaths. Limited industrial hygiene data and reports from former employees were used to categorize workers as high, medium, or low risk for BNA exposure. Statistical analyses included US and local county-based standardized mortality ratios (SMRs). RESULTS: We observed statistically significantly elevated county rate-based SMRs for all causes combined (SMR = 1.98, 95% confidence interval (CI) = 1.56-2.49), all malignant neoplasms combined (28 deaths, SMR = 3.08, 95% CI = 2.05-4.46), respiratory system cancer (12 deaths, SMR = 3.91, 95% CI = 2.02-6.83), and bladder cancer (four deaths, SMR = 16.83, 95% CI = 4.59-43.1). Three bladder cancer cases were classified as high risk (SMR = 26.79, 95% CI = 5.53-78.29). Mortality risks were also elevated for most other malignant and non-malignant cause of death categories examined. CONCLUSIONS: Bladder cancer risk remains highly elevated among Drake/Kilsdonk workers and appears to be causally related to past BNA exposure. While lifestyle and behavioral risk factors may explain some of the mortality excesses for non-urological cancers, the possibility remains that BNA exposure may have also played a role in these and other observed cancer excesses.     

Cohort mortality study of employees at the Celanese plant in Pampa,Texas

BACKGROUND: The mortality experience of chemical workers from the Pampa, Texas Celanese Ltd. plant through 1991 has been previously reported. This study updates that effort and presents an additional seven years of data and follow-up that provided 268 additional cohort members and 71 new deaths. METHODS: Mortality was determined through December 31, 1998, the period for which the National Death Index could provide information on deaths. The mortality experience of Celanese Ltd. employees was compared to that of the general population of the United States. All cause and cause-specific standardized mortality ratios (SMRs) were calculated. RESULTS: For the entire cohort, several causes of death including all causes (SMR = 65.9; 95% confidence interval (CI) = 56.9-76.0), heart disease (SMR = 69.1; 95% CI = 53.6-87.8), and all malignant neoplasms (SMR = 74.2; 95% CI = 56.3-95.9) were significantly less than expected. SMRs were also calculated separately for white men, non-white men, and women. Unlike the initial study, the SMR for prostate cancer among white males was not significantly elevated (SMR=176.1; 95% CI = 76.0-347.0) and was much lower than the prior SMR of 330.4. This suggests that the initial findings, which were based on a small number of deaths, were likely due to chance. CONCLUSIONS: Overall, Celanese Ltd. employees from the Pampa plant have significantly lower than expected SMRs for several causes of death, and no causes of death that are significantly elevated.     

Extreme cause-specific mortality in a cohort of adult prisoners--1988 to 2002: a data-linkage study

OBJECTIVES: Describe the standardized mortality ratio (SMR) and its trend in adults who have served time in prison. Design: A retrospective cohort study of 85,203 adults imprisoned in New South Wales (NSW), Australia, between 1 January 1988 and 31 December 2002. METHODS: We obtained information on deaths by record linkage with the Australian National Death Index (NDI). Mortality rates were estimated using the person-time method. SMRs were calculated using sex, age, and calendar-specific death rates from the NSW population. Time trends in SMRs were assessed using the test for linear trends. RESULTS: The median overall follow-up of the cohort was 7.7 years. We identified 5137 deaths (4714 men, 423 women) among the cohort of which the vast majority (4834, 94%) occurred following release from custody. All-cause SMR was 3.7 (95% CI: 3.6-3.8) in men and 7.8 (95% CI: 7.1-8.5) in women. SMRs were substantially raised for deaths due to mental and behavioural disorders (men: 13.2, 95% CI: 12.3-14.0; women: 62.8, 95% CI: 52.7-74.9) and drug-related deaths (men: 12.8, 95% CI: 12.2-13.5; women: 50.3, 95% CI: 43.7-57.8). The SMR for death by homicide was 10.2 (95% CI: 8.9-11.7) in men and 26.3 (95% CI: 17.8-39.0) in women. Aboriginal men were 4.8 times, and Aboriginal women 12.6 times, more likely to die than the general NSW population. Over the study period on average all-cause SMR decreased significantly in men (p = 0.003) and women (p = 0.05) largely due to the decline in SMRs for drug-related deaths and suicide. CONCLUSION: In the largest study so far reported, mortality of male and female offenders was far greater than expected for all major causes, especially deaths caused by drug overdose. Despite some indication of a reduction in excess mortality in recent years, there remains an overwhelming need for enhanced responses to mental health and drug problems for people who have been in prison.     

Mortality among male licensed pesticide users and their wives.

BACKGROUND: We evaluated the mortality pattern of male licensed pesticide users and their wives in central Italy. METHODS: The cohort consisted of 2978 male farmers licensed for buying and handling toxic pesticides during the period 1971-1973 and 2586 farmers' wives. The Standardized Mortality Ratio (SMRs) and their 95% Confidence Intervals (95% CI) were computed on the basis of regional death rates. RESULTS: We found a lower than expected overall and cancer mortality. Non-Hodgkin's lymphoma was increased among women (SMR = 2.29, 0.62-5.86) but not in male farmers (SMR = 0.90, 0.24-2.30), while both sexes were characterized by an increased risk of leukemia (men: SMR = 1.44, 0.69-2.64; women: SMR = 2.41, 1.04-4.76), mainly due to myeloid leukemia (men: SMR = 2.43, 0.98-5.00; women: SMR = 3.14, 1.02-7.33). CONCLUSIONS: Men and women tend to share the same mortality profile. The statistically significant increase of leukemia with a threefold increased risk of the myeloid subtype only among women suggests that different pattern of exposure or biological differences between genders should be considered in evaluating health risks in agricultural settings.     

An update of mortality from all causes among white uranium miners from the Colorado plateau study group

To place previously recognized mortality risks into the context of the total mortality from all causes, an updated retrospective cohort mortality study was conducted on 3,238 white males from the US Public Health Service cohort of Colorado Plateau uranium miners. Vital status was followed from 1960 through 1990. Life-table analyses used combined New Mexico, Arizona, Utah, and Colorado mortality rates for external comparison and mortality risks within the lowest radon-exposure or duration-employed category for internal comparison. Significantly elevated SMRs were found for pneumoconioses (SMR = 24.1, 95% CI 16.0–33.7), lung cancer (SMR = 5.8, 95% CI 5.2–6.4), tuberculosis (SMR = 3.7, 95% CI 1.9–6.2), chronic obstructive respiratory diseases (SMR = 2.8, 95% CI 2.2–3.5), emphysema (SMR = 2.5, 95% CI 1.9–3.2), benign and unspecified tumors (SMR = 2.4, 95% CI 1.0–4.6), and diseases of the blood and blood-forming organs (SMR = 2.4, 95% CI 1.0–5.0). No significantly lowered SMRs were found for any disease. For lung cancer and pneumoconioses, standardized rate ratios increased with increasing exposure to radon progeny or duration of employment. Most findings from this update are consistent with previous studies. Not observed were previously elevated SMRs for chronic nephritis and for acute alcoholism. New findings observed were elevated SMRs for benign and unspecified tumors and for diseases of the blood and blood-forming organs. The most important long-term mortality risks for the white uranium-miners continue to be lung cancer and pneumoconioses, for which SMRs remain significantly elevated after a mean period of 22.4 years since last uranium mining. Am. J. Ind. Med. 31:211–222, 1997. © 1997 Wiley-Liss, Inc.     

Mortality of a cohort of U.S. workers employed in the crushed stone industry, 1940-1980

The mortality of 3,246 males who had been employed 1 or more years during 1940-1980 at 20 crushed stone operations was evaluated for possible association between employment and death from lung cancer, pneumoconiosis, and other respiratory diseases. Four deaths were attributed to pneumoconiosis. Based on available work histories, at least two of these deaths were probably due to dust exposures in the crushed stone industry. Mortality attributed to pneumoconiosis and other nonmalignant respiratory diseases, including chronic obstructive lung disease, was significantly increased overall (SMR: 1.98; 95%CI: 1.21-3.05), and especially so for a subcohort of crushed stone workers that processed granite (SMR: 7.26; 95%CI: 1.97-18.59). With regard to lung cancer, overall SMRs were elevated (although not statistically significant). Analyzed by rock type, there was a significantly elevated lung cancer SMR among granite workers with at least 20 years latency (SMR: 3.35; 95%CI: 1.34-6.90). Although not definitive, results of this study are consistent with the hypothesis that exposure to respirable silica dust is a risk factor for lung cancer.     

Patterns of mortality among Bangladeshis in England and Wales

Objectives. To investigate the patterns of mortality among Bangladeshis living in England and Wales.

Methods. An analysis of national mortality data, classified by country of birth, for the latest period (1988–1992), using the method of indirect standardization for deriving standardized mortality ratios (SMRs) with the age‐ and sex‐specific rates for England and Wales as the standard ( = 100). The SMRs were derived for Bangladeshi‐born men and women aged 20–69 years for major disease entities.

Results. The mortality among Bangladeshi men was significantly higher (SMR 118 and 95% CI 111–126) than the levels prevalent in England and Wales. In contrast, the mortality among Bangladeshi women was significantly lower (SMR 71 and 95% CI 61–82). The cancer mortality overall was lower than expected in both sexes, with the exception of cancer of the liver and gall bladder. The mortality from breast cancer (SMR 16 and 95% CI 6–34) and cervical cancer (SMR 51 and 95% CI 14–131) was lower than expected. Bangladeshi men experienced high mortality from diabetes (SMR 685 and 95% CI 529–874), coronary heart disease (SMR 148 and 95% CI 134–163) and cerebrovascular disease (SMR 267 and 95% CI 222–319); they also experienced excess deaths from cirrhosis of the liver (SMR 254 and 95% CI 175–357).

Conclusions. The findings establish significant variations in the recent health experiences of Bangladeshi men living in England and Wales, posing a major challenge for purchasers of care. If the Health of the Nation strategy is to ensure that equity in health and health care is to apply to all those living in this country, the Bangladeshi population needs special targeting.     

Wisconsin Farmer Cancer Mortality, 1981 to 1990: Selected Malignancies

Abstract: Cancer mortality risks for Wisconsin white male farmers were examined during the years 1981 to 1990. Four malignancies were studied: Non-Hodgkin's lymphoma, melanoma, colon cancer, and rectal cancer. Occupation coded deaths were segmented into farmer and nonfarmer groups and population counts for the groups were estimated from 1980 and 1990 Bureau of the Census data. Standardized mortality ratios (SMRs) were constructed from the ratio of observed farmer deaths and the expected number of farmer deaths. Expected deaths were generated from the underlying statewide nonfarmer rate for the malignancy multiplied into the farmer population at risk. Farmers had significantly lower mortality risks for melanoma (SMR: 0.659; 95% CI: 0.993-0.326) and colon cancer (SMR: 0.763; 95% CI: 0.928-0.599). Farmers also exhibited a nonsignificant decrement for non-Hodgkin's lymphoma (SMR 0.930; 95% CI: 1.214-0.645). For rectal cancer, farmers experienced a slightly higher but essentially the same risk as nonfarmers (SMR: 1.013; 95%CI: 1.418-0.608)—the SMR was not significant. This study corroborates a number of cancer incidence and mortality investigations demonstrating that farmers generally experience the same or lower mortality risks for these malignancies.     

Mortality in a cohort of asbestos cement workers in Carrara, Italy

BACKGROUND AND OBJECTIVES: The aim of this study was to investigate the mortality of 262 workers (200 men and 62 women) employed in an asbestos cement plant located in Carrara, Italy, exposed to a mixture of chrysotile and crocidolite asbestos in a ratio of 2:5. METHODS: Follow-up started on 1 January, 1963. The vital status and causes of death were ascertained on 31 December, 2003. The Tuscany population mortality was used as reference. The relative risk was estimated by Standardized Mortality Ratio (SMR) and the confidence intervals were calculated at 95% level [95%CI]. RESULTS: Among men, a significant increase in mortality was observed for respiratory disease (14 deaths; SMR = 244.1; IC95% = 133.4-409.5), particularly for pneumoconiosis (10 deaths; SMR= 1,800; IC95% = 856.9-3,300.0; of which 5 deaths due to asbestosis; SMR = 120,000; IC95% = 37,000-270,000), and for pleural cancer (4 deaths; SMR = 2,500; IC95% = 676.8-6,400.0). Non-significant increases were also observed for lung cancer (10 deaths; SMR = 114.2; IC95% = 54.8-209.9), and gastric cancer (7 deaths; SMR= 167.1; IC95% = 67.2-344.3). Among women, significant increases were observed for pneumoconiosis (1 death; SMR = 17,000; 95%CI = 425-93,000), and for liver cancer (3 deaths; SMR = 765.0; IC95% = 157.8-2,200.0). CONCLUSIONS: For males our results were consistent with other mortality studies on asbestos-cement workers. No other cohort studies on asbestos cement workers have dealt with mortality of female workers.     

Study of two cohorts of workers exposed to methyl methacrylate in acrylic sheet production

OBJECTIVES—To study mortality among 4324 workers at two United Kingdom factories, Darwen, Lancashire and Wilton, Cleveland, producing polymethyl methacrylate (PMMA) sheet. The Darwen factory is still active, but the Wilton one was closed in 1970. Also, to investigate patterns of mortality after exposure to methyl methacrylate; in particular, mortality from colon and rectal cancer.
METHODS—All male employees at the Darwen factory with a record of employment in 1949-88 and all men ever employed at the Wilton factory (1949-70) were investigated. The vital status of both cohorts was ascertained on 31 December 1995. The exposure of 1526 subjects at the Darwen plant who were engaged from 1949 onwards could be characterised. The mean duration of exposure was 7.6 years at 13.2 ppm (8 hour time weighted average), although exposures in some work groups were as high as 100 ppm. It was not possible to calculate the cumulative exposure of workers first employed at the Darwen plant before 1949 or workers at the Wilton factory.
RESULTS—In the Darwen cohort, 622 deaths were identified and a further 700 deaths in the Wilton cohort. Mortalities for the cohort were compared with national and local rates and expressed as standardised mortality ratios (SMRs). In the subcohort of Darwen workers with more than minimal exposure to MMA, reduced mortalities compared with national and local rates, were found for all causes (SMR 94), and colorectal cancer (SMR 92), but mortality from all cancers was slightly increased (SMR 104). No relations were found with cumulative exposure to MMA. In the subcohort of Wilton workers, mortality from all causes of death was significantly reduced (SMR 89), but mortality from all cancers (SMR 103) and colorectal cancer (SMR 124) were increased. The excess of colorectal cancer was confined to employees with less than 1 year of employment.
CONCLUSION—The study provided no clear evidence that employment at the factories or exposure to MMA had adversely affected the mortalities of workers.


Keywords: methyl methacrylate; mortality     

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.     

Calcium and vitamin D intake and risk of colorectal cancer: the Multiethnic Cohort Study

The associations of intakes of calcium and vitamin D with colorectal cancer risk were examined in the Multiethnic Cohort Study (Hawaii and Los Angeles, California). In 1993-1996, 85,903 men and 105,108 women aged > or =45 years completed a quantitative food frequency questionnaire. A total of 2,110 incident cases of colorectal cancer (1,138 in men and 972 in women) were identified through December 31, 2001. Cox proportional hazards models were used to calculate multivariate-adjusted relative risks and 95% confidence intervals. Total calcium intake (from foods and supplements) was inversely associated with colorectal cancer risk in both men (highest quintile vs. lowest: relative risk (RR) = 0.70, 95% confidence interval (CI): 0.52, 0.93; p for trend = 0.006) and women (RR = 0.64, 95% CI: 0.50, 0.83; p for trend = 0.003). The inverse association was also seen for total vitamin D intake in men (RR = 0.72, 95% CI: 0.51, 1.00; p for trend = 0.03) but not in women. Intake of dairy products was inversely associated with colorectal cancer risk, especially among nonusers of supplemental calcium (men: RR = 0.77, 95% CI: 0.59, 1.01; women: RR = 0.66, 95% CI: 0.49, 0.89). The findings support the hypothesis of protective roles for calcium, vitamin D, and dairy products in the risk of colorectal cancer.     

A Retrospective Cohort Mortality Study of Italian Commercial Airline Cockpit Crew and Cabin Attendants, 1965–96

Abstract

A retrospective cohort mortality study was conducted among Italian commercial flight personnel for the period 1965-1996. The cohort was composed of 3,022 male cockpit crew members and 3,418 male and 3,428 female cabin attendants. Cause-specific standardized mortality ratios (SMRs) and exact 95% confidence intervals. (CIs) were calculated as estimates of the relative risk. Mortality from all cancers was less than expected forall categories (SMRs of 0.58 for male cockpit crew, 0.67 for male cabin attendants, and 0.90 for female cabin attendants). Among male flight persopnel, the SMR for leukemia was somewhat elevated (SMR 1.73; 95% CI: 0.75–3.41) based on eight deaths, with a positive trend by length of employment (p = 0.046). Additionally, an excess of death by suicide was seen among female cabin attendants (SMR 3.38; 95% CI: 1.24–7.35). Other Italian studies of flight personnel are under way, including a detailed assessment of cosmic radiation exposure and investigations of non-radiation occupational risk factors and prevalence of nonfatal outcomes.     

An updated mortality study of workers at a petroleum refinery in Beaumont,Texas

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. Am. J. Ind. Med. 33:61–81, 1998. © 1998 Wiley-Liss, Inc.     

Extended mortality follow-up of a cohort of dry cleaners

PURPOSE: The mortality follow-up of a cohort of dry cleaners was extended to further evaluate cancers risks associated with organic solvents. METHODS: The underlying and contributing causes of death among 5,369 members of a dry cleaning union in St. Louis were determined through December 31, 1993. The mortality experience of the cohort was compared to that of the US population adjusted for age at entry, year of death, race and gender. RESULTS: The total mortality was about as expected (SMR = 1.0, N = 2351, 95% CI = 1.0-1.1). Excesses were observed for emphysema (SMR = 1.7, N = 21, 95% CI = 1.0-2.5), Hodgkin's disease (SMR = 2.0, N = 5, 95% CI = 0.6-4.6) and cancers of the esophagus (SMR = 2.2, N = 26, 95% CI = 1.5-3.3), larynx (SMR = 1.7, N = 6, 95% CI = 0.6-3.7), lung (SMR = 1.4, N = 125), 95% CI = 1.1-1.6), and cervix (SMR = 1.6, N = 27, 95% CI = 1.0-2.3). These excesses occurred among men and women and blacks and whites. Bladder cancer was elevated among white men and women and kidney cancer among black men and women, but not significantly so. None of these causes of death showed strong relationships with duration or estimated level of exposure to dry cleaning solvents, although relative risks for cancers of the larynx, lung and kidney were larger among subjects estimated to have higher levels of exposure and risks from bladder cancer and chronic nephritis were greater among persons who entered the union after 1960. CONCLUSION: The excesses observed are unlikely to be due to chance because most occurred in earlier as well as the recent follow-up. The specific factors contributing the excesses, however, are not clear. Socioeconomic, lifestyle, and occupational exposures are all possibilities. Lack of information on socioeconomic and lifestyle factors hampers evaluation.