Cancer and other causes of death among a cohort of dry cleaners

Mortality among 5365 members of a dry cleaning union in St. Louis, Missouri, was less than expected for all causes combined (SMR = 0.9) but slightly raised for cancer (SMR = 1.2). Among the cancers, statistically significant excesses occurred for oesophagus (SMR = 2.1) and cervix (SMR = 1.7) and non-significant excesses for larynx (SMR = 1.6), lung (SMR = 1.3), bladder (SMR = 1.7), thyroid (SMR = 3.3), lymphosarcoma and reticulosarcoma (SMR = 1.7), and Hodgkin's disease (SMR = 2.1). Mortality from emphysema was also significantly raised (SMR = 2.0). Eleven of the 13 deaths from oesophageal cancer occurred among black men. The risk of this cancer showed a significant association with estimated cumulative exposure to dry cleaning solvents (rising to 2.8-fold in the highest category) but not with level or duration of exposure. Mortality from kidney cancer was not excessive as reported in other studies. Excesses for emphysema and cancers of the larynx, lung, oesophagus, bladder, and cervix may be related to socioeconomic status, tobacco, or alcohol use. Although the number of deaths was small, the greatest risk for cancers of the lymphatic and haematopoietic system (fourfold) occurred among workers likely to have held jobs where exposures were the heaviest. Small numbers and limited information on exposure to specific substances complicates interpretation of this association but is unlikely to be due to confounding by tobacco use. It was not possible to identify workers exposed to specific dry cleaning solvents but mortality among those entering the union after 1960, when use of perchloroethylene was predominant, was similar to those entering before 1960.     

Cancer and other causes of death among a cohort of dry cleaners.

Mortality among 5365 members of a dry cleaning union in St. Louis, Missouri, was less than expected for all causes combined (SMR = 0.9) but slightly raised for cancer (SMR = 1.2). Among the cancers, statistically significant excesses occurred for oesophagus (SMR = 2.1) and cervix (SMR = 1.7) and non-significant excesses for larynx (SMR = 1.6), lung (SMR = 1.3), bladder (SMR = 1.7), thyroid (SMR = 3.3), lymphosarcoma and reticulosarcoma (SMR = 1.7), and Hodgkin's disease (SMR = 2.1). Mortality from emphysema was also significantly raised (SMR = 2.0). Eleven of the 13 deaths from oesophageal cancer occurred among black men. The risk of this cancer showed a significant association with estimated cumulative exposure to dry cleaning solvents (rising to 2.8-fold in the highest category) but not with level or duration of exposure. Mortality from kidney cancer was not excessive as reported in other studies. Excesses for emphysema and cancers of the larynx, lung, oesophagus, bladder, and cervix may be related to socioeconomic status, tobacco, or alcohol use. Although the number of deaths was small, the greatest risk for cancers of the lymphatic and haematopoietic system (fourfold) occurred among workers likely to have held jobs where exposures were the heaviest. Small numbers and limited information on exposure to specific substances complicates interpretation of this association but is unlikely to be due to confounding by tobacco use. It was not possible to identify workers exposed to specific dry cleaning solvents but mortality among those entering the union after 1960, when use of perchloroethylene was predominant, was similar to those entering before 1960.     

Susceptibility to heat wave-related mortality: a follow-up study of a cohort of elderly in Rome

Background  

Few studies have identified specific factors that increase mortality during heat waves. This study investigated socio-demographic characteristics and pre-existing medical conditions as effect modifiers of the risk of dying during heat waves in a cohort of elderly residents in Rome.     

Effect of cohort definition and follow-up length on occupational mortality rates

The purpose of this study was to clarify the effects of cohort formation, period of entry, and period of follow-up on occupational mortality figures. The study material comprised three cohorts of metal industry workers (6 415 iron foundry workers, 3 901 metal product workers, and 5 398 workers manufacturing electrical devices). The men, hired between 1950 and 1976, were followed until the end of 1978. The number of person-years was approximately 215 800. Different cohort formation criteria and variations in the follow-up modify the results of occupational mortality studies. A cross-sectionally based cohort (workers employed in a certain year or years) produces results different from those for an open cohort (new workers hired during a certain period of time) although the cohorts are formed from the same workplaces. The cohorts for retrospective cohort studies usually contain various periods of entry, periods of follow-up, and age structures. Increased or decreased mortality in a cohort depends on this internal structure. The structure of the cohort becomes especially important when a certain cause of death is concentrated in certain age classes and/or when a period of latency is required, as for tumors. In an attempt to reveal this internal structure the three cohorts were analyzed in five-year calendar periods and stratified according to the length of follow-up. The mortality pattern remained nearly unchanged when the number of periods of entry increased, and it was also comparable with the mortality pattern of the general male population.(ABSTRACT TRUNCATED AT 250 WORDS)     

Exposure-response models based on extended follow-up of a cohort mortality study in the automobile industry

OBJECTIVE: This report describes the extended follow-up of a cohort of 46 399 automobile manufacturing workers with potential exposure to metalworking fluids (MWF). The outcomes of interest were cancers of the esophagus, stomach, colon, rectum, liver, pancreas, larynx, skin, prostate, and brain, as well as leukemia. Additional follow-up increased the power to detect modest elevations in mortality rates in association with specific types of MWF, including synthetic fluids not in widespread use until the 1970s. METHODS: Standardized mortality ratios (SMR) were computed for the most recent 10 years of follow-up, as well as for the entire study period. Adjusted relative risks (RR) were estimated in Poisson regression models with categorical variables for cumulative exposure to each type of MWF and in proportional hazards models with continuous exposure variables. RESULTS: Associations were found between straight MWF and esophageal, laryngeal and rectal cancer; soluble MWF and cancer of the esophagus, larynx, skin, and brain; synthetic MWF and cancer of the esophagus, liver, and prostate. The elevated RR values were modest in magnitude (1.5 to 2.0). SMR values were increased for stomach, liver, and pancreatic cancer and also for leukemia in the last 10 years of follow-up. The SMR values were also elevated for stomach and liver cancer among the persons recently hired. CONCLUSIONS: The results provide further evidence that exposure to metalworking fluids causes cancer among workers in automobile manufacturing. Although airborne exposures declined over the study period, this study suggests that modest risk of several digestive cancers, as well as prostatic cancer and leukemia, may persist at current levels of exposure to water-based metalworking fluids.     

Frequency of emergency department attendances as a predictor of mortality: nine-year follow-up of a population-based cohort

Heavy users of the services of emergency departments (EDs) have in previous studies been found to have psychological, social, economic and other difficulties besides their more or less acute medical problems. In order to establish whether mortality is associated with high ED use, a nine-year follow-up study was conducted of a 10 per cent population sample (n = 17,000), selected from the catchment area of Huddinge Hospital, Sweden. ED visits were found to predict nine-year mortality in the cohort. The group of individuals who had made four or more ED visits during a period of 15 months prior to follow-up (heavy ED users) had a two-fold excess mortality (95 per cent confidence interval (CI) = 1.9-2.1), those who had made one to three ED visits (moderate ED users) had a slightly elevated mortality (standardized mortality ratio SMR = 1.1, 95 per cent CI = 1.0-1.3), while the SMR of the non-users was 0.9 (95 per cent CI = 0.8-1.0). The three predominant causes of death in the cohort were diseases in the circulatory system, tumours and violent death. Heavy ED users had elevated mortality in all diagnoses, the most important excess mortality being from violent death, comprising suicide, probable suicide and alcohol/drug abuse, with an SMR of 6.3 (95 per cent CI = 6.0-6.7). The excess mortality from these causes of the heavy ED users accounted for more than one-third of their total excess mortality.(ABSTRACT TRUNCATED AT 250 WORDS)     

An update of cancer mortality among the French cohort of uranium miners: Extended follow-up and new source of data for causes of death

The follow-up of the French cohort of uranium miners has been extended to 1994, and a new source of information for causes of death has been used. The paper presents the new results regarding the risk of death among the cohort, and analyses the impact of the methodological changes on these results. The extension of the follow-up results in a substantial increase in statistical power compared with previous analysis (+25% for person-years and +74% for the number of deaths). The use of the National Mortality Database as the principal source for causes of death allows to reduce the potential bias in the calculation of standardized mortality ratios (SMR). As a consequence, an excess risk of deaths from laryngeal cancer, suggested in the first analysis, is not confirmed. The analysis shows the existence of an excess risk of deaths from lung cancer among French uranium miners (85 observed deaths, SMR = 1.9, 95% confidence interval CI: 1.5-2.3), and an increase of this risk with cumulative exposure to radon (excess relative risk per 100 working level month = 0.6, 95% CI: 0.1-1.2). These results confirm the existence of a risk of death from lung cancer in a population chronically exposed to relatively low levels of radon.     

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.     

Utilizing multiple vital status tracing services optimizes mortality follow-up in large cohort studies

PURPOSE: To compare the three national-scale death identification services used in our two-stage vital status tracing protocol, Pension Benefit Information Company (PBI), Social Security Administration (SSA), and the Health Care Financing Administration (HCFA), with respect to death identification and confirmation rate, and relevant demographic variables. METHODS: Information on 31,223 subjects with unconfirmed vital status in an ongoing occupational cohort mortality study was simultaneously submitted to PBI, SSA, and HCFA to identify subjects deceased as of December 31, 1992. Subjects whose dates of death were between 1979 and 1992 were then sent to the National Death Index (NDI) to obtain death certificate numbers and supplemental states of death. RESULTS: PBI identified and confirmed the highest number deaths in this cohort. PBI and SSA identified a higher proportion of deaths for persons who died in earlier years and/or who died at a younger age, for both confirmed and unconfirmed deaths. HCFA identified fewer deaths overall and had a smaller proportion of unconfirmed deaths. These deaths occurred in later years among older subjects and had the highest proportion of females. NDI provided exact matches for 92-96% of deaths identified by each of the three services. CONCLUSIONS: PBI was the most comprehensive service, especially for identifying younger subjects and those with an earlier date of death, while HCFA may help to identify deceased female subjects. SSA data can be purchased and used for periodic updates or interactively to identify deaths among subjects with poor identifiers (such as incorrect or missing social security numbers or misspelled names). Because each service makes a valuable contribution to the identification of deceased cohort subjects, all three should be considered for optimal mortality follow-up.     

French cohort of the uranium processing workers: mortality pattern after 30-year follow-up

Objective  

To investigate mortality among nuclear workers with potential internal exposure to uranium.     

An analysis of mortality follow-up through the National Death Index for a cohort of refinery and petrochemical workers

Along with our submission to the National Death Index (NDI) of a cohort of more than 23,000 petrochemical and refinery workers, we included 1,449 known U.S. deaths to determine the completeness of death ascertainment through the NDI. A number of factors that may affect follow-up were examined including sex, race, age and reporting area. Overall, NDI detected 97.1% of known deaths. Follow-up was slightly better for males (97.2%) than for females (92.0%) and was significantly better for whites (97.6%) than for nonwhites (92.0%). Analyses by reporting area showed very complete follow-up from all locations (93.4%-100%) except for the New York City area (71.4%). These findings indicate that NDI is an extremely useful source for vital status follow-up, though follow-up may be somewhat less complete for certain subgroups of an occupational study cohort.     

Marital and cohabitation status as predictors of mortality: a 10-year follow-up of an Italian elderly cohort

The relationship between mortality and marital status has long been recognized, but only a small number of investigations consider also the association with cohabitation status. Moreover, age and gender differences have not been sufficiently clarified. In addition, little is known on this matter about the Italian elderly population. The aim of this study is to examine differentials in survival with respect to marital status and cohabitation status in order to evaluate their possible predictive value on mortality of an Italian elderly cohort. This paper employs data from the Italian Longitudinal Study on Aging (ILSA), an extensive epidemiologic project on subjects aged 65-84 years. Of the 5376 individuals followed-up from 1992 to 2002, 1977 died, and 1492 were lost during follow-up period. The baseline interview was administered to 84% of the 5376 individuals and 65% of them underwent biological and instrumental examination. Relative risks of mortality for marital (married vs. non-married) and cohabitation (not living alone vs. living alone) categories are estimated through hazard ratios (HR), obtained by means of the Cox proportional hazards regression model, adjusting for age and several other potentially confounding variables. Non-married men (HR=1.25; 95% CI: 1.03-1.52) and those living alone (HR=1.42; 95% CI: 1.05-1.92) show a statistically significant increased mortality risk compared to their married or cohabiting counterparts. After age-adjustment, women's survival is influenced neither by marital status nor by cohabitation status. None of the other covariates significantly alters the observed differences in mortality, in either gender. Neither marital nor cohabitation status are independent predictors of mortality among Italian women 65+, while among men living alone is a predictor of mortality even stronger than not being married. These results suggest that Italian men benefit more than women from the protective effect of living with someone.     

Influence of life-related factors and participation in health examination on mortality in a 4.5-year follow-up of a rural cohort

To identify life-related factors causing increased mortality, 2,769 rural residents aged 29-77 were investigated through a self-administered questionnaire in 1990. Death certificates and migration information were inspected during the 4.5-year follow-up period. Age, obesity, life attitude, job, marital status, drinking and smoking habits, previous or current illness, and frequency of participation in health examinations were checked during the baseline survey. The person-year mortality rate was higher among irregular participants in health examinations than among regular participants both among males and females. From Cox’s multiple regression analysis, factors with a significantly high hazard ratio (HR) for mortality were irregular participation (HR=2.05), increase of age (HR=1.54, for 10 years), previous or current illness (HR=2.44), unemployment (HR=1.95), and living without a spouse (HR=2.61) for males; and for females they were having previous or current illness (HR=15.21) and living without a spouse (HR=2.94). Thus, irregular participation in health examinations, unemployment and aging showed a relationship with a higher mortality only in males. A previous or current illness and living without a spouse were related in both sexes.     

The influence of duration of follow-up on the association between alcohol and cause-specific mortality in a prospective cohort study

PURPOSE: To investigate whether duration of follow-up influences the association between alcohol and cause-specific mortality in a prospective cohort study with only baseline assessment of alcohol intake. METHODS: In a cohort of 14,223 men and women participating in the first investigation of the Copenhagen City Heart Study between 1976 and 1978 and followed until 2001, we assessed whether the association between alcohol and mortality was modified by duration of follow-up. The 24 years of follow-up were divided into four intervals, and Cox survival analyses were conducted separately for these four succeeding 6-year periods of follow-up. RESULTS: The authors found differences in the predictive values of alcohol and beverage-specific types of alcohol depending on duration of follow-up both in terms of all-cause mortality and death from coronary heart disease and cancer. The apparent protective effect of a moderate alcohol consumption on coronary heart disease attenuated during prolonged follow-up, whereas high alcohol consumption became associated with higher risk of death from cancer with longer follow-up. CONCLUSIONS: This study accentuates the importance of taking duration of follow-up into consideration when interpreting risk estimates from prospective studies on the association between alcohol and mortality.     

Lower prevalence of heart disease but higher mortality risk during follow-up was found among nonrespondents to a cohort study

OBJECTIVE: The primary aim was to assess the association between response behavior and health status at baseline, and survival in a 5-year follow-up period. A secondary aim was to assess whether reasons for nonresponse were associated with health status at baseline. STUDY DESIGN AND SETTING: Data came from a prospective study cohort consisting of 31,349 men and women aged 45-70 years. Objective retrospective and prospective health information derived from general practitioner registries was available for both respondents and nonrespondents. RESULTS: Results show that among respondents coronary heart disease was more prevalent. Compared with respondents, noncontacts had a higher mortality risk during follow-up. Refusals had hypercholesterolemia more often than did noncontacts, and coronary heart disease or diabetes mellitus less often. CONCLUSION: The paradoxical results that respondents are less healthy at baseline but prospectively have a lower mortality risk may point to a selection effect indicating that the 'worried ill' are more inclined to participate. This effect could imply that observed relationships between risk factors or behaviors and outcomes in cohort studies may be attenuated.     

Cosmic radiation and mortality from cancer among male German airline pilots: extended cohort follow-up

Commercial airline pilots are exposed to cosmic radiation and other specific occupational factors, potentially leading to increased cancer mortality. This was analysed in a cohort of 6,000 German cockpit crew members. A mortality follow-up for the years 1960-2004 was performed and occupational and dosimetry data were collected for this period. 405 deaths, including 127 cancer deaths, occurred in the cohort. The mortality from all causes and all cancers was significantly lower than in the German population. Total mortality decreased with increasing radiation doses (rate ratio (RR) per 10 mSv: 0.85, 95 % CI: 0.79, 0.93), contrasting with a non-significant increase of cancer mortality (RR per 10 mSv: 1.05, 95 % CI: 0.91, 1.20), which was restricted to the group of cancers not categorized as radiogenic in categorical analyses. While the total and cancer mortality of cockpit crew is low, a positive trend of all cancer with radiation dose is observed. Incomplete adjustment for age, other exposures correlated with duration of employment and a healthy worker survivor effect may contribute to this finding. More information is expected from a pooled analysis of updated international aircrew studies.     

Association between self-rated health and mortality: 10 years follow-up to the Pro-Saude cohort study

ABSTRACT: BACKGROUND: The association between self-rated health (SRH) and mortality is well documented in the literature, but studies on the subject among young adults in Latin America are rare, as are those evaluating this association using repeated SRH measures, beyond the baseline measurement. This study aims to evaluate the association between SRH evaluated at three data collection stages and mortality. METHODS: Cox regression models were used to examine the association between SRH (Very good, Good, Fair/Poor) varying over time and mortality, over a 10 year period, in a cohort of non-faculty civil servants at a public university in Rio de Janeiro, Brazil (Pro-Saude Study, n = 4009, men = 44.4 %). RESULTS: About 40 % of the population changed their self-rating over the course of follow-up. After adjustment for self-reported physician-diagnosed diseases and other covariates, men who reported "Fair/Poor" SRH showed relative hazard of death of 2.13 (CI95% 1.03-4.40) and women, 3.43 (CI95% 1.23-9.59), as compared with those who reported "Very good" SRH. CONCLUSIONS: In a population of young adults, our findings reinforce the role of SRH as a predictor of mortality, even controlling for objective measures of health.     

Acrylamide cohort mortality study

The mortality experience of 371 employees assigned to acrylamide monomer and polymerisation operations was examined with particular emphasis on cancers at sites identified from animal studies such as the central nervous system, thyroid gland, other endocrine glands, and mesotheliomas. A total of 29 deaths was observed up until 1982 (38.0 expected). No statistically significant excesses were noted in the total cohort and no deaths were found for the hypothesised sites of cancer. The observed deaths in the total cohort for the all cancers category were somewhat in excess (11 v 7.9); however, this was due entirely to excess cancers of the digestive tract and respiratory system in the subgroup with previous exposure to organic dyes. Among those employees not exposed to organic dyes, four deaths were due to malignancies versus 6.5 expected. This study does not support a cause effect relation between exposure to acrylamide at this work site and overall mortality, total malignant neoplasms, or any specific cancers.