Proportionate Cancer Mortality Ratios Research Articles

Proportionate mortality among unionized construction operating engineers.

This report presents the results of proportionate mortality ratios (PMR) and proportionate cancer mortality ratios (PCMR) among 15,843 members of the International Union of Operating Engineers who had died between 1988-1993. Operating engineers represent one of the 15 unions in the Building and Construction Trades Department and are responsible for the operation and maintenance of heavy earthmoving equipment used in the construction of buildings, bridges, roads, and other facilities. Using U.S. proportionate cancer mortality as the referent, statistically significant elevated mortality was observed for cancers of the lung (PCMR = 1.14, 95% confidence interval (CI) = 1.09-1.19) and bone (PCMR = 2.14, CI = 1.19-3.52). Using U.S. proportionate mortality as the referent, statistically significant elevated mortality was observed for other benign and unspecified neoplasms (PMR = 1.54, CI = 1.09-2.13), emphysema (PMR = 1.37, CI = 1.20-1.55), other injuries (PMR = 1.43, CI = 1.20-1.70) (which included crushing under/in machinery, tractor rollover, run over by crane), and suicide (PMR = 1.22, CI = 1.06-1.40). The PMR for leukemia, and aleukemia (PMR = 1.19, CI = 1.02-1.37), but not the PCMR (1.07, CI = 0.92-1.24), was also significantly elevated. Some of the occupational exposures that may have contributed to these excesses include diesel exhaust, asphalt and welding fumes, silica dust, ionizing radiation, and coal tar pitch. The present study underscores the need to control airborne exposures to these substances and for injury prevention efforts aimed at operating engineers in the construction industry.

Proportionate mortality among unionized construction ironworkers.

This report presents the results of proportionate mortality ratios (PMR) and proportionate cancer mortality ratios (PCMR) among 13,301 members of the International Union of Bridge, Structural, and Ornamental Ironworkers who had been members for a minimum of 1 year, were actively paying dues into the death beneficiary fund, and had died between 1984-1991. Using the United States proportionate mortality rates as the comparison population, statistically significant elevated risks, using 95% confidence intervals (CI), were observed for several types of injuries: falls (N = 259, PMR = 3.57, CI = 3.15-4.03), transportation injuries (N = 363, PMR = 1.22, CI = 1.10-1.35), and other types of injuries (N = 225, PMR = 1.63, CI = 1.43-1.86). The deaths due to falls were significantly elevated for each 10-year age group under age 60 (PMR > 7.00) and for those workers with < 20 years in the union (PMR > 6.00). Elevated mortality risks were also observed for all malignant neoplasms combined (N = 3,682, PMR = 1.09, CI = 1.06-1.13) as well as for site-specific malignant neoplasms of the lung (N = 1,523, PMR = 1.28, CI = 1.21-1.35), pleural mesothelioma (N = 7, PMR = 1.67, CI = 0.67-3.44) and "other and unspecified sites" (N = 307, PMR = 1.29, CI = 1.15-1.44). The category "pneumoconiosis and other respiratory diseases" was also significantly elevated (N = 690, PMR = 1.11, CI = 1.03-1.20); in this category, deaths due to asbestosis had the greatest elevated risk (N = 10, PMR = 3.56, CI = 1.70-6.54). No elevation in risk was found for kidney cancer or for chronic nephritis which were of interest because of Ironworkers' potential exposure to lead. The present study underscores the importance of fall protection and other injury prevention efforts in the construction industry, as well as the need to control airborne exposures to asbestos, welding fumes and other respirable disease hazards.

Mortality of Carpenters' Union members employed in the U.S. construction or wood products industries, 1987-1990.

This study evaluated the mortality of 27,362 members of the U.S. Carpenters' Union who died in 1987-1990. Age-adjusted proportionate mortality ratios (PMRs) and proportionate cancer mortality ratios (PCMRs) were computed using the U.S. age-, gender-, and race-specific proportional mortality for the years of the study. For white male carpenters who were last employed while in construction industry locals, raised mortality was observed for lung cancer (PCMR = 107, CI = 103, 111), bone cancer (PMR = 181, CI = 107, 286), asbestosis (PMR = 283, CI = 158, 457), emphysema (PMR = 115, CI = 102, 130), transportation injuries (PMR = 121, CI = 109, 135), and falls (PMR = 122, CI = 104, 142). For white male carpenters who were last employed while in industrial wood products locals, significantly raised mortality occurred for stomach cancer (PMR = 187, CI = 136, 250), male breast cancer (PCMR = 469, CI = 128, 720), and transportation injuries (PMR = 136, CI = 110, 173). Excess breast cancer was associated with last employment inn wood machining trades. Nasal cancer mortality was not elevated. A total of 121 mesotheliomas were observed. Contributing cause of death analyses revealed raised mortality for these and additional causes; 4,594 (18%) death certificates mentioned occupational and other lung disease as a contributing factor, resulting in significantly elevated mortality. These data show that construction carpenters have moderately elevated mortality for the diseases caused by asbestos (lung cancer and malignant mesothelioma) and from traumatic injuries. The finding of elevated mortality for stomach, bone, and breast cancer was unexpected and requires further evaluation of possible occupational factors. This study confirms that construction carpentry is an extremely hazardous trade. The data suggest that additional preventive action guarding against asbestos exposure and occupational injury is urgently needed in this occupation.

Mortality of farmers and farmers' wives in England and Wales 1979-80, 1982-90.

To examine the mortality patterns of male and female farmers and farmers' wives in England and Wales. Information on all deaths in England and Wales at ages 20-74 during the periods 1979-80 and 1982-90 was obtained from the Office of Population Censuses and Surveys. Proportional mortality ratios (PMRs) and proportional cancer mortality ratios (PCMRs) were used to compare the mortality of farmers with that of the general working population, and of farmers' wives with wives of all working men. Farmers and farmers' wives had high mortality from accidents and suicide and from certain respiratory diseases. Mortality from hernia was also raised. Deaths from cancer were generally below expectations, but the PMR for prostatic cancer was 112 (95%CI 106-118). The PMRs and PCMRs for oesophageal cancer were significantly increased in male farmers from two counties where cider is produced. The occupational hazards of farming continue to be associated with excess mortality, and most of the risks extend also to farmers' wives. Action is needed to reduce deaths, particularly from accidents and suicide.

Risk of lung cancer among former chromium smelter workers.

Hexavalent chromium is a known carcinogen. Previous epidemiologic studies in the 1950s of United States workers from seven facilities producing chromium compounds from chromite ore have reported a markedly increased risk for dying from lung cancer. As part of a high risk notification project of workers from four of these facilities, a mortality study was performed. The cohort was assembled in 1990-1991 from the Social Security records of four former chromate producing facilities in northern New Jersey. The study subjects were known to have worked at these facilities some time between 1937 and 1971. Proportionate mortality and proportionate cancer mortality ratios (PCMR) were calculated. The overall risk for lung cancer was a PCMR of 1.51 (confidence limits [CL] 1.29-1.74) for white men and 1.34 (CL 1.00-1.75) for black men. These risks increased with increasing duration of employment and latency since time of first employment. The PCMR for greater than 20 years duration of work and more than 20 years since first exposure was 1.94 (CL 1.15-3.06) for white men and 3.08 (CL 1.13-6.71) for black men. The risk for lung cancer for white men remains elevated more than 20 years after exposure has ceased (PCMR, 1.29; CL 1.03-1.60). The PCMR for nasal cavity/sinus cancer was also found to be a significantly increased, 5.18 (CL 2.37-11.30). A cluster of bladder cancer was seen among black workers from one facility, (PCMR, 3.30; CL 1.42-6.51). Despite the cessation of exposure, former chromium workers remain at significantly increased risk of lung cancer. Although there have been case reports of nasal cavity/ sinus cancer in association with chromium exposure, this is the first epidemiologic study to report a significant increase in these cancers. Limitations in this study include lack of exposure data and lack of information on smoking habits. The lack of increase in other smoking-related diseases besides lung cancer indicates that the increase in lung cancer cannot be attributed to cigarette smoking. The ongoing elevated risk of lung cancer after cessation of exposure emphasizes the need for developing early detection texts for lung cancer.

Proportionate mortality among construction laborers.

This report presents the results of proportionate mortality ratio (PMR) analyses and proportionate cancer mortality ratio (PCMR) analyses among the 11,685 members of the Laborers' International Union of North America (LIUNA), who died between 1985-1988, using U.S. proportionate mortality rates as the comparison population. Statistically significant elevated mortality risks were observed for all malignant neoplasms (N = 3285, PMR = 1.13, CI = 1.09-1.17), as well as for site-specific neoplasms of the lung (N = 1208, PCMR = 1.06, CI = 1.00-1.12), stomach (N = 170, PCMR = 1.44, CI = 1.23-1.68), and thyroid gland (N = 10, PCMR = 2.24, CI = 1.07-4.12). The PCMRs for these malignant neoplasms were elevated among both white and non-white males, regardless of length of union membership, in most 10-year categories of age at death above 40 and for the three largest LIUNA regions examined. The study also observed 20 mesothelioma deaths, which indicated that some LIUNA members had been previously exposed to asbestos. Statistically significant elevated risks were also observed for deaths from transportation injuries (N = 448, PMR = 1.37, CI = 1.25-1.51), falls (N = 85, PMR = 1.34, CI = 1.07-1.66), and other types of injuries (N = 245, PMR = 1.61, CI = 1.42-1.83). The deaths due to injuries were most often observed among those members who had the shortest amount of time within the union, were younger, and first entered the union after 1955. This is the first study that has examined the general mortality experience limited to construction laborers only (Bureau of Census code 869).

Using Occupational Mortality Data for Surveillance of Work-related Diseases of Women

A recently developed source of occupational mortality data from 28 states for the years 1979 through 1990 can be used to meet goals for the surveillance of women's work-related diseases. A proportionate cancer mortality ratio analysis is used to illustrate use of the data to address the goals of identifying previously unrecognized work-related disease and targeting consultation or health promotion programs to appropriate occupations. Strengths of the data include broad geographical coverage and coverage of all causes of death and numerous industries and occupations. The data set is current and very large, with annual additions. The data have certain limitations. Death certificate information collected regarding occupation and cause of death may not be accurate; furthermore, death certificates have little information on potential confounding factors, such as smoking.

Causes of mortality in primary and secondary school teachers

A proportionate mortality study was conducted on 809 deaths occurring among New Jersey primary and secondary teachers between 1980 and 1984. Three separate sets of expected number of deaths were used, based on U.S. and New Jersey proportionate mortality ratios in the general population and proportionate cancer mortality ratios. Increased cause of death was found for digestive, breast, other genital, and lymphopoietic cancer, and motor vehicle accidents for white female teachers; digestive cancer, heart disease, and nonmalignant genitourinary disease for white male teachers; digestive, brain, and thyroid cancer in black female teachers; and kidney and prostate cancer in black male teachers. Deficits in lung cancer were found for white male teachers and in heart disease for white and black female teachers. Mortality ratios were examined by duration worked and latency since first hired. Further analysis using a nested-case control methodology is recommended.

Cancer and other causes of death among male and female farmers from twenty‐three states

Occupation and industry codes on death certificates from 23 states for 1984-1988 were used to evaluate mortality risks among white and nonwhite, male and female farmers. Proportionate mortality and proportionate cancer mortality ratios were calculated using deaths among nonfarmers from the same states to generate expected numbers. Among farmers there were 119,648 deaths among white men, 2,400 among white women, 11,446 among nonwhite men, and 2,066 among nonwhite women. Deficits occurred in all race-sex groups for infective and parasitic diseases, all cancer combined, lung cancer, liver cancer, diseases of the nervous system, multiple sclerosis, hypertension, and emphysema. As reported in other studies, white male farmers had excesses of cancer of the lymphatic and hematopoietic system, lip, eye, brain, and prostate. Excesses of cancers of the pancreas, kidney, bone, and thyroid were new findings. Regional patterns were evident, particularly among white men. Significant excesses for accidents, vascular lesions of the central nervous system (CNS), and cancers of the prostate tended to occur in most geographic regions, while excesses for mechanical suffocation, non-Hodgkin's lymphoma, and cancers of the lip, brain, and the lymphatic and hematopoietic system were limited to the Central states. Increases among nonwhite men were similar to those in white men for some causes of death (vascular lesions of the CNS and cancers of the pancreas and prostate), but were absent for others (lymphatic and hematopoietic system, lip, eye, kidney, and brain). Women (white and nonwhite) had excesses for vascular lesions of the CNS, disease of the genitourinary system (white women only), and cancers of the stomach and cervix (nonwhite women only). Cancer of the buccal cavity and pharynx was slightly elevated among women, and white women had nonsignificant excesses of multiple myeloma and leukemia. Excesses for leukemia and non-Hodgkin's lymphoma occurred among white men and women, but not among nonwhites. Excesses for several types of accidental deaths were seen among all race-sex groups.

Respiratory disease mortality patterns among South African iron moulders.

To assess the influence of foundry exposure on malignant and non-malignant respiratory disease, the proportional mortality ratio (PMR) was used to compare the cause of death distributions of the 578 dead members of the Iron Moulders Society of South Africa, recipients of the union's death benefit fund between 1961 and 1983. Comparisons were made with the age and period specific white male deaths. For the 419 members where job information was available, the influence of occupation (journeyman, production moulder) was assessed using different techniques--the relative proportional mortality ratio (RPMR), the mortality odds ratio (MOR), and the proportional cancer mortality ratio (PCMR) for comparison. Excess PMRs were found for cancer of the trachea, bronchus, and lung (1.71, p = 0.03; Poisson one sided test) for those over 65 and for non-malignant respiratory disease (1.58, p = 0.01) and for injuries and poisonings (2.61, p less than 0.0001) in those under 65. Reduced PMRs were found for all cancers (0.75, p = 0.03) and all circulatory disease (0.91, p = 0.12) in those under 65. When comparing job types, raised risks were obtained for journeymen using all methods (RPMR, MOR, PCMR) but the small cell sizes rendered the results non-significant. The raised PMRs due to respiratory disease are unlikely to be due to smoking because of a poor association with other causes of death related to smoking. A more likely explanation is that these excess rates for malignant and non-malignant respiratory disease are due to exposure to the foundry environment. Of additional concern are the high PMRs due to injuries and poisonings, which could be related to the high accident rates in the iron and steel industry.

Cancer mortality among northern Georgia carpet and textile workers.

Proportionate cancer mortality was analyzed among white male carpet and textile workers in five northwest Georgia counties for the years 1970-1984. Compared with other Georgians, carpet and textile workers had higher proportions of lymphocytic leukemia (proportionate cancer mortality ratio [PCMR] = 2.9; 95% CI = 1.4-5.4]) and testicular cancer (PCMR = 3.2; 95% CI = 1.0-7.5). The excess mortality from lymphocytic leukemia was even higher when the analysis was limited to workers deemed most likely to work directly in production areas (PCMR = 4.2; 95% CI = 1.7-8.7). Further studies are needed to determine if the observed excesses are the result of workplace exposures.

Cancer and other causes of death among Wisconsin farmers.

Computerized mortality listings for Wisconsin for 1968-1976 were used in proportional mortality ratio (PMR) and proportional cancer mortality ratio (PCMR) analyses to evaluate mortality patterns among Wisconsin farmers. Examination of PCMR trends by per capita county level of agricultural production was limited to the youngest birth cohort (1905-1958) and cancer sites associated with farming exposures in either the present or previous analyses. Among all Wisconsin farmers, significantly decreased PMRs were seen for tobacco- and alcohol-related causes of death, while excesses occurred for accidental causes, asthma, and cancer of the stomach, prostate, eye, and lymphatic and hematopoietic systems. Elevated PCMR's for leukemia and all lymphopoietic cancer and cancers of the stomach, rectum, eye occurred in farmers born 1905-1958, while deficits were observed for cancer of the pancreas and the category, "all other cancers." Increases in PCMR's with level of various agricultural activities were largely associated with cancers of other lymphatic tissue (2/3 of which were multiple myeloma) and the rectum. Certain agricultural exposures were also positively associated with deaths due to cancers of the prostate, brain, lymphosarcoma and reticulosarcoma, and all lymphopoietic cancers. No positive PCMR gradients were observed for leukemia and malignancies of the stomach and eye. Modern chemical practices in farming may account for some of the patterns noted.

A proportional mortality ratio study of workers in a construction equipment and diesel engine manufacturing plant.

The mortality of 461 workers who were employed 10 or more years in a Midwest engine and construction equipment plant was examined, using the method of proportional mortality ratios. Both state and national deaths were used as the standard population. Major exposures in this plant included solvents, cutting oils, and metal fumes and dusts. However, precise exposure data were not available. Among white males, no significant deviations from expected deaths were found. Among black males, significant excess deaths were found for all malignant neoplasms combined, for cancer of the pancreas, and for non-Hodgkin's lymphomas. Proportional cancer mortality ratios produced similar results, although the excess of pancreatic cancer in blacks was only significant among those with 20 or more years of service. Although complete occupational histories were not available, these results may provide hypotheses for future studies of workers in heavy machinery production.

Comparison of SMR, PMR, and PCMR in a cohort of union members potentially exposed to diesel exhaust emissions.

A comparison of cause specific standarised mortality ratios (SMRs) and proportionate mortality ratios (PMRs) or proportionate cancer mortality ratios (PCMRs) was made based on the mortality experience of a cohort of 34 156 members of a heavy equipment operators union. Two types of PMRs or PCMRs were used in the comparison: those based on all deaths and those based on deaths known to the union only. The comparison indicated that, for the entire cohort, both types of PMRs were poor indicators for cancer risk and produced a large number of false positives. On the other hand, PCMRs appeared to be better than PMRs for assessing the direction of site specific cancer risk, but they tended to overstate the magnitude of risk. Analysis by duration of union membership or latency indicated that PMRs or PCMRs based on deaths known to the union tended to overestimate the risk of lung cancer by disproportionately larger amounts in groups with shorter time than in groups with longer time. This differential bias had the net effect of reducing the gradient of any trend or eliminating the trend entirely. In conclusion, PMR or PCMR, based on reasonably sufficient death ascertainment, has a certain usefulness in generating hypotheses, but they are not useful or reliable in measuring the magnitude of risk or in detecting trends in dose response analysis. No conclusion should be drawn from either PMR or PCMR.

Patterns of mortality among migrants to England and Wales from the Indian subcontinent.

Causes of deaths in immigrants to England and Wales from the Indian subcontinent were assessed by ethnic subgroup. Observed and expected deaths for 1975-7 were aggregated to calculate proportional mortality ratios. Observed mortality due to infective and parasitic diseases, endocrine diseases (notably diabetes), diseases of the circulatory system (notably ischaemic heart disease and cerebrovascular disease, in males), and diseases of the digestive system (notably cirrhosis of the liver) exceeded expected mortality. Fewer than expected deaths were due to malignant neoplasms (notably lung cancer and chronic bronchitis); proportional mortality ratios for cancer were lower for Hindu groups than for Moslems and were lowest for Punjabis. Mortality due to ischaemic heart disease, high in all groups, was highest in Moslems. Significantly more Punjabi males died from cerebrovascular disease and cirrhosis of the liver. Diabetes was commonest among Gujaratis. The variation seen in the patterns of mortality in the different ethnic groups indicates the need for further epidemiological and health service research centred on these communities.

A proportionate mortality analysis of California agricultural workers, 1978-1979.

There are few published reports of epidemiologic studies of the risks of agricultural work. Members of this occupational group have been of special concern because of their exposure to pesticides, some of which are mutagens and animal carcinogens. A previous proportionate mortality study of California agricultural workers was based on deaths recorded among white males of this occupational group during 1959-1961. We have conducted a proportionate mortality analysis of all deaths recorded during 1978-1979 among California farm workers and farm owner/managers. In general, the findings of our study are consistent with those of the previous study. For farm workers, we found proportionate mortality ratios (PMRs) which were consistently elevated for all race and sex categories (in which there were 6 or more decedents) for deaths due to motor vehicle accidents, all respiratory disease, and all infective and parasitic diseases. The PMRs for the former three causes of death were also found to be elevated across several race and sex categories for farm owner/managers. We also found a significant and consistent deficit of deaths among farm workers and farm owner/managers due to arteriosclerotic heart disease. The proportionate cancer mortality ratios (PCMRs) for cancer of the stomach and cancer of other lymphatic tissue were elevated, although not necessarily statistically significantly, for several race and sex categories among farm workers and farm owner/managers. The PCMR for cancer of the cervix was statistically significant for white female farmworkers.