Gastrointestinal cancer mortality of workers in occupations with high asbestos exposures

Asbestos, which is a well-known risk factor for lung cancer and malignant mesothelioma, has also been suggested as a gastrointestinal (GI) carcinogen. This study was conducted to assess the relationship between high asbestos exposure occupations and the occurrence of GI cancer. Death certificate data were analyzed from 4,943,566 decedents with information on occupation and industry from 28 states from 1979 through 1990. Elevated proportionate mortality ratios (PMRs) for mesothelioma were used to identify occupations potentially having many workers exposed to asbestos. All PMRs were age-adjusted and sex- and race-specific. The PMRs for GI cancers in white males were then calculated for these occupations after excluding mesothelioma, lung cancer, and non-malignant respiratory disease from all deaths. We identified 15,524 cases of GI cancer in the 12 occupations with elevated PMRs for mesothelioma. When these occupations were combined, the PMRs for esophageal, gastric, and colorectal cancer were significantly elevated at 108 (95% confidence interval = 107–110), 110 (106–113), and 109 (107–110), respectively. Esophageal cancer was elevated in sheet metal workers and mechanical workers. Gastric cancer was elevated in supervisors in production and managers. Colorectal cancer was elevated in mechanical and electrical and electronic engineers. However, high exposure occupations like insulation, construction painter supervisors, plumbers, furnace operators, and construction electricians showed no elevations of GI cancers. In conclusion, this death certificate study supports an association between asbestos exposure and some GI cancer, however the magnitude of this effect is very small. Am. J. Ind. Med. 31:713–718, 1997. © 1997 Wiley-Liss, Inc.     

Cancer mortality among women employed in fast-growing U.S. occupations.

Our study examined cancer mortality before the age of 65 for women employed in the fastest growing and/or traditionally female occupations. Analysis of mortality data from 28 U.S. states for 1984-1995 revealed elevated proportionate cancer mortality ratios (PCMRs). The highest PCMRs observed were thyroid cancer among health aides, lymphatic and multiple myeloma among computer programmers, and brain cancer among actresses and directresses. Some of the excess mortality occurred for occupations that have been previously cited. These included elevated breast and ovarian cancer among teachers, Hodgkin's disease among hairdressers and cosmetologists, and thyroid cancer among health aides and therapists. A few of the associations were new, i.e., had not been previously observed. These included cancer of the connective tissue and lymphatic system among computer programmers, ovarian cancer and leukemia among secretaries, and lymphatic cancer and multiple myeloma among child care workers. These findings should be further investigated with epidemiologic and environmental studies.     

Cancer mortality patterns among hairdressers and barbers in 24 US states, 1984 to 1995

We evaluated cancer mortality patterns among hairdressers and barbers, according to occupation, coded on 7.2 million death certificates in 24 states from 1984 to 1995. Of the 38,721 deaths among white and black hairdressers and barbers of both sexes, 9495 were from all malignant neoplasms. Mortality odds ratios were significantly elevated for all malignant neoplasms, lung cancer, and all lymphatic and hemopoietic cancers among black and white female hairdressers. White female hairdressers had significant excess mortality from cancers of the stomach, colon, pancreas, breast, and bladder and from non-Hodgkin's lymphoma and lymphoid leukemia; mortality from these cancers was also elevated among black female hairdressers. White male hairdressers had significantly elevated mortality from non-melanoma skin cancer and non-Hodgkin's lymphoma. Mortality from all malignant neoplasms, although significantly elevated among both white and black female hairdressers, was significantly below the null for white male hairdressers. Black and white male barbers had significantly elevated mortality from stomach and pharyngeal cancer, respectively. A significant deficit in mortality from all neoplasms and cancers of the pancreas, lung, and prostate was noted for white male barbers. This large study of cancer mortality among hairdressers and barbers showed some differences in mortality patterns by gender and race. Further studies are required to determine if specific occupational exposures may explain some of the elevated cancer rates.     

Assessment of mortality in the construction industry in the United States, 1984–1986

Construction, one of the larger industries in the United States, employs 7.6 million workers, many in skilled trades occupations. Previously published data about potential worksite exposures and mortality of construction site workers are limited. We analyzed occupation and industry codes on death certificates from 19 U.S. states to evaluate mortality risks among men and women usually employed in construction occupations. Proportionate mortality ratios (PMRs) for cancer and several other chronic diseases were significantly elevated among 61,682 white male construction workers who died between 1984 and 1986. Men younger than age 65, who were probably still employed immediately prior to death, had significantly elevated PMRs for cancer, asbestos-related diseases, mental disorders, alcohol-related disease, digestive diseases, falls, poisonings, traumatic fatalities that are usually work-related, and homicides. Elevated PMRs for many of the same causes were observed to a lesser degree for black men and white women whose usual industry was construction. In addition, women experienced excess cancer of the connective tissue and suicide mortality. Various skilled construction trades had elevated PMRs for specific sites, such as bone cancer and melanoma in brickma-sons, stomach cancer in roofers and brickmasons, kidney and bone cancer in concrete/terrazzo finishers, nasal cancer in plumbers, pulmonary tuberculosis in laborers, scrotal cancer and aplastic anemia in electricians, acute myeloid leukemia in boilermakers, rectal cancer and multiple sclerosis in electrical power installers, and lung cancer in structural metal workers. Using a standard population of blue collar workers did not result in fewer elevated PMRs for construction workers. Despite lifestyle differences and other limitations of the study, the large numbers of excess deaths observed in this study indicate the need for preventive action for construction workers. © 1995 Wiley-Liss, Inc.     

The Occupational Cancer Incidence Surveillance Study (OCISS): risk of lung cancer by usual occupation and industry in the Detroit metropolitan area

This case-referent study assesses occupational risk factors associated with lung cancer, utilizing colon and rectum cancer referents. Complete occupational and tobacco use histories were obtained by telephone interview for 5,935 incident lung cancer cases and 3,956 incident colon and rectum cancer referents. The analysis included 43 usual occupational groups and 48 usual industry groups comprised of at least 10 cases. Among all cases, there were significant elevated risks for excavating and mining workers (OR = 4.01), furnace workers (OR = 3.11), armed services personnel (OR = 3.10), agricultural workers (OR = 2.05), driver sales (OR = 2.21), mechanics (OR = 1.72), painters (OR = 1.96), and drivers (OR = 1.88). Industries with significant elevated lung cancer risk included farming (OR = 2.21), mining (OR = 2.98), and primary ferrous metals manufacturing (OR = 2.43). Analyses of white and black men separately revealed that the excess of lung cancer among mechanics is restricted to black males (OR = 4.16). The risk of lung cancer among armed services personnel is higher among black men (OR = 10.54) than among white men (OR = 3.06). Five of the occupations observed more often among lung cancer cases have probable exposure to diesel exhaust.     

Occupation and lung cancer mortality in a nationally representative U.S. Cohort: The National Health Interview Survey (NHIS)

OBJECTIVE: The objective of this study was to assess the risk of lung cancer mortality in a nationally representative sample of U.S. workers by occupation. METHODS: National Death Index linkage identified 1812 lung cancer deaths among 143,863 workers who participated in the 1987, 1988, and 1990-1994 National Health Interview Surveys. RESULTS: Current and former smoking status was predictive of lung cancer mortality (hazard ratio [HR] = 15.1 and 3.8, respectively). Occupations with significantly higher risk for age- and smoking-adjusted lung cancer mortality included heating/air/refrigeration mechanics (HR = 3.0); not specified mechanics and repairers (HR = 2.8); financial records processing occupations (HR = 1.8); freight, stock, and materials handlers (HR = 1.5); and precision production occupations (HR = 1.4). CONCLUSION: Although tobacco use continues to be the single most important risk factor for lung cancer mortality, occupational exposure to lung carcinogens should be targeted as well to further reduce the burden of lung cancer.     

Lung cancer mortality among women employed in high-risk industries and occupations in Harris County, Texas, 1977-1980

Lung cancer is rapidly becoming the leading cause of cancer mortality among women. Interviews conducted with 259 women with lung cancer and 278 women without lung cancer or with their next-of-kin in Harris County, Texas from July 1, 1977 to June 30, 1980 revealed that 12 (4.6%) of the women with lung cancer had never smoked cigarettes. The odds ratio (OR) for current smoking was 15.7. Odds ratios for smoking for living women (OR = 17.5) were higher than for those who were deceased (OR = 12.6). Lifetime occupational histories were classified a priori into high- and low-risk categories. Data were stratified according to employment in a high-risk industry or occupation, a high-risk industry, a high-risk occupation, or both a high-risk industry and occupation. Although not statistically significant, odds ratios for employment in high-risk categories support earlier estimates that attributed 5% of lung cancer mortality in women to employment in hazardous occupations. Employment of a husband or household member in selected industries and occupations yielded significantly increased odds ratios. More cases (15.9%) than controls (6.9%) reported a family history of lung cancer (OR = 2.4). No significant increase in smoking-adjusted odds ratios was found for the use of hair spray, hand-held dryers, or alcohol, or for having lived with a household member who smoked cigarettes.     

General mortality from 1944 through 1994 for a silicon-based chemical company

The objective of this study is to reevaluate the statistically significant elevated risk of lung cancer among men with >or=20 years of employment at Dow Corning Corporation, a manufacturer of silicon-based materials. The cohort included 712 deaths among 8266 employees who were hired from 1943 to 1992 with follow-up through 1994. Standardized mortality ratios (SMRs) were calculated for 63 causes of death. Analysis confirmed a statistically significant increased mortality from cancer of the bronchus, trachea, and lung among men, prior to 1985, who jointly classified with >or=30 years of work duration and >or=30 years since first employed. SMRs for lung cancer after 1985, however, were not statistically significant and were inconsistent across work duration and years since first employed intervals. The study provides no evidence for elevated mortality among Dow Corning workers since the 1991 cohort mortality study. This study describes the updated mortality experience of a large employee cohort from a major silicon-based manufacturer. It illustrates that a well-designed mortality study can be a key component of employee health surveillance efforts in an industrial setting with potential hazardous workplace exposures.     

Race, occupation, and lung cancer: detecting disparities with death certificate data

OBJECTIVES: To determine whether the analysis of death certificate data would reveal the same relationship among race, occupational exposure, and lung cancer mortality observed by a large cohort study. METHODS: An occupation-specific mortality odds ratio (MOR) for lung cancer (ICD-162) versus all other causes was calculated for 218,341 black men and white men who had been employed in the metal industries. RESULTS: Black men were at increased risk for lung cancer mortality when compared with white men among the 4668 oven workers (MOR = 1.38, 95% CI = 1.10 to 1.73), but not among the 33,605 white-collar workers (MOR = 0.95, 95% CI = 0.74 to 1.23). CONCLUSIONS: Our findings corroborate a previously demonstrated association among exposure to carcinogenic coke oven emissions, race, and lung cancer mortality, and support the use of death certificate data to help identify occupations with racial disparities in lung cancer mortality.     

Mortality due to respiratory cancers in the coke oven plants of the Lorraine coalmining industry (Houillères du Bassin de Lorraine).

The main activity of the Houillères du Bassin de Lorraine (Lorraine Collieries), employing 23,000 operatives and executives, is coalmining. The coke production is carried out by two coke oven plants with a workforce of respectively 747 and 552 workers. The coal coking process entails the emission of noxious products such as polycyclic aromatic hydrocarbons (PAH) from the ovens. The influence of occupational exposure on mortality due to respiratory cancers, and particularly to lung and upper respiratory and alimentary tracts cancer, was investigated among a cohort of 534 male workers from the two coke oven plants who had retired from work between 1963 and 1982. The job history of each subject has been precisely reconstructed by indicating the duration of exposure on the ovens, close to the ovens, and in maintenance occupations. The cohort mortality has been analysed according to the method of indirect standardisation with reference to the French male population and by a case-control study concerning the consumption of tobacco per cohort. The mortality due to lung cancer is 2.51 times higher than expected. This excess of mortality differs, but not significantly, between the two coke oven plants (standardised mortality ratio equals 3.05 and 1.75 respectively). It is not significantly higher among subjects exposed for more than five years, directly exposed on the ovens or working near the ovens or at maintenance occupations on the ovens (SMR = 2.78), than among those exposed for less than five years (SMR = 2.35) or those not exposed at all. Even taking into account the excess of mortality due to lung cancers in the Moselle district (1.6 time that of France), the excess of lung cancers does not seem to be explained by the regional factor, or by tobacco and alcohol consumption. Although no significant relation was offered between lung cancer and the duration of exposure to PAH, even when taking smoking habits into account, the carcinogenic role of occupational nuisances cannot be excluded.     

Mortality due to respiratory cancers in the coke oven plants of the Lorraine coalmining industry (Houillères du Bassin de Lorraine)

The main activity of the Houillères du Bassin de Lorraine (Lorraine Collieries), employing 23,000 operatives and executives, is coalmining. The coke production is carried out by two coke oven plants with a workforce of respectively 747 and 552 workers. The coal coking process entails the emission of noxious products such as polycyclic aromatic hydrocarbons (PAH) from the ovens. The influence of occupational exposure on mortality due to respiratory cancers, and particularly to lung and upper respiratory and alimentary tracts cancer, was investigated among a cohort of 534 male workers from the two coke oven plants who had retired from work between 1963 and 1982. The job history of each subject has been precisely reconstructed by indicating the duration of exposure on the ovens, close to the ovens, and in maintenance occupations. The cohort mortality has been analysed according to the method of indirect standardisation with reference to the French male population and by a case-control study concerning the consumption of tobacco per cohort. The mortality due to lung cancer is 2.51 times higher than expected. This excess of mortality differs, but not significantly, between the two coke oven plants (standardised mortality ratio equals 3.05 and 1.75 respectively). It is not significantly higher among subjects exposed for more than five years, directly exposed on the ovens or working near the ovens or at maintenance occupations on the ovens (SMR = 2.78), than among those exposed for less than five years (SMR = 2.35) or those not exposed at all. Even taking into account the excess of mortality due to lung cancers in the Moselle district (1.6 time that of France), the excess of lung cancers does not seem to be explained by the regional factor, or by tobacco and alcohol consumption. Although no significant relation was offered between lung cancer and the duration of exposure to PAH, even when taking smoking habits into account, the carcinogenic role of occupational nuisances cannot be excluded.     

Occupational mortality in Hong Kong, 1979-1983

Occupational mortality among Hong Kong males aged 15 and above were examined for the period 1979-1983, using routine death registration and census data. Age-standardized mortality ratios (SMR) and relative SMR (RSMR) were calculated for each two-digit occupational group and elevated mortality from all and various causes were highlighted. Mortality from ischaemic heart disease was strikingly associated with professional and sales-managerial occupations whereas colorectal cancers were associated with predominantly clerical and sales workers. Mortality from cancer of the buccal cavity and pharynx was elevated in fishermen as well as in farmers, food, drink and tobacco workers, mechanical fitters, and others. Excesses of liver cancer were found in doctors, fishermen and construction workers. Lung cancer deaths were particularly excessive among fishermen, plumbers and welders, construction workers and transport equipment operators. Fishermen were at high risk of death from cancers of the buccal cavity and pharynx, stomach, liver and lung, cerebrovascular diseases and cirrhosis. Miners and quarrymen experienced high mortality from pulmonary tuberculosis and chronic obstructive airways disease whereas construction workers also experienced high mortality from pulmonary tuberculosis as well as cancers of the liver, lung and bladder and non-Hodgkin's lymphomas. Transport workers were at high risk of dying from cancers of the stomach and lung, cerebrovascular diseases and diabetes mellitus. These and other associations were generally in line with those found from other similar surveys or detailed studies. The limitations of such studies are many and discussed in the context of Hong Kong.(ABSTRACT TRUNCATED AT 250 WORDS)     

Mortality due to silico-tuberculosis and lung cancer among 200 whetstone cutters

The objective of the present study was to examine if the mortality due to tuberculosis and cancer in the lungs was elevated in a cohort of 200 male whetstone cutters. 1955-1995 death certificate-based mortality data on the cohort were available, and the data were reviewed in the present study for mortality due to the two diseases to calculate standardized mortality ratios (SMR) in reference to the health statistics of Kyoto prefecture, where the cohort lived. Among the 200 cohort members, 99 men deceased during the observation period, the deaths including 10 cases of lung tuberculosis (of which 9 cases had silicosis together), 20 cases of all malignancies, and 6 cases of lung cancer (5 cases with silicosis). There was a significant elevation in the mortality due to lung tuberculosis (SMR = 3.47) although SMR for all causes was not elevated (1.10). There was no significant change in SMR for all malignancies (0.78), whereas SMR for lung cancer (1.24) tended to be elevated although insignificantly. Lung tuberculosis was a significant complication of silicosis in 1955-1995. Possible elevation in lung cancer SMR among this cohort needs further studies.     

Beryllium: An etiologic agent in the induction of lung cancer,nonneoplastic respiratory disease,and heart disease among industrially exposed workers

On the basis of the clear demonstration of the carcinogenicity of beryllium in several animal species along with the suggestion of an increased risk of lung cancer mortality in humans exposed to beryllium, an epidemiologic study of workers exposed to beryllium at one production facility was undertaken. Within the limitations imposed by the selection of data for calculation of cause-specific expected mortality (use of U.S. white male cause-specific mortality rates with linear extrapolation of 1965–1967 to 1968–1975 vs use of cause-specific mortality rates for the county in which the study facility and the majority of its workers resided), the study demonstrated a statistically significant increased risk of respiratory disease (neoplastic and nonneoplastic) and of heart disease mortality. A possible explanation other than in terms of beryllium was sought for this excessive risk of cause-specific mortality among beryllium-exposed workers. The excessive risk of lung cancer mortality could not be related to an effect of age, chance, self-selection, study group selection, exposure to other agents in the study facility, or place of residence. On the basis of the frequency of cigarette smoking among those cohort members employed in 1967–1968 and the distribution of histologic types of lung cancer among deceased cohort members, it seems unlikely that cigarette smoking per se could have accounted for the increased risk of lung cancer among beryllium-exposed workers in the study cohort. Lifetime employment histories for members of the study cohort were not available, so that definitive statements about the role of other occupational exposures cannot be made. However, information on usual occupations as indicated on death certificates suggests that it is unlikely that some undefined occupational or environmental exposure other than to beryllium could account per se for the excessive lung cancer mortality. This interpretation is further supported by the residential stability of the study cohort in a county having a lung cancer rate significantly lower than that of the entire United States. The findings of a statistically significant excess of lung cancer mortality among cohort members in general (P < 0.05) and among workers observed 25 or more years since onset of beryllium exposure in particular (P < 0.01), when taken in context with the results of earlier animal bioassay and recent epidemiologic studies, are supportive of the hypothesis that beryllium is carcinogenic to man.     

Increased risk for lung cancer and for cancer of the gastrointestinal tract among Geneva professional drivers.

A historical prospective cohort study of 6630 drivers from the Canton of Geneva was carried out to evaluate mortality and incidence of cancer in this occupation. The study population was all men (of all vocations) who held in 1949 a special licence for driving lorries, taxis, buses, or coaches and all new licence holders in the period 1949-61. Men born before 1900 and those with only an ordinary driving licence were excluded. According to the occupation registered on their licence, the 6630 drivers were distributed into three groups: (1) professional drivers (n = 1726), (2) non-professional drivers "more exposed" to exhaust gas and fumes (this group included occupations such as vehicle mechanic, policeman, road sweeper; n = 712), and (3) non-professional drivers "less exposed," composed of all other occupations (n = 4192). The cohort was followed up from 1949 to December 1986 and the trace of 197 men (3%) was lost. Compared with the general population of the Canton of Geneva, professional drivers experienced significant excess risks, taking into account 15 years of latency, for all causes of death (standardised mortality ratio (SMR) 115, 90% confidence interval (90% CI) 107-123) and for all malignant neoplasms (SMR 125, 90% CI 112-140; standardised incidence ratio (SIR) 128, 90% CI 115-142). Cause specific analysis showed significant excesses for lung cancer (SMR 150, 90% CI 123-181; SIR 161, 90% CI 129-198), oesophageal cancer (SMR 183, 90% CI 108-291), stomach cancer (SMR 179, 90% CI 117-263; SIR233, 90% CI 156-336), rectal cancer (SMR 258, 90% CIU 162-392; SIR 200, 90% CI 127-300), and cirrhosis of the liver (SMR 145, 90% CI 104-198). Risk of lung cancer increased significantly with time from first exposure. Among non-professional drivers no significant excess risk was found except for lung cancer mortality among the "less exposed" group (SMR 121, 90% CI 103-140), and for incidence of lung cancer among the "more exposed" group (SIR 161, 90% CI 111-227). The possible casual relation between exposure to engine exhaust emissions and the increased risk for lung cancer and for cancer of the gastrointestinal tract found among professional drivers is discussed.     

Increased risk for lung cancer and for cancer of the gastrointestinal tract among Geneva professional drivers.

A historical prospective cohort study of 6630 drivers from the Canton of Geneva was carried out to evaluate mortality and incidence of cancer in this occupation. The study population was all men (of all vocations) who held in 1949 a special licence for driving lorries, taxis, buses, or coaches and all new licence holders in the period 1949-61. Men born before 1900 and those with only an ordinary driving licence were excluded. According to the occupation registered on their licence, the 6630 drivers were distributed into three groups: (1) professional drivers (n = 1726), (2) non-professional drivers "more exposed" to exhaust gas and fumes (this group included occupations such as vehicle mechanic, policeman, road sweeper; n = 712), and (3) non-professional drivers "less exposed," composed of all other occupations (n = 4192). The cohort was followed up from 1949 to December 1986 and the trace of 197 men (3%) was lost. Compared with the general population of the Canton of Geneva, professional drivers experienced significant excess risks, taking into account 15 years of latency, for all causes of death (standardised mortality ratio (SMR) 115, 90% confidence interval (90% CI) 107-123) and for all malignant neoplasms (SMR 125, 90% CI 112-140; standardised incidence ratio (SIR) 128, 90% CI 115-142). Cause specific analysis showed significant excesses for lung cancer (SMR 150, 90% CI 123-181; SIR 161, 90% CI 129-198), oesophageal cancer (SMR 183, 90% CI 108-291), stomach cancer (SMR 179, 90% CI 117-263; SIR233, 90% CI 156-336), rectal cancer (SMR 258, 90% CIU 162-392; SIR 200, 90% CI 127-300), and cirrhosis of the liver (SMR 145, 90% CI 104-198). Risk of lung cancer increased significantly with time from first exposure. Among non-professional drivers no significant excess risk was found except for lung cancer mortality among the "less exposed" group (SMR 121, 90% CI 103-140), and for incidence of lung cancer among the "more exposed" group (SIR 161, 90% CI 111-227). The possible casual relation between exposure to engine exhaust emissions and the increased risk for lung cancer and for cancer of the gastrointestinal tract found among professional drivers is discussed.     

Silicosis and lung cancer: a mortality study of compensated men with silicosis in New South Wales, Australia

BACKGROUND: Lung cancer mortality has been found to be in excess in several groups with silicosis, but allowance for smoking was not always possible. We investigated the lung cancer mortality in men with silicosis in New South Wales, Australia, who were compensated, making allowance for smoking habits. METHODS: A mortality study of 1467 men with silicosis in New South Wales who were compensated was carried out comparing observed mortality with that expected from the New South Wales death rates adjusting for age and period. Their smoking habits were compared with national survey smoking rates and the expected number of lung cancer deaths adjusted for smoking. Cases were coded for occupation and industry. RESULTS: The observed mortality was higher than expected, but the only site of cancer showing a significant excess was the lung. The group with silicosis had smoked more than the national rates. After adjusting for smoking the standardized mortality ratio for lung cancer was 1.9 (95% confidence interval 1.5-2.3). Although there were differences in lung cancer mortality between industries and occupations, these differences were not statistically significant. CONCLUSIONS: The excess lung cancer death rate may not be entirely due to silica exposure because compensation may have been influenced by the presence of chronic obstructive respiratory disease and there is some evidence that the presence of this disease increases lung cancer risk independently of smoking.     

Literature review of cancer mortality and incidence among dentists

This review assesses the epidemiological literature describing dentist mortality and cancer incidence risk. In the dental workplace a variety of hazards may have been historically present or currently exist which can impact dentists' long-term health, including their mortality and cancer incidence. The epidemiological literature of dentistry's health outcomes was reviewed with a focus on all cancers combined and cancers of the brain, lung, reproductive organs and skin. Relevant studies were identified using MEDLINE and NIOSHTIC through early 2006 and from references cited in the articles obtained from these databases. Dentist cancer mortality and incidence generally showed a favourable risk pattern for lung cancer and overall cancer occurrence. Nevertheless, several studies reported an increased risk for certain cancers, such as those of the skin and, to a lesser extent, the brain and female breast. These elevated risks may be related to social status or education level, or may alternatively represent the impact of hazards in the workplace. The evidence for an increased mortality or cancer incidence risk among dentists must be interpreted in light of methodological limitations of published studies. Future studies of dentists would benefit from the assessment of specific occupational exposures rather than relying on job title alone.     

Histologic differences in occupational risks of lung cancer incidence

A five-year total community study of lung cancer incidence by occupation revealed that 1) virtually all the cases occurred in smokers; 2) all major histologic types of lung cancer were strongly associated with smoking behavior; 3) in most high-risk occupations the significant elevations of risk were limited to one or two histologic types, a specificity suggestive of the importance of workplace carcinogen exposure; and 4) both sensitivity and specificity of the search for occupations with lung cancer hazards were greatly increased by use of histologic type rates rather than total lung cancer rates. The epidemiologic differences among histologic types suggest that the lung cancers might be a group of neoplastic diseases which share a major risk factor (smoking) in common but which differ in respect to exposure to other carcinogens. Eventual control of our lung cancer epidemic will require the allocation of much greater resources to documentation of the occupational risks.