Sinonasal cancer and occupational exposures: a pooled analysis of 12 case–control studies

Objective: In order to examine the associations between sinonasal cancer and occupational exposures other than wood dust and leather dust, the data from 12 case–control studies conducted in seven countries were pooled and reanalyzed. Methods: The pooled data set included 195 adenocarcinoma cases (169 men and 26 women), 432 squamous cell carcinomas (330 men and 102 women), and 3136 controls (2349 men and 787 women). Occupational exposures to formaldehyde, silica dust, textile dust, coal dust, flour dust, asbestos, and man-made vitreous fibers were assessed with a job-exposure matrix. Odds ratios (ORs) were adjusted for age, study, wood dust, and leather dust, or other occupational exposures when relevant. 95% confidence intervals (CIs) were estimated by unconditional logistic regression. Results: A significantly increased risk of adenocarcinoma was associated with exposure to formaldehyde. The ORs for the highest level of exposure were 3.0 (CI = 1.5–5.7) among men and 6.2 (CI = 2.0–19.7) among women. An elevated risk of squamous cell carcinoma was observed among men (OR = 2.5, CI = 0.6–10.1) and women (OR = 3.5, CI = 1.2–10.5) with a high probability of exposure to formaldehyde. Exposure to textile dust was associated with non-significantly elevated risk of adenocarcinoma, among women only: the OR for the high level of cumulative exposure was 2.5 (CI = 0.7–9.0). High level of asbestos exposure was associated with a significantly increased risk of squamous cell carcinoma among men (OR = 1.6, CI = 1.1–2.3). Conclusions: The results of this pooled analysis support the hypothesis that occupational exposure to formaldehyde increases the risk of sinonasal cancer, particularly of adenocarcinoma. They also indicate an elevated risk of adenocarcinoma among women exposed to textile dust, and suggest that exposure to asbestos may increase the risk of squamous cell carcinoma.     

Occupational formaldehyde exposure and increased nasal cancer risk in man

A comprehensive data linkage system for the detailed investigation of occupational cancer has newly been established in the Danish Cancer Registry, providing employment histories back until 1964. Based on this system a study of 839 cases of cancer of the nasal cavities, sinuses and rhinopharnyx and 2,465 cancer controls diagnosed in Denmark during the period 1970-1982 was conducted. Histories of exposure to formaldehyde, wood-dust and 10 other specified compounds or procedures, were assessed by industrial hygienists unaware of the case-control status of the cancer patients under study. Some 4.2% of the male and 0.1% of the female controls had been exposed to formaldehyde. A statistically significant excess risk (p less than 0.05) for carcinoma of the nasal cavity and sinuses among males with a history of exposure to formaldehyde (RR = 2.8), wood-dust (RR = 2.5) and paint lacquer and glue (RR = 2.1) was found. When adjustment was made for wood-dust exposure the relative risk associated with formaldehyde was reduced to 1.6, which is not significantly in excess of 1.0, although still compatible with a 3- to 4-fold increase in risk using conventional 95% confidence limits. The joint action of exposure to wood-dust and formaldehyde was in accordance with an additive effect. The excess risk of sino-nasal cancer with exposure to paint, lacquer and glue remained statistically elevated after adjustment for contemporary exposure to wood-dust and formaldehyde.     

Medical radiation,family history of cancer,and benign breast disease in relation to breast cancer risk in young women,USA

OBJECTIVE: In previous studies breast cancer risk has been increased among women who received high doses (above 100–200 cGy) of ionizing radiation or those exposed to lower doses prior to age 20. Some evidence suggests that such risk may be distinctly elevated among women with a family history of breast or ovarian cancer (probably only carriers of specific gene mutations) and women with benign breast disease (BBD).METHODS: A population-based case–control study in Los Angeles County obtained interview data from 744 women who were aged 40 or younger and diagnosed with breast cancer during 1983–1988, and from 744 matched controls. Women with a positive family history of breast or ovarian cancer reported cancer in a mother, sister, or grandmother. Women with BBD reported a physician diagnosis. Radiation exposure was defined as a history of either radiation therapy or moderate exposure to medical radiography.RESULTS: Breast cancer risk was elevated among women exposed to medical radiation prior to age 20 years (odds ratio (OR) = 1.4, 95% confidence interval (CI) = 1.2–1.8), relative to unexposed women. This increased risk was observed only among women with a history of BBD (OR = 2.4, 95% CI = 1.6–3.7). Overall, risk was not associated with exposure to medical radiation after age 20 years, although among women with a positive family history of breast or ovarian cancer, exposed women had an increased risk (OR = 1.8, 95% CI = 1.0–3.1). Breast cancer risk was not increased among women with a family history of breast/ovarian cancer exposed to medical radiation before age 20 years or those with BBD exposed to medical radiation after age 20 years.DISCUSSION: Study participants may have received radiation doses that are no longer common, hampering study generalizability. Although differences in recall between cases and controls cannot be completely excluded, women with BBD or a family history of breast cancer appear to have greater breast cancer risk following relatively low ionizing radiation exposure than other women in this study.     

Occupation and larynx and hypopharynx cancer: a job-exposure matrix approach in an international case-control study in France,Italy, Spain and Switzerland

Objective: To investigate the effect of exposure to occupational agents on the risk of hypopharyngeal/laryngeal cancer. Methods: Case-control study conducted during 1979–1982 in six centres in South Europe. An occupational history and information on exposure to non-occupational factors were collected for 1010 male cases of hypopharyngeal/laryngeal cancer as well as for 2176 population controls. The exposure to 10 occupational agents was assessed through a job-exposure matrix. As occupational histories had been collected since 1945 major analyses were restricted to subjects aged less than 55 years (315 cases and 819 controls). Results: Significant elevated risks adjusted for non-occupational variables (smoking, alcohol consumption and diet) and other occupational exposures were consistently found for organic solvents (odds ratio (OR) for ever-exposure: 1.7, 95% confidence interval: 1.1–2.5) and asbestos (OR: 1.6, 1.0–2.5). A significant positive trend for both probability of exposure and duration was found for exposure to solvents. A positive association between exposure to formaldehyde and laryngeal cancer was also suggested. No association was found for exposure to arsenic and compounds, chromium and compounds, and polycyclic aromatic hydrocarbons. Analyses restricted to subjects aged 55 or more did not show elevated risks, with the exception of wood dust (OR: 1.8, 1.3-2.7). Conclusions: In our study occupational exposure to solvents was associated with an increased risk of hypopharyngeal/laryngeal cancer. Results also provide additional evidence of an excess of risk for exposure to asbestos.     

Diet in adolescence and the risk of breast cancer: results of the Netherlands Cohort Study

Objectives: In The Netherlands, part of the population experienced food restriction and severe famine during World War II. The purpose of this study was to study the effects of severe undernutrition during adolescence on the risk of breast cancer later in life.Methods: We examined the hypothesis in the Netherlands Cohort Study on diet and cancer (NLCS), among 62,573 women aged 55–69 years. Baseline information on diet and other risk factors was collected with a questionnaire in 1986. Information was collected on residence in the Hunger winter (1944–1945) and War years (1940–1944) and fathers' employment status in 1932–1940 as indicators of exposure. After 6.3 years of follow-up, 1009 incident breast cases were available for analysis.Results: In multivariate case-cohort analysis, residents of the western part of the country in 1944–1945 had an increased breast cancer risk (western city RR=1.1, 95% CI: 0.9–1.4, western rural area RR = 1.5, 95% CI: 1.1–1.9). For the War years (1940–1944) we found no association between breast cancer risk and urban vs. rural residence. Women whose fathers were unemployed during the Depression years (1932–1940) had a non-significant decrease in breast cancer risk (RR = 0.9, 95% CI: 0.7–1.2). Exposure to energy restriction during the adolescent growth spurt or during the period between menarche and birth of the first child did not change the RRs substantially.Conclusions: We found no clear evidence in this study for the hypothesis that energy restriction in adolescence leads to a decreased breast cancer risk.     

Cancer of the gastrointestinal tract and exposure to asbestos in drinking water among lighthouse keepers (Norway)

Objective Previous studies of predominantly ecological design have indicated a possible elevation of gastrointestinal cancer risk in population groups exposed to drinking water contaminated with asbestos from natural sources or asbestos–cement containing water pipes. In the present study the possible effect of ingested asbestos fibers on gastrointestinal cancer risk was investigated in an occupational group where a proportion of the employees was exposed to asbestos in their drinking water.Method A cohort of 726 lighthouse keepers first employed between 1917 and 1967 were followed up for cancer incidence from 1960 to 2002. The standardized incidence ratio (SIR) was calculated as the number of new cancer cases divided by the expected number based on five-year age and sex specific incidence rates in the general rural population of Norway. A 95% confidence interval (CI) was calculated for all SIR values assuming a Poisson distribution of the cancer cases.Results Risk of stomach cancer was elevated in the whole cohort (SIR: 1.6, CI: 1.0–2.3), in the subgroup with definite asbestos exposure (SIR: 2.5, CI: 0.9–5.5), and when the group was followed for 20 years and more after first possible exposure (SIR: 1.7, CI: 1.1–2.7). Less consistent results were found for colon cancer; SIR was 1.5 (CI: 0.9–2.2) overall, 0.8 (CI: 0.1–2.9) among the exposed, and 1.6 (CI: 1.0–2.5) twenty years and more after first possible exposure.Conclusion The results support the hypothesis of an association between ingested asbestos and gastrointestinal cancer risk in general and stomach cancer risk specifically.     

Are the known bladder cancer risk-factors associated with more advanced bladder cancer?

Risk factors for superficial and invasive bladder cancer were examined in a case-control study of 470 cases Identified in 1967–68 in the Brockton and Boston Standard Metropolitan Areas (MA, United States) and of 500 population-based controls. Histologic specimens were reviewed and classified as superficial or invasive, following a standardized protocol. The tobacco-associated risk for superficial bladder cancer was odds ratio (OR)=2.6 (95 percent confidence interval [CI]=1.7–4.1) and the risk for invasive bladder cancer was OR=1.7 (CI=1.1–2.5). For subjects less than 60 years of age, the risks were greater for invasive tumors (OR=4.3, CI=1.2–15) than for superficial tumors (OR=0, CI=0.9–4.2), but this pattern for tobacco use was not found in older subjects. A strong trend of increased risk with increased amount of cigarettes smoked was shown only for invasive bladder tumors. No clear pattern of excess risk for invasive bladder tumors was seen for age at first use and years since last use of tobacco. The risk associated with occupational exposure to aromatic amine bladder carcinogens was OR=1.7 (CI=0.8–3.3) for superficial and OR=1.5 (CI=0.8–3.0) for invasive bladder cancer. For subjects less than 60 years of age, the risks were greater for invasive (OR=12.0, CI=2.1–65) than for superficial tumors (OR=4.3, CI=0.8–24), but this pattern for occupational exposure was not found in older subjects. Risk by age at first exposure to occupational aromaticamine, bladder carcinogens was similar for superficial and invasive tumors. Overall, there was no association between known bladder-cancer risk-factors and more advanced bladder cancer. The relative risk associated with cigarette smoking and occupational exposure to aromatic amines was higher for invasive than superficial cancer only for men less than 60 years of age.Drs Hayes and Zahm are with the Environmental Epidemiology Branch, National Cancer Institute, Bethesda, MD, USA. Authors are affiliated also with the Lucille P. Markey Cancer Center, Lexington, KN, USA (Dr Friedell) and the Department of Epidemiology, University of Alabama, Birmingham, AL, USA (Dr Cole). Address correspondence to Dr Hayes, Environmental Epidemiology Branch, National Cancer Institute, EPN 418, Bethesda, MD 20892, USA.     

Cancer incidence among firefighters in Seattle and Tacoma,Washington (United States)

In order to determine if exposure to carcinogens in fire smoke increases the risk of cancer, we examined the incidence of cancer in a cohort of 2,447 male firefighters in Seattle and Tacoma, (Washington, USA). The study population was followed for 16 years (1974–89) and the incidence of cancer, ascertained using a population-based tumor registry, was compared with local rates and with the incidence among 1,878 policemen from the same cities. The risk of cancer among firefighters was found to be similar to both the police and the general male population for most common sites. An elevated risk of prostate cancer was observed relative to the general population (standardized incidence ratio [SIR]=1.4, 95 percent confidence interval [CI]=1.1–1.7) but was less elevated compared with rates in policement (incidence density ratio [IDR]=1.1, CI=0.7–1.8) and was not related to duration of exposure. The risk of colon cancer, although only slightly elevated relative to the general population (SIR=1.1, CI=0.7–1.6) and the police (IDR=1.3, CI=0.6–3.0), appeared to increase with duration of employment. Although the relationship between firefighting and colon cancer is consistent with some previous studies, it is based on small numbers and may be due to chance. While this study did not find strong evidence for an excess risk of cancer, the presence of carcinogens in the firefighting environment warrants periodic re-evaluation of cancer incidence in this population and the continued use of protective equipment.This research was partially funded through a cooperative agreement with the US Fire Administration of the Federal Emergency Management Agency (EMW 85-K-2089). Dr Demers was supported by a Training Grant in Environmental Epidemiology and Biostatistics from the US National Institute for Environmental Health Sciences (T32 ES07262).     

The contribution of cigarette smoking to bladder cancer in women (pooled European data)

Background: Using a combined analysis of 11 case–control studies from Europe, we have investigated the relationship between cigarette smoking and bladder cancer in women. Methods: Available smoking information on 685 female bladder cancer cases and 2416 female controls included duration of smoking habit, number of cigarettes smoked per day, and time since cessation of smoking habit for ex-smokers. Results: There was an increasing risk of bladder cancer with increasing duration of smoking, ranging from approximately a two-fold increased risk for a duration of less than 10 years (odds ratio (OR) = 1.9, 95% confidence interval (CI) 1.1–3.1) to over a four-fold increased risk for a duration of greater than 40 years (OR = 4.1, 95% CI 3.0–5.5). A dose–response relationship was observed between number of cigarettes smoked per day and bladder cancer up to a threshold limit of 15–20 cigarettes per day, OR = 3.8 (95% CI 2.7–5.4), after which no increased risk was observed. An immediate decrease in risk of bladder cancer was observed for those who gave up smoking. This decrease was over 30% in the immediate 1–4 years after cessation, OR = 0.68 (95% CI 0.38–1.2). However, even after 25 years the decrease in risk did not reach the level of the never-smokers, OR = 0.27 (95% CI 0.21–0.35). Conclusion: The proportion of bladder cancer cases among women attributable to ever smoking was 0.30, (0.25–0.35) and to current smoking was 0.18 (0.14–0.22). These attributable proportions are less than those observed among men, although they are likely to increase in the future as the smoking-related disease epidemic among women matures.     

Cohort mortality and nested case-control study of lung cancer among structural pest control workers in Florida (United States)

A previous report on the mortality of this cohort of Florida (United States) pest control workers found the risk of lung cancer was positively associated with the number of years licensed. An additional follow-up (1977–82) of this male cohort confirmed the excess (SMR=1.4) and the rising risk with increasing number of years licensed (SMR=2.2 among workers employed more than 20 years). A nested case-control study was undertaken to determine the effects of smoking and the type of pesticide exposure on lung cancer risk. Occupational histories and other data were obtained on 65 deceased lung cancer cases, 122 deceased controls, and 172 living controls. Interviews were conducted with next-of-kin regardless of the vital status of the subject. Odds ratios (OR) were adjusted by age and smoking. Adjustments for diet and other occupations had no effect on risk estimates and were not included in the final model. Using information from licensing records, ORs for lung cancer were greater for workers first licensed before age 40 (OR=2.4, 95 percent confidence interval [CI]=1.0–5.9 with deceased controls) and increased from 1.4 (CI=0.7–3.0) for subjects licensed 10–19 years to 2.1 (CI=0.8–5.5) for subjects licensed 20 or more years. Using living controls, an association with duration of employment was observed when years of licensure were lagged five years, but was not observed in unlagged analyses. Using information from the questionnaire, the risk of lung cancer was greater among those who worked as pest control operators than non-pest control workers. Although numbers were typically small, lung cancer risk among pest control operators was associated with reported exposure to carbamates, organophosphates, and phenoxyacetic acids and more specifically with diazinon, DDT, carbaryl, and propoxur. These results further suggest that pesticides may play a role in lung cancer risk and underscore the need for research that focuses on specific chemicals.     

Incidence of selected cancers in Swedish railway workers, 1961–79

Among all Swedish men, 20 to 64 years of age and employed in 1960, railway workers were selected and compared with the population at large, concerning the incidence of leukemia, lymphoma, tumors of the brain, breast, and the pituitary gland. The study was a re-analysis of the 1961–79 incidence data previously showing no increase in risk for leukemia and brain tumors for railway workers. In the present study, follow-up was divided into two 10-year periods, and elevated relative risks (RR) were found for the first decade. For the first decade, engine drivers and conductors combined had an RR of chronic lymphocytic leukemia, acute myeloid leukemia, and lymphoma of 1.9 (95 percent confidence interval [CI]=0.9–4.0), 1.4 (CI=0.4–4.3), and 1.0 (CI=0.5–1.9), respectively. For all brain tumors, the RR was 1.2 (CI=0.8–1.9), with a higher risk estimate for those below age 30 (RR=12.2, CI=2.8–52.5). Three cases of breast cancer and nine cases of tumors of the pituitary gland occurred among engine drivers and conductors, corresponding to RRs of 4.9 (CI=1.6–11.8) and 3.2 (CI=1.6–6.2), respectively. Work on trains entails extremely high exposure to low frequency magnetic fields (EMF). The results give some support to the hypothesis of an association between EMF and certain types of cancers. The outcome for the pituitary gland, being a focal point of hormonal regulation, suggests a hormonal link.The project was funded partially by the National Board of Occupational Safety and Health.     

Cancer risks among female farmers in Sweden

There are few studies on cancer risks among female farmers, particularly on breast cancer and cancer in female genital organs. We have conducted a cohort study of cancer risk among 50,682 women with occupations in agriculture according to the Swedish 1970 census. The cohort was followed up in the nationwide, populationbased, Cancer-Environment Register from 1 January 1971 until death or until 31 December 1987. Expected number of cases was based on annual cancer incidence in five-year age groups. The standardized incidence ratio (SIR) was computed as the ratio between observed and expected number of cases. A total of 4,474 cases of cancer were observed in the cohort from 1971 until 1987cf 5,273 expected, resulting in a significantly decreased SIR of 0.85 (95 percent confidence interval [CI]=0.82–0.87). SIR for breast cancer was significantly decreased (0.83, CI=0.78–0.88), as was the SIR for cervix uteri (0.40, CI=0.31–0.50). For the other female genital organs, SIR was close to one. Other cancer sites with significantly decreased SIRs were: colon (0.90, CI=0.81–1.00); rectum (0.86, CI=0.74–1.00); lung (0.46, CI=0.37–0.57); kidney (0.81, CI=0.68–0.97); urinary organs (0.57, CI=0.45–0.72); connective tissue and muscle (0.62, CI=0.39–0.95); and non-Hodgkin's lymphomas (0.78, CI=0.63–0.96).This study was supported by grant from Kungliga Skogs-och Lanthruksakademien.     

Risk of breast cancer in women exposed to diethylstilbestrol in utero: prelimiinary results (United States)

BACKGROUND: A synthetic estrogen, diethylstilbestrol (DES), was widely prescribed to pregnant women during the 1950s and 1960s but was later discovered to be associated with an increased risk of clear-cell carcinoma of the vagina and cervix in female offspring. DES has not been linked to other cancers in female offspring, but studies of other prenatal factors such as twin gestation and pre-eclampsia have indicated that in-utero estrogen levels may influence breast cancer risk. We evaluated the relation of in-utero DES exposure to the risk of adult breast cancer.METHODS: A cohort of 4821 exposed women and 2095 unexposed women, most of whom were first identified in the mid-1970s, were followed by mailed questionnaires for an average of 19 years. Reported cancer outcomes were validated by medical record review. Breast cancer incidence in DES-exposed daughters was compared with cancer incidence in unexposed daughters with use of Poisson regression analysis, adjusting for year of birth, age at menarche, age at first birth, and number of births.FINDINGS: The rate ratio for incidence of invasive breast cancer in exposed versus unexposed women was 1.4 (95% confidence interval (CI) = 0.7–2.6). DES exposure was not associated with an increased risk of breast cancer in women under 40 years, but among women aged 40 and older the rate ratio was 2.5 (95% CI = 1.0–6.3). The rate ratio for the association of DES exposure with estrogen receptor-positive tumors was 1.9 (95% CI = 0.8–4.5).INTERPRETATION: While not statistically significant, the overall 40% excess risk, arising exclusively from the subset of estrogen receptor-positive cases, raises a concern calling for continued investigation.     

Hormonal risk factors for endometrial cancer: modification by cigarette smoking (United States)

Objectives: To evaluate whether smoking modifies the risk of endometrial cancer associated with body mass index (BMI), postmenopausal hormone use, and other hormonal factors. Methods: Using multivariate adjusted models we examined interview data from a population-based case–control study of Wisconsin women (n = 740 cases, n = 2372 controls). Results: The relative risk for endometrial cancer associated with current smoking was 0.8 (95% CI: 0.6–1.0) compared to never smokers. No clear dose–response relationship was evident for pack-years smoked. When examined according to smoking status the risk associated with the highest quartile of BMI seemed to be greater among non-smokers (OR = 3.6, 95% CI: 2.4–5.3) than among current smokers (OR = 2.8, 95% CI: 1.4–5.6). Among postmenopausal women the risk associated with current use of postmenopausal hormones appeared to be greater among non-smokers (OR = 3.3, 95% CI: 2.3–4.9) than among current smokers (OR = 2.7, 95% CI: 1.3–5.5). Risk for long-term use (10 or more years) compared with never users was 8.3 (95% CI: 4.6–15.1) among never smokers and 2.5 (95% CI: 0.8–7.9) among current smokers. The risk associated with non-insulin-dependent diabetes was greater among non-smokers (OR = 2.5, 95% CI: 1.7–3.6) than current smokers (OR = 1.1, 95% CI: 0.4–3.1). There was no modifying effect of smoking on the risk associated with parity. Conclusion: These results suggest that smoking moderates the risk associated with endometrial cancer among women at greatest risk, specifically women who are obese or who use postmenopausal hormones.     

<Emphasis Type="Italic">CYP1A1</Emphasis> polymorphisms and risk of lung cancer in non-smoking Chinese women: influence of environmental tobacco smoke exposure and <Emphasis Type="Italic">GSTM1/T1</Emphasis> genetic variation

Objective: We examined whether polymorphisms of CYP1A1, which plays a role in the metabolic activation of polycyclic aromatic hydrocarbons (PAHs), confer an increased risk of lung cancer in lifetime non-smoking Chinese women.Methods: A total of 126 incident lung cancer cases, of which 87.7 were pathologically confirmed, and 162 age-matched hospital controls were included. CYP1A1 MspI and Ile⁴⁶²Val polymorphisms were genotyped and tested for association with this disease.Results: An elevated risk of lung cancer was observed among individuals with the MspI CC (OR=1.7, 95 CI=0.9–3.3) and Ile⁴⁶²Val ValVal genotypes (OR=2.8, 95 CI=1.1–7.6). After stratifying by environmental tobacco smoke (ETS) exposure, the risk of lung cancer associated with both polymorphisms was higher among individuals with lower exposure to ETS, compared with those who reported at least weekly exposure. Individuals with the MspI CC genotype showed a two-fold higher risk of lung cancer if they were also null for either GSTM1 or T1 (OR=2.3, 95CI=1.0–5.0 and OR=2.7, 95 CI=1.1–6.9, respectively, compared to other genotype combinations combined).Conclusions: CYP1A1 is a susceptibility gene for lung cancer among non-smoking Asian women and this association can be influenced by ETS exposure and genetic variation at GST genes.     

Anthropometric Measurements and Epithelial Ovarian Cancer Risk in African–American and White women

Previous studies of anthropometric factors and ovarian cancer risk have been inconsistent and none have evaluated the association among African–American women. Data from a population-based, case–control study of 593 cases and 628 controls were used to evaluate ovarian cancer risk in relation to weight, height, body mass index (BMI) and waist-to-hip ratio (WHR). Odds ratios (ORs) and 95% confidence intervals (CIs) were computed and established risk factors were adjusted for using logistic regression models, stratified by race. Among all races, weight at age 18, WHR, weight and BMI one year prior to interview were associated with elevated ovarian cancer risk. When stratified by race, the association between WHR and ovarian was similar among Whites and among African Americans. However, African–American women in the fourth quartile of height had an elevated risk of ovarian cancer (OR = 3.2; 95% CI = 1.3–7.8), but this risk was not apparent in Whites (OR = 1.0; 95% CI␣ = 0.7–1.4). These findings support the hypothesis that obesity is an important risk factor of ovarian cancer among African–Americans and Whites and also suggest that height may be a risk factor specific to African–Americans.^★ This work was performed at the Duke University Comprehensive Cancer, Durham, NC, USA.     

Occupational Exposure to Diesel Engine Emissions and Risk of Cancer in Swedish Men and Women

Objective: To investigate the risk of cancer among workers exposed to diesel emissions in a large record-linkage study from Sweden. Methods: The Swedish Cancer Environment Register III contains nationwide data on cancer incidence during 1971–1989, by occupation and industry of employment as reported in the 1960 and 1970 censuses. After excluding farmers, we classified job and industry titles according to estimated probability and intensity of exposure to diesel emissions. Exposed men in the 1960 census contributed over 7,400,000 person-years, and exposed women contributed over 240,000. We compared them to the remainder of the employed population, using indirect standardization and multivariate Poisson regression analysis. Results: Men exposed in the 1960 census experienced an increased risk of lung cancer: the relative risks (RRs) were 0.95 (95% confidence interval [CI] 0.9–1.0), 1.1 (1.1–1.2) and 1.3 (1.3–1.4) for low, medium, and high intensity of exposure. Corresponding results for probability of exposure were 1.1 (1.0–1.1), 0.9 (0.86–0.94) and 1.2 (1.1–1.2). The risk was higher for squamous cell carcinoma of the lung than for other histological types. Results in women were not suggestive of an effect (RR in the category of medium or high intensity of exposure 1.1, 95% CI 0.6–1.8). A small but significant increase in risk of cancers of the stomach (SIR 1.06), pancreas (SIR 1.05), larynx (SIR 1.09), and the kidney (SIR 1.06) was present among men exposed to diesel emissions, without a clear trend according to either probability or intensity of exposure. The SIR among women was non-significantly increased for stomach, pancreatic, and laryngeal cancers, but not for kidney cancer. Furthermore, a significantly increased risk of oral/pharyngeal (SIR 1.64) and cervical (SIR 1.48) cancers was present among women, with a suggestion of a dose–response relationship. There was no increased risk of bladder cancer in either gender. Conclusions: The results of this study provide evidence of a positive exposure–response relationship between exposure to diesel emissions and lung cancer risk among men. The positive results for other neoplasms, such as stomach, pancreatic, oral/pharyngeal, and cervical cancers, cannot be attributed to diesel exposure, but they deserve attention in future investigations.     

Cancer incidence among Finnish seafarers, 1967–92

A cohort of 30,940 male and 11,529 female seafarers registered in the files of Seafarers' Pension Fund in Finland was followed up through the Finnish Cancer Registry for cancer in 1967–92. Among male seafarers, there were 1,199 cases of cancer, which corresponds to the average cancer incidence in Finnish men. There was a statistically significant excess of non-melanoma skin cancer (standardized incidence ratio [SIR]=1.8, 95 percent confidence interval [CI]=1.2–2.5) and mesothelioma (SIR=2.9, CI=1.2–5.6) in the follow-up category of 20 or more years since the first employment. Alcohol-related cancers were increased among seafarers (SIR for cancer of the mouth and pharynx = 1.; esophagus = 1.4; and liver = 1.5; combined CI=1.1–1.9). Deck crews had a significantly high risk of cancer of the pancreas (SIR=2.0) and also prostate after 10 years since first employment (SIR=1.6). Occupational asbestos exposure among seafarers is likely strong enough to cause excess cases of mesothelioma but not of lung cancer. Occupational exposures also may be associated with increased risk of cancers of the kidney, pancreas, prostate and old-age brain cancer in some of the main occupational categories. Cumulative ultraviolet radiation likely doubles the risk of nonmelanoma skin cancer among older men and repeated sunburns that of skin melanoma in ages below 30 (SIR among deck and engine crew = 4.6, CI=3.1–6.5). Female ship personnel had a significantly elevated total cancer risk (observed number of cases = 732) which increased over follow-up time (SIR in the category 20 years since the first employment was 1.3, CI=1.1–1.5). This excess was attributable primarily to lung cancer (SIR=2.6, CI=2.0–3.3). Also cancers of the cervix uteri, vulva, and vagina showed significant excess after 10 to 20 years since first employment aboard.Address correspondence to Dr Pukkala, Finnish Cancer Registry, Litsankatu 21 B, FIN-00170 Helsinki, Finland. The Finnish Work Environment Fund financially supported this project.Dr Pukkala is with the Finnish Cancer Registry, Helsinki, Finland. Dr Saarni is with the Regional Institute of Occupational Health, Turku, Finland.     

Secondhand smoke exposure in early life and the risk of breast cancer among never smokers (United States)

Evidence is increasing that some early life exposures affect breast cancer risk. Exposure to secondhand smoke (SHS) during childhood may be one such exposure. As part of the WEB Study (Western New York Exposures and Breast Cancer Study), we conducted a population-based, case-control study with 1166 women aged 35 to 79 diagnosed with histologically confirmed, primary, incident breast cancer. Controls (n = 2105) were randomly selected from the Department of Motor Vehicles driver’s license list (≤age 65) and the Center for Medicare & Medicaid Services rolls (>age 65). Participants were queried regarding household and workplace SHS exposure. Person-years of lifetime cumulative SHS exposure were computed as well as cumulative exposure up to 21 years of age. Unconditional logistic regression adjusting for potential confounders was used to calculate odds ratios (OR) and 95% confidence intervals (95% CI). Lifetime cumulative exposure to household SHS was not associated with an increase in breast cancer risk for premenopausal (OR = 1.17, 95% CI = 0.54–2.56) or postmenopausal (OR = 1.29; 95% CI = 0.82–2.01) women. Neither was risk increased among women exposed to SHS before the age of 21 or at the time of birth, menarche, or a women’s first birth. In this study, exposure to SHS either in adult or early life does not appear to be associated with the risk of breast cancer.     

A prospective study of lifestyle factors and the risk of pancreatic cancer in Nord-Trøndelag, Norway

Objectives: Cancer of the pancreas is highly fatal and, despite extensive scrutiny, only cigarette smoking stands out as a likely causal agent in epidemiological studies. To explore to what extent different lifestyle factors are associated with the risk of pancreatic cancer, data from a large health screening survey in a county in Norway were analyzed. Methods: Our study included 31,000 men and 32,374 women initially free from any diagnosed cancer, and during 12 years of follow-up, 166 incident cases of pancreatic cancer were diagnosed at the Cancer Registry. Results: Compared with never smokers, we found a two-fold increased risk among current smokers, and a dose–response association with number of cigarettes (p for trend = 0.02 for both men and women) and with number of pack-years (p for trend = 0.02 for men and 0.01 for women). The risk among former smokers quitting more than 5 years before study entry was close to the risk of never smokers. Compared with persons who reported never or infrequently to be physically worn out after a day's work, the relative risk (RR) among those who nearly always became worn out was 2.9 (95% confidence interval (CI) = 1.4–5.8) for men and 3.8 (95% CI = 1.6–9.2) for women. Divorced or separated men had a risk of 3.1 (95% CI = 1.3–7.2) compared with married men. We observed a higher risk among women in occupations of high socioeconomic status (RR = 2.5; 95% CI = 1.2–5.2), and among men occupied in farming, agriculture or forestry (RR = 2.1; 95% CI = 1.1–4.0), compared with persons in occupations of low socioeconomic status. Conclusions: Our results confirm the findings of previous studies that indicate a causal role of cigarette smoking in pancreatic cancer. Moreover, we found that the risk of former smokers may approach the risk of never smokers within a few years subsequent to quitting.