Cancer incidence among seamen in iceland

The cancer incidence was investigated among 27,884 fishermen and sailors from the merchant fleet who had been members of a pension fund for seamen during 1958-1986 in Iceland. The cancer incidence was followed through 1966-1988. Expected values were based on rates for the general male population in Iceland. In the whole cohort, 758 malignant neoplasms had occurred as compared to 688.43 expected, standardized incidence ratio (SIR) = 1.10, 95% confidence limit (CI) 1.03-1.18. There was an excess for cancer of the stomach, rectum, larynx, and lung and nonmelanoma skin cancer; the SIRs were 1.29, 1.44, 1.77, 1.61, and 1.51, respectively. When analyzing the cancer incidence according to length of employment, the SIRs for many of the cancer sites were high for those with a short employment and many SIRs decreased with increasing length of employment. The SIRs for lung cancer were high in all subgroups. Only for stomach cancer and leukemia was there a substantial increase in SIR with increasing length of employment. The SIR was 1.55 for stomach cancer (CI 1.01-2.27) in the group with longer than 10 years of employment, and 1.97 for leukemia (CI 0.85-3.87) in the same group. It is concluded that the risk of both stomach and lung cancer seems to be associated with the occupation of seamen.     

An ecologic study of nitrate in municipal drinking water and cancer incidence in Trnava District,Slovakia

Contamination of drinking water by nitrate is an evolving public health concern since nitrate can undergo endogenous reduction to nitrite, and nitrosation of nitrites can form N-nitroso compounds, which are potent carcinogens. We conducted an ecologic study to determine whether nitrate levels in drinking water were correlated with non-Hodgkin lymphoma and cancers of the digestive and urinary tracts in an agricultural district (Trnava District; population 237,000) of the Slovak Republic. Routinely collected nitrate data (1975-1995) for villages using public water supplies were computerized, and each village was categorized into low (0-10 mg/L), medium (10.1-20 mg/L), or high (20.1-50 mg/L) average levels of total nitrate in drinking water. Observed cases of cancer in each of these villages were ascertained through the district cancer registry for the time period 1986-1995. Standardized incidence ratios (SIRs) and 95% confidence intervals (CI) for all cancer and selected cancer sites were calculated by indirect standardization using age- and sex-specific incidence rates from the entire district. For all cancer in women, SIRs increased from villages with low (SIR=0.87; 95% CI 0.72-0.95) to medium (SIR=1.07; 95% CI 1.00-1.13) to high (SIR=1.14; 1.06-1.22) levels of nitrate (P for trend <0.001); there was a similar trend for all cancer in men from low (SIR=0.90; 95% CI 0.81-0.99) to medium (SIR=1.08, 95% CI 1.02-1.16), but not for high (SIR=0.94; 0.88-1.02), nitrate levels (P for trend <0.001). This pattern in the SIRs (from low to high nitrate level) was also seen for stomach cancer in women (0.81, 0.94, 1.24; P for trend=0.10), colorectal cancer in women (0.64, 1.11, 1.29; P for trend <0.001) and men (0.77, 0.99, 1.07; P for trend=0.051), and non-Hodgkin lymphoma in women (0.45, 0.90, 1.35; P for trend=0.13) and men (0.25, 1.66, and 1.09; P for trend=0.017). There were no associations for kidney or bladder cancer. These ecologic data support the hypothesis that there is a positive association between nitrate in drinking water and non-Hodgkin lymphoma and colorectal cancer.     

Second primary cancer after in situ and invasive cervical cancer

The Swedish Family-Cancer Database was used to analyze 9,426 second primary cancers in 117,830 subjects diagnosed with in situ and 17,556 subjects with invasive cervical cancer from the years 1958-1996. We calculated standardized incidence ratios (SIRs) from age- and period-specific rates for all women. SIRs were elevated after both in situ and invasive cervical cancer for cancers of the upper aerodigestive tract, anus, pancreas, lung, other female genitals, and urinary bladder. Anus and other female genitals, known targets of human papilloma virus, showed SIRs exceeding 3.0 and 10 or more within the year of diagnosis of cervical cancer, probably implying the effects of diagnostic intensity or transient faltering of host immunosurveillance. Among the remaining sites, smoking appeared to be the major cause, but for urinary bladder cancer it only explained one-half of the excess; human papilloma virus infection, possibly through immunosuppression, could account for the remaining excess. Although urinary bladder cancer showed a relatively small SIR compared with anal cancer, because it is more common, the number of attributable cases was about equal for the two sites. Invasive cervical cancer showed an SIR of 2.3 after in situ cancer. On follow-up, we also observed increased SIRs at many radiosensitive sites 10 or more years after diagnosis of invasive cervical cancer.     

Cancer incidence in the Puerto Rican-born population of Long Island, New York.

BACKGROUND. There are apparently no published data on cancer incidence in the Puerto Rican-born populations of the northeastern United States. METHODS. Standardized incidence ratios (SIRs) were calculated for 1980 through 1986 for the Puerto Rican-born population in Long Island (New York). RESULTS. Significantly reduced SIRs were found for males (SIR = 0.77) but not for females (SIR = 0.91), using expected numbers derived from incidence rates for all areas in the Surveillance, Epidemiology and End Results (SEER) Program (excluding Puerto Rico). Using incidence rates for Puerto Rico to obtain expected numbers, there was evidence for the retention of elevated SIRs for stomach cancer (both sexes) and for significantly elevated SIRs for lung cancer (both sexes), colon-rectum cancer (females), prostate cancer, and breast and uterine corpus cancer. Using rates for SEER areas, the SIRs for lung cancer approached 1.00, in contrast to other US Puerto Rican-born populations. CONCLUSION. The data indicate the need for surveys on smoking and other health-related behaviors in the population studied and provide further evidence for heterogeneity in cancer patterns in US Puerto Rican-born populations.     

Cancer incidence and asbestos in drinking water, Town of Woodstock, New York, 1980-1998

Late in 1985, asbestos contamination was discovered in the public water supply of the Town of Woodstock, Ulster County, New York. Contamination resulted from asbestos-cement pipes installed in the town water system in the mid to late 1950s and the corrosiveness of the local water. The New York State (NYS) Department of Health established the Woodstock Asbestos Exposure Registry (WAER) in 1986 to monitor rates of cancer among individuals who lived on the water supply between 1960 and 1985. Demographic, health, and residential information were collected on 2936 registrants. The follow-up period for observation of cancer was 1980-1998, consistent with the expected lag of 20-30+ years for development of asbestos-related cancers. The NYS Cancer Registry was used to ascertain cancer diagnoses. Standardized incidence ratios (SIRs) for gastrointestinal, respiratory, and total cancers were all approximately 1.00 or less and all 95% confidence intervals (CIs) included 1.00. For individual types of the gastrointestinal cancers, only the SIR for pancreatic cancer was marginally statistically significant at 2.19 (95% CI=1.00-4.16), based on a total of nine observed cases. The excess in pancreatic cancer occurred primarily among men (SIR=3.08; 95% CI=1.13-6.70) and was only slightly elevated among women (SIR=1.39; 95% CI=0.29-4.06). This association may be related to factors other than asbestos exposure such as occupation and lifestyle or to chance. No cases of mesothelioma were observed among WAER participants. There was no increase in incidence by latency or duration of residence on the water supply, but the ability to detect these trends is limited by small numbers and unknown dates of initial exposure. The general pattern of results did not demonstrate a likely link between exposure to asbestos in drinking water and cancer occurrence among participants in the WAER.     

Cancer incidence among Ontario police officers

The National Institute for Occupational Safety and Health (NIOSH) published a report in 1995 suggesting the possibility of increased incidence of testicular cancer, leukemia, and cancers of the brain, eye, and skin among police officers working with traffic radar. NIOSH recommended epidemiologic study of the issue. This report presents the results of a retrospective cohort cancer incidence study among 22,197 officers employed by 83 Ontario police departments. The standardized incidence ratio (SIR) for all tumor sites was 0.90 (95% confidence interval [CI] = 0.83–0.98). There was an increased incidence of testicular cancer (SIR = 1.3, 90%CI = 0.9–1.8) and melanoma skin cancer (SIR = 1.45, 90%CI = 1.1–1.9). These anatomical sites might absorb energy from radar units, but at this time the author has no information about individual exposures to radar emissions, and it is not possible to draw etiologic conclusions. Nested case-control studies are planned to assess individual radar exposures. Am. J. Ind. Med. 34:157–162, 1998. © 1998 Wiley-Liss, Inc.     

A Population-Based Cohort Study of All-Cause and Site-Specific Cancer Incidence Among Patients With Type 1 Diabetes Mellitus in Taiwan

Background

The relationship between type 1 diabetes mellitus (T1DM) and cancer incidence remains unclear. We sought to assess the all-cause and site-specific cancer incidence in patients with T1DM.

Methods

A retrospective cohort study design was employed, in which 14 619 patients with T1DM were retrieved from Taiwan’s National Health Insurance medical claims between 2000 and 2007. The study subjects were followed to the end of 2008, and cancer incidence was assessed. We calculated age-, sex-, and calendar year-standardized incidence ratios (SIRs) of all-cause cancer incidence and site-specific neoplasm incidence, with reference to the general population.

Results

Seven hundred and sixty patients were identified for all-cause cancer over 86 610 person-years, representing an incidence rate of 87.75 cases per 10 000 person-years. The incidence rate was higher in males than in female patients (109.86 vs 69.75 cases per 10 000 person-years). T1DM was associated with a significantly increased SIR of all-cause cancer (1.13; 95% confidence interval [CI], 1.05–1.22). The sex-specific SIR was significantly elevated in female patients (1.19; 95% CI, 1.07–1.33), but the SIR for male patients was insignificantly elevated (1.09; 95% CI, 0.99–1.20). Pancreatic cancer showed the greatest increase in SIR among both male and female patients with T1DM. Male patients experienced significantly increased SIRs for kidney, rectum, liver, and colon neoplasm, and significantly increased SIRs were noted for ovarian, bladder, and colon cancer in female patients.

Conclusions

T1DM was associated with a 13% increase in risk of all-cause cancer incidence. Patients with T1DM should be advised to undergo cancer screening for certain types of cancer.Key words: type 1 diabetes mellitus, neoplasm, cohort studies, incidence densities, standardized incidence ratio     

Rocky Mountain HMO

Rocky Mountain HMOs two-decade history of success on the western slope of Colorado is due not only to the conscious decisions of its managers but also to the geography and demography of its primary market area. The managers of Rocky Mountain HMO sought to build a managed care plan that was physician friendly and that had a local face, explicitly recognizing that their success hinged on the ability to satisfy the needs of both providers and purchasers. Isolated by the Rocky Mountains from major population centers of the state and located beyond the pull of the Salt Lake City, Utah, market to the west, Rocky Mountain HMO had no real managed care competitors on the western slope during its formative years. This lack of competition, combined with the ability to defuse physician resistance to managed care and to provide a satisfactory array of benefits at a reasonably low price, gave Rocky Mountain HMO an impressive share of the western slope health insurance market. Rocky Mountain HMOs expansion plans, in part, are a reaction to real and anticipated increases in managed care competition along the western slope. To maintain competitive premium rates, Rocky Mountain HMO executives perceive the need to spread the fixed costs of its infrastructure by increasing enrollment. As Rocky Mountain HMO expands its market to include all areas of the state, three issues relative to rural areas emerge. First, will Rocky Mountain HMO be able to import its successful rural HMO development strategies to other rural areas of the state at the same time it attempts to develop urban markets, or will rural expansion areas be treated in the same manner as urban expansion areas? Second, what are the consequences of the HMO's change in strategic focus for Rocky Mountain HMO providers and consumers on the western slope? Third, how will increased competition on the western slope affect Rocky Mountain HMO's relationship with its providers and consumers?     

Cancer incidence among Hispanic children in the United States.

OBJECTIVE: To directly compare cancer incidence among Hispanic children and non-Hispanic white children in California and Florida, two states in the United States of America that include nearly one in three Hispanic children in the country.METHODS: Cross-sectional data for 1988 through 1998 pertaining to all incident pediatric cancer cases (age < 15 years) with race/ethnicity coded as either Hispanic or non-Hispanic white came from the Florida Cancer Data System database and the California Cancer Registry database. The results were expressed as age-standardized incidence rates, standardized to the world standard million population. Hispanic rates and non-Hispanic white rates were compared using standardized incidence ratios (SIRs) with 95% confidence intervals (95% CIs.).RESULTS: The SIR for all cancers for Hispanic children compared to non-Hispanic white children was 1.02 (95% CI: 0.99, 1.05). For selected tumor types, SIRs indicated higher incidences among Hispanic children for leukemia (SIR = 1.26; 95% CI: 1.19, 1.34), Hodgkin's lymphoma (SIR = 1.29; 95% CI: 1.08, 1.54), and germ cell tumors (SIR = 1.62; 95% CI: 1.34, 1.96). There were lower incidences for the Hispanic children for central nervous system tumors (SIR = 0.72; 95% CI: 0.66, 0.78) and for sympathetic nervous system tumors (SIR = 0.76; 95% CI: 0.66, 0.87). In terms of interstate differences, the incidence of lymphoma, central nervous system tumors, sympathetic nervous system tumors, and malignant bone tumors was highest among Hispanic youth in Florida; the incidence of hepatic tumors was highest among Hispanic youth in California.CONCLUSIONS: While the overall cancer incidence rate among Hispanic children was similar to that for non-Hispanic white children, significant differences for specific tumor types were identified. Since Hispanic ethnicity may be a confounder for other cancer risk factors (e.g., familial, socioeconomic, or environmental), it is recommended that future research into Hispanic pediatric cancer risk investigate these risk factors.     

Cancer risks to spouses and offspring in the Family-Cancer Database

It is generally accepted that cancer is caused by environmental and inherited factors but these are only partially identified. Family studies can be informative but they do not separate shared lifestyles and genes. We estimate familial risks for concordant cancers between spouses in common cancers of both sexes in order to quantify cancer risks from the shared environment. The risks are compared to those seen between parents and offspring in order to estimate the inherited component. The nation-wide Family-Cancer Database was used as the source of family and cancer data. Standardized incidence ratios (SIRs) were calculated for concordant cancer in offspring by parental cancer and in spouses. Among the 23 cancer sites considered, all but two showed an increased SIR for offspring by father or mother. Only two sites, stomach and lung, showed an increase in SIR of concordant cancer among spouses. Additionally, pancreatic cancer and melanoma were increased in couples where at least one spouse was diagnosed before age 50. If both spouses presented melanoma before age 40, SIR was 3.82 for husbands. SIRs of colon, renal, and skin (squamous cell) cancers were unchanged by spouses' concordant cancer. Shared lifestyle among spouses seems to explain only a small proportion of cancer susceptibility. Because lifestyles are likely to differ more between parents and offspring than between spouses, familial cancer risks between parents and offspring are likely to be more due to heritable rather than environmental effects.     

Community cancer assessment in response to long-time exposure to perchlorate and trichloroethylene in drinking water

In response to concerns about cancer stemming from drinking water contaminated with ammonium perchlorate and trichloroethylene, we assessed observed and expected numbers of new cancer cases for all sites combined and 16 cancer types in a California community (1988 to 1998). The numbers of observed cancer cases divided by expected numbers defined standardized incidence ratios (SIRs) and 99% confidence intervals (CI). No significant differences between observed and expected numbers were found for all cancers (SIR, 0.97; 99% CI, 0.93 to 1.02), thyroid cancer (SIR, 1.00; 99% CI, 0.63 to 1.47), or 11 other cancer types. Significantly fewer cases were observed than expected for cancer of the lung and bronchus (SIR, 0.71; 99% CI, 0.61 to 0.81) and the colon and rectum (SIR, 0.86; 0.74 to 0.99), whereas more cases were observed for uterine cancer (SIR, 1.35; 99% CI, 1.06 to 1.70) and skin melanoma (SIR, 1.42; 99% CI, 1.13 to 1.77). These findings did not identify a generalized cancer excess or thyroid cancer excess in this community.     

Cancer incidence among Danish workers exposed to trichloroethylene

Human evidence regarding the carcinogenicity of the animal carcinogen trichloroethylene (TCE) is limited. We evaluated cancer occurrence among 803 Danish workers exposed to TCE, using historical files of individual air and urinary measurements of TCE-exposure. The standardized incidence ratio (SIR) for cancer overall was close to unity for both men and women who were exposed to TCE. Men had significantly elevated SIRs for non-Hodgkin's lymphoma (SIR = 3.5; n = 8) and cancer of the esophagus (SIR = 4.2; n = 6). Among women, the SIR for cervical cancer was significantly increased (SIR = 3.8; n = 4). No clear dose-response relationship appeared for any of these cancers. We found no increased risk for kidney cancer. In summary, we found no overall increase in cancer risk among TCE-exposed workers in Denmark. For those cancer sites where excesses were noted, the small numbers of observed cases and the lack of dose-related effects hinder etiological conclusions.     

Cancer incidence in a cohort of Swedish sewage workers: extended follow up

OBJECTIVES: To study the cancer incidence in a cohort of Swedish sewage workers. An increased incidence of cancer of the stomach, the kidney and the nervous system in this cohort was previously reported. This new analysis reports on 9 more years of follow up. METHODS: The study is an analysis of a cohort of all 711 employees at 17 Swedish sewage plants employed for at least for 1 year during the years 1965-86. Assessment of exposures was performed by classification of work tasks. Standardised incidence ratios (SIRs), and 95% confidence intervals (95% CIs) were calculated. RESULTS: The total cancer incidence was not significantly increased (SIR = 1.2, 95% CI 0.92 to 1.5) but the incidence of prostate cancer was (SIR = 1.6, 95% CI 1.0 to 2.5), and based on two cases only, there seemed to be a significant increase of cancer of the nose and the nasal sinuses (SIR = 12, 95% CI 1.5 to 44). The incidence of stomach cancer was also increased (SIR = 2.3, 95% CI 0.99 to 4.5). There was no relation between cancer incidence and level of sewage exposure. CONCLUSIONS: Sewage workers did not have an increased risk of cancer, and the increased risk estimates for some specific cancer sites were not conclusive.       

Comparison of different methods for spatial analysis of cancer data in Utah

BACKGROUND: The standardized incidence ratio (SIR) and SaTScan software are used by the Environmental Epidemiology Program (EEP), Utah Department of Health, to investigate health concerns and exposures in Utah (USA). Recently, the EEP acquired the Rapid Inquiry Facility (RIF). The RIF enables access of additional dimensions of data, identifies potentially exposed populations, and computes disease rates and relative risk statistics for that potentially exposed population. OBJECTIVE: In this article we present a comparison of the SIR, SaTScan, and RIF methodologies in an investigation of cancer rates in residents living over contaminated groundwater plumes near Hill Air Force Base (HAFB) in Utah. METHODS: For this study, we used cancer data from the Utah Cancer Registry for cancers of the lung, kidney, and non-Hodgkin lymphoma. We used SIR and the RIF to investigate the cancer rate in a defined population within the study area during six consecutive 5-year time intervals (1975-2004). We used SaTScan and the RIF to explore the study area for clusters. RESULTS: The RIF risk analysis and SIR are mathematically identical. SIR is set up and computed by programming SAS; the RIF risk analysis, on the other hand, is set up through four menu-driven steps. The RIF disease-mapping feature enhanced the interpretation of SaTScan results. We found kidney and lung cancer to be statistically elevated for the potentially exposed population for one and two periods, respectively. SaTScan found two clusters, one outside the potentially exposed population and one that included a portion of that population. CONCLUSION: The RIF is an easy-to-use and useful tool that extends the ability of the investigator to conduct analysis of disease rates and interpret the findings.     

Cancer Incidence in World Trade Center Rescue and Recovery Workers, 2001–2008

Background: World Trade Center (WTC) rescue and recovery workers were exposed to a complex mix of pollutants and carcinogens.Objective: The purpose of this investigation was to evaluate cancer incidence in responders during the first 7 years after 11 September 2001.Methods: Cancers among 20,984 consented participants in the WTC Health Program were identified through linkage to state tumor registries in New York, New Jersey, Connecticut, and Pennsylvania. Standardized incidence ratios (SIRs) were calculated to compare cancers diagnosed in responders to predicted numbers for the general population. Multivariate regression models were used to estimate associations with degree of exposure.Results: A total of 575 cancers were diagnosed in 552 individuals. Increases above registry-based expectations were noted for all cancer sites combined (SIR = 1.15; 95% CI: 1.06, 1.25), thyroid cancer (SIR = 2.39; 95% CI: 1.70, 3.27), prostate cancer (SIR = 1.21; 95% CI: 1.01, 1.44), combined hematopoietic and lymphoid cancers (SIR = 1.36; 95% CI: 1.07, 1.71), and soft tissue cancers (SIR = 2.26; 95% CI: 1.13, 4.05). When restricted to 302 cancers diagnosed ≥ 6 months after enrollment, the SIR for all cancers decreased to 1.06 (95% CI: 0.94, 1.18), but thyroid and prostate cancer diagnoses remained greater than expected. All cancers combined were increased in very highly exposed responders and among those exposed to significant amounts of dust, compared with responders who reported lower levels of exposure.Conclusion: Estimates should be interpreted with caution given the short follow-up and long latency period for most cancers, the intensive medical surveillance of this cohort, and the small numbers of cancers at specific sites. However, our findings highlight the need for continued follow-up and surveillance of WTC responders.     

Underestimation of relative risks by standardized incidence ratios for AIDS-related cancers

PURPOSE: Registry-based studies provide valuable data regarding cancer risk among people with HIV/AIDS (PWHA). Such studies utilize the standardized incidence ratio (SIR) to estimate the relative risk (RR), an etiologically relevant measure. However, SIR may underestimate RR when HIV/AIDS prevalence in the general population or RR is high. We quantified the extent of this underestimation for 3 AIDS-related cancers: Kaposi sarcoma (KS), central nervous system non-Hodgkin lymphoma (CNS NHL) and cervical cancer. METHODS: We used data on cancer risk among PWHA from the U.S. HIV/AIDS Cancer Match Study. SIRs were compared with RRs estimated using two methods: (1) SIRs calculated using pre-AIDS era (1973-1979) cancer incidence rates (SIRpre-AIDS) and (2) SIRs calculated after subtraction of cancers known to be among PWHA from general population rates (SIRexclusion). RESULTS: For KS and CNS NHL, SIRs (117.8 and 133.9, respectively) calculated using overall general population rates substantially underestimated both SIRpre-AIDS (19,778 and 3,612, respectively) and SIRexclusion (657.7 and 536.4, respectively). In contrast, the extent of underestimation was negligible for cervical cancer (SIR = 4.9 vs. SIRexclusion = 5.1). For KS and CNS NHL, SIRs were higher in females than in males. However, SIRpre-AIDS and SIRexclusion estimates were more similar, indicating that SIR differences artifactually reflect differences in HIV/AIDS prevalence between males and females. For KS and CNS NHL, trends across calendar time were weaker in SIRs than in SIRpre-AIDS and SIRexclusion. CONCLUSION: For KS and CNS NHL, SIRs substantially underestimate RRs. This underestimation arises from the exceptionally high relative risk of KS and CNS NHL among PWHA. SIRs must be interpreted cautiously when HIV/AIDS prevalence is high or varies across groups of interest.     

Familial relationships in squamous cell carcinoma of the skin

The Swedish Family-Cancer Database, which was updated in 1999 to cover individuals born after 1934 with their biological parents, totals 9.6 million persons. We used this resource to study invasive and in situ skin cancers. We identified 198 families in which a parent and an offspring had skin cancer. The familial standardized incidence ratios (SIRs) were 2.4 for invasive and 2.8 for in situ skin cancers in offspring. The SIRs for offspring depended only weakly on the age at diagnosis, as evaluated in two age groups. Compared with offspring whose parents had a single skin cancer, offspring whose parents had multiple skin cancers had a 70% increase in SIR. The discordant parental cancer sites that showed associations with skin cancer in offspring were melanoma, ocular melanoma, and a group of cancers observed in immunosuppressed patients.     

Cancer incidence in municipalities near two former nuclear materials processing facilities in Pennsylvania

Because nuclear facilities can release radionuclides into the surrounding environment accidentally or during normal operations, there has been public concern over the possibility of adverse health effects. Two former nuclear materials processing facilities in Armstrong County Pennsylvania have been the focus of such public concern for over 20 y. The Apollo and Parks facilities processed uranium and plutonium fuels for use in nuclear applications. To evaluate the possibility of increased cancer rates in the communities near the Apollo-Parks nuclear processing materials plants, cancer incidence rates were assessed for the years 1993-1997, or nearly 40 y after the plants had begun operation in 1957 and 1960, respectively. The rates of cancer were evaluated among the approximately 17,000 persons living in 1 of 8 municipalities encompassing or near these nuclear sites. Numbers of cancers and mailing addresses (n = 935) were obtained from the Pennsylvania Department of Health. Because mailing addresses in small rural areas do not always reflect actual residences within a municipality, each of 935 addresses was validated (and corrections made when indicated) by contacting area postmasters and using Census Bureau geocoding information, street maps, and aerial photographs. Standardized Incidence Ratios (SIRs) were computed as the ratio of observed numbers of cancers in the study area compared to the expected number derived from general population rates of Pennsylvania. Forty percent of the mailing addresses were found not to be within the boundaries of the study municipalities. After excluding these persons who did not reside in one of the eight municipalities near the Apollo-Parks facilities, 581 cancers remained in contrast to 574.0 expected (SIR 1.01; 95% confidence interval 0.93-1.10). Based upon knowledge of the tissues where uranium or plutonium likely would be deposited after intake, cancers of the lung (SIR 0.88), kidney (SIR 1.05), non-Hodgkin's lymphoma (SIR 1.10), liver (SIR 0.61), and bone (2 observed vs. 1.19 expected) were carefully evaluated, but no significant excesses were noted at these sites. Cancers of the female breast and thyroid and leukemia also were not significantly increased, as expected since these tissues are not sites where uranium or plutonium would concentrate. Overall, no increase in cancer risk could be attributed to living near the two former nuclear materials processing facilities. However, misleading elevations in cancer risks would have been suggested if mailing addresses had not been corrected to exclude addresses that were not within the boundaries of the municipalities for which population data were available. The study had sufficient power to exclude increased cancer risks of 10% or greater.     

Cancer incidence among workers in the asbestos-cement producing industry in Norway

OBJECTIVES: The incidence of cancer among employees of a Norwegian asbestos-cement factory was studied in relation to duration of exposure and time since first exposure. The factory was active in 1942-1968. Most of the asbestos in use was chrysotile, but for technical reasons 8% amphiboles was added. METHODS: For the identification of cancer cases, a cohort of 541 male workers was linked to the Cancer Registry of Norway. The analysis was based on the comparison between the observed and expected number of cancer cases. Standardized incidence ratios (SIR) and 95% confidence intervals (95% CI) were estimated. Period of first employment, duration of employment, and time since first employment were used as indicators of exposure. Poisson regression analysis was used for the internal comparisons. RESULTS: The standardized incidence ratio was 52.5 (95% CI 31.1-83.0) for pleural mesothelioma, on the basis of 18 cases. The highest standardized incidence ratio was found for workers first employed in the earliest production period (SIR 99.0, 95% CI 51.3-173). No peritoneal mesothelioma was found. The standardized incidence ratio for lung cancer was 3.1 (95% CI 2.14.3), but no dose-response effect was observed. The ratio of mesothelioma to lung cancer cases was 1:2. CONCLUSIONS: This study showed a high incidence of mesothelioma and a high ratio of mesothelioma to lung cancer among asbestos-cement workers. The high incidence of mesothelioma was probably due to the fact that a relatively high proportion of amphiboles was used in the production process.     

Exposure to chemical carcinogens and risk of cancer among Finnish laboratory workers

BACKGROUND: Laboratory workers have long been suspected of having increased risks of cancer due to their occupation. We evaluated occupational exposure and cancer incidence among Finnish laboratory workers. MATERIALS AND METHODS: The cohort was comprised of 4,722 laboratory workers reported to the Finnish Register of Workers Exposed to Carcinogens in 1979-1988. The standardized incidence ratios (SIR) for cancers and their 95% confidence intervals (CI) were calculated based on data of the Finnish Cancer Registry. RESULTS: The most common carcinogens, to which these workers were potentially exposed, were chromium (VI), carbon tetrachloride, cadmium, benzene, and chloroform. From this cohort, 174 persons were recorded with primary tumors in 1980-1999. The SIR for cancer of all sites combined was 0.99 (CI 0.85-1.14). None of the cancer-specific SIRs were significantly elevated. Slight excesses were found, e.g., for non-Hodgkin's lymphoma (seven observed, 4.8 expected) and leukemia (four observed, three expected). CONCLUSIONS: This study did not suggest any major cancer risks among Finnish laboratory workers but the follow-up time of the cohort was too short (on an average 15.7 years) to reveal possible cancer risks requiring a longer induction period.