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Epidemiologic evidence on the relationship between chemical pesticides and cancer is reviewed. In animal studies, many pesticides are carcinogenic, (e.g., organochlorines, creosote, and sulfallate) while others (notably, the organochlorines DDT, chlordane, and lindane) are tumor promoters. Some contaminants in commercial pesticide formulations also may pose a carcinogenic risk. In humans, arsenic compounds and insecticides used occupationally have been classified as carcinogens by the International Agency for Research on Cancer. Human data, however, are limited by the small number of studies that evaluate individual pesticides. Epidemiologic studies, although sometimes contradictory, have linked phenoxy acid herbicides or contaminants in them with soft tissue sarcoma (STS) and malignant lymphoma; organochlorine insecticides are linked with STS, non-Hodgkin's lymphoma (NHL), leukemia, and, less consistently, with cancers of the lung and breast; organophosphorous compounds are linked with NHL and leukemia; and triazine herbicides with ovarian cancer. Few, if any, of these associations can be considered established and causal. Hence, further epidemiologic studies are needed with detailed exposure assessment for individual pesticides, taking into consideration work practices, use of protective equipment, and other measures to reduce risk. [ABSTRACT FROM AUTHOR]

The role of tobacco in the etiology of non-Hodgkin's lymphoma (NHL) was evaluated in a combined analysis of data from three population-based case-control studies conducted in four midwestern states of the United States: Nebraska, Iowa, Minnesota, and Kansas. Interviews were obtained from 1,177 cases (993 men, 184 women) and 3,625 controls (2,918 men, 707 women) or, if deceased, from their next-of-kin. Overall, there was no association between NHL and tobacco use (odds ratio [OR] = 1.0, 95 percent confidence interval [CI] = 0.8-1.1) or cigarette smoking (OR = 1.0, CI = 0.8-1.1). A slight negative association evident in analyses by intensity and duration of smoking was not present when interviews from proxy respondents were eliminated. There was a suggestion of a positive association between smoking and NHL among women (OR = 1.3, CI = 0.9-1.9), although there was no clear exposure-response relationship. This large case-control analysis provides no evidence that smoking is linked to the development of NHL among men. The possible role of smoking in the etiology of NHL among women needs further evaluation. [ABSTRACT FROM AUTHOR]

Introduction: Although some persistent organic pollutants (POPs) are considered human carcinogens, results from studies evaluating exposures and breast cancer risk have been inconsistent, potentially related to varying ages at exposure. Additionally, few studies evaluated the association between POPs exposure and mammographic breast density (MBD), an intermediate biomarker of breast cancer risk. We carried out a cross-sectional study to investigate associations between serum POPs concentrations and MBD measured in 1998 in female residents of Triana, Alabama, in a predominately African American population with high POPs exposures, particularly to p,p'-DDT (1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane)., Methods: We measured lipid-adjusted serum concentrations (ng/g lipid) of p,p'-DDT and its main metabolite p,p'-DDE (1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene), polychlorinated biphenyls (PCBs), β-hexachlorocyclohexane (β-HCCH), heptachlor epoxide, oxychlordane, trans-nonachlor, mirex, and aldrin for each woman in our study (n = 210). We also measured two MBD metrics, percent MBD (%MBD) and area of MBD (aMBD). Using adjusted Spearman correlation coefficients (r s ) we evaluated correlations between %MBD and aMBD with individual POPs in the overall population and by age group (19-40, 41-54, and 55-91 years) and also estimated adjusted mean measures of MBD with 95% confidence intervals across tertiles of analytes using generalized linear models (GLM). We calculated p-values for multiplicative interaction by age group using GLM. Additional analyses excluded women with current hormone replacement therapy (HRT) use and evaluated early-life exposure (prior to age 18) during the heaviest contamination period in Triana (1947-90)., Results: Among all women, we found no correlation between p,p'-DDE and %MBD, but after age stratification and exclusion of HRT users, there was a suggestion of a difference by age group, with younger women having a weak positive correlation (r s  = 0.12, p = 0.37) and older women having a weak negative correlation (r s  = -0.12, p = 0.43); p interaction  = 0.06. In contrast, PCBs were weakly positively correlated with %MBD among all women, with the correlation magnitudes increasing after excluding current HRT users (r s-total PCBs  = 0.17, p = 0.03). After age stratification and exclusion of HRT users, correlations for PCBs were higher among younger and middle-age women, with only a handful of these correlations being statistically significant. For β-HCCH, the strongest finding was a negative correlation among older women (r s  = -0.26, p = 0.07). Correlations were positive predominantly in the younger age group for heptachlor epoxide (r s  = 0.27, p = 0.04), oxychlordane (r s  = 0.35, p = 0.006), and trans-nonachlor (r s  = 0.37, p = 0.003), and largely null for the middle and older age groups; p interaction range: 0.03-0.05. Similar patterns were found in GLM analyses using tertiles of exposure and aMBD as the metric for MBD. Women exposed during the heaviest chemical contamination period in Triana prior to age 18 had positive correlations between %MBD and PCBs, heptachlor epoxide, mirex, oxychlordane, and trans-nonachlor., Conclusions: In this population, despite high exposures to p,p'-DDT and thus high serum concentrations of its main metabolite, p,p'-DDE, we did not find strong evidence of a positive association with MBD. In fact, there was some evidence of a negative association among older women for p,p'-DDE; a similar pattern was found for β-HCCH. However, younger women with higher serum levels of PCBs, heptachlor epoxide, oxychlordane, and trans-nonachlor, who were likely exposed in early life, had higher MBD. These findings should be replicated in larger studies., Competing Interests: Declaration of competing interest The authors declare no conflict of interest. The only disclosure we have is that one of the co-authors, SZ, worked in the past as an expert witness for the plaintiffs in litigation related to PCBs and non-Hodgkin's lymphoma., (Published by Elsevier Inc.)

This case-control study was designed to test the hypothesis that the risk of breast cancer varies by type and colour of the hair colouring products used. A total of 608 cases and 609 controls were included in the study. We found no increased risk associated with the overall use of hair dye products or exclusive use of permanent or temporary types of hair dye products. Among those who reported to have exclusively used semi-permanent types of hair colouring products, some of the ORs were elevated. However, none of the ORs related to age at first use, duration of use, total number of applications, and years since first use, was statistically significant. There was also no increased risk of breast cancer associated with exclusive use of dark or light hair colouring products, or use of mixed types or colours of hair dye products. We also found no increased risk of breast cancer associated with hair dye use based on an individual's reason for using a hair colouring product, such as to cover grey or to change natural hair colour. These data suggest that the use of hair colouring products does not have a major impact on the risk of breast cancer.

Background: Migrant and seasonal farmworkers have a high potential for pesticide exposures, yet are rarely included in epidemiologic studies. This study examined the feasibility of assessing prenatal exposures to pesticides and other compounds in pregnant Hispanic farmworkers., Methods: Nine women completed a survey about work experiences during pregnancy. Maternal urine, cord blood, and placenta samples were obtained at delivery for analysis of 51 analytes, including 6 phenoxy acid or triazine herbicides, 21 organochlorine insecticides, 10 PCBs, and 14 volatile organic compounds., Results: Seven of 51 analytes were found in the biological samples. DDE, DDT, dichlorbenzene, toluene, trimethylbenzene, and endosulfan sulfate were detected in cord blood samples, and 2,4-D in urine from one or more women., Conclusions: We documented the feasibility of following farmworkers to assess in utero exposure to pesticides and other contaminants, and demonstrated exposure to these compounds. Difficulties in measuring pesticides with short half lives were noted., (Copyright 2001 Wiley-Liss, Inc.)

Background: Migrant farmworkers have rarely been included in epidemiologic studies. To assess the feasibility of following farmworkers over extended periods, a critical feature of many study designs, we attempted to trace a sample of Mexican-American farmworkers identified in a clinic in Wisconsin., Methods: We randomly chose 100 farmworkers from a migrant health center registration list for 1984-85. In 1995, we searched recent clinic records, made telephone calls, and visited migrant camps to find these farmworkers in Wisconsin during the growing season. We also attempted to find 46 farmworkers at their homes in southwest Texas over a two-week period in 1996 using the address listed in the clinic records, local phone books, and conversations with next-door neighbors., Results: Although 25 farmworkers had reregistered at the clinic in recent years, we found only 6 of them in Wisconsin in 1995. In southwest Texas, we either located or ascertained information about the vital status of 25 of the 46 farmworkers (54%)., Conclusions: Tracing efforts must include extensive contacts in farmworkers' home states and must incorporate a variety of information sources. Tracing farmworkers in epidemiologic studies appears to be feasible but requires more intensive methods over longer periods of time than those used in this study., (Copyright 2001 Wiley-Liss, Inc.)

Background: There is little research into the long-term health effects of pesticides and other agricultural exposures among seasonal and migrant farmworkers in the United States. We present results of a feasibility study that established a cohort of farmworkers for use in epidemiologic research., Methods: Subjects consisted of migrant and seasonal farmworkers who joined the cohort while seeking social services through members of the Association of Farmworker Opportunity Programs (AFOP) and were entered in the National Farmworker Database (NFD) between the end of 1997 and March 1999. We designed an add-on interview with information that enhanced the utility of the database for epidemiologic research., Results: We recruited and obtained basic demographic and employment information on 5,597 farmworkers at very modest cost and effort. Subjects were mostly seasonal (61.5%), female (56.7%), and Hispanic (67.4%), with a median age of 27. Most (62.6%) had not completed high school; almost all (99.1%) reported being U.S. citizens or permanent residents, an eligibility requirement for some of the services provided by AFOP. The majority (62.5%) had engaged in farmwork for less than 10 years, but had performed a wide variety of tasks on different crops, including row crops and tree fruits. Picking was the most common task reported. Most subjects had performed farmwork in Florida, North Carolina, Texas, Michigan, or Georgia. For usual source of health care, 63.7% reported use of U.S. hospitals or emergency rooms/clinics, 42.0% U.S. private physicians, and 29.7% migrant health clinics. Among subjects reporting a prior diagnosis of cancer, primary sources of health care for treatment of that cancer included U.S. private physicians (61.9%), U.S. hospitals or emergency rooms/clinics (23.8%), and migrant health clinics (10.5%)., Conclusions: Results suggest that by adding a brief interview to the existing NFD data collection process, which was designed for other purposes, it is feasible to create an efficient tool for conducting longitudinal epidemiologic research among farmworkers., (Copyright 2001 Wiley-Liss, Inc.)

Background: Epidemiologic studies, particularly case-control studies, often rely on proxy respondents to provide information about subjects' occupational histories. The quality of proxy-reported information in occupational histories has never been evaluated for migrant farmworkers., Methods: We compared occupational histories self-reported by 31 farmworkers with those reported by their wives. The work histories were obtained using an icon/calendar-based questionnaire that was designed to facilitate recall for migrant farmworkers, who typically have complex work histories., Results: The work histories provided by proxy respondents contained 32% fewer jobs and accounted for 24% fewer years than the self-reported histories. Correlations for lifetime duration of employment in different types of jobs were moderate to good for general agricultural jobs in Washington (0.70) and apple-related jobs (0.65), which were held by virtually all of the farmworkers; correlations were moderate to poor for less common jobs and for specific types of tasks. Agreement was better after marriage than before, and for jobs held in the current year compared to other time frames. Overall, the ability of the spouses to provide occupational histories for farmworkers was within the range observed in studies involving other occupations and industries., Conclusions: In studies involving farmworkers, when study subjects cannot be interviewed, spouses can provide useful information on occupational histories. However, the information should be used only for more generalized exposure assessments; it is most appropriate for estimating cumulative duration of agricultural work, or recent work, by place or for common crops., (Published 2001 Wiley-Liss, Inc.)

Background: Migrant and seasonal farmworkers are exposed to pesticides through their work with crops and livestock. Because workers are usually unaware of the pesticides applied, specific pesticide exposures cannot be determined by interviews. We conducted a study to determine the feasibility of identifying probable pesticide exposures based on work histories., Methods: The study included 162 farm workers in seven states. Interviewers obtained a lifetime work history including the crops, tasks, months, and locations worked. We investigated the availability of survey data on pesticide use for crops and livestock in the seven pilot states. Probabilities of use for pesticide types (herbicides, insecticides, fungicides, etc.) and specific chemicals were calculated from the available data for two farm workers. The work histories were chosen to illustrate how the quality of the pesticide use information varied across crops, states, and years., Results: For most vegetable and fruit crops there were regional pesticide use data in the late 1970s, no data in the 1980s, and state-specific data every other year in the 1990s. Annual use surveys for cotton and potatoes began in the late 1980s. For a few crops, including asparagus, broccoli, lettuce, strawberries, plums, and Christmas trees, there were no federal data or data from the seven states before the 1990s., Conclusions: We conclude that identifying probable pesticide exposures is feasible in some locations. However, the lack of pesticide use data before the 1990s for many crops will limit the quality of historic exposure assessment for most workers., (Published 2001 Wiley-Liss, Inc.)

Background: Childhood cancer, notably leukemia, brain cancer, non-Hodgkin's lymphoma, soft tissue sarcoma, and Hodgkin's disease, has been associated with pesticide exposure, often with greater relative risks than among exposed adults, suggesting greater susceptibility in children. These differences in risk may be due to developmental factors or differences in pesticide exposure., Methods: A feasibility study was conducted to determine levels of pesticide metabolites in urine of adults (n = 18) and children (n = 9) in Fresno County, California, an intensely agricultural county in the Central San Joaquin Valley. Spot urine samples were obtained and analyzed for six metabolites of organophosphate (OP) pesticides using gas chromatography with flame photometric detection methods. The metabolites of OP pesticides included DMP, DEP, DMTP, DMDTP, DETP, and DEDTP., Results: Levels were generally low for both adults and children for most metabolites tested. Frequencies of detection ranged from 0 to 37%, with mean levels ranging from non-detectable to 13.22 ppb. However, levels of several metabolites were higher in children than in adults. The most frequently detected metabolite, DMP, was found among 44% of the children and 33% of the adults. DMTP was detected among 33% of the children and 28% of the adults., Conclusions: These results are difficult to interpret given the sampling variation associated with the small sample size. Nevertheless, because OP pesticides have been associated with increased cancer risk in animal and human studies, these results indicate a need to closely monitor children's exposure to environmental chemicals., (Copyright 2001 Wiley-Liss, Inc.)

Background: US migrant and seasonal farmworkers may be exposed to potentially carcinogenic pesticides and other agents. Little epidemiologic research has been conducted on this population., Methods: We examined the proportionate mortality of 26,148 subjects (14,631 white men (WM), 7,299 nonwhite men (NM), 1,081 white women (WW), and 3,137 nonwhite women (NW)) who were identified as farmworkers on death certificates from 24 US states during 1984-1993., Results: Farmworkers had significantly elevated proportionate mortality from injuries, tuberculosis, mental disorders, cerebrovascular disease, respiratory diseases, ulcers, hypertension (NW), and cirrhosis (NW). There was significantly reduced mortality from infectious diseases (other than tuberculosis), endocrine disorders, nervous system diseases, pneumoconioses, arteriosclerotic heart disease (WM), and all cancers combined. Proportionate cancer mortality analyses found excess cancers of the buccal cavity, larynx, esophagus, stomach, skin (NW), and cervix, and deficits for cancers of the colon, breast, kidney, pancreas (NW), and lymphohematopoietic system., Conclusions: The excess deaths from injuries, respiratory disease, and stomach cancer, and the deficits of colon cancer and arteriosclerotic heart disease among farmworkers, are consistent with typical mortality patterns previously observed among farm owner/operators. The excess buccal, laryngeal, esophageal, and cervical cancers, and the deficits of breast cancer and lymphohematopoietic cancers have not generally been observed in studies of farm owner/operators., (Published 2001 Wiley-Liss, Inc.)

Background: Specialized methods are necessary to collect data from migrant farmworkers for epidemiologic research., Methods: We developed a questionnaire that collected lifetime occupational histories and other lifestyle risk factors via a life events/icon calendar, and administered the questionnaire to a convenience sample of 162 migrant farmworkers in nine areas of the U.S., Results: The average duration of the interviews was about 1 h 30 min, with an average of 45 min for the work history section. The occupational histories covered a median of 27.6 years per person for men and 20.8 years per person for women. The median number of years spent in farm jobs was 11.3 for men and 5.8 for women. The median number of farm jobs (crop/task combination) per person was 59 among men and 27 among women. Many farmworkers performed the same crop/task combinations at multiple times throughout their lives, yielding a median of 13 unique farm jobs and 8 unique crops among men and 7 jobs and 5 crops among women., Conclusions: The project demonstrated that it is feasible to collect detailed work histories and other risk factor data from farmworkers, documented the complexity of work histories encountered among farmworkers, and yielded recommendations for refining a questionnaire that will facilitate future epidemiologic research on farmworkers., (Copyright 2001 Wiley-Liss, Inc.)

Background: Self-reported work histories can be critical for both epidemiologic and clinical purposes. However, the complexity of some work histories, such as those of migrant farm workers, can hamper recall, resulting in inaccurate reporting. Memory aids may reduce such error. This study assesses the reliability of work histories collected using such aids in the form of an icon/calendar-based questionnaire., Methods: Thirty-one males engaged in farmwork and other manual labor for a median 28 years (range: 10-64) were interviewed twice, 8-14 months apart, about their lifetime employment. In each interview, subjects were asked about important life events, which were recorded with icons on a calendar. They were then asked to recount their work history, including for each job the tasks, crops or products handled, starting and ending dates, and location. This information was recorded, job-by-job, on the calendar with icons., Results: Interquestionnaire agreement of cumulative reported employment duration (as measured by the correlation coefficient) was moderate to high across all time periods for certain crops (e.g., r = 0.69-0.92 for apple-related work), by location (e.g., r = 0.76-0.95 for Washington State), and for agricultural work in general (r = 0.67-0.94), but was lower for specific tasks. Agreement of job counts was high for total work history for certain crops (e.g., r = 0.93 for apple-related work), by location (e.g., r = 0.90 for Washington State), and for agricultural work in general (r = 0.89), but paradoxically decreased with proximity to the interview date. Agreement of both measures tended to be highest for those tasks and crops in which subjects reported spending the most time. Categorization of subjects into tertiles on the basis of either cumulative duration or counts produced results similar to those observed for job counts., Conclusions: The icon-calendar questionnaire is an effective tool for estimating cumulative duration of certain work categorizations among subjects with complex work histories., (Published 2001 Wiley-Liss, Inc.)

Background: In response to The National Cancer Institute (NCI) concerns about the ability to conduct studies among migrant farmworkers, this study evaluated the feasibility of identifying migrant farmworkers in their home state and tracing them over an extended period of time., Methods: In 1995, a group of 196 persons who had classified themselves as "migrant farmworkers" in two earlier chronic disease studies was identified. The primary objective of the current study was to determine the proportion of these farmworkers who could be located in 1995-1996., Results: Of these farmworkers, 163 were located and were living (83.2%), 15 had died (7.6%), and 18 (9.2%) were lost to follow-up., Conclusions: The excellent follow-up rate was due in part to the high participation rates among persons contacted for information, stability of the farmworkers' permanent homes, predictable timing of migration, and a longstanding health research program with established community contacts., (Copyright 2001 Wiley-Liss, Inc.)

Background: Self-reported work histories are an essential tool for estimating exposure in many occupational epidemiologic studies. However, the transience of some occupations such as farm work can hamper recall, resulting in inaccurate reporting. To address this problem, we have developed an icon/calendar-based questionnaire. This study compares work histories collected via this questionnaire to those collected via a traditional questionnaire., Methods: Eighty-nine farmworkers and non-farmworkers were interviewed twice, 8-10 months apart, about their lifetime employment. In the first interview, subjects were asked to recount their entire work history, starting from the interview date and moving backwards in time ("traditional questionnaire"). In the second interview, subjects were first asked about important life events, which were recorded with icons on a calendar. They were then asked to recount their work history, which was recorded, job-by-job, on the calendar with icons ("icon-calendar questionnaire")., Results: Number of jobs and amount of work time accounted for since first employment were significantly greater using the icon-calendar questionnaire than the traditional questionnaire, the disparity increasing with time from the date of interview. The ratio of number of jobs in the traditional questionnaire to number of jobs in the icon-calendar questionnaire decreased from 100.0% in the most recent time period to 0.0% in the earliest time period. While the percentage of time explained by employment remained relatively constant across time periods in the icon-calendar questionnaire, ranging from 86.3 to 98.9%, it rapidly decreased with time in the traditional questionnaire, from 77.9% in the most recent time period to 0.0% in the earliest time period., Conclusions: The icon-calendar questionnaire was more effective than the traditional questionnaire for obtaining complex work histories during interviews, producing a more complete picture of a person's work history., (Published 2001 Wiley-Liss, Inc.)

Background: To design questionnaires for epidemiologic research among children of migrant farmworkers, researchers need to consider ways to best solicit information about pesticide exposures., Methods: Bilingual facilitators conducted five focus groups with either migrant farmworker mothers or their children (age range 8-16 years) in southern Texas and northeastern Colorado. Guided questions were used to assess activities of migrant farmworker children and the ways to best elicit information about exposure to pesticides., Results: Participants reported a large number of activities that may potentially expose children to pesticides through both direct and indirect routes. Prompting, indirect questions about chemical use, and use of local and trusted facilitators increased information elicited from focus group participants., Conclusions: These focus groups helped to provide information for developing questionnaire items related to pesticide exposure among migrant farmworker children, and highlighted the importance of using bilingual community interviewers and including children as respondents., (Copyright 2001 Wiley-Liss, Inc.)

Background: Epidemiologic studies often must rely upon questionnaire data to assess past exposures. The ability of questionnaires to rank migrant farmworkers according to past pesticide exposure is not known., Methods: We conducted a pilot feasibility study to measure a panel of 21 organochlorine pesticides (OCPs) and correlate levels with reported occupational exposures in 26 Mexican-American migrant farmworkers in Baytown, Texas. The Migrant Farmworker Questionnaire developed by the National Cancer Institute (NCI) was administered and each participant donated a blood sample. Three OCPs [mean (ppb) levels: mirex 1.8, DDT 1.0, and trans-nonachlor 0.7] were detected despite the fact that these chemicals have been banned in the US for many years, and the detected levels were far higher than the standard provided by the referent laboratory. Work clothes, protective attire, and self-reported pesticide exposures were significant predictors of OCP exposure. Similarly, personal hygiene, length of employment, and number of duties also predicted OCP exposure., Conclusions: The results of this study indicate that data obtained from standardized questionnaires may be reasonable indicators of occupational exposure when biomarker data are not available., (Copyright 2001 Wiley-Liss, Inc.)

Recent epidemiological studies have suggested an increased risk of non-Hodgkin lymphoma (NHL) from carbamate insecticide use among farmers. To further explore the possible relationships, we conducted a pooled analysis of three population-based case-control studies conducted in four midwestern states in the United States. A total of 985 white male subjects and 2895 control subjects were included in this analysis. Unconditional logistic regression was used to estimate the association and control for confounding. Compared with nonfarmers, farmers who had ever used carbamate pesticides had a 30% to 50% increased risk of NHL, whereas farmers without carbamate pesticide use showed no increased risk. Analyses for individual carbamate pesticides found a more consistent association with Sevin but not carbofuran, butylate, or S-ethyl dipropylthiocarbamate plus protectant. Among farmers using Sevin, the risk of NHL was limited to those who personally handled the product, those who first used the product for > or = 20 years before their disease diagnosis, and those who used the product for a longer period. These associations persisted after adjusting for other major classes of pesticides. These results suggest an increased risk of NHL associated with carbamate pesticide use, particularly Sevin. Further investigation of the association is warranted.

Background: Fire fighters are exposed to a wide variety of toxic chemicals. Previous studies have reported excess risk of some cancers but have been limited by small numbers or little information on employment characteristics., Methods: We conducted a retrospective cohort mortality study among 7,789 Philadelphia firefighters employed between 1925 and 1986. For each cause of death, the standardized mortality ratios (SMRs) and 95% confidence intervals were estimated. We also compared mortality among groups of firefighters defined by the estimated number of career runs and potential for diesel exposure., Results: In comparison with U.S. white men, the firefighters had similar mortality from all causes of death combined (SMR = 0.96) and all cancers (SMR = 1.10). There were statistically significant deficits of deaths from nervous system diseases (SMR = 0.47), cerebrovascular diseases (SMR = 0.83), respiratory diseases (SMR = 0.67), genitourinary diseases (SMR = 0.54), all accidents (SMR = 0.72), and suicide (SMR = 0.66). Statistically significant excess risks were observed for colon cancer (SMR = 1.51) and ischemic heart disease (SMR = 1.09). The risks of mortality from colon cancer (SMR = 1.68), kidney cancer (SMR = 2.20), non-Hodgkin's lymphoma (SMR = 1.72), multiple myeloma (SMR = 2.31), and benign neoplasms (SMR = 2.54) were increased among firefighters with at least 20 years of service., Conclusions: Our study found no significant increase in overall mortality among Philadelphia firefighters. However, we observed increased mortality for cancers of the colon and kidney, non-Hodgkin's lymphoma and multiple myeloma. There was insufficient follow-up since the introduction of diesel equipment to adequately assess risk.

Experimental studies show that hormonal and nonhormonal activities of polychlorinated biphenyls (PCBs) are structure dependent, suggesting that the breast cancer risk associated with PCBs may vary according to specific PCB congeners. In 1994-1997, the authors conducted a case-control study of Connecticut women to investigate whether breast cancer risk is associated with body burden of PCBs and varies by PCB congeners. A total of 304 breast cancer cases and 186 controls aged 40-79 years were recruited into the study. Fresh breast adipose tissue was analyzed for PCBs. The age- and lipid-adjusted geometric mean tissue levels of total PCBs were not significantly different (p = 0.46) for the cases (478.6 parts per billion) and controls (494.1 parts per billion). The covariate-adjusted odds ratio was 0.7 (95% confidence interval: 0.4, 1.1) for all study participants when the third tertile was compared with the lowest tertile. No individual congeners or groups of congeners were associated with a significantly increased risk of breast cancer. Further stratification by type of breast disease; menopausal, parity, and lactation status; and body size also showed no significant association with body levels of PCBs. These results suggest that environmental exposure to PCBs may not substantially affect breast cancer risk.

This case-control study was designed to investigate the relationship between polychlorinated biphenyls (PCBs) and 1,1-dichloro-2,2'-bis(p-chlorophenyl)ethylene (DDE) and breast cancer risk in Connecticut. Cases were incident breast cancer patients who were either residents of Tolland County or who had a breast-related surgery at the Yale-New Haven Hospital in New Haven County. Controls were randomly selected from Tolland County residents or from patients who had newly diagnosed benign breast diseases or normal tissue at Yale-New Haven Hospital. A total of 475 cases and 502 controls had their serum samples analyzed for PCBs and DDE in 1995-1997. The age- and lipid-adjusted geometric mean serum level of DDE was comparable between the cases (460.1 ppb) and controls (456.2 ppb). The geometric mean serum level of PCBs was also comparable between cases (733.1 ppb) and controls (747.6 ppb). After adjustment for confounding factors, odds ratios of 0.96 (95% confidence interval, 0.67-1.36) for DDE and 0.95 (95% confidence interval, 0.68-1.32) for PCBs were observed when the third tertile was compared with the lowest. Further stratification by parity, lactation, and menopausal and estrogen receptor status also showed no significant association with serum levels of DDE or PCBs. The results by PCB congener groups also showed no major increased risk associated with any of the congener groups. Our study does not support the hypothesis that DDE and PCBs, as encountered through environmental exposure, increase the risk of female breast cancer.

Background: Organochlorine compounds, including organochlorine pesticides, have been suggested by some, but not all, studies to be associated with female breast-cancer risk. So far, studies relating organochlorine compounds and breast-cancer risk have mainly focused on polychlorinated biphenyls (PCBs) and dichlorodiphenyltrichloroethane (DDT) as risk factors for female breast cancer. This paper examines the hypothesis that environmental exposure to trans-nonachlor (TNC) and oxychlordane (OCD), a major metabolite of the insecticide chlordane, increases the, Methods: A total of 304 histologically confirmed, incident primary breast-cancer patients and 186 histologically confirmed incident benign breast-disease controls were included in the study between 1994 and 1997. Breast adipose tissue not needed for diagnostic purposes was collected and analysed for TNC, OCD and other organochlorine compounds. A standardised, structured questionnaire was used to obtain information on major known, or suspected, risk factors for breast cancer., Results: The age and lipid-adjusted geometric mean adipose-tissue levels of OCD were similar between the cases [36.4 p.p.b., 95% confidence interval (CI) 34.7-38.2 p.p.b.] and controls (38.0 p.p.b., 95% Cl 35.7-40.6 p.p.b.). The age and lipid-adjusted geometric mean adipose-tissue levels of TNC between the cases (55.5 p.p.b., 95% CI 52.6-58.5 p.p.b.) and controls (58.1 p.p.b., 95% CI 54.2-62.3 p.p.b.) were also similar. There was no association between breast-cancer risk and mean adipose-tissue levels of OCD and TNC. The covariate-adjusted odds ratio (OR) was 0.7 (95% CI 0.4-1.3) for OCD and 1.1 (95% CI 0.6-1.9) for TNC, when the highest quartile was compared with the lowest. The risk also did not vary based on oestrogen or progesterone receptor status or menopausal status., Discussion: We found no significantly increased risk of breast cancer associated with breast adipose-tissue levels of OCD or TNC; this is consistent with recent epidemiological studies, indicating that environmental exposure to organochlorine compounds does not have an overall significant impact on breast-cancer risk.

Occupational studies have identified many of the established chemical carcinogens. Studies in the next millennium will be needed to identify the hazardous agents in occupations known to have high cancer rates, to assess human risks from animal carcinogens that have not been well evaluated epidemiologically, to provide information on women and minorities, to evaluate interactions with genetic factors and other risk factors, to contribute to our understanding of risks from the spread of chemicals from the workplace to the general environment, and to identify mechanisms of cancer. The traditional retrospective cohort design will be insufficient to meet these needs. Population-based case-control, nested case-control, prospective cohorts, and cross-sectional designs will assume more important roles because of the need to collect information on nonoccupational risk factors and biological tissues. Improvement in the assessment of quantitative exposures is needed for the efficient evaluation of interactions between occupational exposures, genetic factors, and nonoccupational exposures.

Background: The relation between occupational exposure and pancreatic cancer is not well established. A population-based case-control study based on death certificates from 24 U.S. states was conducted to determine if occupations/industries or work-related exposures to solvents were associated with pancreatic cancer death., Methods: The cases were 63,097 persons who died from pancreatic cancer occurring in the period 1984-1993. The controls were 252,386 persons who died from causes other than cancer in the same time period., Results: Industries associated with significantly increased risk of pancreatic cancer included printing and paper manufacturing; chemical, petroleum, and related processing; transport, communication, and public service; wholesale and retail trades; and medical and other health-related services. Occupations associated with significantly increased risk included managerial, administrative, and other professional occupations; technical occupations; and sales, clerical, and other administrative support occupations. Potential exposures to formaldehyde and other solvents were assessed by using a job exposure matrix developed for this study. Occupational exposure to formaldehyde was associated with a moderately increased risk of pancreatic cancer, with ORs of 1.2, 1.2, 1.4 for subjects with low, medium, and high probabilities of exposure and 1.2, 1.2, and 1.1 for subjects with low, medium, and high intensity of exposure, respectively., Conclusions: The findings of this study did not suggest that industrial or occupational exposure is a major contributor to the etiology of pancreatic cancer. Further study may be needed to confirm the positive association between formaldehyde exposure and pancreatic cancer. Published 1999 Wiley-Liss, Inc.

Background: This study evaluates cancer mortality among women employed in two large printing plants in Moscow., Methods: A total of 3,473 women who were actively employed as of December 31, 1978, with a minimum of 2 years employment were followed from 1 January 1979 to 31 December 1993. There were 47,791 person-years observed, with only 51 women lost to follow-up (1.5%). Standardized mortality ratios (SMRs) were calculated using the population of Moscow to generate expected numbers. Analyses by job (compositors, press operators, and bookbinders), age hired, latency, and duration of employment were conducted., Results: Among women employed in the two printing plants, there was a significant excess of esophageal cancer, based on seven deaths (expected = 2.7, SMR = 2.7, 95% CI = 1.1-5.4). Four of the seven esophageal cancer deaths occurred among bookbinders (expected = 1.0, SMR = 4.1, 95% CI = 1.1-10.4), all among workers hired before 1957 (expected = 0.6, SMR = 7.1, 95% CI = 1.9-18.3), the last year benzene was used in bookbinding. Ovarian cancer was also significantly elevated among bookbinders (12 observed, 4.2 expected, SMR = 2.9, 95% CI = 1.5-5.0), which, along with one death from mesothelioma of the abdomen, might be related to the use of asbestos-contaminated talc fillers in paper. Press operators had significantly elevated mortality from stomach cancer (observed = 9, expected = 4.1, SMR = 2.2, 95% CI = 1.0-4.2) and, based on two deaths each, melanoma and bladder cancer., Conclusions: Women in this printing industry cohort experienced excess mortality of cancer of the esophagus and stomach, with suggested increases of melanoma and bladder cancer. Further follow-up of this cohort, which would allow more in-depth analysis of rare cancer sites, latency, and duration of employment, is warranted. Gender comparisons within the cohort should also be conducted to clarify the role of occupational and lifestyle factors in the etiology of cancer among workers in the printing industry.

Background: Health care workers are potentially exposed to a number of carcinogens. Studies among women in this field have focused on white nurses; however, workers in many health care occupations share exposures experienced by nurses., Methods: Cancer mortality was examined among female health care workers using death certificate data collected in 24 U.S. states from 1984 through 1993. Cancer mortality odds ratios (MORs) were calculated by race (white, black) and age group., Results: White nurses had a 30% elevation of mortality due to liver cancer and myeloid leukemia. White registered nurses (RNs) had a small excess and white licensed practical nurses (LPNs) had a small deficit of mortality due to breast cancer. Ovarian cancer was in excess among RNs, but decreased among LPNs. Among black nurses, excesses of death due to kidney cancer (MOR = 1.7) and multiple myeloma (MOR = 1.3), and a significant 50% deficit in mortality due to cancer of the esophagus were found. Black RNs, but not LPNs, had an excess of breast cancer (MOR = 1.3; 95% CI = 1.0-1.5). Ovarian cancer was elevated by 30% in both RNs and LPNs. Excess deaths due to cancers of the breast, ovary, and uterus occurred among white physicians. Among black physicians, lung cancer was significantly elevated (MOR = 2.8). White pharmacists had significant excesses of breast (MOR = 1.5) and ovarian (MOR = 2.4) cancers, and myeloid leukemia (MOR = 2.0). White clinical laboratory technicians had excess deaths from several cancers. The greatest excess was for myeloid leukemia (MOR = 2.3; 95% CI = 1.5-3.4). Excesses among radiologic technologists included cancers of the lung, pancreas, breast, uterus, and ovary., Conclusion: Several findings reported here warrant further investigation. In particular, excesses of myeloid leukemia among nurses, pharmacists, and clinical laboratory technicians and liver cancer among nurses should be investigated in studies with data on occupational and other exposures. Patterns of mortality from breast and ovarian cancer found in this study must be evaluated further in studies with data on reproductive history.

Occupational causes of cancer have not been well-evaluated among women. An increase in the number of women in the work force in jobs with potentially hazardous exposures during the past few decades raises the question as to whether there is a need to enhance our efforts in this area. The inability to evaluate occupational causes of female gynecologic tumors in studies of men, plus the potential for variation in outcome responses between men and women because of gender-based exposure and susceptibility differences, underscore the need for investigations specifically focused on women. Investigations of occupational exposures and cancer risk among women may require design considerations that differ somewhat from studies of men. Issues to consider include the impact of studying outcomes with high survival (e.g., breast cancer), gender-specific exposure patterns and toxicokinetic processing of some chemicals, special limitations in the use of the general population as the referent, and the need to control for established risk factors for gynecologic tumors.

Background: Our aim was to evaluate whether there is a healthy worker effect (HWE) for cancer incidence among women. HWE is a bias found in occupational studies that compare rates of disease among employed people to disease rates for the general population, which includes unemployed people (who may be less healthy than those who are employed)., Methods: Data from the 1960 and 1970 Swedish censuses were used to identify all 1,659,940 Swedish women who were employed in either year. They were followed during 1971-1989 through linkages to the national cancer and death registers. Standardized incidence ratios (SIRs) were computed comparing employed women to the 1,627,873 women who were not employed in either 1960 or 1970., Results: For the 545,857 women employed in both 1960 and 1970, the SIR for all cancers combined was 1.05 (1.04-1.06). When specific cancer sites were analyzed separately, the highest cancer risks were for cancers of the lung and bladder (SIR = 1.2) and reproductive organs (breast, ovary, endometrium, and cervix SIR = 1.1). Overall cancer risks were highest among full-time workers, younger workers, urban workers, and workers with the highest socioeconomic status (based on the woman's job title)., Conclusions: These results show no general HWE for cancer incidence among employed Swedish women.

Earlier studies have provided inconclusive results relating hexachlorobenzene (HCB), an organochlorine fungicide, to female breast cancer risk. The current study, with a total of 304 breast cancer cases and 186 controls recruited in Connecticut between 1994 and 1997, examined the association by directly comparing breast adipose tissue levels of HCB between incident breast cancer cases and noncancer controls. The cases and controls were patients who had breast biopsies or surgery at the Yale-New Haven Hospital (New Haven, CT) and histologically diagnosed either as breast cancer or benign breast disease. Information on major known or suspected risk factors for breast cancer was obtained through in-person interview by trained interviewers. No significant difference in mean breast adipose tissue levels of HCB was observed between breast cancer patients (21.0 ppb) and controls (19.1 ppb) in this large case-control study. The risk also did not vary significantly by menopausal status, estrogen or progesterone receptor status of the breast cancer cases, breast cancer histology, stage of diagnosis, or type of benign breast disease. Among parous women who reported ever breast feeding, an odds ratio (OR) of 0.5 [95% confidence interval (CI), 0.2-1.4] was observed when the highest quartile was compared with the lowest quartile. However, no association was observed among parous women who reported never breast feeding (OR = 0.7; 95% CI, 0.3-1.7 for the fourth quartile). For nulliparous women, the adjusted OR was 2.1 (95% CI, 0.5-8.8) for the third tertile when compared with the lowest based on few subjects. Therefore, our study does not support a positive association between environmental exposure to HCB and risk of breast cancer.

Purpose: The purpose of this study was to evaluate the role of physical activity in the development of non-Hodgkin's lymphoma (NHL)., Methods: Incident NHL cases and population-based controls were identified from three case-control studies conducted in four midwestern states: Iowa, Kansas, Minnesota, and Nebraska. A total of 1177 cases (993 men, 184 women) and 3625 controls (2918 men, 707 women) were interviewed. Usual occupation (all states) and lifetime occupational histories (Iowa and Minnesota only), obtained from interviews, were classified for energy expenditure (EE) and sitting time. Odds ratios (OR) and 95% confidence intervals were calculated comparing moderate and high activity levels with sedentary levels., Results: There was no evidence of an association between NHL and occupational physical activity measured either by EE or sitting time. Among men, the OR associated with usual occupation moderate and high EE were 1.1 and 1.0, respectively. For sitting time, the OR were also 1.1 and 1.0 for moderate and high activity, respectively. Among women, slight nonsignificant elevations in risk of NHL were observed among the high energy level and high activity sitting categories. The trends were not significant. There was no evidence of confounding or effect modification by vital status, hair dye use, or solvent exposure. Among subjects with lifetime occupational histories, there were no significant increases or trends for cumulative or average EE or sitting time. There was no association between occupational physical activity and NHL., Conclusion: Research on nonoccupational physical activity, which in the U.S. is likely the more important component of daily activity than occupational activity, may still be warranted given the laboratory evidence linking physical activity and immune function, an important factor in the etiology of NHL.

Indirect evidence, notably ecological comparisons and an association with skin cancer, links non-Hodgkin's lymphoma (NHL) with exposure to sunlight. We conducted a population-based, nationwide cohort study with exposure to outdoor work inferred from job titles reported in the population and housing censuses in 1960 and/or 1970 and by classifying each individual's work and home addresses according to latitude. Follow-up for cancer incidence was accomplished through record linkages with the virtually complete Swedish Cancer Registry. The cohort included all Swedish residents who were recorded as gainfully employed in both censuses. Altogether 4,171,175 individuals contributing 69,639,237 person-years accrued through 1989 were included in the analyses. We identified 10,381 cases of NHL, 4,018 cases of chronic lymphocytic leukemia (CLL), 11,398 cases of malignant melanoma (MM) and 11,913 cases of squamous cell skin cancer (SCC). We calculated age-adjusted relative risks for NHL, CLL, MM and SCC in strata based on estimated residential and occupational sunlight exposure. Interaction effects were considered for pesticide and solvent exposure. NHL, MM and SCC, but not CLL, were positively associated with increasingly southerly residential latitude, with stronger associations seen for skin cancer compared to NHL. Occupational sun exposure was not associated with the risk of developing any of the studied cancers. Pesticides and solvents also were not related to an increased risk of NHL, nor did these exposures enhance effects of residential or occupational sunlight exposure. Our results provide some support for an association of sunlight exposure with NHL incidence based on the associations seen using geographic latitude of residence as a proxy for exposure. Although type of occupation may be an imperfect index of the biologically relevant ultraviolet (UV) light dose, our data on individual exposure are not consistent with an important role of sunlight in the etiology of NHL.

Part of an investigation of data collection methods in epidemiologic studies of farmers evaluated exposures received by farmers from the application of insecticides to animals. Twenty farmers were monitored during a normal application using a fluorescent dye surrogate for the active ingredient (AI). Two exposure measures were estimated, AI concentration and the time-weighted average for the application period (TWAa). Four application methods were used: high- (n = 5) and low-pressure (n = 3) spraying, backpack (n = 2) and pour-on (n = 10). The two farmers using a backpack sprayer had nondetectable levels of dye. Only two of the farmers using the pour-on method had detectable dye levels, but these levels were high. All of the low- and high-pressure sprayers had detectable amounts of dye. Multiple layers of clothing, gloves, and boots (n = 10) were associated with a low mean AI concentration for the exposed farmers (18 micrograms) and more than two-thirds of the farmers wearing this amount of clothing had nondetectable exposures. In contrast, clothing providing little or no protection was associated with a significantly higher (p < 0.01) average AI concentration (4420 micrograms), and less than a third of the farmers with this degree of protection had nondetectable exposures. Poor work practices (leaking equipment, contact with wet animals or fences, and back splash) were associated with statistically higher exposure levels (p < 0.01) than the absence of such practices. There was a moderate statistically significant association between AI concentration and TWAa with total volume of the AI/dye/water mixture using the Spearman coefficient. Time was significantly inversely proportional to the two exposure measures. The association between the two exposure measures and AI volume was not significant.

Data on recent and historic pesticide use, pesticide application methods, and farm characteristics were collected from 35,879 restricted-use pesticide applicators in the first 2 years of the Agricultural Health Study, a prospective study of a large cohort of private and commercial licensed pesticide applicators that is being conducted in Iowa and North Carolina. (In Iowa, applicators are actually "certified," while in North Carolina they are "licensed"; for ease of reference the term license will be used for both states in this paper.) Commercial applicators (studied in Iowa only) apply pesticides more days per year than private applicators in either state. When the types of pesticides being used by different groups are compared using the Spearman coefficient of determination (r2), we find that Iowa private and Iowa commercial applicators tend to use the same type of pesticides (r2=0.88). White and nonwhite private applicators tended to use the same type of pesticides (North Carolina r2=0.89), as did male and female private applicators (Iowa r2=0.85 and North Carolina r2=0.84). There was less similarity (r2=0. 50) between the types of pesticides being used by Iowa and North Carolina private applicators. A greater portion of Iowa private applicators use personal protective equipment than do North Carolina private applicators, and pesticide application methods varied by state. This heterogeneity in potential exposures to pesticides between states should be useful for subsequent epidemiologic analyses using internal comparison groups., (Copyright 1999 Academic Press.)

Background: Families of farmer pesticide applicators have unusual opportunities for exposure, directly or indirectly, to pesticides. These exposures are not well characterized., Methods: Subjects were 26,793 licensed private pesticide applicators enrolled in the Agricultural Health Study, a cohort study being conducted in Iowa and North Carolina. Questionnaires were completed by the applicators and their spouses., Results: Many indirect exposure opportunities exist; for example, 21% of homes are within 50 yards of pesticide mixing areas, 27% of applicators store pesticides in their homes, and 94% of clothing worn for pesticide work is washed in the same machine as other laundry. Direct exposure opportunities also occur; for example, 51% of wives of applicators worked in the fields in the last growing season, 40% of wives have ever mixed or applied pesticides, and over half of children aged 11 or more do farm chores., Discussion/conclusions: The extent of the opportunities for exposure of family members of farmer pesticide applicators makes studies of their health important.

Background: Precise and valid exposure assessment is generally the primary challenge in retrospective occupational epidemiology studies, particularly when the only available method for exposure characterization is a personal interview. Agricultural workers may represent a particular challenge; for example, whereas many farmers have worked from childhood at the same location, raising the same crops and animals, they may have used different equipment, chemicals, and protective gear over time. One method to assist in recall is the "life events calendar," a cognitive tool based on the subject's own life history to help anchor occupational activities in time., Methods: Unstructured interviews of farmers, focus groups, and pilot interviews among rural men, primarily African-Americans, were conducted to create a questionnaire for obtaining farm history information within the context of personal life events., Results: Farmers used both personal events and national events (as well as events relating directly to farming) to recall their activities. These subjects had extensive history of farming (10-75 years) and chemical use (median lifetime chemicals = 13)., Conclusion: The life events calendar provided a useful tool to facilitate the recall of a lifetime of agricultural activity. Life events calendars are useful additions to the tools available for retrospective occupational exposure assessment.

We conducted a study of occupation and mortality from reproductive cancers among women, based on death certificates from 24 US states for the period 1984-1993. There were 9,523 cervical cancer deaths, 12,335 endometrial cancer deaths, and 25,212 ovarian cancer deaths. Usual occupation and industry, which were obtained from death certificates, were coded using the 1980 Bureau of Census classification system. Mortality odds ratios (MORs) and 95% confidence intervals (CIs) were calculated, using all non-cancer deaths as the referent disease category. In general, jobs involving professional or administrative occupations were related to increased risk of mortality from endometrial and ovarian cancer, while cervical cancer mortality was increased among women employed in manufacturing, service, farm work, and health care technician and aide occupations. Associations with some occupations involving exposure to chemicals and metals, such as the associations between cervical cancer and employment in printing, typesetting, and machine operating occupations, deserve further attention. Similarly, further investigations should be made into the excess of ovarian cancer observed in several occupations in health care, an industry that has numerous hazardous exposures, including radiation, chemotherapeutic drugs, and viruses. The study results reflect, in part, socioeconomic factors and reproductive patterns but may also indicate a possible etiologic role for occupational chemical exposures.

Data from population-based case-control studies of non-Hodgkin's lymphoma among white men from Kansas, Nebraska, Iowa, and Minnesota were pooled to evaluate potential risks from environmental exposures in more detail, while controlling for potential confounding factors. These data provided the opportunity to evaluate the risk of non-Hodgkin's lymphoma from potential exposures to lindane, a pesticide that causes cancer in laboratory animals and has been associated with human cancer in a few epidemiologic investigations. This pooled data set includes 987 individuals with non-Hodgkin's lymphoma and 2,895 population-based controls. Information was obtained by telephone or in person interviews, which included detailed questions on farm practices and agricultural use of chemicals. Logistic regression was used to calculate odds ratios (ORs) adjusted for age, state of residence, and subject or proxy interviews. Reported use of lindane significantly increased the risk of non-Hodgkin's's lymphoma by 50%. Some use characteristics were suggestive of an association. ORs were greater among persons who first used the pesticide 20 years before diagnosis (OR = 1.7) than more recently (OR = 1.3), among those who reported more frequent use (OR = 2.0 for use 5 or more days per year versus 1.6 for fewer than five days per year), and from use on crops (OR = 1.9), rather than from use on animals (OR = 1.3), although these differences were not statistically significant. On the other hand, ORs were lower when based on direct interviews (OR = 1.3) than on data from proxy respondents (OR = 2.1) and adjustment for potential confounding by use of 2,4-D and diazinon reduced the ORs associated with lindane use from 1.5 to 1.2 and 1.3, respectively. Lindane does not appear to be a major etiologic factor in the development of non-Hodgkin's's lymphoma, although a small role cannot be ruled out.