Mortality in a cohort of licensed pesticide applicators in Florida

Disparities in Acute and Chronic Complications of Diabetes Along the U.S. Rural-Urban Continuum

OBJECTIVE

To determine the relative hazards of acute and chronic diabetes complications among people with diabetes across the U.S. rural-urban continuum.

RESEARCH DESIGN AND METHODS

This retrospective cohort study used the OptumLabs Data Warehouse, a deidentified data set of U.S. commercial and Medicare Advantage beneficiaries, to follow 2,901,563 adults (age ≥18 years) with diabetes between 1 January 2012 and 31 December 2021. We compared adjusted hazard ratios (HRs) of diabetes complications in remote areas (population <2,500), small towns (population 2,500-50,000), and cities (population >50,000).

RESULTS

Compared with residents of cities, residents of remote areas had greater hazards of myocardial infarction (HR 1.06 [95% CI 1.02-1.10]) and revascularization (HR 1.04 [1.02-1.06]) but lower hazards of hyperglycemia (HR 0.90 [0.83-0.98]) and stroke (HR 0.91 [0.88-0.95]). Compared with cities, residents of small towns had greater hazards of hyperglycemia (HR 1.06 [1.02-1.10]), hypoglycemia (HR 1.15 [1.12-1.18]), end-stage kidney disease (HR 1.04 [1.03-1.06]), myocardial infarction (HR 1.10 [1.08-1.12]), heart failure (HR 1.05 [1.03-1.06]), amputation (HR 1.05 [1.02-1.09]), other lower-extremity complications (HR 1.02 [1.01-1.03]), and revascularization (HR 1.05 [1.04-1.06]) but a smaller hazard of stroke (HR 0.95 [0.94-0.97]). Compared with small towns, residents of remote areas had lower hazards of hyperglycemia (HR 0.85 [0.78-0.93]), hypoglycemia (HR 0.92 [0.87-0.97]), and heart failure (HR 0.94 [0.91-0.97]). Hazards of retinopathy and atrial fibrillation/flutter did not vary geographically.

CONCLUSIONS

Adults in small towns are disproportionately impacted by complications of diabetes. Future studies should probe for the reasons underlying these disparities.

Investigating the levels of organochlorine pesticides in human milk at three lactational stages: an intensive Ghanaian study

During breastfeeding, the human breasts secrete three different kinds of milk. Research indicates that newborns exposed to organochlorine pesticides (OCPs) during developmental stages, even at low concentrations, may suffer irreparable harm. The study aimed to ascertain whether OCPs levels in human milk vary across lactational stages. University of Health and Allied Sciences Research Ethics Committee (UHAS- REC) examined and approved the study protocol. 47 volunteers were chosen using purposive sampling. Each participant donated 15 ml of each type of breast milk. Colostrum was taken shortly after delivery up to day 4, transitional milk between day 5 and two weeks postpartum, while mature milk was taken two weeks afterwards. A modified version of QuEChERS was used to process 10.0 g aliquot of each breast milk sample, and the resulting extracts analysed for OCPs employing a Gas Chromatograph, Varian CP 3800, fitted with electron capture detector (ECD). The detection threshold was not reached for any of the six OCPs tested. This implied that none of the breast milk components analysed in this study contained any detectable levels of OCPs that might have posed any serious health risks to the infants through breastfeeding. Aldrin, chlordane, DDT, dieldrin, endrin, and heptachlor were not found in detectable quantities in mothers' milk during the three stages of lactation. Our findings are encouraging. The study's findings likely show that the Stockholm Convention's campaign to remove POPs from the environment seems to be yielding positive impact.

The evidence for Mycobacterium avium subspecies paratuberculosis (MAP) as a cause of nonsolar uveal melanoma: a narrative review

Background and Objective

Animal microorganisms have been proposed as a cause of human cancers associated with farming, agricultural occupation or residence, and related downstream exposures. Several studies have described uveal melanoma (UvM) as a farming-associated cancer. A possible suspect is the animal microorganism Mycobacterium avium subspecies paratuberculosis (MAP), the causative agent of paratuberculosis in dairy cows. This microbe is transmitted to humans through various means, including contact with animal faeces, contaminated dust and soil, organic fertilizers, and as workers in slaughterhouses/animal processing facilities. The objective of the current manuscript was to examine the putative association between Mycobacterium avium sub-species paratuberculosis and non-solar UvM.

Methods

Online data sources (PubMed, Scopus, Cochrane Library, and Google) published in English between 1980 to present were searched for key words pertaining to MAP exposure, farming-related occupations and activities, and locations with or in the vicinity of dairy cattle.

Key Content and Findings

While higher than expected rates of eye cancer have been suggested among dairy farmers, with MAP being ubiquitous in their environment, the involvement of MAP in the aetiology of non-solar UvMs (which account for ~97% of UvM cases) remains uncertain.

Conclusions

Alternative explanations exist and future cause-and-effect research is needed to answer this hypothesis. A precautionary approach to exposure continues to be a prudent strategy.

Health of greenspace workers: Morbidity and mortality data from the AGRICAN cohort

INTRODUCTION

Knowledge on the health of greenspace workers is scarce, even though they are exposed to many occupational hazards. The aim of this study was to analyze mortality by cause, prevalence of some non-cancer diseases, and incidence of the main cancers among greenspace workers.

METHODS

A sub-cohort of greenspace workers was formed within the AGRICAN cohort. Demographic information, health characteristics and self-reported diseases at enrollment were described separately in terms of frequencies (%), median and Interquartile Range (IQR) for greenspace workers, farmers, and other non-agricultural workers. Causes of death and cancer incidence were identified through linkage with cancer registries from enrollment (2005-2007) to 2015. Hazard ratio (HR) and 95% Confidence Intervals [95% CI] were estimated using Cox proportional hazard regression with age as the underlying timescale.

RESULTS

The sub-cohort included 6247 greenspace workers who were higher proportion men, younger and more frequently smokers than farmers and non-agricultural workers. Male and female greenspace workers reported more history of allergic diseases; and males, more history of depression. Compared to other workers male greenspace workers showed a non-significant higher mortality from ischemic cardiological diseases (HR = 1.14 [0.81-1.60]). Incidence was higher in male greenspace workers than farmers for overall cancer (HR = 1.15 [1.04-1.27]), cancer of the prostate (HR = 1.21 [1.02-1.44]), thyroid (HR = 2.84 [1.26-6.41]), testis (HR = 3.98 [1.50-10.58]) and skin melanoma (HR = 2.15 [1.33-3.47]). Non-significant increased risks were also found for sarcomas, larynx and breast. In women, risk of breast cancer was higher in greenspace workers than in farmers (HR = 1.71 [1.17-2.50]).

CONCLUSIONS

Whereas greenspace workers have often been included with other pesticide applicators in epidemiological studies, our analyses highlighted the differences between these two populations. They demonstrate the need to study them separately and to investigate more thoroughly the role of specific occupational exposures such as pesticides as well as the effect on women.

Occupational pesticide exposure, cancer and chronic neurological disorders: A systematic review of epidemiological studies in greenspace workers

CONTEXT

The greenspace sector includes a broad range of occupations: gardeners, landscapers, municipal workers, maintenance operators of public facilities, golf-course employees and other sports facilities, horticulturists, plant and tree nursery workers etc. The health impact of occupational pesticide exposure has mainly been studied among farmers. Other professionals such as greenspace workers are also extremely exposed, presenting specific exposure features (practices, types of pesticide used). The aim of this review was to summarize epidemiological literature that examine the relationship between pesticide exposure and the risk of cancer and long-term health effects in greenspace workers.

METHOD

Six main groups of greenspace workers were identified and examined through a systematic literature review based on PubMed and Scopus. The studies were then grouped according to their design, health outcomes and the type of population studied.

RESULTS

Forty-four articles were selected among the 1679 identified. Fifteen studies were conducted exclusively among greenspace workers, while ten also studied these workers with other pesticide applicators. Six were cohorts from the general population in which greenspace workers were identified. Elevated risks were found in several studies for leukaemia, soft-tissue sarcoma, multiple myeloma, non-Hodgkin lymphoma and Parkinson's disease.

DISCUSSION

The majority of studies used rough parameters for defining exposure such as job titles which could lead to the misclassification of exposure, with the risk of false or positive negative conclusions. Health outcomes were mainly collected through registries or death certificates, and information regarding potential confounders was often missing.

CONCLUSION

The review identified only 15 studies conducted exclusively among greenspace workers. Elevated risk was found for several sites of cancer and Parkinson's diseases. Further epidemiological research is needed, conducted specifically on these workers, to better characterize this population, its exposure to pesticides and the related health effects.

Association between pesticide exposure and colorectal cancer risk and incidence: A systematic review

BACKGROUND

Studies investigating the association between pesticide exposure and colorectal cancer (CRC) risk have been inconclusive.

OBJECTIVES

Investigate the association between pesticide exposure and CRC risk through a systematic literature review.

METHODS

CRC has the fourth-highest rate of cancer-caused death in the US after lung cancer, breast cancer in women, and prostate cancer in men. Here we have conducted a systematic literature search on studies examining the association between any pesticide exposure and CRC risk using PubMed, MEDLINE via EBSCO host, and Embase according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses checklist.

RESULTS

Following the review, 139 articles were included for qualitative evaluation. Study participants were farmers, pesticide applicators, pesticide manufacturers, spouses of pesticide applicators, farm residents, Korean veterans of the Vietnam War, rural communities, and those who consumed food with pesticide residues. The studies' results were split between those with significant positive (39 significant results) and inverse (41 significant results) associations when comparing pesticide exposure and CRC risk.

DISCUSSION

From our literature review, we have identified a similar number of significant positive and inverse associations of pesticide exposure with CRC risk and therefore cannot conclude whether pesticide exposure has a positive or inverse association with CRC risk overall. However, certain pesticides such as terbufos, dicamba, trifluralin, S-ethyl dipropylthiocarbamate (EPTC), imazethapyr, chlorpyrifos, carbaryl, pendimethalin, and acetochlor are of great concern not only for their associated elevated risk of CRC, but also for the current legal usage in the United States (US). Aldicarb and dieldrin are of moderate concern for the positive associations with CRC risk, and also for the illegal usage or the detection on imported food products even though they have been banned in the US. Pesticides can linger in the soil, water, and air for weeks to years and, therefore, can lead to exposure to farmers, manufacturing workers, and those living in rural communities near these farms and factories. Approximately 60 million people in the US live in rural areas and all of the CRC mortality hotspots are within the rural communities. The CRC mortality rate is still increasing in the rural regions despite the overall decreasing of incidence and mortality of CRC elsewhere. Therefore, the results from this study on the relationship between pesticide exposure and CRC risk will help us to understand CRC health disparities.

Non-Hodgkin lymphoma among Brazilian agricultural workers: A death certificate case-control study

To estimate the non-Hodgkin lymphoma (NHL) mortality risk among agricultural workers in Brazil's southern states, we used death certificates to identify cases of NHL between the ages of 20 and 69 years from residents of nonurban municipalities between 1996 and 2005 (n = 1,317). Controls were randomly selected from those whose underlying cause of death did not include neoplasm or hematological diseases and paired with cases by sex, age, year of death, and state of residence (n = 2,634). Odds of being an agricultural worker among cases and controls were estimated by conditional logistic regression, stratified and adjusted by sex, state, education, and race. An increased risk of death by NHL was observed among agricultural workers 20-39 years old (OR_adj = 2.06; 95% CI 95%, 1.20-3.14). Our results suggest that the young agricultural workers from southern Brazil were more likely to die of NHL compared to nonagricultural workers.

Cancer incidence in California farm workers, 1988-2010

BACKGROUND

Farmers and farm workers have previously been found to experience decreased risk of some causes of death but elevated risks of certain types of cancer. A previous report on cancer incidence in a farm worker labor union between 1987 and 1997 found increased leukemia, brain, stomach, and uterine cervix cancer rates in this working population.

METHODS

A roster of farm workers was created and electronically linked to the database of the California Cancer Registry. Proportionate cancer incidence (PCIR), stage, and age at diagnosis and histological subtypes of cancer were compared between the United Farm Workers (UFW) members and the Hispanic population of California as well as to the non-Hispanic whites (NHW).

RESULTS

In this population of 139,000 farm workers in California, more than 3,600 cancer diagnoses were recorded between 1988 and 2010. Proportionately more cancer was noted in the UFW than among California NHW for kidney and renal pelvis cancer (PCIR = 1.60), liver (PCIR = 4.24), prostate (PCIR = 1.13), and uterine cervix cancer (PCIR = 2.08). Proportionately less breast (PCIR = 0.85), lung (PCIR = 0.75), skin melanoma (PCIR = 0.18), and urinary bladder cancer (PCIR = 0.59) was found. Stage at diagnosis was more advanced in the farm workers for several cancer sites, although, not for colorectal cancer.

CONCLUSIONS

These farm workers experience proportionally more prostate, kidney and renal pelvis, brain, liver, stomach, cervix and leukemia and less breast, melanoma, and colorectal cancer than reference populations. For many sites, cancer is not diagnosed as early in the farm workers as in the comparison groups, except for colorectal cancer in females and melanoma in males.

Dermal exposure associated with occupational end use of pesticides and the role of protective measures

BACKGROUND

Occupational end users of pesticides may experience bodily absorption of the pesticide products they use, risking possible health effects. The purpose of this paper is to provide a guide for researchers, practitioners, and policy makers working in the field of agricultural health or other areas where occupational end use of pesticides and exposure issues are of interest.

METHODS

This paper characterizes the health effects of pesticide exposure, jobs associated with pesticide use, pesticide-related tasks, absorption of pesticides through the skin, and the use of personal protective equipment (PPE) for reducing exposure.

CONCLUSIONS

Although international and national efforts to reduce pesticide exposure through regulatory means should continue, it is difficult in the agricultural sector to implement engineering or system controls. It is clear that use of PPE does reduce dermal pesticide exposure but compliance among the majority of occupationally exposed pesticide end users appears to be poor. More research is needed on higher-order controls to reduce pesticide exposure and to understand the reasons for poor compliance with PPE and identify effective training methods.

Occupational Exposures and Non-Hodgkin's Lymphoma in Southern Sweden

In a case-control study based on 859 consecutive non-Hodgkin's lymphoma (NHL) cases identified through a tumor registry between 1990 and 1998, the authors collected demographic, occupational, exposure, and education information. Exposures were identified through self-report, reported occupational history, and the use of a job-exposure matrix. Conditional logistic regression analyses of the 859 cases and 1,310 controls showed increased risks in workers exposed to gasoline (odds ratio [OR] 1.46; 95% confidence interval [CI] 1.04, 2.05), aliphatic or alicyclic hydrocarbons (OR 1.75; CI 1.03, 2.99), aromatic hydrocarbons (OR 1.45; (CI 1.13, 1.86), and solvents for mole than five years (OR 1.59: CI 1.11, 2.28), as well as automobile mechanics (OR 1.82; CI 1.18, 2.81) and painters (OR 1.77; CI 1.13, 2.76). Exposures to pesticides and farming were not associated with increased risk. Prior radiotherapy was associated with increased risk (OR 2.84; (CI 1.85, 4.37). Concordance between analyses based on self-reported exposures, occupations, and the job-exposure matrix supported the links between organic solvents and prior radiotherapy and NHL but did not support associations between farming or pesticides and NHL.

Does farming have an effect on health status? A comparison study in west Greece

Investigating the health status of agricultural workers is a challenging goal. Contradictory outcomes concerning farmers' health are reported in the literature. In this cross-sectional study, certain clinical and neurobehavioral health outcomes were compared between farmers and non-farmers living in the same rural area. Farmers (328) and non-farmers (347), matched per age and sex, were selected randomly in an agricultural area in West Greece. Both groups underwent haematological and biochemical examinations and were administered two neurobehavioral tests, namely the Mini-Mental State Examination (MMSE) and the Montgomery-Åsberg Depression Rating Scale (MADRS). Sociodemographic, personal medical, nutritional and lifestyle data were recorded. According to personal statements, farmers suffered from hypertension, cardiovascular, orthopaedic and ENT problems in higher frequency. Haematocrit, haemoglobin and serum cholinesterase's activity were found to be lower among farmers. Lower prevalence of hypertension and better performances on MMSE and MADRS tests were recorded in young farmers in relation to young non-farmers, while these findings were reversed in older ages. Odds Ratios were calculated through multivariate logistic regression models. Factors affecting these impairments remain to be clarified.

The Upper Midwest Health Study: a case-control study of pesticide applicators and risk of glioma

BACKGROUND

An excess incidence of brain cancer in farmers has been noted in several studies. The National Institute for Occupational Safety and Health developed the Upper Midwest Health Study (UMHS) as a case-control study of intracranial gliomas and pesticide uses among rural residents. Previous studies of UMHS participants, using "ever-never" exposure to farm pesticides and analyzing men and women separately, found no positive association of farm pesticide exposure and glioma risks. The primary objective was to determine if quantitatively estimated exposure of pesticide applicators was associated with an increased risk of glioma in male and female participants.

METHODS

The study included 798 histologically confirmed primary intracranial glioma cases (45 % with proxy respondents) and 1,175 population-based controls, all adult (age 18-80) non-metropolitan residents of Iowa, Michigan, Minnesota, and Wisconsin. The analyses used quantitatively estimated exposure from questionnaire responses evaluated by an experienced industrial hygienist with 25 years of work on farm pesticide analyses. Odds ratios (ORs) and 95 % confidence intervals (CIs) using unconditional logistic regression modeling were calculated adjusting for frequency-matching variables (10-year age group and sex), and for age and education (a surrogate for socioeconomic status). Analyses were separately conducted with or without proxy respondents.

RESULTS

No significant positive associations with glioma were observed with cumulative years or estimated lifetime cumulative exposure of farm pesticide use. There was, a significant inverse association for phenoxy pesticide used on the farm (OR 0.96 per 10 g-years of cumulative exposure, CI 0.93-0.99). No significant findings were observed when proxy respondents were excluded. Non-farm occupational applicators of any pesticide had decreased glioma risk: OR 0.72, CI 0.52-0.99. Similarly, house and garden pesticide applicators had a decreased risk of glioma: OR 0.79, CI 0.66-0.93, with statistically significant inverse associations for use of 2,4-D, arsenates, organophosphates, and phenoxys.

CONCLUSIONS

These results are consistent with our previous findings for UMHS of reported farm pesticide exposure and support a lack of positive association between pesticides and glioma.

Occupational pesticide exposures and cancer risk: a review

A review of the epidemiological literature linking pesticides to cancers in occupational studies worldwide was conducted, with particular focus on those articles published after the release of IARC Monograph 53 (1991): Occupational Exposures in Insecticide Applications and Some Pesticides. Important new data are now available. Chemicals in every major functional class of pesticides including insecticides, herbicide, fungicides, and fumigants have been observed to have significant associations with an array of cancer sites. Moreover, associations were observed with specific chemicals in many chemical classes of pesticides such as chlorinated, organophosphate, and carbamate insecticides and phenoxy acid and triazine herbicides. However, not every chemical in these classes was found to be carcinogenic in humans. Twenty-one pesticides identified subsequent to the last IARC review showed significant exposure-response associations in studies of specific cancers while controlling for major potential confounders. This list is not an exhaustive review and many of these observations need to be evaluated in other epidemiological studies and in conjunction with data from toxicology and cancer biology. Nonetheless, it is reasonable and timely for the scientific community to provide a multidisciplinary expert review and evaluation of these pesticides and their potential to produce cancer in occupational settings.

A weight-of-evidence review of colorectal cancer in pesticide applicators: the agricultural health study and other epidemiologic studies

OBJECTIVE

To systematically evaluate epidemiologic studies on pesticides and colon cancer and rectal cancer in agricultural pesticide applicator populations using a transparent "weight-of-evidence" (WOE) methodological approach.

METHODS

Twenty-nine (29) publications from the Agricultural Health Study (AHS) and 13 additional epidemiologic studies were identified that reported data for pesticide applicators and/or specific pesticide compounds and colorectal, colon, or rectal cancer. The AHS evaluated pesticide applicators as well as dose-response associations for specific pesticide compounds, whereas the large majority of non-AHS evaluated applicators but did not analyze specific compounds or dose-response trends. This WOE assessment of 153 different pesticide-outcome pairs emphasized several key evidentiary features: existence of statistically significant relative risks, magnitude of observed associations, results from the most reliable exposure assessments, and evidence of convincing dose-response relationships (i.e., those monotonically increasing, with statistically significant trend tests).

RESULTS

Occupation as a pesticide applicator or pesticide application as a farming-related function was not associated with increasing the risk of colon or rectal cancer. Deficits of colon or rectal cancer were observed across most studies of pesticide applicators. After applying the WOE methodology to the epidemiologic studies of specific pesticide compounds and colon or rectal cancer, a number of pesticide-outcome pairs were identified and evaluated further based on positive statistical associations. Of these, only two-aldicarb and colon cancer and imazethapyr and proximal colon cancer-appears to warrant further discussion regarding a possible causal relationship, although the epidemiologic data are limited. For the remainder, a lack of a clear dose-response trend, inconsistencies in associations between exposure metrics and comparison groups, imprecise associations, variable participation rates for analyses of specific compounds, and the reliance upon data from one study (the AHS) limit interpretation regarding risk.

CONCLUSION

The available epidemiologic evidence does not support a causal relationship between occupation as a pesticide applicator or specific pesticide exposures and colon or rectal cancer.

Occupational vs. industry sector classification of the US workforce: which approach is more strongly associated with worker health outcomes?

OBJECTIVES

Through use of a nationally representative database, we examined the variability in both self-rated health and overall mortality risk within occupations across the National Occupational Research Agenda (NORA) Industry Sectors, as well as between the occupations within the NORA Industry sectors.

METHODS

Using multiple waves of the National Health Interview Survey (NHIS) representing an estimated 119,343,749 US workers per year from 1986 to 2004, age-adjusted self-rated health and overall mortality rates were examined by occupation and by NORA Industry Sector.

RESULTS

There was considerable variability in the prevalence rate of age-adjusted self-rated poor/fair health and overall mortality rates for all US workers. The variability was greatest when examining these data by the Industry Sectors. In addition, we identified an overall pattern of increased poor/fair self-reported health and increased mortality rates concentrated among particular occupations and particular Industry Sectors.

CONCLUSIONS

This study suggests that using occupational categories within and across Industry Sectors would improve the characterization of the health status and health disparities of many subpopulations of workers within these Industry Sectors.

TCDD and cancer: a critical review of epidemiologic studies

The authors reviewed the epidemiologic studies on exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and cancer risk, published since the last full-scale review made by the International Agency for Research on Cancer Monographs program in 1997. The update of a cohort of US herbicide producers generated negative results overall; the internal analysis provided evidence of an increased "all-cancer" risk in the highest exposure category, with a statistically significant exposure-response association in some of the many analyses performed. The update of a similar Dutch cohort did not confirm the previously observed association with TCDD exposure. The updated surveillance of the Seveso population provided evidence of increased all-cancer mortality 15-20 years after exposure among those living in the most contaminated area but might also reflect random variation, as overall excesses in the most recent follow-up were not observed. Corresponding data on cancer incidence offer little support to the mortality results. Updated results from cohort studies of Vietnam veterans potentially exposed to TCDD did not consistently suggest an increased risk of cancer. Results of additional, smaller studies of other occupational groups potentially exposed to TCDD, and of community-based case-control studies, did not provide consistent evidence of an increased cancer risk. In conclusion, recent epidemiological evidence falls far short of conclusively demonstrating a causal link between TCDD exposure and cancer risk in humans. The emphasis on results for overall cancer risk-rather than risk for specific neoplasms-is not justified on epidemiologic grounds and is not a reason for ignoring the weaknesses of the available evidence.

Mortality and cancer incidence among British agricultural pesticide users

BACKGROUND

Although the acute effects of pesticides in humans are well known, uncertainty still exists about the health effects of chronic low-level exposure to pesticides.

AIMS

To compare mortality and cancer incidence experienced by a cohort of British pesticide users to that of the Great Britain (GB) population.

METHODS

The Pesticide Users Health Study (PUHS) comprises users of agricultural pesticides who have Certificates of Competence under the Control of Pesticides Regulations 1986. Participants were followed up between 1987 and 2004 (cancer incidence) or 2005 (mortality). Standardized mortality ratios (SMRs) and Standardized incidence ratios (SIRs) were estimated for outcomes of interest identified from the literature.

RESULTS

Altogether, 62,960 pesticide users were followed up for 829,709 person-years (to 31 December 2005). Most participants were male (94%) and based in England (86%). All-cause mortality was lower for both men [SMR 0.58, 95% confidence interval (CI) 0.55-0.60] and women (SMR 0.71, 95% CI 0.52-0.98) compared to the GB population. Mortality and incidence were below those expected for all cancers combined among men (SMR 0.71, 95% CI 0.66-0.77; SIR 0.85, 95% CI 0.81-0.90), particularly for cancers of the lip, oral cavity and pharynx, digestive organs and respiratory system. The incidence of testicular cancer, non-melanoma skin cancer and multiple myeloma were above expected. Mortality from injury by machinery was significantly above expected for men (SMR 4.21, 95% CI 2.11-8.42).

CONCLUSIONS

This study suggests that pesticide users in the PUHS are generally healthier than the national population but may have excesses of non-melanoma skin cancer, testicular cancer and multiple myeloma.

Mortality in the agricultural health study, 1993-2007

Comparing agricultural cohorts with the general population is challenging because the general healthiness of farmers may mask potential adverse health effects of farming. Using data from the Agricultural Health Study, a cohort of 89,656 pesticide applicators and their spouses (N = 89, 656) in North Carolina and Iowa, the authors computed standardized mortality ratios (SMRs) comparing deaths from time of the enrollment (1993-1997) through 2007 to state-specific rates. To compensate for the cohort's overall healthiness, relative SMRs were estimated by calculating the SMR for each cause relative to the SMR for all other causes. In 1,198,129 person-years of follow-up, 6,419 deaths were observed. The all-cause mortality rate was less than expected (SMR(applicators) = 0.54, 95% confidence interval (CI): 0.52, 0.55; SMR(spouses) = 0.52, 95% CI: 0.50, 0.55). SMRs for all cancers, heart disease, and diabetes were significantly below 1.0. In contrast, applicators experienced elevated numbers of machine-related deaths (SMR = 4.15, 95% CI: 3.18, 5.31), motor vehicle nontraffic accidents (SMR = 2.80, 95% CI: 1.81, 4.14), and collisions with objects (SMR = 2.12, 95% CI: 1.25, 3.34). In the relative SMR analysis for applicators, the relative mortality ratio was elevated for lymphohematopoietic cancers, melanoma, and digestive system, prostate, kidney, and brain cancers. Among spouses, relative SMRs exceeded 1.0 for lymphohematopoietic cancers and malignancies of the digestive system, brain, breast, and ovary. Unintentional fatal injuries remain an important risk for farmers; mortality ratios from several cancers were elevated relative to other causes.

Plasma organochlorines and subsequent risk of prostate cancer in Japanese men: a nested case-control study

BACKGROUND

Although accumulating evidence suggests that exposure to organochlorine pesticides and polychlorinated biphenyls (PCBs) may contribute to the development of prostate cancer, few investigations have used biological samples to classify exposure to specific organochlorines. To our knowledge, this is the first prospective study to investigate the association between blood levels of organochlorines and prostate cancer risk.

METHODS

We conducted a nested case-control study using data from the Japan Public Health Center-based Prospective (JPHC) Study. A total of 14,203 men 40-69 years old who returned the baseline questionnaire and who provided blood samples were followed from 1990 to 2005. Using a mean follow-up period of 12.8 years, we identified 201 participants who were newly diagnosed with prostate cancer. Two matched controls for each case were selected from the cohort. We used a conditional logistic regression model to estimate the odds ratios (ORs) and 95% confidence intervals (CIs) for prostate cancer in relation to plasma levels of nine organochlorines: PCBs, dichlorodiphenyltrichloroethane (DDT), hexachlorobenzene (HCB), beta-hexachlorocyclohexane (beta-HCH), trans- and cis-nonachlor, oxychlordane, and mirex.

RESULTS

No statistically significant association with total prostate cancer was seen for any plasma organochlorine, although we did observe an insignificant inverse association for plasma HCB and beta-HCH. Total PCB in plasma was also inversely associated with advanced prostate cancer but without statistical significance.

CONCLUSION

Our results suggest that no overall association exists between prostate cancer and organochlorines at the levels measured in our study population.

Pesticides and myocardial infarction incidence and mortality among male pesticide applicators in the Agricultural Health Study

Acute organophosphate and carbamate pesticide poisonings result in adverse cardiac outcomes. The cardiac effects of chronic low-level pesticide exposure have not been studied. The authors analyzed self-reported lifetime use of pesticides reported at enrollment (1993-1997) and myocardial infarction mortality through 2006 and self-reported nonfatal myocardial infarction through 2003 among male pesticide applicators in the Agricultural Health Study. Using proportional hazard models, the authors estimated the association between lifetime use of 49 pesticides and fatal and nonfatal myocardial infarction. There were 476 deaths from myocardial infarction among 54,069 men enrolled in the study and 839 nonfatal myocardial infarctions among the 32,024 participants who completed the follow-up interview. Fatal and nonfatal myocardial infarctions were associated with commonly reported risk factors, including age and smoking. There was little evidence of an association between having used pesticides, individually or by class, and myocardial infarction mortality (e.g., insecticide hazard ratio (HR) = 0.91, 95% confidence interval (CI): 0.67, 1.24; herbicide HR = 0.74, 95% CI: 0.49, 1.10) or nonfatal myocardial infarction incidence (e.g., insecticide HR = 0.85, 95% CI: 0.66, 1.09; herbicide HR = 0.91, 95% CI: 0.61, 1.36). There was no evidence of a dose response with any pesticide measure. In a population with low risk for myocardial infarction, the authors observed little evidence of increased risk of myocardial infarction mortality or nonfatal myocardial infarction associated with the occupational use of pesticides.

Epidemiologic studies in agricultural populations: observations and future directions

This paper reviews epidemiologic studies of cancer among agricultural populations to identify possible associations and to provide a focus for future investigations. Meta-analyses of mortality surveys of farmers find excesses of several cancers, including connective tissue, non-Hodgkin's lymphoma, Hodgkin's disease, multiple myeloma and cancers of the skin, stomach, and brain, and deficits for total mortality, heart disease, total cancer, and cancers of the esophagus, colon, lung, and bladder. Meta-analyses of studies of individual cancers also support these findings, indicating a need to identify exposures and lifestyle factors that might account for this mortality pattern. Although cancer studies of other occupations that might have pesticide exposures in common with farmers show some similarities with observations among farmers, the overall patterns are quite different. This suggests that pesticides are not likely to fully explain the cancer and other disease patterns observed among farmers. Because exposures vary by type of farm operation, exposures for individual farmers can differ considerably. Studies in the future need to focus on the full range of exposures to fully understand the cancer pattern in farmers.

Does exposure to agricultural chemicals increase the risk of prostate cancer among farmers?

Several studies suggest that farmers may be at increased risk of prostate cancer. The present analysis, based on a large population-based case-control study conducted among men in the Montreal area in the early 1980's, aim at identifying occupational chemicals which may be responsible for such increases. The original study enrolled 449 prostate cancer cases, nearly 4,000 patients with other cancers, as well as 533 population controls. Subjects were interviewed about their occupation histories, and a team of industrial hygienists assigned their past exposures using a checklist of some 300 chemicals. The present analysis was restricted to a study base of men who had worked as farmers earlier in their lives. There were a total of 49 men with prostate cancers, 127 with other cancers and 56 population controls. We created a pool of 183 controls combining the patients with cancers at sites other than the prostate and the population controls. We then estimated the odds ratio for prostate cancer associated with exposure to each of 10 agricultural chemicals, i.e., pesticides, arsenic compounds, acetic acid, gasoline engine emissions, diesel engine emissions, polycyclic aromatic hydrocarbons from petroleum, lubricating oils and greases, alkanes with >or=18 carbons, solvents, and mononuclear aromatic hydrocarbons. Based on a model adjusting for age, ethnicity, education, and respondent status, there was evidence of a two-fold excess risk of prostate cancer among farmers with substantial exposure to pesticides [odds ratio (OR)=2.3, 95% confidence interval (CI) 1.1-5.1], as compared to unexposed farmers. There was some suggestion, based on few subjects, of increased risks among farmers ever exposed to diesel engine emissions (OR=5.7, 95% CI 1.2-26.5). The results for pesticides are particularly noteworthy in the light of findings from previous studies. Suggestions of trends for elevated risks were noted with other agricultural chemicals, but these are largely novel and need further confirmation in larger samples.

Prostate cancer prevention by short-term anti-androgens: the rationale behind design of pilot studies

This paper sets out to review evidence that low-grade prostate inflammation is a precursor of prostate cancer development and the mechanisms by which it may account for the more than 50 years natural history from first infection to cancer. Though as yet there is no clear-cut specific associated infection, there is clear evidence that some sexually acquired infections damage the prostate and increase serum PSA with slow recovery back to normal. The demonstration that low-level solar exposure is protective provides a possible mechanism due to vitamin D's known benefit through action to boost macrophage-mediated immune surveillance. This observation and data demonstrating that non-steroidal anti-inflammatory drugs (NSAIDs) protect against prostate cancer provide the justification for trials of these two agents combined with short course intermittent anti-androgen therapy in populations at high risk of prostate cancer.

Pesticides and prostate cancer: a review of epidemiologic studies with specific agricultural exposure information

Prostate cancer is the most commonly diagnosed cancer in US men, and the second most commonly diagnosed cancer among men worldwide. Although pesticides have been implicated in studies of prostate cancer among farmers, meta-analyses have found heterogeneity across studies, and a number of exposures and lifestyle factors may be unique to farmers. The purpose of this paper is to review the epidemiologic literature to evaluate the hypothesis that agricultural exposure to pesticides is causally associated with prostate cancer risk. We analyzed the eight cohort studies and five case-control studies that quantified and/or evaluated agricultural exposure to particular pesticide classes or chemicals. Despite sporadic positive findings, these studies did not show consistently increased risks to support a causal association between agricultural pesticide use and prostate cancer. Studies using an 'external' comparison group must be interpreted in the context of confounding by differences in prostate-specific antigen screening intensity. Furthermore, most studies did not adjust for potential confounders other than age and time period. It is clearly not possible to exonerate any particular pesticide as a putative cause of prostate cancer - to do so would require an inverse empirical association with an upper confidence limit below the null value. Existing evidence does not point to any pesticide as satisfying widely used guidelines for establishing causation: a strong, exposure-dependent and demonstrably unconfounded, unbiased association, documented in several studies.

Prostate cancer in Mexican-Americans: identification of risk factors

BACKGROUND

There is a paucity of information regarding prostate cancer (PCa) risk factors among Hispanics, the fastest-growing ethnic group in the United States.

METHODS

This population-based case-control study included 176 Texas men of Mexican descent with PCa and 174 age- and ethnicity-matched controls. Demographic, lifetime occupational history, family history of cancer, lifestyle (e.g., smoking, alcohol, diet, and recreational physical activity) and anthropometric information were collected by personal interviews. Chemical exposure and physical activity were determined using job-exposure matrices for each reported job.

RESULTS

Logistic regression models adjusted for relevant covariates were used to evaluate their independent effects. Compared to controls, cases were three times more likely to work in jobs with high agrichemical exposure (OR = 3.44, 95% CI 1.84-6.44), and 54% less likely to work in jobs with moderate/high occupational physical activity (OR = 0.46, 95% CI 0.28-0.77). In analyses stratified by stage, cases with organ-confined PCa were three times more likely to have high agrichemical exposure (OR = 3.39, 9%CI 1.68-6.84), and 56% less likely to have moderate/high levels of occupational physical activity (OR = 0.44, 95% CI 0.26-0.76). Increased risk of being diagnosed with advanced PCa was associated with obesity at time of diagnosis (OR = 2.50, 95% CI 1.20-5.20) and high levels of agrichemical exposure (OR = 4.65, 95% CI 1.97-10.97), but not with occupational physical activity.

CONCLUSIONS

This case-control study, the first conducted in a homogeneous Hispanic population, identified modifiable PCa risk factors, such as physical activity and agrichemical exposure, which may be useful in developing interventions for this understudied population.

Prostate cancer prevention: past, present, and future

Prostate cancer is the most common male malignancy and the second or third leading cause of cancer death among men in the West. The descriptive epidemiology of prostate cancer suggests that it is a preventable disease. Prevention has the theoretical advantage of not only saving lives, but also reduce the morbidity of radical prostate cancer therapy. This article reviews the past, present, and future of prostate cancer prevention. In particular, the evidence and scientific data of a variety of prevention strategies are reviewed. Strategies reviewed include dietary fat reduction and supplementation with vitamins D and E, and selenium. Dietary intake of soy, green tea, and tomato-rich products (lycopene) are also reviewed. Data regarding pharmacological intervention with cyclo-oxygenease inhibitors, antiestrogens, and in particular 5-alpha reductase inhibitors are reviewed. The results of the Prostate Cancer Prevention Trial including the controversy surrounding higher-grade cancers among men randomized to finasteride are also summarized. Finally, a variety of trial designs as well as a roster of current phase 2 trials are presented. Probably no cancer is being investigated more thoroughly in the context of prevention as prostate cancer in 2007. Definitive answers to pivotal phase 3 trials will be available in the coming 2 to 7 years.

The non-Hodgkin lymphomas: a review of the epidemiologic literature

The non-Hodgkin lymphomas (NHL) are a heterogeneous group of B-cell and T-cell neoplasms that arise primarily in the lymph nodes. NHL incidence rates in the US doubled between about 1970 and 1990, and stabilized during the 1990s. NHL accounts for approximately 3.4% of cancer deaths in the US. Although some of the observed patterns in NHL have been related to HIV/AIDS, these conditions cannot fully explain the magnitude of the changes; neither do changes in classification systems nor improved diagnostic capabilities. Studies of occupational and environmental exposures (e.g., pesticides, solvents) have produced no consistent pattern of significant positive associations. Inverse associations with ultraviolet radiation exposure and alcohol and fish intake, and positive associations with meat and saturated fat intake have been reported in several studies; additional studies are needed to confirm or refute these associations. Family history of NHL or other hematolympho-proliferative cancers and personal history of several autoimmune disorders are associated with increased risk of NHL, but are not likely to account for a large proportion of cases. HIV and other infectious agents, such as human herpesvirus 8 and Epstein-Barr, appear to be associated with differing types of NHL, such as some B-cell lymphomas. Future epidemiologic studies should evaluate associations by NHL type, enhance exposure information collected, and elucidate factors that may identify susceptible (or resistant) subpopulations because of genetic, immunologic or other characteristics. The extent to which the etiology of NHL types may differ is important to resolve in ongoing and future studies.

Non-Hodgkin lymphoma and pesticide exposure: 25 years of research

Over the past 40 years, a substantial rise in the incidence of non-Hodgkin lymphoma (NHL) has been observed. Epidemiologic studies aimed at understanding this rise have revealed some association with occupational exposure. NHL is common among farmers, where pesticides have been described as the culprit. The association between pesticides and NHL has been demonstrated mainly in case-control studies, while retrospective cohorts have been less convincing. Pesticides including chlorphenol and phenoxyacetic acid herbicides, organochlorines, and organophosphate insecticides, carbamates, and fungicides have been associated with NHL. Although the causality has not been clearly proven, both genotoxic and nongenotoxic mechanisms for lymphomagenesis have been proposed. The leveling-off of NHL incidence in certain countries may be the result of a favorable change in pesticide usage patterns. Future studies, such as the Agricultural Health Study, may clarify the uncertainties regarding this issue.

A case-control study of farming and prostate cancer in African-American and Caucasian men

OBJECTIVE

To determine the risk of prostate cancer associated with farming by duration, recency and specific activities among African-Americans and Caucasians.

METHODS

This population-based case-control study had information on farming-related activities for 405 incident prostate cancer cases and 392 controls matched for age, race and region in South Carolina, USA, from 1999 to 2001. Cases with histologically confirmed, primary invasive prostate cancer who were aged between 65 and 79 years were ascertained through the South Carolina Central Cancer Registry. Appropriately matched controls were identified from the Health Care Financing Administration Medicare Beneficiary File. Data were collected using computer-assisted telephone interviewing, and adjusted odds ratios (aOR) were estimated using unconditional logistic regression.

RESULTS

Farming was associated with increased risk of prostate cancer in Caucasians (aOR 1.8; 95% confidence interval (CI) 1.3 to 2.7) but not in African-Americans (aOR 1.0; 95% CI 0.6 to 1.6). Regarding specific farming activities, farmers who mixed or applied pesticides had a higher risk of prostate cancer (aOR 1.6; 95% CI 1.2 to 2.2). Increased risk of prostate cancer was observed only for those farming <5 years.

CONCLUSIONS

Increased risk of prostate cancer for farmers in this study may be attributable to pesticide exposure. Racial differences in the association between farming and prostate cancer may be explained by different farming activities or different gene-environment interactions by race.

Pesticide exposure and lung cancer mortality in Leningrad province in Russia

This study was carried out to examine the association between pesticide exposure and lung cancer mortality. We conducted an autopsy based case-control study in Leningrad Province in Russia. A total of 540 lung cancer cases and 582 controls were identified among subjects who had died in the hospitals of the Leningrad province between 1993 and 1998. Using work history records, we assessed exposure to pesticide at the level of industry and job title. Unconditional logistic regression was used to calculate adjusted odds ratio for pesticide exposure and lung cancer mortality. There was no association between ever exposure to pesticide and lung cancer mortality overall (odds ratio=1.06, 95% confidence interval=0.82-1.36) and in both men (odds ratio=1.11, 95% confidence interval=0.84-1.46) and women (odds ratio=0.74, 95% confidence interval=0.37-1.46). We observed no statistically significant odds ratio by duration of pesticide exposure, intensity of pesticide exposure, and cumulative pesticide exposures with lung cancer mortality in both smokers and nonsmokers. Odds ratio also did not differ when the analysis was restricted to individuals who had exposure data with high confidence scores. Our findings suggest no associations between pesticide exposures and mortality of lung cancer in the population of the Leningrad province in Russia that deserves further evaluation.

Occupational exposures and haematological malignancies: overview on human recent data

OBJECTIVE

Occupational causes of haematological malignancies are relatively uncommon, under-studied and under-identified. They are also often unrecognized by clinicians. This review summarizes the principal epidemiologic studies on this topic.

METHODS

We analyzed the recent relevant human data found in the Medline, the Pascal and the BDSP databases.

RESULTS

Benzene and ionizing radiation are the only agents conclusively demonstrated to be carcinogenic to the haematopoietic system. In particular, both exposures are strongly associated with acute myeloid leukaemia. Low doses of both may also be related to myeloid malignancies. Infectious agents and pesticides are also thought to induce lymphoproliferative cancers. Some studies show an association between haematological malignancies and low-frequency electromagnetic fields and organic solvents. All of these suspected occupational causes must be confirmed by further studies.

CONCLUSIONS

Better knowledge and understanding of occupational causes of haematological malignancies are necessary to improve their prevention and compensation.

Residential proximity to agricultural pesticide use and incidence of breast cancer in California, 1988-1997

California is the largest agricultural state in the United States and home to some of the world's highest breast cancer rates. The objective of our study was to evaluate whether California breast cancer rates were elevated in areas with recent high agricultural pesticide use. We identified population-based invasive breast cancer cases from the California Cancer Registry for 1988-1997. We used California's pesticide use reporting data to select pesticides for analysis based on use volume, carcinogenic potential, and exposure potential. Using 1990 and 2000 U.S. Census data, we derived age- and race-specific population counts for the time period of interest. We used a geographic information system to aggregate cases, population counts, and pesticide use data for all block groups in the state. To evaluate whether breast cancer rates were related to recent agricultural pesticide use, we computed rate ratios and 95% confidence intervals using Poisson regression models, adjusting for age, race/ethnicity, and neighborhood socioeconomic status and urbanization. This ecologic (aggregative) analysis included 176,302 invasive breast cancer cases and 70,968,598 person-years of observation. The rate ratios did not significantly differ from 1 for any of the selected pesticide categories or individual agents. The results from this study provide no evidence that California women living in areas of recent, high agricultural pesticide use experience higher rates of breast cancer.

Relative and absolute cancer mortality of women in agriculture in northern Italy

Most studies of cancer risk related to agricultural exposures have focused on male operators. Cancer mortality in a cohort of 38 962 women engaged in agriculture (Province of Forlì, 1969-1993) was compared with that of the rest of the female residents using the ratio of age-standardized (Europe) mortality rates (ASR) with 95% confidence interval (CI). Moreover, mortality time trends in both subsets of the population were evaluated. The cohort yielded 798 439 person-years with 2397 cancer deaths. Total ASR ratio was 0.86 (95% CI 0.80-0.92). Only gastric cancer was associated with a significant but declining excess mortality (ASR ratio 1.26; 95% CI 1.11-1.43). Total ASR ratio decreased from 1.07 (95% CI 0.95-1.20) in 1969-1976 to 0.74 (95% CI 0.66-0.82) in 1985-1993. This resulted from a downward mortality trend restricted to the cohort. In particular, mortality from cancers of the oesophagus, stomach and colon/rectum decreased more steeply in the cohort. Mortality from liver cancer decreased only in the cohort. Mortality from cancers of the pancreas, lung, breast, bladder and skin melanoma remained stable in the cohort whilst increasing in the rest of the population. In conclusion, risk excesses previously reported were not confirmed. Agricultural workers qualified as a subset of the female population with atypical, favourable epidemiologic characteristics.

Did TCDD Exposure or Service in Southeast Asia Increase the Risk of Cancer in Air Force Vietnam Veterans Who Did Not Spray Agent Orange?

OBJECTIVE

We sought to examine cancer incidence in 1482 Air Force veterans who served in Southeast Asia (SEA) and who were not occupationally exposed to herbicides.

METHODS

Cancer incidence between 1982 and 2003 was determined by record review and Cox proportional hazards models were used to estimate risk ratios across serum 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and years served in SEA categories.

RESULTS

All sites cancer risk increased with TCDD (relative risk = 1.6, 95% confidence interval = 1.2-2.2). The risk of prostate cancer increased with years of SEA service but not with TCDD. TCDD and years of SEA service interacted with all sites cancer; the risk was greatest in those with the highest TCDD levels and the longest time served in SEA.

CONCLUSIONS

These results suggest nonoccupational exposures to TCDD or other factors while in SEA may contribute to cancer risk in these veterans.

Gliomas and Farm Pesticide Exposure in Men: The Upper Midwest Health Study

The National Institute for Occupational Safety and Health evaluated farm pesticide exposure and glioma risk in a study that included 457 glioma cases and 648 population-based controls, all adult men (18-80 yr old) and nonmetropolitan residents of Iowa, Michigan, Minnesota, and Wisconsin. Multiple logistic regressions were used to control for farm residence, age, age group, education, and exposure to other pesticides. No associations were found between glioma and 12 specific pesticides. We estimated adjusted odds ratios (ORs) and 95% confidence intervals (CIs) and found reduced glioma risk for insecticides (OR = 0.53, CI = 0.37-0.77), fumigants (OR = 0.57, CI = 0.34-0.95), and organochlorines (OR = 0.66, CI = 0.47-0.94). In analyses excluding proxy respondents (47% of cases) most CIs included 1.0. No positive association of farm pesticide exposure and glioma was found. Other farm exposures may explain the excess brain cancer risk seen in previous studies.

Prostate cancer among pesticide applicators: a meta-analysis

OBJECTIVES

To analyse data from peer-reviewed, case-referent and cohort studies, studying the occurrence of prostate cancer in pesticide applicators and in some other, related, occupational categories, in order to determine a possible relationship of cancer of the prostate with pesticide exposure; to calculate a meta-rate ratio and to compare it with the meta-rate ratios obtained in a previous meta-analysis performed over a shorter time (1995-2001) in a broader exposure category, including many pesticide-related agricultural and non-agricultural occupations.

METHODS

Medline was searched for the years between 1966 and 2003, and relevant studies were identified from 1986 on. We conducted a meta-analysis of 22 studies complying with the inclusion criteria in order to pool their relative risk (RR) estimates. Studies were summarised and assessed for homogeneity and publication bias.

RESULTS

The meta-rate ratio, based on 22 estimates of RR, is 1.24 [95% confidence interval (95% CI) 1.06-1.45]. This pooled risk estimate for the occupational categories selected is higher than the one previously calculated for farmers in general over a shorter period of publication. Substantial heterogeneity of rate ratios exists between the different studies. The major source of heterogeneity identified is geographic location. Increased meta-rate ratios are observed for studies derived from North America as well as from Europe, the meta-rate ratios from Europe being lower than those from North America. There is no obvious indication of publication bias.

CONCLUSION

The increased meta-rate ratio for prostate cancer in agricultural pesticide applications provides additional evidence for a possible relationship between pesticide exposure and prostate cancer. The homogeneity observed between the individual rate ratios, after we had regrouped the data according to geographic location, tends to increase the consistency of the association. However, the data available from the individual studies do not provide sufficient exposure information for firm conclusions to be drawn about pesticide exposure as the cause of prostate cancer, independently from other factors.

Breast cancer risk and historical exposure to pesticides from wide-area applications assessed with GIS

Pesticides are of interest in etiologic studies of breast cancer because many mimic estrogen, a known breast cancer risk factor, or cause mammary tumors in animals, but most previous studies have been limited by using one-time tissue measurements of residues of only a few pesticides long banned in the United States. As an alternative method to assess historical exposures to banned and current-use pesticides, we used geographic information system (GIS) technology in a population-based case-control study of 1,165 women residing in Cape Cod, Massachusetts, who were diagnosed with breast cancer in 1988-1995 and 1,006 controls. We assessed exposures dating back to 1948 (when DDT was first used there) from pesticides applied for tree pests (e.g., gypsy moths), cranberry bogs, other agriculture, and mosquito control on wetlands. We found no overall pattern of association between pesticide use and breast cancer. We found modest increases in risk associated with aerial application of persistent pesticides on cranberry bogs and less persistent pesticides applied for tree pests or agriculture. Adjusted odds ratios for these exposures were 1.8 or lower, and, with a few exceptions, confidence intervals did not exclude the null. The study is limited by uncertainty about locations of home addresses (particularly before 1980) and unrecorded tree pest and mosquito control events as well as lack of information about exposures during years when women in the study lived off Cape Cod and about women with potentially important early life exposures on Cape Cod who were not included because they moved away.

Dietary Fat and Prostate Cancer

PURPOSE

Data from histopathological and migratory studies suggest that 1 or more late stage environmental promoters are involved in the development of clinical carcinoma of the prostate. Laboratory investigations and variously designed epidemiological studies in man have suggested that dietary fat may be one of these candidate tumor promoters but other studies have questioned this association. The biologically plausible associations that have been hypothesized include total energy consumption, altered androgen metabolism, oxidative stress, specific fatty acid consumption and pesticide intake. We provide a critical appraisal of the existing evidence for an association between dietary fat consumption and prostate cancer, and review the biologically plausible relationships.

MATERIALS AND METHODS

All 33 published case-control and cohort studies that examined the relationship between prostate cancer and dietary fat or specific fatty food types were critically appraised. Eight studies suggested a statistically significant association, and many studies noted significant associations for specific types of fatty foods (eg milk or meat) and prostate cancer.

RESULTS

In light of the inherent biases in the methodology of studying dietary fat intake and carcinoma of the prostate, we conclude that the evidence is consistent.

CONCLUSIONS

Corroborative studies in humans are required to better define this relationship. Prospective studies of dietary intervention should be encouraged.

Mortality among a Cohort of Female Farm Residents in New York State

A retrospective cohort study of mortality among 6,405 female farm residents who were New York Farm Bureau members, or spouses or relatives of members, was conducted from 1980 through 1993. Similar to previous findings for male farmers, the cohort experienced significantly lower mortality rates for all causes combined (including malignant neoplasms and cardiovascular disease), compared with rural nonfarm female residents. These findings suggest that farmers and farm residents of both genders have favorable habits with respect to several lifestyle factors. The results of this study were consistent with those from other studies of farm populations worldwide.

Occupation related pesticide exposure and cancer of the prostate: a meta-analysis

AIMS

To summarise recent literature on the risk of prostate cancer in pesticide related occupations, to calculate the meta-rate ratio, and to compare it to data from meta-analyses previously published.

METHODS

A meta-analysis of 22 epidemiological studies, published between 1995 and 2001, was conducted in order to pool their rate ratio estimates. Studies were summarised and evaluated for homogeneity and publication bias.

RESULTS

The meta-rate ratio estimate, based on 25 estimators of relative risk from 22 studies, was 1.13 (95% CI 1.04 to 1.22). Significant heterogeneity of rate ratios existed among the different studies. Therefore, a stratified analysis was carried out. Major sources of heterogeneity identified were geographic location, study design, and healthy worker effect. Overall, pooled risk estimates for studies derived from Europe were lower than those derived from the USA/Canada. A significant increase in rate ratio was observed for the occupation category of pesticide applicators, whereas no significant increase was observed for farmers. There was no evidence of publication bias.

CONCLUSION

This increased meta-rate ratio for prostate cancer in different pesticide related occupations, including farmers, is very similar to three, previously published, meta-rate ratios for prostate cancer in farmers calculated from studies published before 1995. Although the underlying data do not identify pesticide exposure as an independent cause for prostate cancer, the fact that an increased meta-rate ratio is again obtained points to occupational exposure to pesticides as a possible factor. Future epidemiological studies should focus, as far as possible, on reliable methods to estimate actual exposure.

Prevalence of pesticide exposure in young males (</= 50 years) with adenocarcinoma of the prostate

Evidence implicating pesticides as causative agents of prostate cancer is controversial, and specifically, data in young adults is lacking. Hence, we performed a preliminary study evaluating the relationship between pesticide exposure and prostate cancer in young males. After approval from the University of North Dakota Institutional Review Board and Human Subjects Committee, a retrospective study was performed on all young males (</ = 50 years) with a biopsy-proven diagnosis of carcinoma of the prostate. The records of all patients aged less than/equal to 50 years, with a diagnosis of adenocarcinoma of the prostate, from January 1991 through December 2001 were reviewed. Pesticide risk assessment interviews were performed by a single member of the team, for consistency, via telephone on the basis of a pre-determined questionnaire investigating occupations and hobbies with special emphasis on: Duration of exposure. An exposure index was calculated for each interviewed subject according to the following formula: hours/day x days/year x years. Patients with an exposure index >2400 hours were considered as 'exposed.' The 2400 hour cut-off value was chosen on the basis of previous reports indicating that this figure represents heavy exposure to genotoxic agents. Statistical analysis was obtained using SPSS-10ledR;. Between 1991 and 2001, 61 young males with adenocarcinoma of the prostate were identified, of whom 56 patients with a mean age of 47 years (range: 40-49) had complete records of treatment and could be contacted for completion of the questionnaire. The most common stage at presentation was Stage III and the mean Gleason's score was 7.5 (range 5-9). Interestingly, almost a third (16/56, 28.6%) of patients had stage IV disease at presentation. 37/56 (66.1%) patients had 'significant' exposure in our study. In addition, interestingly, the mean survival in the subgroup of patients with pesticide exposure was 11.3 months (SD: +/- 2.3 months), while the mean survival in the patients without pesticide exposure (n = 19) was 20.1 months (SD: +/- 3.1 months), with p-value <0.01. Although our study is relatively small, it does reveal preliminary evidence linking pesticide exposure to the early development of, possibly aggressive, prostate adenocarcinoma. Future, larger, epidemiological studies are needed to confirm the findings of our study.

Mortality among triazine herbicide manufacturing workers

Atrazine produces mammary gland cancer in one strain of rats and has been classified as an endocrine modulator. Epidemiologic studies have reported associations between agricultural use of atrazine and several forms of cancer. This study evaluated mortality patterns among workers at a plant that made atrazine and other triazine herbicides. The study covered the time period 1970-1997 and included 2213 people employed for at least 6 mo in operations related to the manufacture or formulation of atrazine and other triazine herbicides at a plant in Louisiana (LA). Vital status was determined for all but six subjects. Standardized mortality ratios (SMRs) with 95% confidence intervals (CIs) compared employees' mortality rates with those of the LA industrial corridor general population. Subjects had a total of 32,473 person-years of observation and a median of 15.8 yr since hire. There were 84 observed/118 expected deaths from all causes combined (SMR = 72, CI = 57-89) and 22/21 total cancer deaths (SMR = 106, CI = 66-160). Subjects had 4/1.1 deaths from non-Hodgkin's lymphoma (SMR = 372, CI = 101-952); this increase was not concentrated in the subgroup with long duration of employment and many years since hire. There were 6/4.8 (SMR = 124, CI = 46-271) digestive cancer and 7/6.3 (SMR = 112, CI = 45-230) lung cancer deaths. Data on other forms of cancer were sparse. This study was limited by its small size, by the relatively young age and short follow-up of its subjects, and by the lack of exposure data. It did not provide evidence that employment in triazine herbicide manufacturing and formulating operations was associated causally with overall or cause-specific mortality.

National Health Interview Survey mortality among US farmers and pesticide applicators

BACKGROUND

The mortality experience of pesticide-exposed workers across the US has not been thoroughly studied.

METHODS

Cox regression mortality analyses adjusted for the complex sample survey design were performed on mortality-linked 1986-1994 National Health Interview Survey (NHIS) data.

RESULTS

Nine thousand four hundred seventy-one farmers and pesticide applicators with 571 deaths were compared to 438,228 other US workers with 11,992 deaths. Age-adjusted risk of accidental death, as well as cancers of the nervous and lymphatic/hematopoietic systems, was significantly elevated in male and female pesticide-exposed workers; breast, prostate, and testicular cancer mortality risks were not elevated.

CONCLUSIONS

Compared to all other workers, farmers and pesticide applicators were at greater risk of accidental mortality. These pesticide-exposed workers were not at an increased risk of cancers possibly associated with exposure to estrogen analogue compounds, but were at an increased risk of hematopoietic and nervous system cancers. NHIS mortality follow-up represents an important occupational health surveillance instrument.

Review of 2,4-dichlorophenoxyacetic acid (2,4-D) epidemiology and toxicology

The scientific evidence in humans and animals relevant to cancer risks, neurologic disease, reproductive risks, and immunotoxicity of 2,4-D was reviewed. Despite several thorough in vitro and in vivo animal studies, no experimental evidence exists supporting the theory that 2,4-D or any of its salts and esters damages DNA under physiologic conditions. Studies in rodents demonstrate a lack of oncogenic or carcinogenic effects following a lifetime dietary administration of 2,4-D. Epidemiologic studies provide scant evidence that exposure to 2,4-D is associated with soft tissue sarcoma, non-Hodgkin's lymphoma, Hodgkin's disease, or any other cancer. Overall, the available evidence from epidemiologic studies is not adequate to conclude that any form of cancer is causally associated with 2,4-D exposure. There is no human evidence of adverse reproductive outcomes related to 2,4-D. The available data from animal studies of acute, subchronic, and chronic exposure to 2,4-D, its salts, and esters show an unequivocal lack of systemic toxicity at doses that do not exceed renal clearance mechanisms. There is no evidence that 2,4-D in any of its forms activates or transforms the immune system in animals at any dose. At high doses, 2,4-D damages the liver and kidney and irritates mucous membranes. Although myotonia and alterations in gait and behavioral indices are observed after overwhelming doses of 2,4-D, alterations in the neurologic system of experimental animals are not observed with the administration of doses in the microgram/kg/day range. It is unlikely that 2,4-D has any neurotoxic potential at doses below those required to induce systemic toxicity.