Incidence and risk factors of cancer among men and women in Norwegian agriculture

Agricultural exposure and risk of ovarian cancer in the AGRIculture and CANcer (AGRICAN) cohort

BACKGROUND

Ovarian cancer is rare with a poor prognosis and few established risk factors. Hormones and reproductive factors significantly impact its development, suggesting a potential link with endocrine disrupters.

METHODS

In the AGRICAN cohort, 59 391 female farmers completed data on lifelong agricultural exposures and reproductive life. Cox models with attained age as timescale (HR and 95% CI) were used. The role of hormonal factors as potential confounders was considered along with specific time windows for exposure (childhood, puberty and menopause). Female farmers were the reference group (for the principal analyses).

RESULTS

Between enrolment (2005-2007) and the end of follow-up (31 December 2017), 262 incident ovarian cancers were identified. An increased risk was observed for females involved in pigs (HR=2.12 (95% CI 1.27 to 3.52)) including during puberty (HR=1.83 (95% CI 1.13 to 2.94)), fruit-growing (HR=2.17 (95% CI 1.09 to 4.30)) and potato seed treatment (HR=2.81 (95% CI 1.29 to 6.09)). Conversely, females born on farms growing grain cereals (HR=0.64 (95% CI 0.46 to 0.90)) or pig-breeding (HR=0.78 (95% CI 0.55 to 1.12)) presented a reduced risk of ovarian cancer. Triazine herbicide exposure was not associated with ovarian cancer. The effect of agricultural exposures remained unchanged in multivariate models considering contraception, parity, puberty age, menopause age and body mass index.

CONCLUSION

This study is the first to assess the association between specific agricultural exposures and ovarian cancer comprehensively. Some of the positive associations observed suggest that some pesticide exposure (especially during puberty) could play a role in the development of ovarian cancer. On the other hand, agricultural exposure during early life could have a protective effect, as observed for lung cancer among farmers. Finally, we did not confirm the previous putative effect of exposure to triazine herbicides.

Exposure to pesticides and risk of Hodgkin lymphoma in an international consortium of agricultural cohorts (AGRICOH)

PURPOSE

Some pesticides may increase the risk of certain lymphoid malignancies, but few studies have examined Hodgkin lymphoma (HL). In this exploratory study, we examined associations between agricultural use of 22 individual active ingredients and 13 chemical groups and HL incidence.

METHODS

We used data from three agricultural cohorts participating in the AGRICOH consortium: the French Agriculture and Cancer Cohort (2005-2009), Cancer in the Norwegian Agricultural Population (1993-2011), and the US Agricultural Health Study (1993-2011). Lifetime pesticide use was estimated from crop-exposure matrices or self-report. Cohort-specific covariate-adjusted overall and age-specific (< 40 or ≥ 40 years) hazard ratios (HRs) and 95% confidence intervals (CIs) were estimated using Cox regression and combined using random effects meta-analysis.

RESULTS

Among 316 270 farmers (75% male) accumulating 3 574 815 person-years at risk, 91 incident cases of HL occurred. We did not observe statistically significant associations for any of the active ingredients or chemical groups studied. The highest risks of HL overall were observed for the pyrethroids deltamethrin (meta-HR = 1.86, 95% CI 0.76-4.52) and esfenvalerate (1.86, 0.78-4.43), and inverse associations of similar magnitude were observed for parathion and glyphosate. Risk of HL at ≥ 40 years of age was highest for ever-use of dicamba (2.04, 0.93-4.50) and lowest for glyphosate (0.46, 0.20-1.07).

CONCLUSION

We report the largest prospective investigation of these associations. Nonetheless, low statistical power, a mixture of histological subtypes and a lack of information on tumour EBV status complicate the interpretability of the results. Most HL cases occurred at older ages, thus we could not explore associations with adolescent or young adult HL. Furthermore, estimates may be attenuated due to non-differential exposure misclassification. Future work should aim to extend follow-up and refine both exposure and outcome classification.

Cancer incidence in agricultural workers: Findings from an international consortium of agricultural cohort studies (AGRICOH)

BACKGROUND

Agricultural work can expose workers to potentially hazardous agents including known and suspected carcinogens. This study aimed to evaluate cancer incidence in male and female agricultural workers in an international consortium, AGRICOH, relative to their respective general populations.

METHODS

The analysis included eight cohorts that were linked to their respective cancer registries: France (AGRICAN: n = 128,101), the US (AHS: n = 51,165, MESA: n = 2,177), Norway (CNAP: n = 43,834), Australia (2 cohorts combined, Australian Pesticide Exposed Workers: n = 12,215 and Victorian Grain Farmers: n = 919), Republic of Korea (KMCC: n = 8,432), and Denmark (SUS: n = 1,899). For various cancer sites and all cancers combined, standardized incidence ratios (SIR) and 95% confidence intervals (CIs) were calculated for each cohort using national or regional rates as reference rates and were combined by random-effects meta-analysis.

RESULTS

During nearly 2,800,000 person-years, a total of 23,188 cancers were observed. Elevated risks were observed for melanoma of the skin (number of cohorts = 3, meta-SIR = 1.18, CI: 1.01-1.38) and multiple myeloma (n = 4, meta-SIR = 1.27, CI: 1.04-1.54) in women and prostate cancer (n = 6, meta-SIR = 1.06, CI: 1.01-1.12), compared to the general population. In contrast, a deficit was observed for the incidence of several cancers, including cancers of the bladder, breast (female), colorectum, esophagus, larynx, lung, and pancreas and all cancers combined (n = 7, meta-SIR for all cancers combined = 0.83, 95% CI: 0.77-0.90). The direction of risk was largely consistent across cohorts although we observed large between-cohort variations in SIR for cancers of the liver and lung in men and women, and stomach, colorectum, and skin in men.

CONCLUSION

The results suggest that agricultural workers have a lower risk of various cancers and an elevated risk of prostate cancer, multiple myeloma (female), and melanoma of skin (female) compared to the general population. Those differences and the between-cohort variations may be due to underlying differences in risk factors and warrant further investigation of agricultural exposures.

Occupational Exposure and Multiple Myeloma Risk: An Updated Review of Meta-Analyses

The precise etiology of multiple myeloma remains elusive, but both genetic and environmental factors have been suggested to contribute to disease risk. Several occupational categories and toxic agents have been implicated as potentially causative, yet findings from the literature are inconsistent. The aim of this review was to summarize and critically comment on the accumulated epidemiological evidence, across published meta-analyses, about the association between occupational exposure and risk of multiple myeloma. Overall, results from eleven meta-epidemiological studies underscore a significantly increased risk for firefighters, hairdressers, and employees exposed to engine exhaust, whereas farming and methylene chloride exposure have been non-significantly correlated with the disease. Further epidemiological studies are of utmost importance whilst emphasis should be placed on occupational hazard surveillance, as such studies will obtain a more accurate picture of disease occurrence in working populations, and will enable both the implementation of preventive actions and the evaluation of their effectiveness.

Farming, Pesticides, and Brain Cancer: A 20-Year Updated Systematic Literature Review and Meta-Analysis

Twenty additional years of epidemiologic literature have become available since the publication of two meta-analyses on farming and brain cancer in 1998. The current systematic literature review and meta-analysis extends previous research and harmonizes findings. A random effects model was used to calculate meta-effect estimates from 52 studies (51 articles or reports), including 11 additional studies since 1998. Forty of the 52 studies reported positive associations between farming and brain cancer with effect estimates ranging from 1.03 to 6.53. The overall meta-risk estimate was 1.13 (95% CI = 1.06, 1.21), suggesting that farming is associated with a 13% increase in risk of brain cancer morbidity or mortality. Farming among white populations was associated with a higher risk of brain cancer than among non-white populations. Livestock farming (meta-RR = 1.34; 95% CI = 1.18, 1.53) was associated with a greater risk compared with crop farming (meta-RR = 1.13; 95% CI = 0.97, 1.30). Farmers with documented exposure to pesticides had greater than a 20% elevated risk of brain cancer. Despite heterogeneity among studies, we conclude that the synthesis of evidence from 40 years of epidemiologic literature supports an association between brain cancer and farming with its potential for exposure to chemical pesticides.

Occupational pesticide exposure increases risk of acute myeloid leukemia: a meta-analysis of case-control studies including 3,955 cases and 9,948 controls

The impact of pesticides on health is a major public health concern. A higher risk to develop chronic lymphoid malignancies has been demonstrated to be associated with occupational pesticide exposure (OPE). By contrast, little is known of the impact of OPE on the occurrence of myeloid malignancies especially acute myeloid leukemia (AML). The purpose of this meta-analysis is to summarize data on the association between OPE and AML. A relevant dataset of case-control studies was extracted. Among 6784 references extracted, 14 were selected, representing 3,955 AML patients and 9,948 control subjects diagnosed between 1976 and 2010. An adverse association was found between OPE and AML (OR = 1.51; 95%CI: 1.10-2.08), not affected by sensitivity analyses. Funnel plot asymmetry suggested a publication bias underestimating OR. Stratified analysis showed the association to be driven by studies with: (1) monocentric AML patients and hospital-based control population, (2) Newcastle-Ottawa scale > 6 and the group of studies identified as with the lowest risk, (3) exposure assessment through peer-to-peer interview, (4) diagnosis in North America and Asia and after 1995, (5) restriction to de novo AML. Moreover, the association between OPE and AML was significant with insecticides. These findings broaden the spectrum of pesticide toxicity to myeloid malignancies.

Synthetic Pesticides and Health in Vulnerable Populations: Agricultural Workers

PURPOSE OF REVIEW

This review aims to summarize epidemiological literature published between May 15, 2018, and May 14, 2019, that examines the relationship between exposure to synthetic pesticides and health of agricultural workers.

RECENT FINDINGS

Current research suggests that exposure to synthetic pesticides may be associated with adverse health outcomes. Agricultural workers represent a potentially vulnerable population, due to a combination of unique social and cultural risk factors as well as exposure to hazards inherent in agricultural work. Pesticide exposure among agricultural workers has been linked to certain cancers, DNA damage, oxidative stress, neurological disorders, and respiratory, metabolic, and thyroid effects. This review describes literature suggesting that agricultural workers exposed to synthetic pesticides are at an increased risk of certain cancers and neurological disorders. Recent research on respiratory effects is sparse, and more research is warranted regarding DNA damage, oxidative stress, metabolic outcomes, and thyroid effects.

Physician Notified Work-Related Diseases Among Farmers in Norway: Data from 2007 - 2016

Introduction: This study provided a profile of work-related diseases in the farming sector notified by physicians to the Norwegian Labor Inspection Authority's (NLIA) Registry for Work-Related Diseases (RAS) over a 10-year period.Methods: Data for the occupational code "farmers" were extracted from RAS for the period 2007-2016. We performed a descriptive analysis to obtain frequency, percentage, and incidence distribution of the data. We also explored the relationship of the notified diagnosis with gender, age, occupational exposures and the type of reporting physicians.Results: Four hundred and sixty-nine cases of work-related diseases among farmers were notified in the period 2007-2016. Eighty-seven percent of the reported cases were males. The incidence of work-related diseases for the entire study period was computed to be 114/100 000 workers. The incidence and number of cases notified were highest among males and for the age group 55-74 years. Noise was the most frequently reported occupational exposure accounted for 291 cases. Hearing loss constituted for 62% of the notified cases, followed by respiratory diseases that accounted for 20% of the cases. Forty-eight cases of skin diseases, while only a few cases of musculoskeletal (n = 7) and mental disorders (n = 1) were notified. There was a strong association (λ = 0.51) between occupational exposure and notified diagnosis, and a moderate association (λ = 0.32) between type of reporting physician and the notified diagnosis.Conclusion: This profile of the physician notified work-related diseases among farmers in Norway yielded a suppressed estimate of the actual incidence of cases. The biased distribution of nature and number of work-related diseases amongst farmers is primarily attributed to the significant undercount of cases. Physician underreporting of cases to the NLIA coupled with lack of Occupational Health Services coverage of workers in the farming sector contributes to this undercount of cases.

Animal farming and the risk of lymphohaematopoietic cancers: a meta-analysis of three cohort studies within the AGRICOH consortium

OBJECTIVE

Animal farming entails a variety of potential exposures, including infectious agents, endotoxins and pesticides, which may play a role in the aetiology of lymphohaematopoietic cancers (LHCs). The aim of this study was to assess whether farming specific animal species is associated with the risk of overall LHC or its subtypes.

METHODS

Data from three prospective cohort studies in the USA, France and Norway which are part of the Agricultural Cohort consortium and which collected information about animal farming and cancer were used. Analyses included 316 270 farmers and farm workers. Adjusted Cox models were used to investigate the associations of 13 histological subtypes of LHC (n=3282) with self-reported livestock (cattle, pigs and sheep/goats) and poultry (ever/never and numbers raised) farming. Cohort-specific HRs were combined using random-effects meta-analysis.

RESULTS

Ever animal farming in general or farming specific animal species was not meta-associated with overall LHC. The risk of myeloid malignancies decreased with increasing number of livestock (p trend=0.01). Increased risk of myeloproliferative neoplasms was seen with increasing number of sheep/goats (p trend <0.01), while a decreased risk was seen with increasing number of livestock (p trend=0.02). Between cohorts, we observed heterogeneity in the association of type of animal farmed and various LHC subtypes.

CONCLUSIONS

This large-scale study of three prospective agricultural cohorts showed no association between animal farming and LHC risk, but few associations between specific animal species and LHC subtypes were observed. The observed differences in associations by countries warrant further investigations.

Pesticide use and risk of non-Hodgkin lymphoid malignancies in agricultural cohorts from France, Norway and the USA: a pooled analysis from the AGRICOH consortium

BACKGROUND

Pesticides are commonly used in agriculture, and previous studies endorsed the need to further investigate the possible association between their use and risk of lymphoid malignancies in agricultural workers.

METHODS

We investigated the relationship of ever use of 14 selected pesticide chemical groups and 33 individual active chemical ingredients with non-Hodgkin lymphoid malignancies (NHL) overall or major subtypes, in a pooled analysis of three large agricultural worker cohorts. Pesticide use was derived from self-reported history of crops cultivated combined with crop-exposure matrices (France and Norway) or self-reported lifetime use of active ingredients (USA). Cox regression models were used to estimate cohort-specific hazard ratios (HRs) and 95% confidence intervals (CIs), which were combined using random effects meta-analysis to calculate meta-HRs.

RESULTS

During follow-up, 2430 NHL cases were diagnosed in 316 270 farmers accruing 3 574 815 person-years under risk. Most meta-HRs suggested no association. Moderately elevated meta-HRs were seen for: NHL and ever use of terbufos (meta-HR = 1.18, 95% CI: 1.00-1.39); chronic lymphocytic leukaemia/small lymphocytic lymphoma and deltamethrin (1.48, 1.06-2.07); and diffuse large B-cell lymphoma and glyphosate (1.36, 1.00-1.85); as well as inverse associations of NHL with the broader groups of organochlorine insecticides (0.86, 0.74-0.99) and phenoxy herbicides (0.81, 0.67-0.98), but not with active ingredients within these groups, after adjusting for exposure to other pesticides.

CONCLUSIONS

Associations of pesticides with NHL appear to be subtype- and chemical-specific. Non-differential exposure misclassification was an important limitation, showing the need for refinement of exposure estimates and exposure-response analyses.

Occupational Risk Factors for Prostate Cancer: A Meta-analysis

Prostate cancer is the second most common cancer in men worldwide. There are many occupational factors that have been suggested to cause prostate cancer. Our aim was to evaluate the evidence for causality by a literature review of occupational factors. We searched literature in Medline and SCOPUS from 1966 to June 30, 2015 to identify occupational risk factors for prostate cancer. The following risk factors were selected: farmers/agricultural workers, pesticides - whole group, and separately organophosphate and organochlorine pesticides, carbamates and triazines, cadmium, chromium, cutting fluids, acrylonitrile, rubber manufacturing, whole body vibration, shift work, flight personnel, ionizing radiation, and occupational physical activity. For each factor a literature search was performed and presented as meta-analysis of relative risk and heterogeneity (Q and I2 index). A total of 168 original studies met the inclusion criteria with 90,688 prostate cancer cases. Significantly increased risks were observed for the following occupational exposures: pesticides (metaRR = 1.15, 95% confidence interval [CI] = 1.01-1.32; I2 = 84%), and specifically group of organochlorine pesticides (meta relative risk [metaRR] = 1.08, 95% CI = 1.03-1.14; I2 = 0%), chromium (metaRR = 1.19, 95% CI = 1.07-1.34; I2 = 31%), shift work (metaRR = 1.25, 95% CI = 1.05-1.49; I2 = 78%) and pilots (metaRR = 1.41, 95% CI = 1.02-1.94; I2 = 63%) and occupational physical activity in cohort studies (metaRR = 0.87, 95% CI = 0.81-0.94; I2 = 0%). The literature review supports a causal association for a few of the previously suggested factors.

Insecticide Use and Breast Cancer Risk among Farmers' Wives in the Agricultural Health Study

BACKGROUND

Some epidemiologic and laboratory studies suggest that insecticides are related to increased breast cancer risk, but the evidence is inconsistent. Women engaged in agricultural work or who reside in agricultural areas may experience appreciable exposures to a wide range of insecticides.

OBJECTIVE

We examined associations between insecticide use and breast cancer incidence among wives of pesticide applicators (farmers) in the prospective Agricultural Health Study.

METHODS

Farmers and their wives provided information on insecticide use, demographics, and reproductive history at enrollment in 1993-1997 and in 5-y follow-up interviews. Cancer incidence was determined via cancer registries. Among 30,594 wives with no history of breast cancer before enrollment, we examined breast cancer risk in relation to the women's and their husbands' insecticide use using Cox proportional hazards regression to estimate adjusted hazard ratios (HRs) and 95% confidence intervals (CIs).

RESULTS

During an average 14.7-y follow-up, 39% of the women reported ever using insecticides, and 1,081 were diagnosed with breast cancer. Although ever use of insecticides overall was not associated with breast cancer risk, risk was elevated among women who had ever used the organophosphates chlorpyrifos [HR=1.4 (95% CI: 1.0, 2.0)] or terbufos [HR=1.5 (95% CI: 1.0, 2.1)], with nonsignificantly increased risks for coumaphos [HR=1.5 (95% CI: 0.9, 2.5)] and heptachlor [HR=1.5 (95% CI: 0.7, 2.9)]. Risk in relation to the wives' use was associated primarily with premenopausal breast cancer. We found little evidence of differential risk by tumor estrogen receptor status. Among women who did not apply pesticides, the husband's use of fonofos was associated with elevated risk, although no exposure-response trend was observed.

CONCLUSION

Use of several organophosphate insecticides was associated with elevated breast cancer risk. However, associations for the women's and husbands' use of these insecticides showed limited concordance. Ongoing cohort follow-up may help clarify the relationship, if any, between individual insecticide exposures and breast cancer risk. https://doi.org/10.1289/EHP1295.

Postnatal risk factors for testicular cancer: The EPSAM case-control study

Testicular cancer is considered to originate from an impaired differentiation of fetal germ cells, but puberty could represent another time window of susceptibility. Our study aimed at investigating the association between environmental exposures acting during puberty/adolescence (13-19 years of age) and the risk of testicular cancer. We used data of the EPSAM study, a case-control study on germ-cell testicular cancer conducted in the province of Turin, Italy, involving cases diagnosed between 1997 and 2008. Histologically confirmed cases (n = 255) and controls (n = 459) completed a postal questionnaire focusing in particular on the pubertal period (namely age 13 years) with questions on physical activity (competitive sports, gardening), lifestyle (alcohol consumption, smoking), occupational history and medical conditions. All analyses were adjusted for the matching variables, cryptorchidism and educational level. Having done at least one competitive sport during puberty (odds ratio [OR]: 0.72, 95% confidence interval: 0.52-1.00), gardening activities during puberty (OR: 0.62, 0.42-0.94) and having a lower weight than peers during puberty (OR: 0.64, 0.42-0.97) were all inversely associated with the risk of testicular cancer. No evidence of association between smoking or alcohol consumption during puberty and the risk of testicular cancer was observed. Regarding agriculture-related occupations, we found an association with the risk of testicular cancer both for occasional jobs during puberty (OR: 2.40, 95% CI: 1.08-5.29) and ever employment in adolescence (OR: 2.59, 95% CI: 0.83-8.10). Our results suggest that postnatal exposures could play a role in testicular cancer aetiology, at least when acting in puberty or adolescence.

Central nervous system tumors and agricultural exposures in the prospective cohort AGRICAN

Studies in farmers suggest a possible role of pesticides in the occurrence of Central Nervous System (CNS) tumors but scientific evidence is still insufficient. Using data from the French prospective agricultural cohort AGRICAN (Agriculture & Cancer), we investigated the associations between exposure of farmers and pesticide users to various kinds of crops and animal farming and the incidence of CNS tumors, overall and by subtypes. Over the 2005-2007, 181,842 participants completed the enrollment questionnaire that collected a complete job calendar with lifetime history of farming types. Associations were estimated using proportional hazards models with age as underlying timescale. During a 5.2 years average follow-up, 273 incident cases of CNS tumors occurred, including 126 gliomas and 87 meningiomas. Analyses showed several increased risks of CNS tumors in farmers, especially in pesticide users (hazard ratio = 1.96; 95% confidence interval: 1.11-3.47). Associations varied with tumor subtypes and kinds of crop and animal farming. The main increases in risk were observed for meningiomas in pig farmers and in farmers growing sunflowers, beets and potatoes and for gliomas in farmers growing grasslands. In most cases, more pronounced risk excesses were observed among pesticide applicators. Even if we cannot completely rule out the contribution of other factors, pesticide exposures could be of primary concern to explain these findings.

George DM, Loffredo CA, Amr S. Nonoccupational exposure to agricultural work and risk of urinary bladder cancer among Egyptian women

This study examined the associations between nonoccupational exposure to agricultural work, through husband or head of household (H/HH) occupation, and urinary bladder cancer risk among Egyptian women. A total of 1,167 women (388 bladder cases and 779 age- and residence-matched, population-based controls) from a multicenter case-control study were included in the analysis. Adjusted odds ratios (AORs) and 95% confidence intervals (CIs) were estimated using logistic regression. Among married women, those who reported H/HH to be an agricultural worker were at increased risk for bladder cancer as compared to those with H/HH in other occupations, AOR = 1.54, 95% CI [1.09, 2.18]; among unmarried women the risk was not increased, AOR = 0.77, 95% CI [0.45, 1.32]. Nonoccupational exposure to agricultural work, defined as living with an agricultural worker, increased the risk for bladder cancer among married Egyptian women.

Adjustment for tobacco smoking and alcohol consumption by simultaneous analysis of several types of cancer

PURPOSE

Tobacco smoking and alcohol consumption are risk factors for several types of cancer and may act as confounders in aetiological studies. Large register-based cohorts often lack data on tobacco and alcohol. We present a method for computing estimates of cancer risk adjusted for tobacco and alcohol without exposure information.

METHODS

We propose the use of confirmatory factor analysis models for simultaneous analysis of several cancer sites related to tobacco and alcohol. In the analyses, the unobserved pattern of smoking habits and alcohol drinking is considered latent common factors. The models allow for different effects on each cancer site, and also for appropriate latent site-specific factors for subgroup variation. Results may be used to compute expected numbers of cancer from reference rates, adjusted for tobacco smoking and alcohol consumption. This method was applied to results from a large, published study of work-related cancer based on census data (1970) and 21 years of cancer incidence data from the national cancer registry.

RESULTS

The results from our analysis were in accordance with recognised risks in selected occupational groups. The estimated relative effects from tobacco and alcohol on cancer risk were largely in line with results from Nordic reports. For lung cancer, adjustment for tobacco implied relative changes in SIR between a decrease from 1.16 to 0.72 (Fishermen), and an increase from 0.47 to 0.95 (Forestry workers).

CONCLUSIONS

We consider the method useful for achieving less confounded estimates of cancer risk in large cohort studies with no available information on smoking and alcohol consumption.

Assessment of occupational exposure to pesticides in a pooled analysis of agricultural cohorts within the AGRICOH consortium

BACKGROUND

This paper describes methods developed to assess occupational exposure to pesticide active ingredients and chemical groups, harmonised across cohort studies included in the first AGRICOH pooling project, focused on the risk of lymph-haematological malignancies.

METHODS

Three prospective agricultural cohort studies were included: US Agricultural Health Study (AHS), French Agriculture and Cancer Study (AGRICAN) and Cancer in the Norwegian Agricultural Population (CNAP). Self-reported pesticide use was collected in AHS. Crop-exposure matrices (CEMs) were developed for AGRICAN and CNAP. We explored the potential impact of these differences in exposure assessment by comparing a CEM approach estimating exposure in AHS with self-reported pesticide use.

RESULTS

In AHS, 99% of participants were considered exposed to pesticides, 68% in AGRICAN and 63% in CNAP. For all cohorts combined (n=316 270), prevalence of exposure ranged from 19% to 59% for 14 chemical groups examined, and from 13% to 46% for 33 active ingredients. Exposures were highly correlated within AGRICAN and CNAP where CEMs were applied; they were less correlated in AHS. Poor agreement was found between self-reported pesticide use and assigned exposure in AHS using a CEM approach resembling the assessment for AGRICAN (κ -0.00 to 0.33) and CNAP (κ -0.01 to 0.14).

CONCLUSIONS

We developed country-specific CEMs to assign occupational exposure to pesticides in cohorts lacking self-reported data on the use of specific pesticides. The different exposure assessment methods applied may overestimate or underestimate actual exposure prevalence, and additional work is needed to better estimate how far the exposure estimates deviate from reality.

Occupational exposure to pesticides and bladder cancer risk

BACKGROUND

In the developed world, occupational exposures are a leading cause of bladder cancer. A few studies have suggested a link between pesticide exposures among agricultural populations and bladder cancer.

METHODS

We used data from the Agricultural Health Study, a prospective cohort study which includes 57 310 pesticide applicators with detailed information on pesticide use, to evaluate the association between pesticides and bladder cancer. We used Poisson regression to calculate rate ratios (RRs) and 95% confidence intervals (CIs) to estimate the association between each of 65 pesticides and 321 incident bladder cancer cases which accrued over the course of follow-up (1993-2011), adjusting for lifestyle and demographic and non-pesticide farm-related exposures, including those previously linked to bladder cancer. We conducted additional analyses stratified by smoking status (never, former, current).

RESULTS

We observed associations with bladder cancer risk for two imidazolinone herbicides, imazethapyr and imazaquin, which are aromatic amines. Ever use of imazaquin (RR = 1.54, 95% CI: 1.05, 2.26) was associated with increased risk whereas the excess risk among users of imazethapyr was evident among never smokers (RR in highest quartile vs non-exposed = 3.03, 95% CI: 1.46, 6.29, P-interaction = 0.005). We also observed increased risks overall and among never smokers for use of several chlorinated pesticides including chlorophenoxy herbicides and organochlorine insecticides.

CONCLUSIONS

Several associations between specific pesticides and bladder cancer risk were observed, many of which were stronger among never smokers, suggesting that possible risk factors for bladder cancer may be more readily detectable in those unexposed to potent risk factors like tobacco smoke.

Parental occupational pesticide exposure and the risk of childhood leukemia in the offspring: findings from the childhood leukemia international consortium

Maternal occupational pesticide exposure during pregnancy and/or paternal occupational pesticide exposure around conception have been suggested to increase risk of leukemia in the offspring. With a view to providing insight in this area we pooled individual level data from 13 case-control studies participating in the Childhood Leukemia International Consortium (CLIC). Occupational data were harmonized to a compatible format. Pooled individual analyses were undertaken using unconditional logistic regression. Using exposure data from mothers of 8,236 cases, and 14,850 controls, and from fathers of 8,169 cases and 14,201 controls the odds ratio (OR) for maternal exposure during pregnancy and the risk of acute lymphoblastic leukemia (ALL) was 1.01 [95% confidence interval (CI) 0.78, 1.30] and for paternal exposure around conception 1.20 (95% 1.06, 1.38). For acute myeloid leukemia (AML), the OR for maternal exposure during pregnancy was 1.94 (CI 1.19, 3.18) and for paternal exposure around conception 0.91 (CI 0.66, 1.24.) based on data from 1,329 case and 12,141 control mothers, and 1,231 case and 11,383 control fathers. Our finding of a significantly increased risk of AML in the offspring with maternal exposure to pesticides during pregnancy is consistent with previous reports. We also found a slight increase in risk of ALL with paternal exposure around conception which appeared to be more evident in children diagnosed at the age of 5 years or more and those with T cell ALL which raises interesting questions on possible mechanisms.

Acute myeloid leukemia risk by industry and occupation

Acute myeloid leukemia (AML) is the most common type of leukemia found in adults. Identifying jobs that pose a risk for AML may be useful for identifying new risk factors. A matched case-control analysis was conducted using California Cancer Registry data from 1988 to 2007. This study included 8999 cases of AML and 24 822 controls. Industries with a statistically significant increased AML risk were construction (matched odds ratio [mOR] = 1.13); crop production (mOR = 1.41); support activities for agriculture and forestry (mOR = 2.05); and animal slaughtering and processing (mOR = 2.09). Among occupations with a statistically significant increased AML risk were miscellaneous agricultural workers (mOR = 1.76); fishers and related fishing workers (mOR = 2.02); nursing, psychiatric and home health aides (mOR = 1.65); and janitors and building cleaners (mOR = 1.54). Further investigation is needed to confirm study findings and to identify specific exposures responsible for the increased risks.

Agricultural workers and urinary bladder cancer risk in Egypt

The authors examined the associations between farming and the risk for squamous cell (SCC) or urothelial cell (UC) carcinoma of the urinary bladder among Egyptians. The authors used data from a multicenter case-control study (1,525 male and 315 female cases, and 2,069 male and 547 female age- and residence-matched, population-based controls) to calculate adjusted odds ratios (AORs) and 95% confidence intervals (CIs). Men in farming and who never smoked had increased risk for either SCC or UC (AOR [95% CI]: 4.65 [2.59-8.36] and 6.22 [3.82-10.15], respectively). If they ever smoked, their risks were 2.27 (1.75-2.95) and 1.93 (1.58-2.35), respectively. Women in farmer households were at increased risk for SCC (1.40 [0.93-2.09] and UC [1.25 (0.82-1.89]), although not statistically significant. Occupational and environmental exposures to farming increased the risk for bladder cancer among Egyptians.

Pesticides and human chronic diseases: evidences, mechanisms, and perspectives

Along with the wide use of pesticides in the world, the concerns over their health impacts are rapidly growing. There is a huge body of evidence on the relation between exposure to pesticides and elevated rate of chronic diseases such as different types of cancers, diabetes, neurodegenerative disorders like Parkinson, Alzheimer, and amyotrophic lateral sclerosis (ALS), birth defects, and reproductive disorders. There is also circumstantial evidence on the association of exposure to pesticides with some other chronic diseases like respiratory problems, particularly asthma and chronic obstructive pulmonary disease (COPD), cardiovascular disease such as atherosclerosis and coronary artery disease, chronic nephropathies, autoimmune diseases like systemic lupus erythematous and rheumatoid arthritis, chronic fatigue syndrome, and aging. The common feature of chronic disorders is a disturbance in cellular homeostasis, which can be induced via pesticides' primary action like perturbation of ion channels, enzymes, receptors, etc., or can as well be mediated via pathways other than the main mechanism. In this review, we present the highlighted evidence on the association of pesticide's exposure with the incidence of chronic diseases and introduce genetic damages, epigenetic modifications, endocrine disruption, mitochondrial dysfunction, oxidative stress, endoplasmic reticulum stress and unfolded protein response (UPR), impairment of ubiquitin proteasome system, and defective autophagy as the effective mechanisms of action.

Occupation and leukemia in Nordic countries

OBJECTIVE

We studied occupational variation of the risk of acute myeloid leukemia, chronic lymphocytic leukemia, and other leukemia in Nordic countries.

METHODS

The study cohort comprised 15 million persons older than 30 years who participated in the population censuses in 1960, 1970, 1980/1981, 1990, or all of these years in five Nordic countries. Standardized incidence ratios (SIRs) were estimated for 53 occupations and one group of economically inactive persons.

RESULTS

Significantly increased risks were observed for acute myeloid leukemia among drivers (SIR = 1.16; 95% confidence interval [CI], 1.07-1.26) and food workers (SIR = 1.13; 95% CI, 1.01-1.27); for chronic lymphocytic leukemia among farmers (SIR = 1.09; 95% CI, 1.04-1.14) and clerical workers (SIR = 1.07; 95% CI, 1.01-1.14); and for other leukemia among seamen (SIR = 1.24; 95% CI, 1.04-1.49), "other health workers" (SIR = 1.22; 95% CI, 1.02-1.47), chemical process workers (SIR = 1.18; 95% CI, 1.01-1.38), and sales agents (SIR = 1.15; 95% CI, 1.06-1.25).

CONCLUSION

Observed modest occupational variation of leukemia risk might be associated with occupational or lifestyle factors.

Prostate cancer and toxicity from critical use exemptions of methyl bromide: environmental protection helps protect against human health risks

BACKGROUND

Although ozone-depleting methyl bromide was destined for phase-out by 2005, it is still widely applied as a consequence of various critical-use-exemptions and mandatory international regulations aiming to restrict the spread of pests and alien species (e.g. in globalized transport and storage). The withdrawal of methyl bromide because of its environmental risk could fortuitously help in the containment of its human toxicity.

METHODS

We performed a systematic review of the literature, including in vitro toxicological and epidemiological studies of occupational and community exposure to the halogenated hydrocarbon pesticide methyl bromide. We focused on toxic (especially chronic) or carcinogenic effects from the use of methyl bromide, on biomonitoring data and reference values. Eligible epidemiological studies were subjected to meta-analysis.

RESULTS

Out of the 542 peer reviewed publications between 1990-2011, we found only 91 referring to toxicity of methyl bromide and 29 using the term "carcinogenic", "neoplastic" or "mutagenic". Several studies provide new additional data pertaining to the mechanistic aspects of methyl bromide toxicity. Few studies have performed a detailed exposure assessment including biomonitoring. Three evaluated epidemiological studies assessed a possible association between cancer and methyl bromide. Overall, exposure to methyl bromide is associated with an increased risk of prostate cancer OR, 1.21; 95% CI (0,98-1.49), P = 0.076. Two epidemiological studies have analyzed environmental, non-occupational exposure to methyl bromide providing evidence for its health risk to the general public. None of the epidemiological studies addressed its use as a fumigant in freight containers, although recent field and case reports do refer to its toxic effects associated with its use in shipping and storage.

CONCLUSIONS

Both the epidemiological evidence and toxicological data suggest a possible link between methyl bromide exposure and serious health problems, including prostate cancer risk from occupational and community exposure. The environmental risks of methyl bromide are not in doubt, but also its health risks, especially for genetically predisposed subjects, should not be underestimated.

Multiple myeloma and occupational exposures: a population-based case-control study

OBJECTIVE

The present study aims to identify occupational exposures associated with incidence of multiple myeloma (MM).

METHODS

A population-based case-control study of MM (ICD-9 203) was conducted among Canadian males, with a total of 342 cases and 1506 controls contributing to the final analyses. Conditional logistic regression was used to estimate odds ratios (OR) and confidence intervals (CI), stratifying by age groups and province of residence.

RESULTS

Based on the most parsimonious multivariable model, the following variables were significantly associated with an increased incidence of MM: exposure to coal dust (OR 1.7, 95% CI 1.2-2.4), long-held occupations as a carpenter (OR 3.2, 95% CI 1.4-7.1) or a machinist (OR 2.4, 95% CI 1.0-5.8); and immediate family member having been previously diagnosed with certain cancers (OR 1.4, 95% CI 1.1-1.8).

CONCLUSION

In this study of Canadian men, a higher risk of MM may be associated with exposure to coal dust, long-held occupations as a carpenter or machinist, and a positive family history of cancer.

Breast cancer risk by occupation and industry: analysis of the CECILE study, a population-based case-control study in France

BACKGROUND

It has been suggested that certain occupational exposures may play a role in breast cancer etiology. The recognition of high-risk occupations may give clues about potential mammary carcinogens in the work place.

METHODS

We conducted a population-based case-control study in France including 1,230 breast cancer cases and 1,315 population controls with detailed information on lifetime work history. Odds ratios for women ever employed in an occupation or industry were adjusted for well-established risk factors for breast cancer.

RESULTS

Adjusted odds ratios were marginally increased in some white-collar occupations, as well as in textile workers (2.4; 95% CI [0.9-6.0]), rubber and plastics product makers (1.8; 95% CI [0.9-3.5]), and in women employed for more than 10 years as nurses (1.4; 95% CI [0.9-2.1]) and as tailors/dressmakers (1.5; 95% CI [0.9-2.6]). The incidence of breast cancer was increased among women employed in the manufacture of chemicals, of non-metallic mineral products, and decreased among women in agriculture.

CONCLUSIONS

These findings suggest a possible role of occupational exposures in breast cancer, including night-shift work, solvents and endocrine disrupting chemicals and require further studies with detailed assessment of occupational exposures.

AGRICOH: a consortium of agricultural cohorts

AGRICOH is a recently formed consortium of agricultural cohort studies involving 22 cohorts from nine countries in five continents: South Africa (1), Canada (3), Costa Rica (2), USA (6), Republic of Korea (1), New Zealand (2), Denmark (1), France (3) and Norway (3). The aim of AGRICOH, initiated by the US National Cancer Institute (NCI) and coordinated by the International Agency for Research on Cancer (IARC), is to promote and sustain collaboration and pooling of data to investigate the association between a wide range of agricultural exposures and a wide range of health outcomes, with a particular focus on associations that cannot easily be addressed in individual studies because of rare exposures (e.g., use of infrequently applied chemicals) or relatively rare outcomes (e.g., certain types of cancer, neurologic and auto-immune diseases). To facilitate future projects the need for data harmonization of selected variables is required and is underway. Altogether, AGRICOH provides excellent opportunities for studying cancer, respiratory, neurologic, and auto-immune diseases as well as reproductive and allergic disorders, injuries and overall mortality in association with a wide array of exposures, prominent among these the application of pesticides.

Season of birth and risk for adult onset glioma

Adult onset glioma is a rare cancer which occurs more frequently in Caucasians than African Americans, and in men than women. The etiology of this disease is largely unknown. Exposure to ionizing radiation is the only well established environmental risk factor, and this factor explains only a small percentage of cases. Several recent studies have reported an association between season of birth and glioma risk. This paper reviews the plausibility of evidence focusing on the seasonal interrelation of farming, allergies, viruses, vitamin D, diet, birth weight, and handedness. To date, a convincing explanation for the occurrence of adult gliomas decades after a seasonal exposure at birth remains elusive.

Associations of common variants in genes involved in metabolism and response to exogenous chemicals with risk of multiple myeloma

BACKGROUND

We examined risk of multiple myeloma (MM) associated with variants in genes involved in metabolism and response to exogenous chemicals [cytochrome P450 enzymes (CYP1B1, CYP2C9), epoxide hydrolase (EPHX1), paraoxonase 1 (PON1), arylhydrocarbon hydroxylase receptor (AHR), and NAD(P)H:quinone oxidoreductase (NQO1)].

METHODS

This study included 279 MM cases and 782 controls in a pooled analysis of two population-based case-control studies. One common variant from each candidate gene was genotyped using DNA from blood or buccal cells. We estimated risk of MM associated with each genotype, controlling for race, gender, study site, and age, using odds ratios (OR) and 95% confidence intervals (CI).

RESULTS

Evaluations of the CYP1B1 V432L variant (rs1056836) suggested increased risk of MM among persons with the CG and GG genotypes compared to the CC genotype [OR (95% CI)=1.4 (1.0-2.0)]. Similar results were seen in analyses stratified by race and gender. We did not find any associations between MM and the CYP2C9, EPHX1, NQO1, or PON1 genes.

CONCLUSIONS

CYP1B1 activates chemicals such as polycyclic aromatic hydrocarbons and dioxins to create oxidized, reactive intermediates, and higher gene activity has been shown for the G allele. We conducted the largest analysis to date on MM and these genetic variants and our results provide preliminary evidence that variation in CYP1B1 may influence susceptibility to MM.

Assessment of pesticide exposure control practices among men and women on fruit-growing farms in British Columbia

Exposure to pesticides can be reduced by wearing personal protective equipment (PPE) or by implementing alternative pest control techniques, such as Integrated Pest Management (IPM). A cross-sectional telephone survey was conducted to explore the prevalence of these practices and the factors that may be associated with them among men and women involved in fruit growing in British Columbia (BC), Canada. Survey variables were developed using a framework that incorporated aspects of farm structure, health promotion, and risk perception theories. Three hundred and eighty people took part in the survey (response rate 75%). Of those who applied pesticides (n = 119), 63% indicated that they usually wore PPE during application. Individual equipment use varied. Gloves were worn most frequently (84%), followed by a spray suit (77%) and breathing protection (75%). Peer-related factors and farm-specific characteristics such as the type of crops grown were most strongly associated with PPE use, whereas perception of pesticide risk was only weakly associated with this practice. IPM techniques had been tried on 62% of the conventional farms in the study. A range of factors was significantly associated with the use of IPM, including cultural, attitudinal, experiential, and risk-based and farm-specific variables. These results suggest that decisions to adopt exposure control practices may reflect consideration from the multiple dimensions that make up farm life, including structural characteristics of the farm as well as the attributes of the individuals who live on farms. These findings provide a better understanding of current practices and may help in the development of programs to promote pesticide exposure control practices in the BC farming community.

Epidemiology of the plasma-cell disorders

This review of the plasma-cell disorders begins with the definition of monoclonal gammopathy of undetermined significance (MGUS). The prevalence of MGUS in white and black populations is described. MGUS is a common finding in the medical practice of all physicians, and thus it is important to both the patient and the physician to determine whether the monoclonal protein remains stable or progresses to multiple myeloma (MM), Waldenström's macroglobulinemia (WM), primary systemic amyloidosis (AL), or a related disorder. The long-term (almost 40 years) follow-up data of 241 patients in the Mayo Clinic population is provided. In a large study of 1384 patients with MGUS from southeastern Minnesota, the risk of progression to MM, WM, AL, or other disorders was approximately 1% per year. Risk factors for progression are provided. The incidence of MM in Olmsted County, Minnesota, remained stable for the 56-year span 1945-2001. The apparent increase in incidence and mortality rates among patients with MM in many studies is due to improved case ascertainment, especially among the elderly. The incidence and mortality rates of MM in the United States and other countries are presented. The major emphasis is on the cause of MM, which is unclear. Exposure to radiation from atomic bombs, therapeutic and diagnostic radiation, and in workers in the nuclear industry field are addressed. Many studies involving agricultural occupations, exposure to benzene, petroleum products, and engine exhaust and other industrial exposures are discussed. Tobacco use, obesity, diet, and alcohol ingestion are all possible causes of MM. Clusters of MM have been noted. Multiple cases of MM have been found in first-degree relatives.

Shared occupational risks for transitional cell cancer of the bladder and renal pelvis among men and women in Sweden

BACKGROUND

Unlike cancer of the bladder, cancer of the renal pelvis is not considered an occupational cancer and little is known about risks among women.

METHODS

Using the Swedish national census and cancer registry-linked data (1971-1989), we identified transitional cell cancers of the renal pelvis (N = 1,374) and bladder (N = 21,591). Correlation between cancer sites for the standardized incidence ratios (SIR) were determined using Pearson's coefficient of the log SIR. Relative risks of job exposure matrix variables were calculated using Poisson regression.

RESULTS

Both cancer sites were significantly elevated among women and men employed in the machine/electronics industry, sedentary work, and indoor work, and men in the metal industry. The highest proportion of the bladder (12%) and renal pelvis (14%) cancers occurred among men employed in shop and construction metal work. Risks by industry were more correlated among women (r = 0.49, P = 0.002) than men (r = 0.24, P = 0.04). Cancers of the renal pelvis were elevated in several occupational and industry groups for which there was no elevated bladder cancer risk.

CONCLUSION

Cancers of the renal pelvis and bladder share common occupational risk factors that may be more frequent among women. In addition, there may be some jobs that pose an increased risk specifically for cancer of the renal pelvis but not bladder.

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.

Socio-economic and occupational risk factors for gastric cancer: a cohort study in Sweden

The effects of socio-economic/occupational factors on gastric cancer at various subsites (including corpus, cardia and unspecified cancers) are not well known. To investigate this issue, we carried out a follow-up study on the economically active Swedish population, based on the Swedish Family-Cancer Database. We calculated standardized incidence ratios and 95% confidence intervals for different occupational groups, adjusted for age, period, region and socio-economic status. The reference group was all the economically active population. Manual workers and farmers were at an increased risk of stomach cancer. An increased risk of corpus cancer was observed for male miners and quarry workers, fishermen, construction workers, packers, loaders and warehouse workers, clerical workers and female assistant nurses and postal workers. For cardia cancer, significantly increased standardized incidence ratios were observed for gardeners, transport workers, bricklayers and chemical process workers among men. Only male miner and quarry workers showed significantly increased risk of unspecified cancer. In conclusion, the present study indicates that socio-economic groups differ in risk by almost a factor of two for corpus and unspecified cancers, and less for cardia cancers. Cement and mineral dusts appear as major occupational risk factors.

Multiple myeloma: A review of the epidemiologic literature

Multiple myeloma, a neoplasm of plasma cells, accounts for approximately approximately 15% of lymphatohematopoietic cancers (LHC) and 2% of all cancers in the US. Incidence rates increase with age, particularly after age 40, and are higher in men, particularly African American men. The etiology is unknown with no established lifestyle, occupational or environmental risk factors. Although several factors have been implicated as potentially etiologic, findings are inconsistent. We reviewed epidemiologic studies that evaluated lifestyle, dietary, occupational and environmental factors; immune function, family history and genetic factors; and the hypothesized precursor, monoclonal gammopathies of undetermined significance (MGUS). Because multiple myeloma is an uncommon disease, etiologic assessments can be difficult because of small numbers of cases in occupational cohort studies, and few subjects reporting exposure to specific agents in case-control studies. Elevated risks have been reported consistently among persons with a positive family history of LHC. A few studies have reported a relationship between obesity and multiple myeloma, and this may be a promising area of research. Factors underlying higher incidence rates of multiple myeloma in African Americans are not understood. The progression from MGUS to multiple myeloma has been reported in several studies; however, there are no established risk factors for MGUS. To improve our understanding of the causes of multiple myeloma, future research efforts should seek the causes of MGUS. More research is also needed on the genetic factors of multiple myeloma, given the strong familial clustering of the disease.

Effect of selected insecticides on growth rate and stress protein expression in cultured human A549 and SH-SY5Y cells

Two organochlorines (dienochlor, endosulfan) and one neonicotinoid (imidacloprid) insecticides were investigated as putative cellular aggressors, both as pure chemicals and as commercial formulations, in order to evaluate the additional toxicity due to additives present in the commercial formulations. Toxicity was evaluated on human cells in vitro, by culturing neuronal SH-SY5Y and pulmonary A549 cell lines for 3 days in the presence of increasing concentrations of the selected pesticides. LOEC (lowest observed effect concentration), IC50 (concentration leading to a 50% decrease of cell growth) and expression changes of molecular chaperones involved in cellular protein quality control were determined. The investigated molecular chaperones were the cytosolic resident heat shock proteins (HSP27, HSP72/73, and HSP90) and the glucose regulated proteins (GRP78, GRP94) located in the endoplasmic reticulum (ER). Organochlorines were found to be the most toxic in both A549 and SH-SY5Y cells, IC50 being respectively 0.95 and 0.36 microM for dienochlor, 34 and 20 microM for endosulfan, 1.8 and 1.5 mM for imidacloprid. This shows that neuronal cells were more sensitive than pulmonary cells. LOEC and IC50 appeared at lower concentrations of active molecule when using the commercial formulations Techn'ufan (endosulfan) and Confidor (imidacloprid), indicating an additional adverse effect of additives. Insecticide concentrations higher than IC50 were found to induce an underexpression of all cytosolic HSPs, probably resulting from a general inhibition of protein synthesis. HSP27 was found to be underexpressed at concentrations of imidacloprid or endosulfan (as Techn'ufan) lower than IC50. This underexpression of the anti-apoptotic HSP27 could contribute to the increase of cell mortality. GRP78 was up-regulated by endosulfan in A549, but not in SH-SY5Y cells, suggesting a damaging effect on proteins specific to pulmonary cells. Conversely, HSP72/73 was found to be down-regulated, resulting probably from the ER unfolded protein response (UPR) as previously reported [Skandrani, D., Gaubin, Y., Vincent, C., Beau, B., Murat, J.C., Soleilhavoup, J.P., Croute, F., 2006. Relationship between toxicity of selected insecticides and expression of stress protein (HSP, GRP) in cultured human cells: effects of commercial formulations versus pure active molecules. Biochim. Biophys. Acta 1760 (1), 95-103].

Agricultural pesticide use and risk of glioma in Nebraska, United States

BACKGROUND

To evaluate the risk of the adult glioma associated with farming and agricultural pesticide use, the authors conducted a population based case control study in eastern Nebraska.

METHODS

Telephone interviews were conducted with men and women diagnosed with gliomas (n = 251) between 1988 and 1993 and controls (n = 498) randomly selected from the same geographical area. Unconditional logistic regression was used to calculate adjusted odds ratios (ORs) for farming and for use of individual and chemical classes of insecticides and herbicides, including pesticides classified as nitrosatable (able to form N-nitroso compounds upon reaction with nitrite). Non-farmers were used as the reference category for all analyses.

RESULTS

Among men, ever living or working on a farm and duration of farming were associated with significantly increased risks of glioma (> or =55 years on a farm OR = 3.9, 95% CI 1.8 to 8.6); however, positive findings were limited to proxy respondents. Among women, there were no positive associations with farming activities among self or proxy respondents. Specific pesticide families and individual pesticides were associated with significantly increased risks among male farmers; however, most of the positive associations were limited to proxy respondents. For two herbicides and three insecticides, use was positively associated with risk among both self and proxy respondents. Based on a small number of exposed cases, ORs were significantly increased for the herbicides metribuzin (OR = 3.4, 95% CI 1.2 to 9.7) and paraquat (OR = 11.1, 95% CI 1.2 to 101), and for the insecticides bufencarb (OR = 18.9, 95% CI 1.9 to 187), chlorpyrifos (OR = 22.6, 95% CI 2.7 to 191), and coumaphos (OR = 5.9, 95% CI 1.1 to 32).

CONCLUSION

The authors found significant associations between some specific agricultural pesticide exposures and the risk of glioma among male farmers but not among female farmers in Nebraska; however, most of the positive associations were limited to proxy respondents. These findings warrant further evaluation in prospective cohort studies where issues of recall bias are not a concern.

Insecticide urinary metabolites in nonoccupationally exposed populations

The wide use of insecticides in agricultural and residential settings has resulted in environmental contamination, leading to increased concern about exposure of the population and possible chronic effects on health. This review summarizes the studies that have measured urinary metabolites to assess exposure of nonoccupationally exposed population to nonpersistent insecticides, organophosphates (OPs), carbamates, and pyrethroids. Electronic search yielded 36 different studies performed in a small number of countries for the last 20 years, most of them dealing with OP urinary metabolites. Dialkylphosphates, specific metabolites of OPs, and specific metabolites of pyrethroids or carbamates, have been investigated. Results indicate that a wide range of the population, adults as well as children, is exposed to OPs and to a lesser extent to pyrethroids and carbamates. Levels are one to several orders of magnitude lower than those in occupational studies. The contribution of the different sources of insecticide exposure remains uncertain. Food contamination, as well as environmental and residential contamination, appears to influence exposure, especially in the case of children. Residential use of insecticides, having pets, and living near gardens or fields have all been inconstantly related to higher urinary metabolite levels. Occupational exposure of the parents, especially of the agricultural workers, seems to be a predictive factor of higher exposure of their children. More studies investigating every source and pathway of exposure of randomized population samples and in other countries than the United States, in particular in developing countries, could improve our knowledge of factors influencing insecticide exposure of the population.

Lymphohematopoietic Cancers in the United Farm Workers of America (UFW), 1988–2001

OBJECTIVE

Agricultural risk factors for lymphohematopoietic cancers (LHC) in Hispanic farm workers in California were examined in a nested case-control study embedded in a cohort of 139,000 ever members of a farm worker labor union in California.

METHODS

Crop and pesticide exposures were estimated by linking county/month and crop specific job history information from union records with California Department of Pesticide Regulation pesticide use reports during the 20-year period prior to cancer diagnosis.

RESULTS

A total of 131 LHC diagnosed in California between 1988 and 2001 were included in the analysis. Analyses were conducted by gender and subtype of non-Hodgkins lymphoma (nodal, extra nodal) and by leukemia histology (lymphocytic, granulocytic). Odds ratios were calculated by stratification and by unconditional logistic regression. Risk for all LHC was elevated in workers cultivating vegetables (OR = 1.67, 95% CI = 1.12-2.48). Risk of leukemia was associated with exposure to the pesticides mancozeb (OR = 2.35, 95% CI = 1.12-4.95) and toxaphene (OR = 2.20, 95% CI = 1.04-4.65) while NHL risk was increased in association with 2,4-D (OR = 3.80, 95% CI=1.85-7.81). Risk of leukemia was particularly elevated among female workers and for granulocytic versus lymphocytic leukemia for several chemicals. No associations were noted for multiple myeloma.

CONCLUSIONS

California farm workers employed where mancozeb and toxaphene were used had an increased risk of leukemia compared to farm workers employed elsewhere. Employment in farms using 2,4-D was associated with an increased risk of NHL.

Mortality among Participants in the Agricultural Health Study

PURPOSE

This analysis of the Agricultural Health Study cohort assesses the mortality experience of licensed pesticide applicators and their spouses.

METHODS

This report is based on 52,393 private applicators (who are mostly farmers) and 32,345 spouses of farmers in Iowa and North Carolina. At enrollment, each pesticide applicator completed a 21-page enrollment questionnaire. Mortality assessment from enrollment (1994-1997) through 2000 provided an average follow-up of about 5.3 years, 447,154 person-years, and 2055 deaths.

RESULTS

Compared with the general population in the two states, the cohort experienced a very low mortality rate. Standardized mortality ratios (SMRs) for total mortality, cardiovascular disease, diabetes, COPD, total cancer, and cancers of the esophagus, stomach, and lung were 0.6 or lower for both farmers and spouses. These deficits varied little by farm size, type of crops or livestock on the farm, years of handling pesticides, holding a non-farm job, or length of follow up. SMRs among ever smokers were not as low as among never smokers, but were still less than 1.0 for all smoking-related causes of death. No statistically significant excesses occurred, but slightly elevated SMRs, or those near 1.0, were noted for diseases that have been associated with farming in previous studies.

CONCLUSIONS

Several factors may contribute to the low mortality observed in this population, including the healthy worker effect typically seen in cohorts of working populations (which may decline in future years), a short follow-up interval, and a healthier lifestyle manifested through lower cigarette use and an occupation that has traditionally required high levels of physical activity.

Patterns of pesticide use and their determinants among wives of farmer pesticide applicators in the Agricultural Health Study

Pesticide exposure among farmers' wives is poorly characterized. Using questionnaire data from a cohort study of licensed pesticide applicators and their spouses, we investigated patterns of pesticide use among farmers' wives (n = 31,173). Wives reported a wide range of pesticide use: 36% never used pesticides during their lifetimes, whereas the heaviest pesticide users (10%) reported lifetime use of 3 or more agricultural pesticides plus commonly used residential pesticides. We identified 5 ordinal pesticide-use categories and studied factors associated with each category through polytomous logistic regression. Engaging in field work and household hygiene practices that could increase exposure were associated with pesticide use, and associations appeared to strengthen with increasing pesticide use category. Farm women reporting the heaviest pesticide use could exacerbate their exposure by engaging in practices that could increase pesticide contact.

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.