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.

Herbicide exposure during occupational knapsack spraying in French gardeners and municipal workers

CONTEXT

There is a lack of data on pesticide exposure levels during spraying with a knapsack, while it could have important implications for their users' health.

METHODS

We assessed levels and determinants of exposure in 24 male private landscapers/gardeners and municipal workers in France in 2011. Actual dermal exposure to glyphosate was assessed with cotton undergarments and gloves, and a cotton coverall changed between mixing and spraying to assess the contribution of each phase and body area to overall contamination. A field monitor observed the whole workshift and filled in a standardized observation grid.

RESULTS

The median actual contamination was 5,256 µg for the body, and 4,620 µg for hands. Spraying was more exposing than mixing/loading for all body parts except hands, which contributed to nearly 90% of body exposure during mixing/loading, and 30% during spraying, followed by back (14%). In the most exposed quartile, levels were close to some observations in agriculture.

CONCLUSION

Our study provides new data on pesticide exposure levels of knapsack sprayer users; it should lead to a reinforced prevention, in order to make exposures as low as possible and lessen the risk of chronic diseases.

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.

Agriculture Exposure and Time to Pregnancy Among Women Enrolled in the French Prospective Cohort AGRICAN

OBJECTIVES

In few retrospective studies, prolonged time-to-pregnancy (TTP) was observed for women exposed to pesticides especially in flower production. The present study investigated time-to-pregnancy in the AGRICAN cohort.

METHODS

Analyses were performed on 616 women reporting a pregnancy (2005 to 2017), and data on agricultural activities performed before the last pregnancy was retrospectively collected. Fecundability odds ratios (fOR) were estimated using a discrete time analogue of Cox proportional hazard model adjusted on maternal and paternal age, body mass index (BMI), and alcohol consumption.

RESULTS

A decrease in fecundability was non-significantly associated with farm work (adjusted fOR = 0.86; 95% confidence interval [CI]: 0.71 to 1.05). Decreases were also observed for nightwork (afOR = 0.75; 95% CI: 0.49 to 1.15) and exposure to vibrations (afOR = 0.68; 95% CI: 0.43 to 1.09).

CONCLUSION

Women working on a farm before conception appeared to experience a longer TTP. Negative associations were suggested for some agricultural activities and working conditions.

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.

Agricultural exposures to carbamate herbicides and fungicides and central nervous system tumour incidence in the cohort AGRICAN

BACKGROUND

Pesticides exposures could be implicated in the excess of Central Nervous System (CNS) tumors observed in farmers, but evidence concerning individual pesticides remains limited. Carbamate derivative pesticides, including herbicides and fungicides (i.e. (thio/dithio)-carbamates), have shown evidence of carcinogenicity in experimental studies in animals. In the French AGRICAN cohort, we assessed the associations between potential exposures to carbamate herbicides and fungicides and the incidence of CNS tumors, overall and by histological subtype.

METHODS

AGRICAN enrolled 181,842 participants involved in agriculture. Incident CNS tumors were identified by linkage with cancer registries from enrollment (2005-2007) until 2013. Individual exposures were assessed by combining information on lifetime periods of pesticide use on crops and the French crop-exposure matrix PESTIMAT, for each of the 14 carbamate and thiocarbamate herbicides and the 16 carbamate and dithiocarbamate fungicides registered in France since 1950. Associations were estimated using proportional hazard models with age as the underlying timescale, adjusting for gender, educational level and smoking.

RESULTS

During an average follow-up of 6.9 years, 381 incident cases of CNS tumors occurred, including 164 gliomas and 134 meningiomas. Analyses showed increased risks of CNS tumors with overall exposure to carbamate fungicides (Hazard Ratio, HR = 1.88; 95% CI: 1.27-2.79) and, to a lesser extent, to carbamate herbicides (HR = 1.44; 95% CI: 0.94-2.22). Positive associations were observed with specific carbamates, including some fungicides (mancozeb, maneb, metiram) and herbicides (chlorpropham, propham, diallate) already suspected of being carcinogens in humans.

CONCLUSIONS

Although some associations need to be corroborate in further studies and should be interpreted cautiously, these findings provide additional carcinogenicity evidence for several carbamate fungicides and herbicides.

Lung cancer risk and occupational exposures in crop farming: results from the AGRIculture and CANcer (AGRICAN) cohort

Objectives

Farmers are considered at lower risk of lung cancer. However, specific tasks can expose them to hazardous air contaminants such as pesticides, diesel exhaust and mineral dust. This study aimed to assess the associations between various crops and related tasks and the risk of lung cancer, overall and by histological subtypes.

Methods

AGRIculture and CANcer is a prospective French cohort of individuals affiliated to the agricultural health insurance scheme. Incident lung cancers (n=897) were identified by cancer registries from enrolment (2005–2007) to 2013. Data on crop and livestock exposure during lifetime were obtained from the enrolment questionnaire. We used a Cox model with attained age as timescale, adjusted for gender, smoking history and exposure to cattle and horses. Effects of duration and surface were assessed and analyses stratified on gender and smoking status were performed.

Results

Winegrowers were at higher risk of adenocarcinoma (HR=1.27 (95% CI 0.94 to 1.72)). We also found an association between pea growing and small cell lung cancer: significant effect of duration (ptrend=0.04) and the suggestion of a surface–effect relationship (ptrend=0.06); increased risk (HR=2.38 (95% CI 1.07 to 5.28)) for pesticide users; and significant effect of duration (ptrend=0.01) for harvesters. The risk of squamous cell carcinoma was increased for sunflower growing (HR=1.59 (95% CI 0.97 to 2.62), fruit-tree pruning (HR=1.44 (95% CI 0.92 to 2.27)) and pesticide use on beets (HR=1.47 (95% CI 0.92 to 2.34)). Corn and/or wheat/barley growers were at lower risk of lung cancer.

Conclusions

Our results suggest associations between lung cancer and several crop-related tasks, even if we cannot rule out some chance findings due to multiple comparisons.

Occupational exposure to pesticides: development of a job-exposure matrix for use in population-based studies (PESTIPOP)

Occupational exposure to pesticides concerns a wide population of workers not only in agriculture. The reliability of self-reported information on pesticide use is questionable because of the diversity of use. The PESTIPOP job-exposure matrix has been designed to assess pesticide occupational exposure in the general population. The matrix is composed of two axes: the first axis corresponding to jobs (combinations of occupations and industries) and the second one to pesticide exposure. The estimated exposure metric is the probability of exposure coupled with a reliability assessment (low, medium or high). These metrics were defined by combining different sources: (1) an a priori expert assessment (Agricultural industry experts); (2) data from a multicenter case-control study on brain tumors in the general population (occupational history, specific questionnaires); and (3) an a posteriori expert assessment based on the data of a case-control study. So far, 2559 jobs have been identified and 209 (8%) were found to be exposed to pesticides. Jobs with agricultural exposure had a higher exposure probability than jobs with non-agricultural exposure (wood preservation, park maintenance, pest control). Indirect exposure was more frequent than direct exposure. The PESTIPOP matrix will be transcoded into international classifications for use in epidemiological studies.

Exposure to Farm Animals and Risk of Lung Cancer in the AGRICAN Cohort

Epidemiologic studies have found lower risks of lung cancer in farmers. However, little is known about the types of agricultural activities concerned. In the Agriculture and Cancer cohort, we assessed the relationship between animal farming and lung cancer by investigating the types of animals, tasks, and timing of exposure. Analyses included 170,834 participants from the Agriculture and Cancer (AGRICAN) cohort in France. Incident lung cancers were identified through linkage with cancer registries from enrollment (2005-2007) to 2011. A Cox model, adjusting for pack-years of cigarette smoking, was used to calculate hazard ratios and 95% confidence intervals. Lung cancer risk was inversely related to duration of exposure to cattle (≥40 years: hazard ratio = 0.60, 95% confidence interval: 0.41, 0.89; P for trend < 0.01) and to horse farming (≥20 years: hazard ratio = 0.64, 95% confidence interval: 0.35, 1.17; P for trend = 0.09), especially for adenocarcinomas, but not with poultry or pig farming. More pronounced decreased risks were reported among individuals who had cared for animals, undertaken milking, and who had been exposed to cattle in infancy. Our study provides strong evidence of an inverse association between lung cancer and cattle and horse farming. Further research is warranted to identify the etiologic protective agents and biological mechanisms.

Cancer incidence in the AGRICAN cohort study (2005-2011)

BACKGROUND

Numerous studies have been conducted among farmers, but very few of them have involved large prospective cohorts, and few have included a significant proportion of women and farm workers. Our aim was to compare cancer incidence in the cohort (overall, by sex, and by work on farm, occupational status and pesticide use) within the general population.

METHODS

More than 180,000 participants in the AGRICAN cohort were matched to cancer registries to identify cancer cases diagnosed from enrolment (2005-2007) to 31st December 2011. We calculated standardized incidence ratios (SIRs) and 95% confidence intervals (95%CIs).

RESULTS

Over the period, 11,067 incident cancer cases were identified (7304 men and 3763 women). Overall cancer incidence did not differ between the cohort and the general population. Moreover, SIRs were significantly higher for prostate cancer (SIR=1.07, 95%CI 1.03-1.11) and non-Hodgkin lymphoma (SIR=1.09, 95%CI 1.01-1.18) among men, skin melanoma among women (SIR=1.23, 95%CI 1.05-1.43) and multiple myeloma (men: SIR=1.38, 95%CI 1.18-1.62; women: SIR=1.26, 95%CI 1.02-1.54). In contrast, SIRs were lower for upper aerodigestive tract and respiratory cancers. Increase in risk was greater in male farm workers for prostate and lip cancer, in female farm workers for skin melanoma, and in male farm owners for multiple myeloma. Moreover, incidence of multiple myeloma and skin melanoma was higher among male and female pesticide users respectively.

CONCLUSION

We found a decreased incidence for tobacco-related cancers and an increased incidence of prostate cancers, skin melanoma and multiple myeloma. Specific subgroups had a higher cancer incidence related to occupational status and pesticide use.

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.

Use of Dieselized Farm Equipment and Incident Lung Cancer: Findings from the Agricultural Health Study Cohort

BACKGROUND

Diesel exhaust is a known lung carcinogen. Farmers use a variety of dieselized equipment and thus may be at increased risk of lung cancer, but farm exposures such as endotoxins may also be protective for lung cancer.

OBJECTIVES

We evaluated the relative risk of incident lung cancer, including histological subtype, from enrollment (1993-1997) to 2010-2011 in relation to farm equipment use in the Agricultural Health Study (AHS), a prospective cohort study of pesticide applicators and spouses in Iowa and North Carolina, USA.

METHODS

Farm equipment use was reported by 21,273 farmers and 29,840 spouses. Rate ratios (RRs) were estimated separately for farmers and spouses with Poisson regression models adjusted for smoking and other confounders. We conducted stratified analyses by exposure to animals or stored grain, a surrogate for endotoxin exposure.

RESULTS

Daily diesel tractor use (vs. no use) was positively associated with lung cancer in farmers (RR = 1.48; 95% CI: 0.87, 2.50; 35 exposed, 32 unexposed cases), particularly adenocarcinoma (RR = 3.39; 95% CI: 1.23, 9.33; 12 exposed, 7 unexposed cases). The association of adenocarcinoma with daily (vs. low/no) use of diesel tractors was stronger for farmers with no animal or stored grain exposures (RR = 6.23; 95% CI: 2.25, 17.25; 5 exposed, 18 unexposed cases) than among farmers with these exposures (RR = 1.19; 95% CI: 0.51, 2.79; 7 exposed, 27 unexposed cases) (p-interaction = 0.05).

CONCLUSIONS

This study provides preliminary evidence of an increased risk of lung adenocarcinoma among daily drivers of diesel tractors and suggests that exposure to endotoxins may modify the impact of diesel exposure on lung cancer risk. Confirmation of these findings with more exposed cases and more detailed exposure information is warranted.

CITATION

Tual S, Silverman DT, Koutros S, Blair A, Sandler DP, Lebailly P, Andreotti G, Hoppin JA, Beane Freeman LE. 2016. Use of dieselized farm equipment and incident lung cancer: findings from the Agricultural Health Study Cohort. Environ Health Perspect 124:611-618; http://dx.doi.org/10.1289/ehp.1409238.

Agricultural exposure and asthma risk in the AGRICAN French cohort

Epidemiological studies have reported an increased risk of respiratory diseases in agricultural population, but a protective "farm-effect" has also been reported for asthma. In the AGRICAN cohort, self-reported doctor-diagnosed asthma was analyzed according to allergy, in relation with history of life-time exposure to 13 crops and 5 livestock, pesticide exposure and early life on a farm, taking into account sex, age, education and body mass index. Among the 1246 asthmatics (8.0%), 505 were allergic (3.3%) and 719 non-allergic (4.6%). In multivariate analysis, a significant excess was observed, only for allergic asthma, in vine-growing (OR=1.43, p=0.002), fruit-growing (OR=1.58, p=0.001), greenhouses (OR=1.66, p=0.02), grasslands (OR=1.35, p=0.009), beets (OR=1.52, p=0.003) and horses (OR=1.35, p=0.04). Pesticide use and history of pesticide poisoning were significantly associated with allergic asthma in grassland, vineyards and fruit-growing and with non-allergic asthma in beets. Living on a farm in the first year of life tended to be protective for childhood allergic asthma in farms with livestock (OR=0.72, p=0.07) but deleterious in farms with vineyards, fruit or vegetables (OR=1.44, p=0.07). In AGRICAN, an increased risk of allergic asthma was observed with crop exposure, pesticide use and early life on a farm, especially in vine-growing, grassland, beets, fruit and vegetable-growing.

Short-term effects of airborne pollens on asthma attacks as seen by general practitioners in the Greater Paris area, 2003-2007

AIMS

To investigate for the first time the short-term effects of airborne pollen counts on general practitioner (GP) consultations for asthma attacks in the Greater Paris area between 2003-2007.

METHODS

Counts were available for common pollens (Betula, Cupressa, Fraxinus and Poaceae). Weekly data on GP visits for asthma attacks were obtained from the French GP Sentinel Network. A quasi-Poisson regression with generalised additive models was implemented. Short-term effects of pollen counts were assessed using single and multi-pollen models after adjustment for air pollution and influenza.

RESULTS

A mean weekly incidence rate of 25.4 cases of asthma attacks per 100,000 inhabitants was estimated during the study period. The strongest significant association between asthma attacks and pollen counts was registered for grass (Poaceae) in the same week of asthma attacks, with a slight reduction of the effect observed in the multi-pollen model. Adjusted relative risk for Poaceae was 1.54 (95% CI: 1.33-1.79) with an inter-quartile range increase of 17.6 grains/m3 during the pollen season.

CONCLUSIONS

For the first time, a significant short-term association was observed between Poaceae pollen counts and consultations for asthma attacks as seen by GPs. These findings need to be confirmed by more consistent time-series and investigations on a daily basis.

[The decrease in asthma-related mortality in France]

INTRODUCTION

Asthma-related morbidity, mortality and socio- economic cost represent significant public health problems. Despite efficient therapies, in 1999 asthma still killed around 2000 people in France.

METHODS

This study investigated the changes in asthma-related mortality in metropolitan France between 1980 and 2005 and examined its regional disparities. Annual age- and gender-specific mortality rates for asthma were calculated, as well as age-standardized rates. The change in asthma-related mortality was estimated by the annual average rate of change fitted using a log-linear regression model. Lastly, regional disparities were mapped.

RESULTS

After having levelled off between 1990 and 1995, asthma- related mortality significantly decreased. From 2000 onwards the drop was more rapid in men than in women. The observed decrease was significant only in people aged more than 35 years. Moreover, regional disparities could be seen.

CONCLUSIONS

The decline of asthma-related mortality that started in 1986 continued until 2005. Potential explanations could be better patient care due to consensus, including the use of inhaled corticosteroids and therapeutic education, and improvement in the recording of deaths.