Mortality among Participants in the Agricultural Health Study

Occupational exposure to endotoxins and small cell lung cancer: a systematic review with meta-analysis

The relationship of occupational exposure to endotoxins with different histologic subtypes of lung cancer has not been established. Our objective was to conduct a systematic review with meta-analysis to assess the effect of exposure to endotoxins on the development of small cell lung cancer (SCLC). A bibliographic search was conducted using MEDLINE, Embase, CENTRAL, and Web of Science databases until December 2022, including all cohort and/or case-control studies that examined occupational exposure to endotoxins and SCLC. Risk of bias was assessed using the U.S. Office of Health Assessment and Translation tool. A random effects model was applied, publication bias were assessed, and a sensitivity analysis was conducted. Four papers were selected for meta-analysis purposes. A total of 144 incident cases of SCLC and 897 population or hospital controls were included. Occupational exposure to endotoxins was considered for textile/leather industry and agricultural sector workers exposed to endotoxins originating from wool, cotton, or leather dust. Except for one study, all investigations were classified as having a low probability of risk of biases. The results of the meta-analysis were not statistically significant (pooled OR: 0.86; 95% CI:0.69-1.08). In addition, neither between-study heterogeneity (I2=0%;p=0.92) nor publication bias was observed (p=0.49). The results of the sensitivity analysis, after including five studies that assessed the risk of SCLC among textile industry and crop/livestock farm workers (not specifically exposed to endotoxins), showed a negative statistically non-significant association and low between-study heterogeneity (pooled OR: 0.90; 95% CI:0.79-1.02; I2=22%;p=0.23). Subjects exposed to occupational exposure to endotoxins seem to exhibit a negative association with the development of SCLC, although the results are not conclusive.

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

BACKGROUND

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

OBJECTIVES

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

METHODS

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

RESULTS

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

DISCUSSION

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

A Scoping Review of Non-Occupational Exposures to Environmental Pollutants and Adult Depression, Anxiety, and Suicide

PURPOSE OF REVIEW

Despite a call for better understanding of the role of environmental pollutant influences on mental health and the tremendous public health burden of mental health, this issue receives far less attention than many other effects of pollutants. Here we summarize the body of literature on non-occupational environmental pollutant exposures and adult depression, anxiety, and suicide-in PubMed, Embase, Web of Science, and PsychINFO through the end of year 2018.

RECENT FINDINGS

One hundred twelve articles met our criteria for further review. Of these, we found 88 articles on depression, 33 on anxiety, and 22 on suicide (31 articles covered multiple outcomes). The earliest article was published in 1976, and the most frequent exposure of interest was air pollution (n = 33), followed by secondhand smoke (n = 20), metals (n = 18), noise (n = 17), and pesticides (n = 10). Other exposures studied less frequently included radiation, magnetic fields, persistent organic pollutants (POPs), volatile organic compounds, solvents, and reactive sulfur compounds. The current literature, although limited, clearly suggests many kinds of environmental exposures may be risk factors for depression, anxiety, and suicide. For several pollutants, important limitations exist with many of the studies. Gaps in the body of research include a need for more longitudinal, life-course studies, studies that can measure cumulative exposures as well as shorter-term exposures, studies that reduce the possibility of reverse causation, and mechanistic studies focused on neurotoxic exposures.

Assessment of relationship between farmer's syndrome and neurotoxic symptoms in farming couples

The purpose of this study was to evaluate the relationship between farmer’s syndrome and neurotoxic symptoms in farming couples. The study was conducted on 348 farmers (174 couples) in Chungnam Province of South Korea. We obtained information on general and agricultural characteristics, farmer’s syndrome, and neurotoxic symptoms through face-to-face surveys from 2014 to 2019. The Korean version of the diagnostic standard scale was used for farmer’s syndrome, and the Swedish Q16 questionnaire was used for neurotoxic symptoms. Logistic regression analysis was used to identify neurotoxic symptoms affected by farmer’s syndrome. The prevalence of ‘positive’ neurotoxic symptoms was higher in wives (72.4%) than in husbands (56.9%). Compared with husbands with ‘negative and probable’ farmer’s syndrome (reference), husbands with ‘positive’ farmer’s syndrome were more likely to have ‘positive’ neurotoxic symptoms (odds ratio [OR] = 5.37, 95% confidence interval [CI] = 2.01–14.30). Compared with wives with ‘negative and probable’ farmer’s syndrome (reference), wives with ‘positive’ farmer’s syndrome were more likely to have ‘positive’ neurotoxic symptoms (OR = 7.07, 95% CI = 2.58–19.38). Therefore, neurotoxic symptoms in both husbands and wives were significantly associated with farmer’s syndrome. However, wives had a higher risk of neurotoxic symptoms than husbands. The findings of this study might be useful as important data for establishing and training agricultural safety and health policy.

Farm working experience could reduce late-life dependency duration among Japanese older adults: The Yamanashi Healthy-Active Life Expectancy cohort study based on the STROBE guidelines

With the advance of medical care, the duration of dependency on nursing care in later life has increased worldwide. There is a question of whether farm work could extend or shorten the dependency duration. We investigated the association between farm work experience and the duration of dependency on nursing support or care in late life.We randomly selected 600 adults aged ≥65 years, who were independent and not hospitalized, as part of the Yamanashi Healthy-Active Life Expectancy cohort and followed them for 13 years. We defined the duration of dependency as the time from reception of long-term care insurance benefits to death, and we adjusted for multiple covariates.We analyzed data from 225 adults (139 men and 86 women) who died during the follow-up period. Ninety four had received long-term care benefits. Mean age was 79.6 years (standard deviation [SD]: 6.3) in individuals with farm work experience and 80.1 years (SD: 7.2) in individuals without farm work experience. The estimated duration of dependency on long-term care was 1.3 years (standard error [SE]: 0.4) in individuals with farm work experience vs 2.1 years (SE: 0.5) in individuals without farm work experience (P = .01). The estimated duration of dependency in individuals with farm work experience and without farm work experience was 0.4 years (SE: 0.5) vs 1.3 years (SE: 0.6) in men respectively (P = .03) and 1.6 years (SE: 0.9) vs 2.4 years (SE: 0.9) in women, respectively (P = .16). The sensitivity analysis yielded an estimated duration of 1.2 years (SE: 0.5) in those with farm work experience and 2.3 years (SE: 0.5) in those without farm work experience (P = .004).Individuals with farm work experience required less long-term care prior to death, suggesting that agricultural and physical activities promote health. Policymakers focusing on preventing the need for nursing care in older populations could consider promoting farming or gardening.

An Exploratory Study of Occupational Safety and Health with Limited Resource African-American Farmers

Objectives: Limited resource African-American farmers exist at the nexus of several correlates of disparities (e.g., minority, poor, rural, and agricultural) and beyond the reach of most health promotion programs. Minimal research addresses their occupational safety and health. We proposed to explore such concerns with them.Methods: We conducted phenomenological interviews with nine farmers about work practices, farm operations, safety practices, health, and sources of information and assistance. We audio-recorded, transcribed, and analyzed interviews to code topics and identify themes.Results: The farmers varied in background, land ownership, farm products, and degree of resource limitation. We identified six themes: limited capital and sources of information, old unsafe machinery and equipment, a pragmatic resilient attitude, distrust of public institutions and agencies, lack of safety training useful on their farms, and personal health conditions.Conclusion: These themes raise hypotheses about limited resource African-American farmers' experience with agricultural safety and health compounded by various economic, environmental, behavioral, social, and institutional determinants. We recommend that these hypotheses be pursued with effective community engagement and partnership to collect and interpret needed data from samples representative of the population of these farmers, including comparison with other limited resource farmer populations.

Association between intake of fruits and vegetables by pesticide residue status and coronary heart disease risk

BACKGROUND

Fruit and vegetable (FV) intake is recommended for the prevention of coronary heart disease (CHD). FVs are also an important source of exposure to pesticide residues. Whether the relations of FV intake with CHD differ according to pesticide residue status is unknown.

OBJECTIVE

To examine the associations of high- and low-pesticide-residue FVs with the risk of CHD.

METHODS

We followed 145,789 women and 24,353 men free of cardiovascular disease and cancer (excluding non-melanoma skin cancer) at baseline and participating in three ongoing prospective cohorts: the Nurses' Health Study (NHS: 1998-2012), the NHS-II (1999-2013), and the Health Professionals Follow-up Study (HPFS: 1998-2012). FV intake was assessed via food frequency questionnaires. We categorized FVs as having high- or low-pesticide-residues using a validated method based on pesticide surveillance data from the US Department of Agriculture. Multivariable Cox proportional hazards models were used to estimate hazard ratios (HRs) and 95% confidence intervals (95%CI) of CHD in relation to high- and low-pesticide-residue FV intake.

RESULTS

A total of 3707 incident CHD events were identified during 2,241,977 person-years of follow-up. In multivariable-adjusted models, a greater intake of low-pesticide-residue FVs was associated with a lower risk of CHD whereas high-pesticide-residue FV intake was unrelated to CHD risk. Specifically, compared with individuals consuming <1 serving/day of low-pesticide-residue FVs, those consuming ≥4 servings/day had 20% (95CI: 4%, 33%) lower risk of CHD. The corresponding HR (comparing ≥4 servings/day to <1 serving/day) for high-pesticide-residue FV intake and CHD was 0.97 (95%CI: 0.72, 1.30).

CONCLUSIONS

Our data suggested exposure to pesticide residues through FV intake may modify some cardiovascular benefits of FV consumption. Further confirmation of these findings, especially using biomarkers for assessment of pesticide exposure, is needed.

Overall and cause-specific mortality in a cohort of farmers and their spouses

OBJECTIVES

Lower mortality rates compared with the general population have been reported for Agricultural Health Study (AHS) participants (enrolled 1993-1997) followed through 2007. We extended analysis of mortality among AHS participants (51 502 private pesticide applicators, their 31 867 spouses and 4677 commercial pesticide applicators from North Carolina and Iowa) through 2015 and compared results using several analytical approaches.

METHODS

We calculated standardised mortality ratios (SMRs), causal mortality ratios (CMR) and relative SMRs (rSMR) using state-specific mortality rates of the general populations as the referent.

RESULTS

Over the average 16 years of follow-up (1999-2015), 9305 private applicators, 3384 spouses and 415 commercial applicators died. SMRs and CMRs, with expected deaths calculated using the person-time among the cohort and the general population, respectively, indicated lower overall mortality in all study subgroups (SMRs from 0.61 to 0.69 and CMRs from 0.74 to 0.89), although CMRs indicated elevated mortality in private applicators from North Carolina and in ever-smokers. In SMR analyses, there were fewer than expected deaths from many causes, but deaths from some external causes including transportation-related injuries and mechanical forces were elevated in private applicators. CMRs indicated higher than expected deaths from prostate cancer, lymphohaematopoietic cancers, Parkinson's and Alzheimer's disease, and chronic glomerulonephritis in private applicators, and non-Hodgkin's lymphoma in spouses (from 1.19 to 1.53). rSMR results were generally elevated, similar to CMR findings.

CONCLUSIONS

AHS participants experienced lower overall mortality than the general population.Mortality from a few specific causes was increased in private applicators, specifically when CMR and rSMR approaches were used.

Health Indicators of a Cohort of Midwest Farmers: Health Outcomes of Participants in the Certified Safe Farm Program

Occupational illness, injury, and fatality rates for those working in production agriculture are higher than in any other industry. A potential risk factor contributing to occupational injuries across all industries is acute or chronic co-morbidity (e.g., obesity, high blood pressure, high cholesterol), and related health issues that increase the risk for an occupational injury or illness. These chronic health conditions have been associated not only with increased risk for injuries, but also higher health-care costs, and greater absenteeism. Certified Safe Farm (CSF) is a comprehensive intervention program aimed to reduce occupational health and safety hazards and to promote general health among farmers. Prior publications have described CSF program efforts to reduce hazardous exposures, disabling injuries, organic dust toxic syndrome, occupational health-care costs, and to increase positive occupational health behaviors. This paper reports on the general health indicators of a cohort of 438 Iowa farm owner/operators enrolled in the CSF program. Overall, this study found that the farming population in Iowa has higher body mass index (BMI), but lower total cholesterol, low-density lipoprotein (LDL), and lower prevalence of hypertension compared to the general population. There was evidence that the combination of high blood pressure, cholesterol, and BMI were related to increased injury rates. Poor self-reported health status was also related to increased injuries but was not related to clinical health indicators. The CSF intervention led to improvements on health outcomes, particularly among those in the 35 to 49 age group. Little research has focused on the individual's general health status as a predictor of risk of occupational injury. This study suggests the need for additional research and interventions integrating occupational safety and health prevention along with health promotion.

Potential Roles of Innate Immune Chemokine and Cytokine Network on Lipopolysaccharide-Based Therapeutic Approach in Ovarian Cancer

Ovarian cancer (OC), the deadliest gynecological cancer, results in poor overall survival, urgently requiring a novel therapeutic approach. As cumulative exposures to endotoxins decreased OC risk epidemiologically, we evaluated if LPS, a Toll-like receptor 4 agonist known as active component of endotoxins, could increase survival in the murine peritoneal dissemination model of SKOV-3 OC cells. LPS significantly increased the mean survival time of more than 116 days compared with 63 days in the control. Furthermore, no tumor burden was present in three mice among eight LPS-treated mice. SKOV-3 cells were not responsive to LPS and showed unaltered chemokine signature. Rather than direct effects to OC cells, LPS was found to increase proinflammatory chemokines and cytokines, such as CXCL1, CXCL8, TNF, and IL-1B, in innate immune system. Taken together, LPS is likely to potentiate the cytotoxic-related innate immunogenicity via proinflammatory chemokines and cytokines, which attenuates the peritoneal dissemination of OC.

Site-specific cancer mortality inequalities by employment and occupational groups: a cohort study among Belgian adults, 2001-2011

OBJECTIVE

This study probes into site-specific cancer mortality inequalities by employment and occupational group among Belgians, adjusted for other indicators of socioeconomic (SE) position.

DESIGN

This cohort study is based on record linkage between the Belgian censuses of 1991 and 2001 and register data on emigration and mortality for 01/10/2001 to 31/12/2011.

SETTING

Belgium.

PARTICIPANTS

The study population contains all Belgians within the economically active age (25-65 years) at the census of 1991.

OUTCOME MEASURES

Both absolute and relative measures were calculated. First, age-standardised mortality rates have been calculated, directly standardised to the Belgian population. Second, mortality rate ratios were calculated using Poisson's regression, adjusted for education, housing conditions, attained age, region and migrant background.

RESULTS

This study highlights inequalities in site-specific cancer mortality, both related to being employed or not and to the occupational group of the employed population. Unemployed men and women show consistently higher overall and site-specific cancer mortality compared with the employed group. Also within the employed group, inequalities are observed by occupational group. Generally manual workers and service and sales workers have higher site-specific cancer mortality rates compared with white-collar workers and agricultural and fishery workers. These inequalities are manifest for almost all preventable cancer sites, especially those cancer sites related to alcohol and smoking such as cancers of the lung, oesophagus and head and neck. Overall, occupational inequalities were less pronounced among women compared with men.

CONCLUSIONS

Important SE inequalities in site-specific cancer mortality were observed by employment and occupational group. Ensuring financial security for the unemployed is a key issue in this regard. Future studies could also take a look at other working regimes, for instance temporary employment or part-time employment and their relation to health.

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.

Pesticide Exposure and Risk of Rheumatoid Arthritis among Licensed Male Pesticide Applicators in the Agricultural Health Study

BACKGROUND

The occupation of farming has been associated with rheumatoid arthritis (RA); pesticides may account for this association, but there are few studies.

OBJECTIVES

We investigated associations between RA and use of pesticides in the Agricultural Health Study.

METHODS

The study sample was drawn from male pesticide applicators enrolled in 1993–1997 who provided questionnaire data at baseline and at least once during follow-up (over a median 18 y; interquartile range 16–19). Incident RA cases (n=220), confirmed by physicians or by self-reported use of disease-modifying antirheumatic drugs, were compared with noncases (n=26,134) who did not report RA. Odds ratios (ORs) and 95% confidence intervals (CIs) were estimated using logistic regression, adjusting for enrollment age, state, smoking pack-years, and education. We evaluated the association of RA with the use of 46 pesticides and across 4 levels (never use and tertiles) of lifetime days of use for 16 pesticides with OR≥1.2 for ever use.

RESULTS

Incident RA was associated with ever use of fonofos (OR = 1.70; 95% CI: 1.22, 2.37), carbaryl (OR = 1.51; 95% CI: 1.03, 2.23), and chlorimuron ethyl (OR = 1.45; 95% CI: 1.01, 2.07) compared with never use. Statistically significant exposure–response trends in association with RA were observed for lifetime days of use of atrazine [OR_tertile3= 1.62 (95% CI: 1.09, 2.40); p_trend=0.01] and toxaphene [OR_tertile3= 2.42 (95% CI: 1.03, 5.68); p_trend=0.02]. Exposure–response was nonlinear for fonofos [OR_tertile1= 2.27 (95% CI: 1.44, 3.57); OR_tertile2= 0.98 (95% CI: 0.54, 1.80); OR_tertile3= 2.10 (95% CI: 1.32, 3.36); p_trend=0.005] and suggestive for carbaryl (p_trend=0.053).

CONCLUSIONS

Our results provide novel evidence of associations between exposure to some pesticides and RA in male farmers. https://doi.org/10.1289/EHP1013.

Revisiting cancer 15 years later: Exploring mortality among agricultural and non-agricultural workers in the Serrana Region of Rio de Janeiro

Background Agricultural production has expanded dramatically throughout Brazil. Previous research in the Serrana Region found that from 1979 to 1998, agricultural workers experienced high mortality rates from certain cancers compared to non-agricultural workers [Meyer et al. (2003): Environ Res 93:264-271].

METHODS

New data were obtained for 1999-2013 and Mortality Odds Ratios (MORs) were utilized to compare cancer and other mortality between male agricultural workers in the Serrana Region and non-agricultural workers in the Serrana Region, Rio de Janeiro, and Porto Alegre, and to compare mortality odds to previous decades.

RESULTS

Respectively, compared to aforementioned reference-groups, agricultural workers experienced highest MORs for stomach (1.55 [95%CI: 1.13-2.12], 2.30 [95%CI: 1.72-3.08], 2.28 [95%CI: 1.69-3.08]) and esophageal cancers (95%CI: 1.93 [1.38-2.7], 1.93 [95%CI: 1.38-2.71], 3.12 [95%CI: 2.30-4.24]), greater than reported in previous decades. Agricultural workers experienced higher mortality for external-causes, respiratory, and cardiovascular problems compared to urban reference-groups.

CONCLUSION

Agricultural workers may be at increasing risk for cancer and other mortality. Efforts are needed to investigate distinct risk-factors among this group. Am. J. Ind. Med. 60:77-86, 2017. © 2016 Wiley Periodicals, Inc.

Occupational chemical exposure and diabetes mellitus risk

Diabetes mellitus (DM) is a group of metabolic diseases that may originate from an interaction between genetic and lifestyle risk factors. However, the possible role of occupational chemical exposures in the disease development and progression remains unclear. Therefore, this review aimed to provide a comprehensive evaluation of the relationship between occupational exposure to specific chemical substances or industrial activities and DM morbidity and mortality outcomes. Although some positive findings may support the diabetogenic role of certain pesticides and dioxins in different workplaces, the variable conditions of exposure, the lack of quantitative environmental or biological monitoring data and the different outcomes evaluated do not allow defining a specific exposure-disease causality. Therefore, further epidemiological studies will be necessary to adequately assess modes of action for different substances, dose–response relationships as well as individual susceptibility factors potentially affecting the exposure-disease continuum. Overall, this appears important to adequately assess, communicate and manage risks in occupational chemical exposure settings with the aim to protect workers and build healthier job conditions for diabetic employees.

An Italian population-based case-control study on the association between farming and cancer: Are pesticides a plausible risk factor?

This population-based case-control study investigated the association between farming (a proxy for pesticide exposure) and cancer in the Vercelli suburban area (northwest Italy). The residents, aged 25 to 79 years, in the above-mentioned area during the period 2002-2009 were considered. Cases were all the first hospital admissions for cancer. Controls were all the subjects not included in the cases and not excluded from the study. Cases and controls were classified according to whether they occupationally resulted farmers or nonfarmers during the period 1965-2009. Cancer odds ratios (ORs) between farmers and nonfarmers were calculated with generalized linear mixed models adjusted by gender and age. Farmers showed higher odds for all cancers (OR=1.459; p < .001), nonmelanoma skin cancer, colorectal cancer, and breast cancer. The results suggest a plausible association between pesticide exposure and cancer occurrence.

Serum Endotoxins and Flagellin and Risk of Colorectal Cancer in the European Prospective Investigation into Cancer and Nutrition (EPIC) Cohort

BACKGROUND

Chronic inflammation and oxidative stress are thought to be involved in colorectal cancer development. These processes may contribute to leakage of bacterial products, such as lipopolysaccharide (LPS) and flagellin, across the gut barrier. The objective of this study, nested within a prospective cohort, was to examine associations between circulating LPS and flagellin serum antibody levels and colorectal cancer risk.

METHODS

A total of 1,065 incident colorectal cancer cases (colon, n = 667; rectal, n = 398) were matched (1:1) to control subjects. Serum flagellin- and LPS-specific IgA and IgG levels were quantitated by ELISA. Multivariable conditional logistic regression models were used to calculate ORs and 95% confidence intervals (CI), adjusting for multiple relevant confouding factors.

RESULTS

Overall, elevated anti-LPS and anti-flagellin biomarker levels were not associated with colorectal cancer risk. After testing potential interactions by various factors relevant for colorectal cancer risk and anti-LPS and anti-flagellin, sex was identified as a statistically significant interaction factor (Pinteraction < 0.05 for all the biomarkers). Analyses stratified by sex showed a statistically significant positive colorectal cancer risk association for men (fully-adjusted OR for highest vs. lowest quartile for total anti-LPS + flagellin, 1.66; 95% CI, 1.10-2.51; Ptrend, 0.049), whereas a borderline statistically significant inverse association was observed for women (fully-adjusted OR, 0.70; 95% CI, 0.47-1.02; Ptrend, 0.18).

CONCLUSION

In this prospective study on European populations, we found bacterial exposure levels to be positively associated to colorectal cancer risk among men, whereas in women, a possible inverse association may exist.

IMPACT

Further studies are warranted to better clarify these preliminary observations.

Pesticide Exposures and Body Mass Index (BMI) of Pesticide Applicators From the Agricultural Health Study

Endocrine-disrupting chemicals, including pesticides, may be associated with weight gain. This is the first longitudinal study to examine a potential association between weight gain and pesticides using data on 8,365 male pesticide applicators from the Agricultural Health Study (AHS) cohort established in 1993. The relationship between total cumulative days of exposure to pesticide functional/chemical classes and to the four most frequently used individual pesticides was studied in relation to body mass index (BMI) at the time of 5-yr follow-up (beginning in 1998) with the length of the exposure period dating back to age 20 yr. Multiple regression, Spearman correlation, ordinal logistic regression, and logistic regression models all utilized a Bonferroni-adjusted p value, were adjusted for relevant covariates, and were stratified by state of residence (Iowa/North Carolina) and presence/absence of weight-related health conditions. Adjusted multiple regression yielded statistically significant positive parameter estimates for the study sample and Iowa subgroups with consistent findings for triazine herbicides and atrazine: Change in BMI per 100 cumulative pesticide exposure days ranged from 0.07 to 0.11 for triazine herbicides and from 0.10 to 0.19 for atrazine. Ordinal logistic regression compared normal weight with overweight and with obese using the zero exposure category as referent. Statistically significant adjusted odds ratios identified for the study sample and both state subgroups for the highest level of atrazine exposure ranged from 1.4 to 1.7. Further investigation is warranted to evaluate the associations identified here.

Overview of the National Occupational Mortality Surveillance (NOMS) system: leukemia and acute myocardial infarction risk by industry and occupation in 30 US states 1985-1999, 2003-2004, and 2007

BACKGROUND

Cancer and chronic disease are leading causes of death in the US with an estimated cost of $46 billion.

METHODS

We analyzed 11 million cause-specific deaths of US workers age 18-64 years in 30 states during 1985-1999, 2003-2004, and 2007 by occupation, industry, race, gender, and Hispanic origin.

RESULTS

The highest significantly elevated proportionate leukemia mortality was observed in engineers, protective service, and advertising sales manager occupations and in banks/savings &loans/credit agencies, public safety, and public administration industries. The highest significantly elevated smoking-adjusted acute myocardial infarction mortality was noted in industrial and refractory machinery mechanics, farmers, mining machine operators, and agricultural worker occupations; and wholesale farm supplies, agricultural chemical, synthetic rubber, and agricultural crop industries.

CONCLUSIONS

Significantly elevated risks for acute myocardial infarction and leukemia were observed across several occupations and industries that confirm existing reports and add new information. Interested investigators can access the NOMS website at http://www.cdc.gov/niosh/topics/NOMS/.

Nitrate in drinking water and bladder cancer risk in Spain

BACKGROUND

Nitrate is a widespread contaminant in drinking water and ingested nitrate under conditions resulting in endogenous nitrosation is suspected to be carcinogenic. However, the suggested association between nitrate in drinking water and bladder cancer remains inconsistent. We evaluated the long-term exposure to drinking water nitrate as a risk factor for bladder cancer, considering endogenous nitrosation modifiers and other covariables.

METHODS

We conducted a hospital-based case-control study of bladder cancer in Spain (1998-2001). Residential histories and water consumption information were ascertained through personal interviews. Historical nitrate levels (1940-2000) were estimated in study municipalities based on monitoring records and water source. Residential histories of study subjects were linked with nitrate estimates by year and municipality to calculate individual exposure from age 18 to recruitment. We calculated odds ratios (OR) and 95% confidence intervals (CI) for bladder cancer among 531 cases and 556 controls with reliable interviews and nitrate exposure information covering at least 70% of years from age 18 to interview.

RESULTS

Average residential levels ranged from 2.1mg/L to 12.0mg/L among regions. Adjusted OR (95%CI) for average residential levels relative to ≤ 5 mg/L were 1.2 (0.7-2.0) for >5-10mg/L and 1.1 (0.6-1.9) for >10mg/L. The OR for subjects with longest exposure duration (>20 years) to highest levels (>9.5mg/L) was 1.4 (0.9-2.3). Stratification by intake of vitamin C, vitamin E, meat, and gastric ulcer diagnosis did not modify these results. A non-significant negative association was found with waterborne ingested nitrate with an OR of 0.7 (0.4-1.0) for >8 vs. ≤ 4 mg/day. Adjustment for several covariables showed similar results to crude analyses.

CONCLUSION

Bladder cancer risk was inconsistently associated with chronic exposure to drinking water nitrate at levels below the current regulatory limit. Elevated risk is suggested only among subjects with longest exposure duration to the highest levels. No evidence of interaction with endogenous nitrosation modifiers was observed.

Occupation and thyroid cancer

Numerous occupational and environmental exposures have been shown to disrupt thyroid hormones, but much less is known about their relationships with thyroid cancer. Here we review the epidemiology studies of occupations and occupational exposures and thyroid cancer incidence to provide insight into preventable risk factors for thyroid cancer. The published literature was searched using the Web of Knowledge database for all articles through August 2013 that had in their text 'occupation' 'job' 'employment' or 'work' and 'thyroid cancer'. After excluding 10 mortality studies and 4 studies with less than 5 exposed incident cases, we summarised the findings of 30 articles that examined thyroid cancer incidence in relation to occupations or occupational exposure. The studies were grouped by exposure/occupation category, study design and exposure assessment approach. Where available, gender-stratified results are reported. The most studied (19 of 30 studies) and the most consistent associations were observed for radiation-exposed workers and healthcare occupations. Suggestive, but inconsistent, associations were observed in studies of pesticide-exposed workers and agricultural occupations. Findings for other exposures and occupation groups were largely null. The majority of studies had few exposed cases and assessed exposure based on occupation or industry category, self-report, or generic (population-based) job exposure matrices. The suggestive, but inconsistent findings for many of the occupational exposures reviewed here indicate that more studies with larger numbers of cases and better exposure assessment are necessary, particularly for exposures known to disrupt thyroid homeostasis.

Parkinson's disease and pesticide exposure--a new assessment

Parkinson's disease (PD) is an idiopathic disease and its pathological feature is a loss of pigmented neurons in the substantia nigra. Some commonly used pesticides possess neurotoxicity, and exposure to such compounds may trigger mechanisms similar to those in the development of idiopathic PD. We conducted a systematic review of epidemiological studies, aiming at a critical evaluation of the association between the development of PD and pesticide exposure. Reported effect sizes (ES) in the relevant studies were pooled into the meta-analysis to derive summary ES. The summary ES suggested a significantly positive association between PD and overall pesticide use (non-occupational and/or occupational pesticide use) [1.42; 95% confidence interval (CI) 1.32 to 1.52, the fixed-effects model], as well as between PD and occupational pesticide exposure (1.49 with a 95% CI of 1.34-1.66). Both occupational herbicide and occupational insecticide exposure showed a significant association with PD. The results of the meta-analysis reported in this study suggest the existence of a statistically positive association between PD and pesticide exposure. The majority of the studies that were pooled in the meta-analysis were case-control design with very few cohort studies and most with poor exposure characterization thus, any further case-control studies using similar methodologies are unlikely to have a significant impact or understanding on the currently-reported association between pesticide exposure and the development of idiopathic PD. Therefore, we believe that if further epidemiological studies are going to be conducted in the area, they should be prospective cohort studies that will include accurate exposure assessment.

Physical activity and sedentary behavior in relation to esophageal and gastric cancers in the NIH-AARP cohort

Introduction

Body mass index is known to be positively associated with an increased risk of adenocarcinomas of the esophagus, yet there is there limited evidence on whether physical activity or sedentary behavior affects risk of histology- and site-specific upper gastrointestinal cancers. We used the NIH-AARP Diet and Health Study to assess these exposures in relation to esophageal adenocarcinoma (EA), esophageal squamous cell carcinoma (ESCC), gastric cardia adenocarcinoma (GCA), and gastric non-cardia adenocarcinoma (GNCA).

Methods

Self-administered questionnaires were used to elicit physical activity and sedentary behavior exposures at various age periods. Cohort members were followed via linkage to the US Postal Service National Change of Address database, the Social Security Administration Death Master File, and the National Death Index. Cox proportional hazards regression models were used to estimate hazard ratios (HR) and 95 percent confidence intervals (95%CI)

Results

During 4.8 million person years, there were a total of 215 incident ESCCs, 631 EAs, 453 GCAs, and 501 GNCAs for analysis. Strenuous physical activity in the last 12 months (HR_{>5 times/week vs. never}=0.58, 95%CI: 0.39, 0.88) and typical physical activity and sports during ages 15–18 years (p for trend=0.01) were each inversely associated with GNCA risk. Increased sedentary behavior was inversely associated with EA (HR_{5–6 hrs/day vs. <1 hr}=0.57, 95%CI: 0.36, 0.92). There was no evidence that BMI was a confounder or effect modifier of any relationship. After adjustment for multiple testing, none of these results were deemed to be statistically significant at p<0.05.

Conclusions

We find evidence for an inverse association between physical activity and GNCA risk. Associations between body mass index and adenocarcinomas of the esophagus do not appear to be related to physical activity and sedentary behavior.

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

BACKGROUND

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

METHODS

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

CONCLUSIONS

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

Agricultural exposures and stroke mortality in the Agricultural Health Study

Exposures associated with common agricultural activities may increase risk of stroke. The authors evaluated associations between self-reported agricultural activities including pesticide use and handling of crops and stroke mortality among 51,603 male pesticide applicators enrolled in the Agricultural Health Study (AHS). Vital status was obtained through 2008. Stroke mortality was defined by underlying or contributing cause of death (ICD-9 430-438, ICD-10 I60-I69). Information regarding lifetime pesticide use, working with crops or animals, engagement in other agricultural activities, and potential confounders was self-reported at enrollment. Cox proportional hazards models, with age as the time scale, were used to estimate hazard ratios (HR) and 95% confidence intervals (CI) adjusted for state of residence, smoking status, and alcohol consumption. Median follow-up time was 13 yr, during which 308 stroke deaths occurred. No measure of overall or specific pesticide use was positively associated with mortality due to stroke. Stroke mortality was inversely associated with handling hay, grain, or silage at least once each year as reported at enrollment (HR: 0.75; 95% CI: 0.58, 0.98). There was no evidence of an association between pesticide use and stroke mortality. The inverse association between handling of hays and grains and stroke mortality may be due to (1) those engaging in such activities being healthier than those who did not or (2) exposure to some biological agent present in hays and grains. Further investigation of incident stroke, rather than stroke mortality, as well as stroke subtypes, is needed to determine the full role of agricultural exposures and stroke.

Mortality in the California Farmer Health Study cohort

Western agriculture, in comparison with Midwestern and Eastern, is more diverse, with a drier climate, mild winters, and different exposures. This randomly selected cohort of 1947 Californian farmers confirmed the usual finding: a lower mortality rate than general population (by 50%). A low smoking prevalence and healthy worker effect are likely contributors. Although farmers were more likely to die from injuries and skin cancer, death was less likely from Alzheimer's and cerebrovascular diseases. Within the cohort, disability and persistent wheeze were associated with increased mortality. The 200 deaths were insufficient to determine the significance of rare diseases.

Mortality and morbidity study of petrochemical employees in a polluted site

BACKGROUND

The area of Gela was included among the 57 Italian polluted sites of national interest for environmental remediation because of its widespread contamination from a petrochemical complex. The present study investigates mortality and morbidity of the cohort of Gela petrochemical workers with the aim of disentangling occupational from residential risk.

METHODS

Mortality was assessed for 5,627 men hired from 1960, year of the plant start-up, to 1993; it was followed up for vital status in the period 1960-2002. Morbidity was analysed for 5,431 workers neither dead nor lost to follow-up from 1960 to 2001 and was based on Hospital Discharge Records in the period 2001-2006. The work experience was classified in terms of job categories such as blue collars, white collars, and both--workers who shifted from blue to white collar (95%) or vice versa. An ad hoc mobility model was applied to define qualitative categories of residence in Gela, as residents and commuters. Standardized Mortality Ratios (SMRs) and Mortality Rate Ratios (MRRs) were computed, the latter by using a Poisson regression model. Morbidity was analyzed in terms of Hospital Discharge Odds Ratios (HDORs) through a logistic regression model. While performing the internal comparisons, white collars was the reference category for the job analysis, and commuters was the reference category for the residential analysis.

RESULTS

In the light of epidemiological evidence about health risk from petrochemical industries in both occupational and environmental settings, and/or on the basis of information about occupational and residential contamination and health risk in the area of Gela, noteworthy results are shown for lung cancer [MRR: 2.11 (CI 90%; 0.96-4.63) in blue collars; 1.71 (1.09-2.69) in residents], respiratory diseases [HDOR: 2.0 (1.0-3.0) in blue collars; 1.4 (0.96-2.06) in residents] and genitourinary diseases [HDOR: 1.34 (1.06-1.68) in blue collars; 1.23 (1.04-1.45) in residents].

CONCLUSIONS

The results support a role of the exposures in the occupational and residential settings, the latter due to the local ascertained contamination, in affecting the workers' health. These results underline the urgent need of water, soil, air and food-chain monitoring programs, to discover active sources of exposure and consequently define public health interventions.

A review of pesticide exposure and cancer incidence in the agricultural health study cohort

We reviewed epidemiologic evidence related to occupational pesticide exposures and cancer incidence in the Agricultural Health Study (AHS) cohort. Studies were identified from the AHS publication list available on a Medline/PubMed database search in March 2009. Findings related to lifetime-days and/or intensity-weighted lifetime-days of pesticide use are the primary focus of this review, because these measures allow for the evaluation of potential exposureresponse relationships. Most of the 32 pesticides examined were not strongly associated with cancer incidence in pesticide applicators. Increased rate ratios and positive exposureresponse patterns were reported for 12 pesticides currently registered in Canada and/or the United States. Exposure misclassification is also a concern in the AHS and may limit the analysis of exposureresponse patterns. Epidemiologic evidence outside the AHS remains limited with respect to most of the observed associations, but animal toxicity data support the biological plausibility of relationships observed six pesticides. Continued follow-up is needed to clarify associations reported to date. In particular, further evaluation of registered pesticides is warranted.

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSION

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

Mortality patterns of Australian male farmers and farm managers

OBJECTIVE

To compare the all-cause and specific-cause death rates of Australian male farmers and farm managers aged 25-74 years, with other Australian men.

METHODS

Data were extracted from the Australian Bureau of Statistics Death Registration Collection covering the calendar years of 1999-2002. Denominator data for male farmers and farm managers were drawn from the 2001 Australian Population Census. Direct age-standardized death rates were calculated and compared with the general Australian male population.

RESULTS

The 4025 male farmers or farm managers who died in this period represented 3.35% of all male deaths in the 25-74 year age range. The all-cause death rate for farmers and farm managers (730/100,000) was 33% higher than that of the Australian male population of the same age (549/100,000) (standardized mortality ratio (SMR)=1.33). Causes of death related to neoplasms (SMR=1.37), circulatory disease (SMR=1.40) and all external causes (SMR=1.37), were all statistically higher than the comparison population. Within these groupings, ischaemic heart disease (SMR=1.39), other circulatory disease (SMR=1.42), prostate cancer (SMR=2.40), lymphohaematopoietic cancer (SMR=1.80) and transport injuries (SMR=2.06), were all significantly higher.

CONCLUSION

These data indicate that Australian male farmers and farm managers are a disadvantaged group in terms of health status. The elevated rates of all-cause and specific-cause mortality compared with the Australian comparison population, illustrate both the need and scope for further investigation of these issues.

Biomonitoring of rural workers exposed to a complex mixture of pesticides in the municipalities of Tianguá and Ubajara (Ceará state, Brazil): genotoxic and cytogenetic studies

In recent years, the use of pesticides in agriculture has been steadily increasing, and associations between exposure to agricultural chemicals and DNA damage and cancer have been reported. Brazil is one of the world leaders in pesticide use; however, studies that evaluate the impact of pesticide exposure on cancer incidence and mortality are very scarce in the Brazilian population. The alkaline comet assay and the chromosome aberration (CA) test were used to evaluate primary DNA damage in the peripheral blood lymphocytes of workers exposed to a complex mixture of pesticides in two small rural communities in the municipalities of Tianguá and Ubajara, located in the western part of Ceará State (Northeast Brazil), which are among the largest agricultural areas of the state. The comet assay showed that the damage index and damage frequency observed in the exposed groups were significantly higher in relation to the controls (P < 0.05). On the other hand, no differences were detected regarding structural and numerical CAs in the communities evaluated. Additionally, the observed levels of DNA strand breaks and frequencies of CAs, stratified for exposure time, were not statistically different for individuals of either rural community. Our results suggest that the damages caused by pesticides in our study area were not great enough to induce permanent mutations or to interfere with mitotic apparatus formation; minimal pesticide damages could have undergone cellular repair, explaining the absence of structural and numerical CAs.

Pollution sources and mortality rates across rural-urban areas in the United States

PURPOSE

To conduct an assessment of rural environmental pollution sources and associated population mortality rates.

METHODS

The design is a secondary analysis of county-level data from the Environmental Protection Agency (EPA), Department of Agriculture, National Land Cover Dataset, Energy Information Administration, Centers for Disease Control and Prevention, the US Census, and others. We described the types of pollution sources present in metropolitan and nonmetropolitan counties and examined the associations between these sources and rates of all-cause, cardiovascular, respiratory, and cancer mortality while controlling for age, race, and other covariates.

FINDINGS

Rural counties had 65,055 EPA-monitored pollution discharge sites. As expected, rural counties had significantly greater exposure to potential agriculture-related pollution. Regression models specific to rural counties indicated that greater density of water pollution sources was significantly associated with greater total and cancer mortality. Rural air pollution sources were associated with greater cancer mortality rates. Rural coal mining areas had higher total, cancer, and respiratory disease mortality rates. Agricultural production was generally associated with lower mortality rates. Greater levels of human development were significantly related to higher adjusted total and cancer mortality.

CONCLUSIONS

The association between pollution sources and mortality risk is not a phenomenon limited to metropolitan areas. Results carry policy implications regarding the need for effective environmental standards and monitoring. Further research is needed to better understand the types and distributions of pollution in rural areas, and the health consequences that result.

Mortality in the agricultural health study, 1993-2007

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

Endotoxin and cancer

Exposure to endotoxin, a component of gram-negative bacterial cell walls, is widespread in many industrial settings and in the ambient environment. Heavy-exposure environments include livestock farms, cotton textile facilities, and saw mills. In this article, we review epidemiologic, clinical trial, and experimental studies pertinent to the hypothesis that endotoxin prevents cancer. Since the 1970s, epidemiologic studies of cotton textile and other endotoxin-exposed occupational groups have consistently demonstrated reduced lung cancer risks. Experimental animal toxicology research and some limited therapeutic trials in cancer patients offer additional support for an anticarcinogenic potential. The underlying biological mechanisms of anticarcinogenesis are not entirely understood but are thought to involve the recruitment and activation of immune cells and proinflammatory mediators (e.g., tumor necrosis factor α and interleukin-1 and -6). In view of the current state of knowledge, it would be premature to recommend endotoxin as a cancer-chemopreventive agent. However, further epidemiologic and experimental investigations that can clarify further dose-effect and exposure-timing relations could have substantial public health and basic biomedical benefits.

A review of pesticide exposure and cancer incidence in the Agricultural Health Study cohort

OBJECTIVE

We reviewed epidemiologic evidence related to occupational pesticide exposures and cancer incidence in the Agricultural Health Study (AHS) cohort.

DATA SOURCES

Studies were identified from the AHS publication list available at http://aghealth.nci.nih.gov as well as through a Medline/PubMed database search in March 2009. We also examined citation lists. Findings related to lifetime-days and/or intensity-weighted lifetime-days of pesticide use are the primary focus of this review, because these measures allow for the evaluation of potential exposure-response relationships.

DATA SYNTHESIS

We reviewed 28 studies; most of the 32 pesticides examined were not strongly associated with cancer incidence in pesticide applicators. Increased rate ratios (or odds ratios) and positive exposure-response patterns were reported for 12 pesticides currently registered in Canada and/or the United States (alachlor, aldicarb, carbaryl, chlorpyrifos, diazinon, dicamba, S-ethyl-N,N-dipropylthiocarbamate, imazethapyr, metolachlor, pendimethalin, permethrin, trifluralin). However, estimates of association for specific cancers were often imprecise because of small numbers of exposed cases, and clear monotonic exposure-response patterns were not always apparent. Exposure misclassification is also a concern in the AHS and may limit the analysis of exposure-response patterns. Epidemiologic evidence outside the AHS remains limited with respect to most of the observed associations, but animal toxicity data support the biological plausibility of relationships observed for alachlor, carbaryl, metolachlor, pendimethalin, permethrin, and trifluralin.

CONCLUSIONS

Continued follow-up is needed to clarify associations reported to date. In particular, further evaluation of registered pesticides is warranted.

Pesticide use and myocardial infarction incidence among farm women in the agricultural health study

OBJECTIVE

To evaluate the relationship between pesticide use and myocardial infarction (MI) among farm women.

BACKGROUND

Little is known about the potential association between pesticide use and cardiovascular outcomes.

METHODS

We used logistic regression to evaluate pesticide use and self-reported incident nonfatal MI among women in the Agricultural Health Study.

RESULTS

Of those MI-free at enrollment (n = 22,425), 168 reported an MI after enrollment. We saw no association with pesticide use overall. Six of 27 individual pesticides evaluated were significantly associated with nonfatal MI, including chlorpyrifos, coumaphos, carbofuran, metalaxyl, pendimethalin, and trifluralin, which all had odds ratios >1.7. These chemicals were used by <10% of the cases, and their use was correlated, making it difficult to attribute the risk elevation to a specific pesticide.

CONCLUSION

Pesticides may contribute to MI risk among farm women.

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.