Search

BackgroundRecently, the International Agency for Research on Cancer (IARC) Programme for the Evaluation of Carcinogenic Risks to Humans has been criticized for several of its evaluations, and also for the approach used to perform these evaluations. Some critics have claimed that failures of IARC Working Groups to recognize study weaknesses and biases of Working Group members have led to inappropriate classification of a number of agents as carcinogenic to humans.ObjectivesThe authors of this Commentary are scientists from various disciplines relevant to the identification and hazard evaluation of human carcinogens. We examined criticisms of the IARC classification process to determine the validity of these concerns. Here, we present the results of that examination, review the history of IARC evaluations, and describe how the IARC evaluations are performed.DiscussionWe concluded that these recent criticisms are unconvincing. The procedures employed by IARC to assemble Working Groups of scientists from the various disciplines and the techniques followed to review the literature and perform hazard assessment of various agents provide a balanced evaluation and an appropriate indication of the weight of the evidence. Some disagreement by individual scientists to some evaluations is not evidence of process failure. The review process has been modified over time and will undoubtedly be altered in the future to improve the process. Any process can in theory be improved, and we would support continued review and improvement of the IARC processes. This does not mean, however, that the current procedures are flawed.ConclusionsThe IARC Monographs have made, and continue to make, major contributions to the scientific underpinning for societal actions to improve the public's health.

BACKGROUND: Agricultural work and occupational pesticide use have been associated with increased risk of renal cell carcinoma (RCC), the most common form of kidney cancer. However, few prospective studies have investigated links to specific pesticides. OBJECTIVE: We evaluated the lifetime use of individual pesticides and the incidence of RCC. METHODS: We evaluated the associations between intensity-weighted lifetime days (IWDs) of 38 pesticides and incident RCC in the Agricultural Health Study, a prospective cohort of licensed pesticide applicators in Iowa and North Carolina. Among 55,873 applicators, 308 cases were diagnosed between enrollment (1993-1997) and the end of follow-up (2014-2015). We estimated incidence rate ratios (RRs) and 95% confidence intervals (CIs) using Poisson regression, controlling for potential confounding factors, with lagged and unlagged pesticide exposures. RESULTS: There was a statistically significant increased risk of RCC among the highest users of 2,4,5-T compared with never users [unlagged R[R.sub.IWD Tertile 3] = 2.92 (95% CI: 1.65, 5.17; [p.sub.trend] = 0.001)], with similar risk estimates for lagged exposure [20-y lag R[R.sub.IWD Tertile 3] = 3.37 (95% CI: 1.83, 6.22; [p.sub.trend] = 0.001)]. In 20-y lagged analyses, we also found exposure--response associations with chlorpyrifos [R[R.sub.IWD Quartile 4] = 1.68 (95% CI: 1.05, 2.70; [p.sub.trend] = 0.01)], chlordane [R[R.sub.IWD Tertile 3] = 2.06 (95% CI: 1.10, 3.87; [p.sub.trend] = 0.02)], atrazine [R[R.sub.IWD Quartile 4] = 1.43 (95% CI: 1.00, 2.03; [p.sub.trend] = 0.02)], cyanazine [R[R.sub.IWD Quartile 4] = 1.61 (95% CI: 1.03, 2.50; [p.sub.trend] = 0.02)], and paraquat [R[R.sub.IWD >Median] = 1.95 (95% CI: 1.03,3.70; [p.sub.trend] = 0.04)]. CONCLUSIONS: This is, to our knowledge, the first prospective study to evaluate RCC risk in relation to various pesticides. We found evidence of associations with RCC for four herbicides (2,4,5-T, atrazine, cyanazine, and paraquat) and two insecticides (chlorpyrifos and chlordane). Our findings provide insights into specific chemicals that may influence RCC risk among pesticide applicators. Confirmation of these findings and investigations of the biologic plausibility and potential mechanisms underlying the observed associations are warranted. https://doi.org/10.1289/EHP6334, Introduction The incidence of renal cell carcinoma (RCC), the most common form of kidney cancer, has been steadily increasing in the United States for several decades (Noone et al. 2018; [...]

BACKGROUND: Evidence is limited that long-term human exposure to organophosphate (OP) pesticides, without poisoning, is associated with adverse peripheral nervous system (PNS) function. OBJECTIVE: We investigated associations between OP pesticide [...]

Background: Farmers have a higher incidence of multiple myeloma, and there is suggestive evidence of an elevated prevalence of its precursor, monoclonal gammopathy of undetermined significance (MGUS), relative to the general population. Pesticide exposures are suspected to play a role; however, the biologic plausibility for associations with multiple myeloma remains unclear. Objectives: Our objectives were to examine the prevalence of MGUS and evaluate associations with a wide range of pesticides in a large sample of farmers. Methods: We obtained sera and assessed MGUS among 1,638 male farmers [greater than or equal to] 50 years of age in the Agricultural Health Study (AHS), a prospective cohort in Iowa and North Carolina. Odds ratios (ORs) and 95% confidence intervals (CIs) were computed to estimate associations with MGUS for recent use (within the 12 months before phlebotomy) and cumulative intensity-weighted lifetime days of use of specific pesticides. Results: The age-standardized MGUS prevalence was significantly elevated among AHS farmers (7.7%) compared with demographically similar men in the National Health and Nutrition Examination Survey (2.8%) or Olmsted County, Minnesota (3.8%; p < 0.001). Recent use of permethrin was associated with MGUS [recent use vs. no recent use, OR = 1.82 (95% CI: 1.06, 3.13)], especially among those who had also used it in the past [recent and past use vs. never use, OR = 2.49 (95% CI: 1.32, 4.69)]. High intensity-weighted lifetime use of the organochlorine insecticides aldrin and dieldrin was associated with MGUS relative to those who never used either of these pesticides [OR = 2.42 (95% CI: 1.29, 4.54); ptiend = 0.006]. We also observed a positive association with high lifetime use of petroleum oil/distillates as an herbicide, as well as an inverse association with fonofos use. Discussion: This is the largest investigation of MGUS in farmers and the first to identify an association with MGUS for permethrin, a pyrethroid insecticide previously associated with multiple myeloma. Given the continued widespread use of permethrin in various residential and commercial settings, our findings may have important implications for exposed individuals in the general population. https://doi.org/10.1289/EHP6960, Introduction An excess in the incidence of multiple myeloma (MM), an aggressive plasma cell malignancy, has been consistently observed in studies of farmers and other agricultural workers conducted over the [...]

BACKGROUND: Occupational pesticide use is associated with lung cancer in some, but not all, epidemiologic studies. In the Agricultural Health Study (AHS), we previously reported positive associations between several pesticides and lung cancer incidence. OBJECTIVE: We evaluated use of 43 pesticides and 654 lung cancer cases after 10 years of additional follow-up in the AHS, a prospective cohort study comprising 57,310 pesticide applicators from Iowa and North Carolina. METHODS: Information about lifetime pesticide use and other factors was ascertained at enrollment (1993-1997) and updated with a follow-up questionnaire (1999-2005). Cox proportional hazards models were used to calculate hazard ratios (HRs) and 95% confidence intervals (CIs), adjusting for smoking (smoking status and pack-years), sex, and lifetime days of use of any pesticides. Results: Hazard ratios were elevated in the highest exposure category of lifetime days of use for pendimethalin (1.50; 95% CI: 0.98, 2.31), dieldrin (1.93; 95% CI: 0.70, 5.30), and chlorimuron ethyl (1.74; 95% CI: 1.02, 2.96), although monotonic exposure-response gradients were not evident. The HRs for intensity-weighted lifetime days of use of these pesticides were similar. For parathion, the trend was statistically significant for intensity-weighted lifetime days (p = 0.049) and borderline for lifetime days (p = 0.073). None of the remaining pesticides evaluated was associated with lung cancer incidence. CONCLUSIONS: These analyses provide additional evidence for an association between pendimethalin, dieldrin, and parathion use and lung cancer risk. We found an association between chlorimuron ethyl, a herbicide introduced in 1986, and lung cancer that has not been previously reported. Continued follow-up is warranted., Introduction Lung cancer is the leading cause of cancer related death in the United States (American Cancer Society 2017) and in the world (Torre et al. 2015). Lung cancer mortality [...]

To investigate factors associated with pesticide-related visits to health care providers (i.e., doctor or hospital visits), responses to self-administered questionnaires received from35,879 licensed restricted-use pesticide applicators participating in the Agricultural Health Study were analyzed. (In Iowa, applicators are actually certified, whereas in North Carolina they are licensed; for ease of reference, the term license will be used for both states in this paper.) The cohort reported a total of more than 10.9 million pesticide-application days. These applications were associated with one or more pesticide-related health care visits by 2,214 applicators (7.0% of theapplicator cohort for whom health care visit data were available). The odds of a pesticide-related health care visit were increased for commercial applicators compared to private applicators [odds ratio (OR= 1.77; 95% confidence interval (CI), 1.52-2.06) and for applicatorswho used insecticides 70 times or more in their lifetime compared tothose who used insecticides less frequently (OR = 1.43; CI, 1.26-1.63). After adjusting for the number of applications in a logistic regression model, significantly higher odds of health care visits were observed among North Carolina applicators compared to Iowa applicators (OR = 1.35; CI, 1.17-1.52), among applicators who mixed their own pesticides (OR = 1.65; CI, 1.22-2.23), and among applicators who personally repaired their pesticide application equipment at least once per year (OR = 1.12; CI, 1.06-1.25). Significantly lower odds were found among female versus male applicators (OR = 0.68; CI, 0.46-0.99) and among applicators who graduated from high school versus those who did not (OR = 0.82; CI, 0.71-0.94 for high school graduates and OR = 0.79; CI, 0.68-0.91 for those with at least some college). Several methods of pesticide application to crops, seed, or stored grain were also associated with significantly elevated odds ratios of health care visits. [ABSTRACT FROM AUTHOR]

In a statewide survey of 856 Iowa municipal drinking water supplies in 1986--1987 the Rathbun rural water system was found to contain elevated levels of triazine herbicides. Rates of low birth weight, prematurity, and intrauterine growth retardation (IUGR) in live singleton births during the period 1984--1990 by women living in 13 communitiesserved by the Rathbun water system were compared to other communities of similar size in the same Iowa counties. The Rathbun communities had a greater risk of IUGR than southern Iowa communities with other surface sources of drinking water (relative risk = 1.8; 95% CI = 1.3,2.7). Multiple linear regression analyses revealed that levels of the herbicides atrazine, metolachlor, and cyanazine were each significant predictors of community IUGR rates in southern Iowa after controlling for several potentially confounding factors including maternal smoking and socioeconomic variables. The association with IUGR was strongest for atrazine, but all three herbicides were intercorrelated andthe independent contributions of each to IUGR risk could not be determined. We conclude that communities in southern Iowa with drinking water supplies contaminated with herbicides have elevated rates of IUGR compared to neighboring communities with different water supplies. Because of the limitations of the ecologic design of this study, including aggregate rather than individual measures of exposure and limited ability to control for confounding factors related to source of drinking water and risk of IUGR, a strong causal relationship between any specific water contaminant and risk of IUGR cannot yet be inferred. The association between the water supplied to the Rathbun communities and the increased risk of IUGR should be considered a preliminary finding that needs to be verified by more detailed epidemiologic studies. [ABSTRACT FROM AUTHOR]