Pesticides and prostate cancer: A review of epidemiologic studies with specific agricultural exposure information
Prostate cancer is the most commonly diagnosed cancer in US men, and the second most commonly diagnosed cancer among men worldwide. Although pesticides have been implicated in studies of prostate cancer among farmers, meta-analyses have found heterogeneity across studies, and a number of exposures and lifestyle factors may be unique to farmers. The purpose of this paper is to review the epidemiologic literature to evaluate the hypothesis that agricultural exposure to pesticides is causally associated with prostate cancer risk. We analyzed the eight cohort studies and five case-control studies that quantified and/or evaluated agricultural exposure to particular pesticide classes or chemicals. Despite sporadic positive findings, these studies did not show consistently increased risks to support a causal association between agricultural pesticide use and prostate cancer. Studies using an 'external' comparison group must be interpreted in the context of confounding by differences in prostate-specific antigen screening intensity. Furthermore, most studies did not adjust for potential confounders other than age and time period. It is clearly not possible to exonerate any particular pesticide as a putative cause of prostate cancer - to do so would require an inverse empirical association with an upper confidence limit below the null value. Existing evidence does not point to any pesticide as satisfying widely used guidelines for establishing causation: a strong, exposure-dependent and demonstrably unconfounded, unbiased association, documented in several studies.
Available from: Virginie Dupont
- "Epidemiology studies and animal models have shown that specific endocrine-disrupting compounds may influence the development of prostate cancer (Hess-Wilson and Knudsen 2006; Mink et al. 2008). Studies in animal models also showed augmentation of prostate carcinogenesis with several other environmental estrogenic compounds including UV filters and bisphenol A especially during utero and neonatal time as well as during puberty (Prins 2008). "
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ABSTRACT: A review was undertaken on the occurrence, toxicity, and degradation of triclosan (TCS; 5-chloro-2,4-dichlorophenoxy)phenol) in the environment. TCS is a synthetic, broad-spectrum antibacterial agent incorporated in a wide variety of household and personal care products such as hand soap, toothpaste, and deodorants but also in textile fibers used in a range of other consumer products (e.g., toys, undergarments and cutting boards among other things). OCCURRENCE: Because of its partial elimination in sewage treatment plants, most reports describe TCS as one of the most commonly encountered substances in solid and water environmental compartments. It has been detected in a microgram per liter or microgram per kilogram level in sewage treatment plants (influents, effluents, and sludges), natural waters (rivers, lakes, and estuarine waters), and sediments as well as in drinking water.
Moreover, due to its high hydrophobicity, TCS can accumulate in fatty tissues and has been found in fish and human samples (urine, breast milk, and serum). TCS is known to be biodegradable, photo-unstable, and reactive towards chlorine and ozone.
As a consequence, it can be transformed into potentially more toxic and persistent compounds, such as chlorinated phenols and biphenyl ethers after chlorination, methyl triclosan after biological methylation, and chlorinated dibenzodioxins after photooxidation. The toxicity of TCS toward aquatic organisms like fish, crustaceans, and algae has been demonstrated with EC50 values near TCS environmental concentrations. It has even been shown to produce cytotoxic, genotoxic, and endocrine disruptor effects.
Furthermore, the excessive use of TCS is suspected to increase the risk of emergence of TCS-resistant bacteria and the selection of resistant strains.
Environmental Science and Pollution Research 11/2011; 19(4):1044-65. DOI:10.1007/s11356-011-0632-z · 2.83 Impact Factor
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ABSTRACT: Approximately one in six men in the United States will develop prostate cancer during their lifetime. Genetic and environmental variables play a role in determining prostate cancer risk. This article highlights the latest evidence regarding the risk factors for prostate cancer. The current screening strategies using prostate-specific antigen and digital rectal examination are also discussed, as well as the limitations of these protocols and potential methods for improving early detection.
Primary care 10/2009; 36(3):603-21. DOI:10.1016/j.pop.2009.04.007 · 0.74 Impact Factor
Available from: Aaron Blair
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ABSTRACT: Terbufos is the fourth most commonly used organophosphate insecticide (OP) in the United States. Terbufos has not been demonstrated to be carcinogenic in rodents, although non-arsenical insecticides, including OPs, have been associated with excess cancer in epidemiologic studies. We investigated associations between use of terbufos and the incidence of cancer.
The Agricultural Health Study is a prospective cohort study of 57,310 licensed pesticide applicators from Iowa and North Carolina. Detailed information about 50 pesticides, including terbufos, and potential confounders was obtained from self-administered questionnaires. Terbufos intensity-weighted lifetime exposure-days were defined as (lifetime exposure-days) x (exposure intensity score). Cases include all first primary cancers diagnosed between enrollment and December 31, 2005. Hazard ratios (HR) and 95% CI were calculated with Cox proportional hazards models, adjusting for potential confounders.
Overall cancer risk was slightly increased among terbufos users [HR 1.21 (1.06-1.37)]. Suggestive associations were observed between terbufos use and cancers of the prostate (HR(highest tertile) = 1.21; 95% CI = 0.99-1.47) and lung (HR(middle tertile) = 1.45; 95% CI = 0.95-2.22) and leukemia (HR(middle tertile) = 2.38; 95% CI = 1.35-4.21) and non-Hodgkin's lymphoma (HR(middle tertile) = 1.94; 95% CI = 1.16-3.22), although the exposure-response gradients were non-monotonic and p for trends were not significant.
We found suggestive associations between occupational terbufos use and several cancer sites. However, cautious interpretation of these results is warranted by the lack of existing experimental and epidemiologic evidence to support carcinogenic effects of terbufos.
Cancer Causes and Control 02/2010; 21(6):871-7. DOI:10.1007/s10552-010-9514-9 · 2.74 Impact Factor
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