Pesticide-Induced Diseases: Diabetes

According to the American Diabetes Association, diabetes is a group of diseases characterized by high blood glucose levels that result from defects in the body’s ability to produce and/or use insulin. Type 1 diabetes is usually diagnosed in children and young adults. In type 1 diabetes, the body does not produce insulin. Type 2 diabetes is the most common form of diabetes and is most common in communities of color and the aged population. In type 2 diabetes, either the body does not produce enough insulin or the cells ignore the insulin. Pesticides and other environmental factors are almost always linked to type 2 diabetes.

  • Sublethal exposures of diazinon alters glucose homostasis in Wistar rats: Biochemical and molecular evidences of oxidative stress in adipose tissues.
    Disorder of glucose homeostasis is one of the most important complications following exposure to organophosphorous (OPs) pesticides. The present study focused on tumor necrosis factor alpha (TNFα), glucose transporter type 4 (GLUT4), and nuclear factor kappa-light-chain-enhancer of activated B cells (Nf-κB) in a sublethal model of toxicity by diazinon as a common OPs. Animals were treated for 4 weeks and serum insulin was measured in fasting condition. In adipose tissue, oxidative stress markers including reactive oxygen species (ROS), nicotinamide adenine dinucleotide phosphate (NADPH) oxidase and TNFα were evaluated. The mRNA expression of GLUT4, Nf-κB and glyceraldehyde 3-phosphate dehydrogenase (GAPDH) were also determined by real time reverse transcription polymerase chain reaction (RT-PCR). Diazinon at dose of 70mg/kg/day impaired GTT and diminished insulin level while augmented ROS, NADPH oxidase, and TNFα. On the basis of biochemical and molecular findings, it is concluded that diazinon impairs glucose homeostasis through oxidative stress and related proinflammatory markers in a way to result in a reduced function of insulin inside adipose tissue. Although, diazinon interfered with pancreatic influence on the adipose tissue most probably via stimulation of muscarinic receptors, current data are not sufficient to introduce adipose tissue as a target organ to OPs toxicity. Considering the potential of OPs to accumulate in adipose tissue, it seems a good candidate organ for future studies. Although, hyperglycemia was not induced by diazinon but increased AUC0-180min leads us to the point that diazinon induces kind of instability in glucose homostasis and diabetes.
    [Pakzad M, Fouladdel S, et al. 2013. Pestic Biochem Physiol. 105(1):57-61]
  • Growing burden of diabetes in sub- saharan Africa: contribution of pesticides ?
    The diabetes burden is growing in Sub-Saharan Africa (SSA). The low overall access to health care has been documented to contribute to the high diabetes-related mortality. Due to economic, demographic, epidemiological and nutrition transitions in SSA, the growing prevalence of diabetes appears to be related to obesogenic lifestyles and the intergenerational impact of malnutrition in women of childbearing age. Both overnutrition and undernutrition have been associated with the development of diabetes and other chronic diseases. Africans are also suspected of being genetically predisposed to diabetes. According to existing data in developed countries, exposure to pesticides, particularly organochlorines and metabolites, is associated with a higher risk of developing type 2 diabetes and its comorbidities. In African countries, pesticide exposure levels often appear much higher than in developed countries. Furthermore, undernutrition, which is still highly prevalent in SSA, could increase susceptibility to the adverse effects of organic pollutants. Therefore, the growing and inadequate use of pesticides may well represent an additional risk factor for diabetes in SSA. Additionally, high exposure to pesticides in African infants in utero and during the perinatal period may increase the intergenerational risk of developing diabetes in SSA.
    [Azandjeme CS, Bouchard M, Fayomi B, et al. 2013. Curr Diabetes Rev. 9(6):437-49]
  • Pesticides and human diabetes: a link worth exploring?
    Traditionally, the risk factors for diabetes have largely focused on genetics and lifestyle. Great emphasis is placed on lifestyle measures and finding novel pharmacological treatment options to combat diabetes, but there is increasing evidence linking environmental pollutants, especially pesticides, to the development of insulin resistance and Type 2 diabetes. Pesticide use has increased dramatically worldwide and the effects of pesticides on glucose metabolism are too significant for a possible diabetogenic link to be dismissed. The aim of this review article was to assess the links between pesticides and human diabetes with the goal of stimulating further research in this area.
    [Swaminathan K. 2013. Diabet Med. 30(11):1268-71]
  • Does early-life exposure to organophosphate insecticides lead to prediabetes and obesity
    Researchers gave neonatal rats chlorpyrifos, diazinon or parathion in doses devoid of any acute signs of toxicity, straddling the threshold for barely-detectable cholinesterase inhibition. Organophosphate exposure during a critical developmental window altered the trajectory of hepatic adenylyl cyclase/cyclic AMP signaling, culminating in hyperresponsiveness to gluconeogenic stimuli. Consequently, the animals developed metabolic dysfunction resembling prediabetes. When the organophosphate-exposed animals consumed a high fat diet in adulthood, metabolic defects were exacerbated and animals gained excess weight compared to unexposed rats on the same diet. At the same time, the high fat diet ameliorated many of the central synaptic defects caused by organophosphate exposure, pointing to nonpharmacologic therapeutic interventions to offset neurodevelopmental abnormalities, as well as toward fostering dietary choices favoring high fat intake. These studies show how common insecticides may contribute to the increased worldwide incidence of obesity and diabetes.
    [Slotkin, T.A. 2011. Reproductive Toxicology. 31: 297–301.]
  • Low Dose of Some Persistent Organic Pollutants Predicts Type 2 Diabetes: A Nested Case–Control Study
    Study links low dose exposure to some persistent organic pollutants (POPs) to type 2 diabetes. The authors report that some POPs, including highly chlorinated PCBs, PBB153 and the organochlorine insecticides trans-nonachlor, oxychlordane and mirex, were associated with type 2 diabetes over an 18-year period, especially in obsese people. However, POPs did not show a traditional dose–response relationship with diabetes. Instead, POPs showed strong associations at relatively low exposures. The authors conclude that exposure to relatively low concentrations of certain POPs may play a role in the increased incidence of diabetes in the United States.
    [Lee D-H, et al. 2010. Environ Health Perspect 118(9): doi:10.1289/ehp.0901480]
  • An Environment-Wide Association Study (EWAS) on Type 2 Diabetes Mellitus
    An analysis of 266 potential environmental contributors to type 2 diabetes links the disease to individuals who have higher levels of polychlorinated biphenyls (PCBs) and the pesticide heptachlor, as well a form of vitamin E found at high levels in soybean and corn oil. The researchers used NHANES data from 1999 to 2006. Type 2 diabetes prevalence among those with high levels of heptachlor epoxide, a break down product of heptachlor, was at about two times higher than those with low levels of the compound.  
    [Patel CJ,  et al. 2010. PLoS ONE 5(5): e10746.]
  • Arsenic Exposure and Prevalence of Type 2 Diabetes in US Adults
    Using National Health and Nutrition Examination Survey (NHANES) data, this study investigates the association of arsenic exposure, as measured in urine, with the prevalence of type 2 diabetes in a representative sample of US adults. Common sources of inorganic arsenic exposure include dietary exposure, drinking water pollution, and contamination associated with arsenic wood preservatives such as sawdust, smoke, direct contact, and hazardous waste sites. After adjustment for diabetes risk factors and markers of seafood intake, participants with type 2 diabetes had a 26% higher level of total arsenic (95% confidence interval [CI], 2.0%-56.0%) than participants without type 2 diabetes.
    [Navas-Acien, Ana, et al. 2008. JAMA. 300(7):814-822]
  • Incident Diabetes and Pesticide Exposure among Licensed Pesticide Applicators: Agricultural Health Study, 1993–2003
    A study by the National Institutes of Health (NIH), including the National Institute of Environmental Health Sciences (NIEHS) and the National Cancer Institute (NCI), finds pesticide applicators with regular exposure to pesticides to be at a greater risk of type-2 diabetes. Seven different pesticides produced an increase in risk. Applicators who had used the insecticides aldrin, chlordane, and heptachlor more than 100 lifetime days had 51%, 63%, and 94% increased odds of diabetes, respectively. Researchers looked at data from 31,787 pesticide applicators in North Carolina and Iowa over a period of five years, enrolled in the Agricultural Health Study. [Montgomery et al. American Journal of Epidemiology 2008 167(10):1235-1246]
  • Environmental pollution and diabetes: a neglected association
    Using cross-sectional data from the 1999–2002 National Health and Nutrition Examination Survey (NHANES), University of Cambridge scientists  reported a strong correlation between insulin resistance (which can lead to adult onset diabetes) and serum concentrations of persistent organic pollutants (POPs), especially for organochlorine pesticide compounds. The scientists are advocating additional research into the little understood links between environmental pollution and adult onset diabetes.
    [Oliver, AH et al. 2008. The Lancet, Vol. 371, Issue 9609, Pages 287-288]
  • Pesticide Exposure and Self-Reported Gestational Diabetes Mellitus in the Agricultural Health Study
    Study finds exposure of pregnant women to agricultural pesticides during the first trimester may double the risk of gestational diabetes. The study group was comprised of 11,273 women married to licensed pesticide applicators. Agricultural pesticide exposure during pregnancy, such as mixing or applying pesticides or repairing pesticide application equipment, resulted in an odds ratio of 2.2 (95% CI 1.5-3.3).
    [Saldana, T., et al. Diabetes Care. March 2007 30:529-534]
  • A strong dose-response relation between serum concentrations of persistent organic pollutants and diabetes: results from the National Health and Examination Survey 1999-2002
    Cross-sectional associations of the serum concentrations of persistent organic pollutants (POPs) with diabetes prevalence were investigated in 2,016 adult participants in the National Health and Nutrition Examination Survey 1999-2002. Six POPs (2,2',4,4',5,5'-hexachlorobiphenyl, 1,2,3,4,6,7,8-heptachlorodibenzo-p-dioxin, 1,2,3,4,6,7,8,9-octachlorodibenzo-p-dioxin, oxychlordane, p,p'-dichlorodiphenyltrichloroethane, and trans-nonachlor) were selected, because they were detectable in >or=80% of participants. Compared with subjects with serum concentrations below the limit of detection, after adjustment for age, sex, race and ethnicity, poverty income ratio, BMI, and waist circumference, diabetes prevalence was strongly positively associated with lipid-adjusted serum concentrations of all six POPs. The association was consistent in stratified analyses and stronger in younger participants, Mexican Americans, and obese individuals. There were striking dose-response relations between serum concentrations of six selected POPs and the prevalence of diabetes. The strong graded association could offer a compelling challenge to future epidemiologic and toxicological research.
    [Lee DH, Lee IK, Song K, Steffes M, Toscano W, et al. 2006. Diabetes Care. 29(7):1638-44.]
  • Increased Rate of Hospitalization for Diabetes and Residential Proximity of Hazardous Waste Sites
    Study finds increased rate of hospitalization for diabetes in those who live close to hazardous waste sites containing persistent organic pollutants (POPs), including pesticides. The rate ratios for diabetes discharges for people residing in POP sites, after adjustment for potential confounders were 1.23 [95% confidence interval (CI), 1.15–1.32]. In a subset of POP sites along the Hudson River, where there is higher income, less smoking, better diet, and more exercise, the rate ratio was 1.36 (95% CI, 1.26–1.47) compared to clean sites.
    [Kouznetsova M,  et al. 2006 Environ Health Perspect 115(1)]