Pesticide-Induced Diseases: Alzheimer's Disease

According to the Alzheimer’s Association, Alzheimer’s disease (AD), the most common form of dementia, is a progressive and fatal brain disease. As many as 5.3 million Americans are living with Alzheimer’s disease. Alzheimer’s destroys brain cells, causing memory loss and problems with thinking and behavior severe enough to affect work, lifelong hobbies or social life. Alzheimer’s gets worse over time, it is fatal, and has no current cure.

• Cognitive impairment and increased Aβ levels induced by paraquat exposure are attenuated by enhanced removal of mitochondrial H2O2
• This study investigated the effects of paraquat pesticide exposure on wild-type mice and β-amyloid precursor protein (APP) transgenic mice. Results show that wild-type mice and APP transgenic mice after paraquat exposure had increased oxidative damage specifically in mitochondria of cerebral cortex and exhibited mitochondrial dysfunction. Results demonstrate that mitochondrial damage is a key mechanism underlying cognitive impairment and elevated amyloidogenesis induced by paraquat.
  [Chen, L., et al. 2011. Neurobiol Aging. [Epub ahead of print]
  
• Association between environmental exposure to pesticides and neurodegenerative diseases
  This study examined the influence of environmental pesticide exposure on a number of neuropsychiatric conditions and discusses their underlying pathologic mechanisms. A total of 17,429 hospital records were collected between 1998 and 2005. Prevalence rates and the risk of having Alzheimer's disease, Parkinson's disease, multiple sclerosis and suicide were significantly higher in districts with greater pesticide use as compared to those with lower pesticide use. This study supports and extends previous findings that environmental exposure to pesticides may affect the human health by increasing the incidence of certain neurological disorders at the level of the general population.
  [Parrón, T., et al. 2011. Toxicol Appl Pharmacol. Epub ahead of print]
• Occupational exposure to pesticides increases the risk of incident AD
  Study of individuals from an agricultural community in Utah shows increased risks among pesticide-exposed individuals for all-cause dementia, with hazard ratio (HR) 1.38 and 95% confidence interval (CI) 1.09–1.76, and for Alzheimer’s Disease (AD) (HR 1.42, 95% CI 1.06–1.91). The risk of AD associated with organophosphate exposure (HR 1.53, 95% CI 1.05–2.23) was slightly higher than the risk associated with organochlorines (HR 1.49, 95% CI 0.99–2.24)
  [Hayden KM, et al. 2010. Neurology, May 11;74(19):1524-30]
• Occupational risk factors in Alzheimer's disease: a review assessing the quality of published epidemiological studies
  Eleven studies explored the relationship of AD with solvents, seven with EMF, six with pesticides, six with lead and three with aluminium. For pesticides, studies of greater quality and prospective design found increased and statistically significant associations.
  [Santibáñez M, et al. 2007. Occup Environ Med. Nov;64(11):723-32. Epub 2007 May 24]
• Neurodegenerative Diseases and Exposure to Pesticides in the Elderly
  Study of 1,507 French elderly (1992–1998) shows lower cognitive performance was observed in subjects who had been occupationally exposed to pesticides. In men, the relative risks of developing Parkinson’s disease and Alzheimer’s disease for occupational exposure assessed by a job exposure matrix were 5.63 (95% confidence interval: 1.47, 21.58) and 2.39 (95% confidence interval: 1.02, 5.63), respectively.
  [Baldi, I, et al. Am J Epidemiol 2003; 157:409-414.]
• Risk factors for Alzheimer's disease: a population-based, longitudinal study in Manitoba, Canada
  Study of a longitudinal, population-based study of dementia in Manitoba, Canada shows occupational exposure to fumigants and/or defoliants was a significant risk factor for Alzheimer's disease (relative risk [RR] = 4.35; 95% CI : 1.05--17.90).
  [Tyas SL, et al. Int J Epidemiol. 2001 Jun;30(3):598-9]