There has been some discussion as to whether herbicides or insecticides have
been implicated in Parkinson's. The following are some abstracts on the
subject. The full text versions are probably in your closest medical library.
 
 
Authors
  Fleming L.  Mann JB.  Bean J.  Briggle T.  Sanchez-Ramos JR.
Institution
  Department of Epidemiology and Public Health, University of Miami School
  of Medicine, FL 33136.
Title
  Parkinson's disease and brain levels of organochlorine pesticides.
Source
  Annals of Neurology.  36(1):100-3, 1994 Jul.
Abstract
  Epidemiological studies have suggested an etiologic relationship between
  pesticide exposure and Parkinson's disease (PD). Organochlorine pesticides
  were assayed in postmortem brain samples from 20 PD, 7 Alzheimer's disease
  (AD), and 14 nonneurological control cases. The three groups were similar
  in age at death, sex, and demographic variables. Only two of 16 pesticide
  residues screened were detected. A long-lasting residue of DDT (pp-DDE)
  was found in the majority of cases of PD and AD, as well as in all the
  control cases; pp-DDT was significantly more likely to be found in AD
  controls than the PD cases (Fisher's exact two-tailed, p = 0.04). Dieldrin
  was detected in 6 of 20 PD brains, 1 of 7 AD, and in none of 14 control
  samples. Despite the relatively small number of brains assayed, the
  association between Dieldrin and the diagnosis of PD was highly
  significant (p = 0.03). Dieldrin, a lipid-soluble, long-lasting
  mitochondrial poison, should be investigated as a potential etiological
  agent of Parkinsonism.
 
 
Authors
  Bell IR.  Schwartz GE.  Amend D.  Peterson JM.  Kaszniak AW.  Miller CS.
Institution
  Department of Psychiatry, University of Arizona Health Sciences Center,
  Tucson 85724.
Title
  Psychological characteristics and subjective intolerance for xenobiotic
  agents of normal young adults with trait shyness and defensiveness. A
  parkinsonian-like personality type?.
Source
  Journal of Nervous & Mental Disease.  182(7):367-74, 1994 Jul.
Abstract
  The present study examines the psychological characteristics and
  self-reported responses to xenobiotic agents such as tobacco smoke and
  pesticide of normal young adults with personality traits similar to those
  claimed for Parkinsonian patients. Previous research, though
  controversial, has suggested that persons with idiopathic Parkinson's
  disease (PD) have premorbid personality traits that may include shyness
  and repressive defensiveness. Other epidemiological evidence indicates
  that PD patients may have premorbidly increased prevalence of anxiety,
  affective, and/or somatoform disorders; decreased rates of smoking and
  alcohol consumption; and elevated exposure to herbicides or pesticides. A
  total of 783 college students enrolled in an introductory psychology
  course completed the Cheek-Buss Scale (shyness), the Marlowe-Crowne Social
  Desirability Scale (defensiveness), Symptom Checklist 90 (revised), the
  Mastery Scale, a health history checklist, and rating scales for frequency
  of illness from alcohol and 10 common environmental chemicals. Subjects
  were divided into four groups on the basis of above- versus below-median
  scores on the Cheek-Buss and Marlowe-Crowne scales (persons high in
  shyness and defensiveness, those high only in shyness, those high only in
  defensiveness, and those low in both shyness and defensiveness). The group
  high in shyness but low in defensiveness had the highest, whereas the
  group low in shyness but high in defensiveness had the lowest, total
  scores on the SCL-90-R; the two shyest groups were lowest in sense of
  mastery.(ABSTRACT TRUNCATED AT 250 WORDS)
 
Authors
  Hubble JP.  Cao T.  Hassanein RE.  Neuberger JS.  Koller WC.
Institution
  Department of Neurology, University of Kansas Medical Center, Kansas City
  66160-7314.
Title
  Risk factors for Parkinson's disease [see comments].
Comments
  Comment in: Neurology 1993 Sep;43(9):1641-3, Comment in: Neurology 1994
  Aug;44(8):1557-8
Source
  Neurology.  43(9):1693-7, 1993 Sep.
Abstract
  Parkinson's disease (PD) has been associated with rural living, well-water
  consumption, and pesticide exposure; however, the individual risk
  contribution of these variables has not been established. We examined
  social and medical histories of predominantly rural populations to
  determine relative risk factors for PD. Patients and controls were
  surveyed regarding residency, occupation, medical history, and social and
  dietary habits. An initial multiple logistic regression model was
  confounded by excessive variable colinearity. Principal factor analysis
  yielded three factors: rural living (including years of rural residency
  and ground-water use), pesticide use, and male lifestyle (male gender,
  head trauma, male-dominated occupations). Other variables did not load in
  factor analysis and were entered separately, with the three factor scores,
  in a second multiple logistic regression model. Significant predictors of
  PD emerged (in order of strength): pesticide use, family history of
  neurologic disease, and history of depression. The predicted probability
  of PD was 92.3% (odds ratio = 12.0) with all three predictors positive.
  Pesticide use (distinguishable from rural living) can be considered a risk
  factor for the development of PD, with family history of neurologic
  disease and history of depression serving as weaker predictors of PD.
 
 
Authors
  Butterfield PG.  Valanis BG.  Spencer PS.  Lindeman CA.  Nutt JG.
Institution
  Center for Research on Occupational and Environmental Toxicology, Oregon
  Health Sciences University, Portland 97201.
Title
  Environmental antecedents of young-onset Parkinson's disease.
Source
  Neurology.  43(6):1150-8, 1993 Jun.
Abstract
  We conducted an exploratory study of young-onset Parkinson's disease
  (YOPD) to examine occupational and environmental factors associated with
  disease risk. This case-control study included 63 YOPD patients (diagnosis
  on or before age 50); controls (n = 68) were diagnosed with rheumatoid
  arthritis. Crude odds ratios (ORs) were computed to identify exposure
  variables for logistic regression analyses. After controlling for the
  variables of race, educational level, sex, age, age at diagnosis, and
  family history of Parkinson's disease (PD), PD was positively associated
  with insecticide exposure (OR = 5.75, p < 0.001), past residency in a
  fumigated house (OR = 5.25, p = 0.046), herbicide exposure (OR = 3.22, p =
  0.033), rural residency at time of diagnosis (OR = 2.72, p = 0.027), and
  nuts and seed eating 10 years before diagnosis (OR = 1.49, p = 0.021). PD
  was inversely associated with cigarette smoking at 5 years (OR = 0.50, p =
  0.027), 10 years (OR = 0.43, p = 0.012), and 15 years (OR = 0.37, p =
  0.005) before diagnosis, farm residency (OR = 0.38, p = 0.018), and
  exposure to dimethyl sulfoxide (OR = 0.10, p < 0.001). These findings are
  consistent with hypotheses linking PD to exposure to pesticide agents.
 
 
Authors
  Semchuk KM.  Love EJ.  Lee RG.
Institution
  Department of Community Health Sciences, Faculty of Medicine, University
  of Calgary, AB, Canada.
Title
  Parkinson's disease and exposure to agricultural work and pesticide
  chemicals.
Source
  Neurology.  42(7):1328-35, 1992 Jul.
Abstract
  This population-based case-control study of 130 Calgary residents with
  neurologist-confirmed idiopathic Parkinson's disease (PD) and 260 randomly
  selected age- and sex-matched community controls attempted to determine
  whether agricultural work or the occupational use of pesticide chemicals
  is associated with an increased risk for PD. We obtained by personal
  interviews lifetime occupational histories, including chemical exposure
  data, and analyzed the data using conditional logistic regression for
  matched sets. In the univariate analysis, a history of field crop farming,
  grain farming, herbicide use, or insecticide use resulted in a
  significantly increased crude estimate of the PD risk, and the data
  suggested a dose-response relation between the PD risk and the cumulative
  lifetime exposure to field crop farming and to grain farming. However, in
  the multivariate analysis, which controlled for potential confounding or
  interaction between the exposure variables, previous occupational
  herbicide use was consistently the only significant predictor of PD risk.
  These results support the hypothesis that the occupational use of
  herbicides is associated with an increased risk for PD.
 
 
Authors
  Wechsler LS.  Checkoway H.  Franklin GM.  Costa LG.
Institution
  Department of Environmental Health, University of Washington, Seattle
  98195.
Title
  A pilot study of occupational and environmental risk factors for
  Parkinson's disease.
Source
  Neurotoxicology.  12(3):387-92, 1991 Fall.
Abstract
  Increasingly, the etiology of Parkinson's disease (PD) has been linked to
  exposures to environmental toxicants. This epidemiologic pilot study used
  a self-administered questionnaire among 34 PD cases and 22 other neurology
  clinic control patients. All subjects were at least 40 years old. Risk
  factors investigated included occupation, well-water use, pesticide use,
  metal exposures, medical history, smoking, alcohol consumption, and drug
  use. Twenty-six percent of the male PD cases reported having been employed
  in farming versus eleven percent for male controls (OR = 3.1, 95% C.I. =
  0.3 to 35). Sixteen percent of male cases versus none of the controls
  reported employment as welders. No clear trends involving exposure to
  either occupational or home pesticides emerged. In assessing occupational
  exposures to metals, aluminum and copper exposures tended to be more
  common among male cases than male controls. Additionally, as reported in
  other studies, smoking showed an inverse relationship with PD. Although
  the findings reported here are provocative, these results are
  statistically imprecise and must be interpreted cautiously because of the
  small number of subjects included in the study.
 
Authors
  Chapman LJ.  Sauter SL.  Henning RA.  Levine RL.  Matthews CG.  Peters HA.
Institution
  Department of Neurology, University of Wisconsin Medical School, Madison.
Title
  Finger tremor after carbon disulfide-based pesticide exposures.
Source
  Archives of Neurology.  48(8):866-70, 1991 Aug.
Abstract
  Index finger tremor accompanying voluntary movement was studied in 19
  age-matched control subjects and in 19 grain industry employees
  chronically exposed to carbon disulfide-based fumigants. Visual judgments
  of tremor amplitude made by neurologists during clinical examinations
  equaled the sensitivity of computerized tremor amplitude measurements.
  Tremor frequency variations detectable only with computerized measurement
  were present in grain workers with and without increased tremor
  amplitudes. Frequency differences discriminated between normal subjects
  and 74% of the grain workers. The distribution of tremor frequency power
  in the grain workers was often sequestered at 5 to 7 Hz, reminiscent of
  tremor in idiopathic Parkinson's disease. These findings suggest that the
  measurement of subtle tremor frequency changes may provide an early
  indication of chronic carbon disulfide poisoning.
 
 
Authors
  Bachurin SO.  Tkachenko SE.  Lermontova NN.
Institution
  Institute of Physiologically Active Substances, USSR Academy of Sciences,
  Chernogolovka, Moscow District.
Title
  Pyridine derivatives: structure-activity relationships causing
  parkinsonism-like symptoms. [Review]
Source
  Reviews of Environmental Contamination & Toxicology.  122:1-36, 1991.
Abstract
  In recent years, sufficient evidence has surfaced to implicate
  low-molecular-weight organic compounds in certain known neurological
  disorders. At this time, 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine
  (MPTP) is considered the compound capable of inducing conditions most
  similar to idiopathic parkinsonism in clinical, biochemical, and
  histopathological characteristics. Substances containing MPTP-like
  fragments are used as herbicides, drugs and intermediates in the synthesis
  of many heterocyclic compounds. The mechanistic study of toxic MPTP action
  has enabled development of criteria for appraising potential
  parkinsonogenic properties of similar chemical structures. Key features of
  MPTP action include the following: 1. Ability to pass through the
  blood-brain barrier (BBB). 2. Enzymatic biotransformation to the
  neuroactive form (pyridine metabolites). 3. Transfer to neurons via a
  neuromediator reuptake system. 4. Action on intracellular targets. This
  review discusses data concerning the effects of metabolite structure on
  the major steps in the neurotropic action mechanism of MPTP-like
  compounds. Special attention is focused on the key steps defining the
  selectivity of MPTP's neuronal action, i.e., the activation step caused by
  monoamine oxidase (MAO) and interaction with the dopamine (DA) reuptake
  system. Most structural MPTP analogs (including certain pesticide
  preparations) used in our experiments and described in the literature
  exhibit no degenerative MPTP-like properties. This is probably related to
  the fact that each consecutive stage in the MPTP neurotoxicity mechanism
  makes rather stringent demands on metabolite structure. The number of
  structures which concurrently meet the requirements of all the processes
  is finite. This, however, does not invalidate the hypotheses concerning
  the ecotoxic nature of idiopathic parkinsonism. Possible ecotoxins may
  have only a partial, presymptomatic effect which, however, promotes
  age-related neurodegenerative processes and accelerates development of
  parkinsonism. This concept necessitates designing special tests of the
  possible neurotoxic properties of compounds found in the environment which
  may be functional MPTP analogs. [References: 147]
 
 
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