Occupational pesticide exposure and screening tests for neurodegenerative disease among an elderly population in Costa Rica

Rollins School of Public Health, Emory University, 1518 Clifton Road, Atlanta, United States. Electronic address: .
Environmental Research (Impact Factor: 4.37). 10/2012; 120. DOI: 10.1016/j.envres.2012.08.014
Source: PubMed


Pesticides have been associated with Parkinson's disease (PD) in many studies, and with Alzheimer's disease (AD) in a few.

We conducted screening tests for neurologic disease and occupational pesticide use in a population-based sample of 400 elderly subjects at two government-run clinics in Costa Rica; 361 subjects who failed the initial screen were given both the mini-mental states exam (MMSE) and a modified version of a 10-item united Parkinson's disease rating motor subscale (UPDRS). Among subjects who failed either test, 144 were then examined by a neurologist.

Past occupational pesticide exposure was reported by 18% of subjects. Exposed subjects performed worse on the MMSE than the non-exposed (mean 24.5 versus 25.9, p=0.01, adjusted for age, sex, and education). The exposed had significantly elevated risks of abnormal scores on two UPDRS items, tremor-at-rest (OR 2.58, 1.28-5.23), and finger-tapping (OR=2.94, 95% CI 1.03-8.41). Thirty-three (23%) of those examined by the neurologist were diagnosed with possible/probable PD, 3-4 times the expected based on international data; 85% of these cases had not been previously diagnosed. Among subjects who took the UPDRS, the exposed had an increased risk of PD (OR=2.57, 95% CI 0.91-7.26). No excess risk was found for a diagnosis of AD or mild cognitive impairment.

Elderly subjects with past occupational pesticide exposure performed significantly worse on screening tests for dementia and PD, and had an increased risk of an eventual PD diagnosis. Screening may be particularly appropriate among elderly subjects with past pesticide exposure.

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    • "These pesticide-exposed subjects had an increased risk of PD (OR ¼2.57, 95% CI 0.91–7.26), whereas no excess risk was found for a diagnosis of AD or mild cognitive impairment (Steenland et al., 2013). Of our screened subjects, 92% failed Step 1 tests, which consisted of a 3 item-recall test and animal recognition test for cognition, and self-reported tremor/ balance problems and a spiral drawing tests for motor deficits (Wesseling et al., 2013). "
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    ABSTRACT: Background: We previously screened 400 elderly Costa Ricans for neurodegenerative disease. Those reporting occupational pesticide exposure (18%) had an increased Parkinson׳s disease (PD) risk (OR 2.57, 95% CI 0.91-7.26), and worse cognition (Mini-Mental States Exam (MMSE) 24.5 versus 25.9 points, p=0.01). We subsequently measured long-lasting organochlorine pesticides (β-HCH, DDE, DDT, and dieldrin) in a sub-sample (n=89). Dieldrin and β-HCH have been linked to PD, and DDE to Alzheimer׳s disease. Methods: We ran regression models for MMSE and tremor-at-rest to assess associations with pesticides in 89 subjects. Results: The percent of β-HCH, DDE, DDT (parent compound for DDE), and dieldrin above their limit of detection (LOD) were 100%, 93%, 75%, and 57%, respectively. Tremor-at-rest was found in 21 subjects, and the mean MMSE was 25. Those who reported occupational pesticide exposure (n=36) had more detectable dieldrin samples (p=0.005), and higher mean levels of dieldrin (p=0.01), than those not reporting exposure. Other pesticides did not differ between those with and without self-reported occupational exposure. There was a positive but non-significant trend of higher risk for tremor-at-rest with higher dieldrin (p=0.10 for linear trend). Neither DDE nor DDT showed a relationship with MMSE. However, after excluding two outliers with the lowest MMSE scores, higher DDT levels showed some modest association with lower MMSE (p=0.09 for linear trend). Conclusions: Our data are limited by small sample size. However, dieldrin was high in our population, has been previously linked to PD, and could be partly responsible for the excess PD risk seen in our population.
    Environmental Research 08/2014; 134C:205-209. DOI:10.1016/j.envres.2014.07.024 · 4.37 Impact Factor
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    • "Support for this proposal comes from a consideration of other environmental diseases that have been attributed to exposures to these chemicals. POPs exposures have been associated with type 2 diabetes (Zeliger, 2013; Lee et al., 2010; Carpenter 2008); immunological disorders (Hertz-Picciotto et al., 2008; Noakes et al., 2006; Tryphonas, 1998), musculoskeletal disorders (Lee et al., 2007), reproductive interferences (EPA, 2008; Nishijo et al., 2008; Herz-Picciotto et al., 2008), endocrine disruption (Snyder & Mulder, 2001; Colborn et al., 1997), periodontal disease (Lee et al., 2008), neurological disease (Kodavanti, 2005; Patri et al., 2009; Gamble, 2000; White & Proctor, 1997; Burbacher, 1993), neurodevelopmental disorders (Grandjean & Landrigan, 2006; Polanska et al., 2012; Korrich & Sagiv, 2008; Yolton et al., 2011;) and neurodegenerative diseases, including ALS, Alzheimer's and Parkinson's diseases (Parron et al., 2011; Loane et al., 2013; Chen et al., 2013; Steenland et al., 2012; Wang et al., 2011; Dardiotis et al., 2013; Caudle et al., 2012; Weisskopf et al., 2010; Moulton & Yang, 2012; Mayeux & Stern, 2012; Zaganas et al., 2013; Sienko et al., 1990; Vincenti et al., 2012). The onset of many different cancers has been associated with exposures to the chemicals described here. "
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    ABSTRACT: Environmental chemical exposure has been linked to numerous diseases in humans. These diseases include cancers; neurological and neurodegenerative diseases; metabolic disorders including type 2 diabetes, metabolic syndrome and obesity; reproductive and developmental disorders; and endocrine disorders. Many studies have associated the link between exposures to environmental chemicals and cardiovascular disease (CVD). These chemicals include persistent organic pollutants (POPs); the plastic exudates bisphenol A and phthalates; low molecular weight hydrocarbons (LMWHCs); and poly nuclear aromatic hydrocarbons (PAHs). Here it is reported that though the chemicals reported on differ widely in chemical properties and known points of attack in humans, a common link exists between them. All are lipophilic species that are found in serum. Environmentally induced CVD is related to total lipophilic chemical load in the blood. Lipophiles serve to promote the absorption of otherwise not absorbed toxic hydrophilic species that promote CVD.
    Interdisciplinary toxicology 06/2013; 6(2):55-62. DOI:10.2478/intox-2013-0010
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    ABSTRACT: Many studies have associated environmental exposure to chemicals with neurological impairments (NIs) including neuropathies, cognitive, motor and sensory impairments; neurodevelopmental disorders (NDDs) including autism and attention deficit hyperactivity disorder (ADHD); neurodegenerative diseases (NDGs) including Alzheimer's disease, Parkinson's disease and amyotrophic lateral sclerosis (ALS). The environmental chemicals shown to induce all these diseases include persistent organic pollutants (POPs), the plastic exudates bisphenol A and phthalates, low molecular weight hydrocarbons (LMWHCs) and polynuclear aromatic hydrocarbons (PAHs). It is reported here that though these chemicals differ widely in their chemical properties, reactivities and known points of attack in humans, a common link does exist between them. All are lipophilic species found in serum and they promote the sequential absorption of otherwise non-absorbed toxic hydrophilic species causing these diseases.
    Interdisciplinary toxicology 09/2013; 6(3):103-110. DOI:10.2478/intox-2013-0018
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