[Show abstract][Hide abstract] ABSTRACT: To examine genetic associations of polymorphisms in the dopamine receptor D2 (DRD2) and D3 (DRD3) genes with risk of Parkinson's disease (PD).
The study included 1325 newly diagnosed patients with PD and 1735 controls from a consortium of five North American case-control studies. We collected risk factor information by in-person or telephone interview. Six DRD2 and two DRD3 polymorphisms were genotyped using a common laboratory. Odds ratios were estimated using logistic regression.
Among non-Hispanic whites, homozygous carriers of Taq1A DRD2 (rs1800497) polymorphism had an increased risk of PD compared to homozygous wildtype carriers (OR=1.5, 95% CI 1.0-2.3). In contrast, the direction of association for Taq1A polymorphism was opposite for African-Americans, showing an inverse association with PD risk (OR=0.10, 95% CI 0.2-0.7). Among white Hispanics who carried two alleles, the Ser9Gly DRD3 (rs6280) polymorphism was associated with a decreased risk of PD (OR=0.4, 95% CI 0.2-0.8). The inverse association of smoking with PD risk was not modified by any of the DRD2 or DRD3 polymorphisms.
DRD2 polymorphisms are unlikely to be true disease-causing variants; however, three DRD2 polymorphisms (including Taq1A) may be in linkage disequilibrium with possible disease associated variants in the DRD2-ANKK1-NCAM1-TTC12 gene cluster.
Journal of the neurological sciences 06/2011; 307(1-2):22-9. · 2.32 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: In 1-methyl-4-phenyl 1,2,3,6-tetrahydropyridine animal models of Parkinson's disease (PD), caffeine protects neurons by blocking the adenosine receptor A2A (ADORA2A). Caffeine is primarily metabolized by cytochrome P450 1A2 (CYP1A2). Our objective was to examine whether ADORA2A and CYP1A2 polymorphisms are associated with PD risk or modify the caffeine-PD association.
Parkinson's Epidemiology and Genetic Associations Studies in the United States (PEGASUS) included five population-based case-control studies. One laboratory genotyped four ADORA2A and three CYP1A2 polymorphisms in 1325 PD cases and 1735 age- and sex-matched controls. Information regarding caffeine (coffee) consumption and other lifestyle factors came from structured in-person or telephone interviews. Odds ratios (OR) and 95% confidence intervals (CI) were estimated using logistic regression.
Two ADORA2A polymorphisms were inversely associated with PD risk - rs71651683, a 5' variant (adjusted allelic OR = 0.51, 95% CI 0.33-0.80, permutation-adjusted P = 0.015) and rs5996696, a promoter region variant (adjusted OR for AC and CC genotypes compared with the AA wild-type genotype were 0.76 (95% CI 0.57-1.02) and 0.37 (95% CI 0.13-1.01), respectively (permutation-adjusted P for trend = 0.04). CYP1A2 polymorphisms were not associated with PD risk; however, the coffee-PD association was strongest among subjects homozygous for either variant allele rs762551 (P(interaction) = 0.05) or rs2470890 (P(interaction) = 0.04).
In this consortium study, two ADORA2A polymorphisms were inversely associated with PD risk, but there was weak evidence of interaction with coffee consumption. In contrast, the coffee-PD association was strongest among slow metabolizers of caffeine who were homozygous carriers of the CYP1A2 polymorphisms.
European Journal of Neurology 05/2011; 18(5):756-65. · 3.85 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: To estimate the number of acetaminophen overdose-related emergency department (ED) visits and hospitalizations in the United States, characterize these by intentionality, age, and gender, and compare the strengths and limitations of the utilized databases.
We used data from the National Hospital Ambulatory Medical Care Survey (NHAMCS) and the National Electronic Injury Surveillance System (NEISS) to estimate the number of relevant ED visits in the United States between 2000 and 2007, and the National Hospital Discharge Survey (NHDS) to estimate the number of relevant hospitalizations in the United States between 1991 and 2006. National estimates and their standard errors were calculated using information provided in each database. We used the standard United States population in 2000 to calculate age-adjusted rates.
We estimate an annual average of 44,348 (NHAMCS, 2000-2007) or 78,414 (NEISS, 2006-2007) acetaminophen overdose-related ED visits and 33,520 (NHDS, 2000-2006) hospitalizations. For 2000-2006 we calculated an age-adjusted rate of 13.9 acetaminophen overdose-related hospitalizations per 100,000 US population, with the highest rate (15.7) occurring from 2005 to 2006. Between 1991 and 2006, there was no decrease noted in hospitalizations for intentional or unintentional overdoses. The majority of overdoses reported in NEISS (69.8%) and NHDS (74.2%) were classified as intentional (suicides or suicidal gestures), whereas in NHAMCS, intentionality was evenly distributed.
Our results suggest that acetaminophen overdose, both intentional and unintentional, remains a significant public health concern. With an understanding of their methodological characteristics and limitations, these national databases can be useful tools to characterize acetaminophen overdose-related ED visits and hospitalizations.
Pharmacoepidemiology and Drug Safety 02/2011; 20(8):819-26. · 2.90 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Experimental evidence supports a preventative role for non-steroidal anti-inflammatory drugs (NSAIDs) in Parkinson's disease (PD).
We investigated associations between use of aspirin, nonaspirin NSAIDs, and acetaminophen and PD in a large population-based case-control study using Danish health and pharmacy registries. We identified 1,931 PD cases reported in hospital or outpatient clinic records who had received a primary diagnosis of PD between 2001 and 2006, and 9,651 age- and sex-matched controls from the Danish population register. Prescription medication use was documented in a pharmacy database covering all residents of Denmark since 1995.
Adjusting for age, sex, use of cardiovascular disease drugs, diagnosis of chronic pulmonary obstructive disorder, and Charlson comorbidity scores, and excluding prescriptions filled within 5 years before diagnosis, we found no evidence for an association between PD and either aspirin use (OR = 0.97; 95% CI 0.82, 1.14) or nonaspirin NSAID use (OR = 0.97; 95% CI 0.86, 1.09), regardless of intensity of use; further, there was no association between use of ibuprofen or acetaminophen and PD.
Our findings provide no evidence for a protective effect of nonaspirin and aspirin NSAID prescription drug use shortly before PD onset.
[Show abstract][Hide abstract] ABSTRACT: The objective of this study was to investigate whether statin (3-hydroxy-3-methylglutaryl-coenzyme A reductase inhibitor) use is associated with risk of Parkinson's disease (PD) in Denmark. We identified 1,931 patients with a first time diagnosis of PD reported in hospital or outpatient clinic records between 2001 and 2006. We density matched to these patients 9,651 population controls by birth year and sex relying on the Danish population register. For every participant, we identified pharmacy records of statin and anti-Parkinson drug prescriptions since 1995 and before index date from a prescription medication use database for all Danish residents. Whenever applicable, the index dates for cases and their corresponding controls were advanced to the date of first recorded prescription for anti-Parkinson drugs. In our primary analyses, we excluded all statin prescriptions 2-years before PD diagnosis. Employing logistic regression adjusting for age, sex, diagnosis of chronic obstructive pulmonary disease, and Charlson comorbidity, we observed none to slightly inverse associations between PD diagnosis and statin prescription drug use. Inverse associations with statin use were only observed for short-term (<or=1 yrs) statin users (2-year lag OR 0.57; 95% CI 0.36 to 0.89); and suggested at higher intensity statin use (2-year lag OR 0.69; 95% CI 0.45-1.04). No associations were seen among long-term users and no difference by sex, age, or type of statins used (lipophilic/hydrophilic). We found little evidence for a neuroprotective role of statins in PD except for short-term or high intensity users. Yet, further investigations into the contributions of intensity, duration, and lag periods of statin use may still be warranted.
Movement Disorders 07/2010; 25(9):1210-6. · 5.63 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Although of great interest and suggested in prior reports, possible α-synuclein (SNCA) gene-environment interactions have not been well investigated in humans.
We used a population-based approach to examine whether the risk of Parkinson's disease (PD) depended on the combined presence of SNCA variations and two important environmental factors, pesticide exposures and smoking.
Similar to recent meta- and pooled analyses, our data suggest a lower PD risk in subjects who were either homozygous or heterozygous for the SNCA REP1 259 genotype, and a higher risk in subjects who were either homozygous or heterozygous for the REP1 263 genotype, especially among subjects with an age of onset ≤68 years. More importantly, while analyses of interactions were limited by small cell sizes, risk due to SNCA variations seemed to vary with pesticide exposure and smoking, especially in younger onset cases, suggesting an age-of-onset effect.
[Show abstract][Hide abstract] ABSTRACT: Investigators have hypothesized that consuming pesticide-contaminated well water plays a role in Parkinson's disease (PD), and several previous epidemiologic studies support this hypothesis.
We investigated whether consuming water from private wells located in areas with documented historical pesticide use was associated with an increased risk of PD.
We employed a geographic information system (GIS)-based model to estimate potential well-water contamination from agricultural pesticides among 368 cases and 341 population controls enrolled in the Parkinson's Environment and Genes Study (PEG). We separately examined 6 pesticides (diazinon, chlorpyrifos, propargite, paraquat, dimethoate, and methomyl) from among 26 chemicals selected for their potential to pollute groundwater or for their interest in PD, and because at least 10% of our population was exposed to them.
Cases were more likely to have consumed private well water and to have consumed it on average 4.3 years longer than controls (p = 0.02). High levels of possible well-water contamination with methomyl [odds ratio (OR) = 1.67; 95% confidence interval (CI), 1.00-2.78]), chlorpyrifos (OR = 1.87; 95% CI, 1.05-3.31), and propargite (OR = 1.92; 95% CI, 1.15-3.20) resulted in approximately 70-90% increases in relative risk of PD. Adjusting for ambient pesticide exposures only slightly attenuated these increases. Exposure to a higher number of water-soluble pesticides and organophosphate pesticides also increased the relative risk of PD.
Our study, the first to use agricultural pesticide application records, adds evidence that consuming well water presumably contaminated with pesticides may play a role in the etiology of PD.
Environmental Health Perspectives 12/2009; 117(12):1912-8. · 7.26 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Human, animal and cell models support a role for pesticides in the etiology of Parkinson disease. Susceptibility to pesticides may be modified by genetic variants of xenobiotic enzymes, such as paraoxonase, that play a role in metabolizing some organophosphates.
We examined associations between Parkinson disease and the organophosphates diazinon, chlorpyrifos, and parathion, and the influence of a functional polymorphism at position 55 in the coding region of the PON1 gene (PON1-55). From 1 January 2001 through 1 January 2008, we recruited 351 incident cases and 363 controls from 3 rural California counties in a population-based case-control study. Participants provided a DNA sample, and residential exposure to organophosphates was determined from pesticide usage reports and a geographic information system (GIS) approach. We assessed the main effects of both genes and pesticides in unconditional logistic regression analyses, and evaluated the effect of carrying a PON1-55 MM variant on estimates of effects for diazinon, chlorpyrifos, and parathion exposures.
Carriers of the variant MM PON1-55 genotype exposed to organophosphates exhibited a greater than 2-fold increase in Parkinson disease risk compared with persons who had the wildtype or heterozygous genotype and no exposure (for diazinon, odds ratio = 2.2 [95% confidence interval = 1.1-4.5]; for chlorpyrifos, 2.6 [1.3-5.4]). The effect estimate for chlorpyrifos, was more pronounced in younger-onset cases and controls (<or=60 years) (5.3 [1.7-16]). No increase in risk was noted for parathion.
The increase in risk we observed among PON1-55 variant carriers for specific organophosphates metabolized by PON1 underscores the importance of considering susceptibility factors when studying environmental exposures in Parkinson disease.
[Show abstract][Hide abstract] ABSTRACT: Research suggests that independent and joint effects of genetic variability in the dopamine transporter (DAT) locus and pesticides may influence Parkinson's disease (PD) risk.
In 324 incident PD patients and 334 population controls from our rural California case-control study, we genotyped rs2652510, rs2550956 (for the DAT 5' clades), and the 3' variable number of tandem repeats (VNTR). Using geographic information system methods, we determined residential exposure to agricultural maneb and paraquat applications. We also collected occupational pesticide use data. Employing logistic regression, we calculated odds ratios (ORs) for clade diplotypes, VNTR genotype, and number of susceptibility (A clade and 9-repeat) alleles and assessed susceptibility allele-pesticide interactions.
PD risk was increased separately in DAT A clade diplotype carriers [AA vs. BB: OR = 1.66; 95% confidence interval (CI), 1.08-2.57] and 3' VNTR 9/9 carriers (9/9 vs. 10/10: OR = 1.8; 95% CI, 0.96-3.57), and our data suggest a gene dosing effect. Importantly, high exposure to paraquat and maneb in carriers of one susceptibility allele increased PD risk 3-fold (OR = 2.99; 95% CI, 0.88-10.2), and in carriers of two or more alleles more than 4-fold (OR = 4.53; 95% CI, 1.70-12.1). We obtained similar results for occupational pesticide measures.
Using two independent pesticide measures, we a) replicated previously reported gene-environment interactions between DAT genetic variants and occupational pesticide exposure in men and b) overcame previous limitations of nonspecific pesticide measures and potential recall bias by employing state records and computer models to estimate residential pesticide exposure.
Our results suggest that DAT genetic variability and pesticide exposure interact to increase PD risk.
Environmental Health Perspectives 07/2009; 117(6):964-9. · 7.26 Impact Factor