PD Epidemiology: Pesticide Exposure, Polymorphism Meta-Analysis

Subject: PD Epidemiology: Pesticide Exposure, Polymorphism Meta-Analysis

Date: 9/13/2000

1. Parkinson's disease mortality and pesticide exposure in California 1984-1994
B Ritz, F Yu
International J Epidemiology 2000;29:323-329

Mortality from Parkinson's disease is correlated with environmental pesticide exposure, according to this study.

Death rates due to or associated with PD were compared to death rates due to ischemic heart disease in 58 California counties from 1984 to 1994. Counties were ranked by pesticide use, determined from state pesticide registry and agricultural census data.

Results showed that mortality from PD as the underlying cause of death "was 19-47% higher in counties reporting the use of restricted agricultural pesticides compared to PD mortality in counties reporting no use of restricted pesticides for agricultural purposes." A weak relationship was seen between pesticide exposure and PD as an associated (versus underlying) cause of death. While no dose-response relationship was observed, the risk of dying from PD was correlated with percent of land treated for the single year in which this data was analyzed.

2. Variability and validity of polymorphism association studies in Parkinson's disease
EK Tan, M Khajavi, JI Thornby, S Nagamitsu, J Jankovic, T Ashizawa
Neurology 2000;55:533-538

Meta-analysis was performed on 84 polymorphism association studies in Parkinson's disease looking at 14 genes: dopamine receptors (DRD2, DRD4), dopamine transporter (DAT), monoamine oxidases (MAOA, MAOB), catechol-O-methyltransferase (COMT), N- acetyltransferase (NAT2), APOE, glutathione transferases (GSTT1, GSTM1, GSTP1, GSTZ1), and two mitochondrial genes (tRNA-glu, ND2).

Genes were included for analysis if they were the subject of 4 or more studies. The authors excluded studies of cytochrome P450 enzyme polymorphisms because a meta-analysis has recently been published.

Significant associations were found for 4 polymorphisms:

--MAOB, (GT)n dinucleotide repeat. Alleles with 188 or more base pairs are more common in PD patients (p=0.003, OR=2.58, 95% CI=1.38-4.82)

--NAT2. Frequency of slow acetylator alleles is higher in PD patients (p=0.006, OR=1.33, 95% CI=1.08-1.62)

--GSTT1 deletion. Frequency of deletions is higher in PD patients (p=0.048, OR=1.34, 95% CI=1.0-1.79)

--tRNA-glu. Frequency of A4336G polymorphism is higher in PD patients. (p=0.04, OR=3, 95% CI=1.1-8.2)

Other E-MOVE reports on polymorphism associations in PD:
GST
http://www.wemove.org/emove/article.asp?ID=26
MAOB
http://www.wemove.org/emove/article.asp?ID=44
APOE
http://www.wemove.org/emove/article.asp?ID=48