PEAK2

(conducted at the Division of Research in conjunction with Stanford University and The Parkinson’s Institute; Funded by: The Tobacco Related Disease Research Program)

This is an extension of the work done in PEAK1 with the primary objective being to examine genetic, environmental and behavioral factors that may explain the inverse smoking association with Parkinson's disease (PD). The primary hypothesis is that PD patients are less likely than controls to exhibit genotypes predictive of nicotine addiction. Dopamine receptor genotypes that have been characterized as low-addictive potential genotypes will be examined as effect modifiers and confounders of the smoking association with PD. If passive smoke exposure is inversely associated with smoking, this would suggest that a chemical or metabolic aspect of tobacco exposure is reducing the risk of PD, whereas if no inverse association with passive smoke exposure is observed, this would suggest that the inverse association observed with direct cigarette smoking is not causal.

This study will use blood samples and risk factor data obtained from subjects in a completed NIH-funded case-control study conducted within the Northern California Kaiser Permanente Medical Care Program. A lifetime history of cigarette smoking has already been obtained for the study subjects, which include 509 incident PD cases and 541 age- and gender-matched controls. Genomic DNA has already been collected from 89% of study subjects and is available for genotyping. PCR-RFLP based methods will be used to genotype blood samples for genetic loci that have been consistently shown to be associated with the susceptibility to addictive behaviors. By combining laboratory-based investigation of these putative susceptibility genes with information regarding cigarette smoking and other addictive behaviors, we hope to gain insight regarding the nature of the inverse associations of cigarette smoking and other addictive behaviors and Parkinson’s disease.

CURRENT STATUS

This study has completed data collection. Analyses are currently under way.