Parkinson's disease and brain levels of organochlorine pesticides

TLDR

Epidemiological studies suggest a link between pesticide exposure and Parkinson’s disease. The study aims to investigate dieldrin, a lipid‑soluble, long‑lasting mitochondrial poison, as a potential etiological agent of Parkinsonism. Researchers assayed organochlorine pesticides in postmortem brain samples from 20 PD, 7 AD, and 14 control cases, with groups matched for age, sex, and demographics. Only two residues were detected: DDT was present in most PD, AD, and all control brains, whereas dieldrin appeared in 30 % of PD cases but none of the controls, showing a significant association with Parkinson’s disease (p = 0.03).

Abstract

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.