Environmental antecedents of young‐onset Parkinson's disease

Abstract

We conducted an exploratory study of young-onset Parkinson's disease (YOPD) to examine occupational and environmental factors associated with disease risk. This case-control study included 63 YOPD patients (diagnosis on or before age 50); controls (n = 68) were diagnosed with rheumatoid arthritis. Crude odds ratios (ORs) were computed to identify exposure variables for logistic regression analyses. After controlling for the variables of race, educational level, sex, age, age at diagnosis, and family history of Parkinson's disease (PD), PD was positively associated with insecticide exposure (OR = 5.75, p < 0.001), past residency in a fumigated house (OR = 5.25, p = 0.046), herbicide exposure (OR = 3.22, p = 0.033), rural residency at time of diagnosis (OR = 2.72, p = 0.027), and nuts and seed eating 10 years before diagnosis (OR = 1.49, p = 0.021). PD was inversely associated with cigarette smoking at 5 years (OR = 0.50, p = 0.027), 10 years (OR = 0.43, p = 0.012), and 15 years (OR = 0.37, p = 0.005) before diagnosis, farm residency (OR = 0.38, p = 0.018), and exposure to dimethyl sulfoxide (OR = 0.10, p < 0.001). These findings are consistent with hypotheses linking PD to exposure to pesticide agents.

Epidemiology and etiology of Parkinson’s disease: a review of the evidence

“…A similar Danish study also reported a weak association (standardized hospitalization ratio, SHR, 1.30, 95% CI 1.03-1.63) [354]. Among 29 case-control studies that studied rural living as an exposure, 11 reported an increased risk of PD [136,141,142,147,153,289,293,303,305,309,314] with ORs ranging between 1.5 and 4.9. One study reported an inverse association [350], whereas the others found no association [131, 143-146, 154, 291, 307, 311, 312, 315, 316, 321, 325, 356-358].…”

“…Another population-based study reported increased risk with occupational exposure to insecticides (OR 2.05, 95% CI 1.03-4.03) [290]. Exposure to insecticides more than 10 times a year was associated with increased risk in the study of young-onset PD [153] (OR 5.75, p=0.001).…”

“…Another hospital-based study among young-onset PD cases and patients with reumathoid arthritis as controls reported an increased risk with herbicide exposure more than 10 times a year (OR 3.22, p value 0.03) [153]. A population-based study reported increased risk with any occupational exposure to herbicides (OR 4.10, 95% CI 1.37-12.24), but no associations following agricultural or recreational herbicide exposure [321,322].…”

“…Some case-control studies reported results for specific categories of pesticides, such as herbicides, insecticides, or fungicides, rather than pesticides overall. Of 18 studies that analyzed exposure to herbicides, 10 found increased risk of PD, either for herbicides as a group of substances, or for specific herbicides, such as paraquat, nitrile herbicides or 2,4-Dichlorophenoxyacetic acid [153,154,290,293,302,304,[321][322][323][324], with ORs ranging between 1.6 and 5.8. The other 8 studies reported no association between herbicides and PD [131,143,292,299,301,315,316,325].…”

“…Of 17 studies, 9 reported increased risk of PD either for insecticides as a group, or for specific insecticides [153,154,156,290,302,306,321,322,324], with ORs ranging from 1.2 to 5.8. The other 8 studies, all mentioned above, reported no association for insecticides as a group or for specific insecticides [143,292,299,301,304,315,316,325].…”