People with prior incidence of traumatic brain injury and exposure to lead were shown to be at elevated risk of Parkinson disease development, with family history also found to influence risk.
In determining risk of PD, the study authors said that conflicting research has been published on whether genetic factors play a role in the pathogenesis of the condition. As a result, they noted that PD is likely caused by a complex interaction between genetic and environmental risk factors, which include exposure to pesticides, toxic metals, solvents, and history of traumatic brain injury.
“Identifying environmental factors that increase PD risk would allow exposure mitigation and disease prevention efforts while facilitating the experimental investigation of mechanisms and intervention opportunities,” noted the study authors.
Along with prior studies that have found a positive link between rural living and the development of PD, a spatial analysis of US Medicare beneficiaries showed a concentration of PD in the Midwest and Northeast.
In contrast with the Midwest, potential environmental risk factors of PD such as agriculture and pesticide use are not prevalent in the Northeast, which researchers say underscores the need to identify additional lifestyle factors associated with PD in rural Northeastern populations.
They conducted a questionnaire-based case-control study of people with PD (n = 97) who resided in a rural area on the New Hampshire/Vermont border and age- and sex-matched controls from the general population (n = 195) between 2017 and 2020. Participants were evaluated for lifestyle factors, including a variety of specific jobs, hobby-related activities, and associated chemical exposures.
“In addition to exposure and physical activity, participants reported on the family medical history of ‘diagnosis of neurological disorder’ (PD, dementia or Alzheimer disease, multiple sclerosis, or other) within each of their family members,” they added.
Based on univariate analyses, findings indicated that a higher proportion of patients with PD in the rural area (57.9%) reported participation in strenuous athletic activities, such as running, swimming, or other competitive sports than controls (43.2%), but this association was mitigated after adjusting for head trauma as a confounding factor (odds ratio [OR], 1.69; 95% CI, 0.93–3.13).
Furthermore, reports of suffering head trauma or a concussion that caused one to black out or lose consciousness prior to the diagnosis date were found to be much more frequent among those with PD (42.7%) than in controls (18.4%), which remained significant after adjusting for age, sex, smoking, family history, and athletic activity (OR, 4.17; 95% CI, 2.23-7.98).
Family history of PD in a first- or second-degree relative was also found to be significantly greater in cases than in controls (22.7% vs 6.7%; P < .001), with a 2.67-fold increased risk of PD associated with activities involving lead (OR, 2.67; 95% CI, 1.05-6.80; adjusted P = .038).
“Implicating these factors in PD risk favors public health efforts in exposure mitigation while also motivating future work mechanisms and intervention opportunities,” concluded the study authors.
Andrew AS, Anderson FL, Lee SL, Von Herrmann KM, Havrda MC. Lifestyle factors and Parkinson’s disease risk in a rural New England case-control study. Parkinsons Dis. Published online July 2, 2021. doi:10.1155/2021/5541760