Parkinson’s disease is caused by a loss of nerve cells in the part of the brain called the substantia nigra. “Nerve cells in this part of the brain are responsible for producing a chemical called dopamine,” explains the NHS. Dopamine sends a signal between parts of the brain and nervous system that help control and coordinate body movements.
It is not known exactly what causes a loss of dopamine but certain lifestyle behaviours have been identified.
According to a study published in the journal Parkinson’s Disease, history of head trauma or concussion and exposure to lead may more than double the risk of Parkinson’s.
In determining risk of Parkinson’s, 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 Parkinson’s 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 Parkinson’s.
To gather their findings, the researchers conducted a questionnaire-based case-control study of people with Parkinson’s.
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’ (Parkinon’s, dementia or Alzheimer disease, multiple sclerosis, or other) within each of their family members,” the researchers said.
The researchers found that 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 Parkinson’s than in controls.
The association remained significant after adjusting for age, sex, smoking, family history, and athletic activity.
Family history of Parkinson’s in a first or second-degree relative was also found to be significantly greater in cases than in controls.
What’s more, the researchers observed a 2.67-fold increased risk of Parkinson’s associated with activities involving lead.
“Implicating these factors in Parkinson’s risk favours public health efforts in exposure mitigation while also motivating future work mechanisms and intervention opportunities,” concluded the study authors.
Other possible causes
“Parkinsonism” is the umbrella term used to describe the symptoms of tremors, muscle rigidity and slowness of movement.
According to the NHS, Parkinson’s disease is the most common type of parkinsonism, but there are also some rarer types where a specific cause can be identified.
These include parkinsonism caused by:
- Medication (drug-induced parkinsonism) – where symptoms develop after taking certain Medications, such as some types of antipsychotic medication, and usually improve once the Medication is stopped
- Other progressive brain conditions – such as progressive supranuclear palsy, multiple systems atrophy and corticobasal degeneration
- Cerebrovascular disease – where a series of small strokes cause several parts of the brain to die.
How is parkinsonism diagnosed?
Parkinson’s UK explained: “You should be referred to a Parkinson’s specialist for the diagnosis of any parkinsonism.
“They may wish to explore different things before giving you a diagnosis.”
According to the health body, your specialist will look at your medical history, ask you about your symptoms and do a medical examination.