Sudden Blood Pressure Drop Not an Early Marker of Parkinson’s, Study Finds
Orthostatic hypotension, a sudden drop in blood pressure when changing positions, can significantly affect both function and quality of life for people with Parkinson’s disease. However, this non-motor symptom — typically attributed to later disease stages — is not associated with an increased risk of Parkinson’s and as such is not an early marker of the neurodegenerative disease, a study has found.
Published in Movement Disorders, the study is titled “Orthostatic Hypotension: A Prodromal Marker of Parkinson’s Disease?”
The symptoms of orthostatic hypotension — which is characterized by the inability to maintain adequate blood pressure and flow to the brain upon standing — include dizziness, lightheadedness, fatigue, and blurred vision. These can add to the other symptoms of Parkinson’s.
A rare subtype of the condition, called neurogenic orthostatic hypotension, is caused by the impaired release of the signaling molecule norepinephrine upon standing. That malfunction is due to an impairment of the autonomic nervous system, which regulates functions such as the heart and respiratory rate or digestion. Such impairments are often associated with an underlying neurodegenerative disorder, such as Parkinson’s.
“Determining whether orthostatic hypotension should be considered a prodromal [early] marker of Parkinson’s is important because prodromal markers allow earlier recognition of Parkinson’s and could help to identify individuals eligible for neuroprotective trials,” the researchers wrote.
To learn more, the team of scientists, from the Erasmus MC University Medical Center, in the Netherlands, now investigated the association between Parkinson’s and orthostatic hypotension in 6,910 participants from the first cohort (group) of the Rotterdam Study, a large population-based study initiated in 1990.
The main goal was determining whether orthostatic hypotension was related to having Parkinson’s.
The researchers followed Parkinson’s-free participants for the occurrence of the disease until 2016, and then studied the association between orthostatic hypotension and the risk of Parkinson’s. Data was analyzed using statistical models adjusted for age and sex.
At the study’s start (baseline), among participants who underwent orthostatic hypotension examination, 6,237 had no prevalent Parkinson’s (mean age of 68.9 years, 59.2% women ).
The 62 participants (1.0%) who had Parkinson’s at baseline were older (mean age 77.4 years) and included relatively fewer women (56.5%). On average, the Parkinson’s patients were 73.5 years at diagnosis, and were diagnosed 3.7 years before the orthostatic hypotension measurement.
Orthostatic hypotension was present in 1,220 participants without Parkinson’s (19.6%) and in 25 individuals (40.3%) with the disease. Parkinson’s patients were significantly more likely to have orthostatic hypotension (by 88%) and early orthostatic hypotension (by 86%) than those without the disease. However, the association between Parkinson’s and neurogenic orthostatic hypotension was not statistically significant.
During long-term follow-up (a median of 16.1 years), 122 participants were diagnosed with Parkinson’s that had developed over the study’s course (mean age of 78.8 years at diagnosis).
The team found that the presence of orthostatic hypotension at the beginning of the study was not associated with an increased risk of developing Parkinson’s. Also, there was no association between neurogenic, early, or delayed orthostatic hypotension at baseline and the risk of Parkinson’s.
There was an increased risk of death in those with orthostatic hypotension and neurogenic orthostatic hypotension compared with individuals without sudden blood pressure drops when standing, the researchers found.
When the team repeated the analysis with different cutoffs for follow‐up time — five, 10, and 15 years — the results remained the same.
“Our study suggests that orthostatic hypotension is common in patients with [Parkinson’s], but that orthostatic hypotension is not associated with an increased risk of Parkinson’s and thus is not a prodromal [early] marker of [Parkinson’s] in the general population,” the researchers concluded.