Parkinson’s Patients Less Likely to Catch Common Cold: Study
Fewer cases of cold with Parkinson’s than Alzheimer’s, migraine, epilepsy, stroke
People with early-stage Parkinson’s disease may be about 70% less likely to catch the common cold than those with other common brain diseases, a Japanese study suggests.
The study, “Are patients with Parkinson’s disease at a lower risk of catching the common cold? Propensity score matching,” was published as a short communication in Parkinsonism & Related Disorders.
People with Parkinson’s appear to have more brain inflammation than those without the disease, which is thought to contribute to its development and progression.
But inflammation can call on immune cells for protection, which has led a team of researchers in Japan to speculate that people with Parkinson’s may be kept safe from mild infections such as the common cold, at least while the disease is at its early stages.
They drew on data from people, ages 40 years or older, who filed insurance claims in the country between 2010 and 2021, including 726 people with a diagnosis of Parkinson’s who were at the early stages of disease. As a control, the researchers collected data from 11,753 people with other common brain diseases, including Alzheimer’s, migraine, epilepsy, or stroke.
Those with Parkinson’s were significantly older (70.3 vs. 67.4 years) and included a significantly greater proportion of men (54.6% vs. 50.1%). Most (75.3%) Parkinson’s patients were followed by a neurologist.
Results showed that there were significantly fewer cases of common cold among people with Parkinson’s (3.4%) than among those with Alzheimer’s (9.8%), migraine (13.3%), epilepsy (11%), or stroke (8.8%).
After adjusting for potential influencing factors, such as age, sex, specific disease, and periods of before or after the onset of the COVID-19 pandemic, the researchers found that a Parkinson’s diagnosis reduced the odds of catching the common cold by about 70%. The pandemic period was also associated with a 50% less chance of reports of the common cold.
Being a woman and being followed by a neurologist were found to be independently associated with an increased chance of catching the common cold — by 59% and 30%, respectively.
The researchers used a method called propensity score matching to match each Parkinson’s patient followed by a neurologist to one or more people from the other groups who had similar characteristics and who were also followed by a neurologist in order to better adjust for the effects of potential influencing factors.
A total of 276 Parkinson’s patients were matched to 276 people with Alzheimer’s, also a neurodegenerative disease. After matching, the rate of common colds was still significantly lower among people with Parkinson’s (3.4%) than among those with Alzheimer’s (8.2%).
Similar results were seen when matching 547 Parkinson’s patients to 547 people with non-neurodegenerative diseases (3.1% vs. 13%).
“Our data demonstrated a low incidence of colds in PD [Parkinson’s disease] relative to that observed in other kinds of common brain diseases,” the researchers wrote, adding this might be due to Parkinson’s patients not complaining “about common cold symptoms (or requested medications) even when symptomatic” or to a possibility that “the [disease-associated] features of PD might reduce the risk of catching a cold relative to other brain diseases.”
More research is needed to confirm these findings, assess whether this lower risk covers other types of mild infections, and determine the reasons for this potentially lower risk among early-stage Parkinson’s patients, they said.
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