A new study says COVID-19 can cause dementia. How real is the risk?
Since the early days of the coronavirus pandemic, people have become increasingly concerned about the extent to which COVID-19 infection may affect our brains – and whether what has become known as “brain fog” may develop into something more extreme. .
A new study, published this week in JAMA Neurologysuggests that COVID-19 survivors over the age of 60 may face an increased risk of mild cognitive impairment, cognitive decline, and even dementia.
But like much of the research collected on COVID-19, the results should be treated with caution, Bay Area experts say.
The study followed more than 1,400 COVID-19 survivors aged 60 or older who had been discharged from hospitals in Wuhan, China between February and April 2020, during the first months of the crisis. Researchers used patients’ uninfected spouses as a control population.
The purpose of the study was to test the one-year trajectory for cognitive changes in older COVID-19 survivors. Participants were tested on their cognitive functions using a questionnaire and a telephone interview, both six months and one year after their return.
Of the 1,438 participants, 1,178 were classified as non-serious diseases, while 260 were classified as having serious illness – a category that included difficulty breathing, low oxygen saturation and high respiratory rate.
The authors of the study wrote that at the end of the year-long study, 12% of the participants showed cognitive impairment. Of this group, 3% had dementia and a further 9% had mild cognitive problems. The researchers noted that of the participants affected by serious illness, 15% developed dementia compared to only 1% among people suffering only from mild COVID-19.
Of course, these results raise alarms for the many people around the world who are concerned about the effects of COVID-19 could have on the brainor who already manages “lang COVID. “
Although it was difficult to measure definitively, an estimated 32% of people who have experienced long-term COVID reported having brain fog as one of their symptoms, according to a study published January in the Journal of the Neurological Sciences.
Bay Area dementia experts say the new Wuhan study, while a meaningful contribution to the ever-emerging field of research on neurological connections to COVID-19, could take bigger scientific leaps than it should.
“They used a language that was very evocative, just like COVID-19 increases the number of mild cognitive impairment and dementia, and I don’t think their data really shows that,” said Dr. Joanna Hellmuth, a neurologist at UCSF’s Memory and Aging Center, who specializes in dementia. “I do not want people to worry unnecessarily about this.”
A major problem in the study was its methodology, Hellmuth said. Clinicians would typically not diagnose dementia through a telephone screening, and there could have been several factors – from anxiety and fatigue to outside help or even the quality of the internet connection – that could have affected participants’ performance.
Another problem, Hellmuth said, could lie in the test. Given that all participants were hospitalized, the population group of the study may have included individuals who are already more vulnerable to cognitive problems or with other risk factors. Plus the soothing role now available from vaccines, as well as the potential reduction of prolonged COVID symptoms over time, may not have been adequately considered.
Risk factors for dementia include diabetes, lack of exercise, high blood pressure, high cholesterol, blood clotting disorders and more.
“COVID-19, despite all our attempts to look for it, is very challenging to find in the brain,” said Hellmuth, who has studied the effects of HIV on the brain for many years, saying that even HIV, an objective “worse virus for the brain, “has not been associated with higher dementia rates.
Nor has she seen a single case of someone getting dementia after COVID-19, though she did not rule out that it was possible. But given all that we know (and still do not know) about the virus, it can be unnecessarily anxious to make such a crucial leap, she warned.
“I think this study adds to existing concerns that there are long-term health effects of COVID-19, which may include cognitive decline,” said Dr. Victor Henderson, a Stanford professor specializing in dementia. “This study certainly does not prove it, but it raises a red flag that this could be an issue that needs to be looked at more carefully as time goes on.”
Henderson reiterated many of Hellmuth’s concerns, adding that the scope of the study still looked at a very specific country, culture and time, where the standard of care for COVID-19 patients was very different than it is now. Taken together, these factors mean that it is difficult to justify such comprehensive conclusions – not to mention extrapolating them to the general public.
And although an ambitious addition to the growing literature on COVID-19, the results of the study still span a very short period of time, he said.
“A year is not a long time,” Henderson said. “It’s still not very long compared to the horizon for dementia.”