Between Mar. 1 and Aug. 1, the US Centers for Disease Control and Prevention (CDC) recorded 225,530 more deaths than previous years’ averages, otherwise known as excess deaths. But during that period, deaths attributed to Covid-19 had only just topped 150,500.

Of those deaths not attributed to the coronavirus, the two leading causes were heart disease, which spiked in March and April, and Alzheimer’s and dementia, which increased first in March and April and again in June and July, when cases increased dramatically in the southern US.

Although the CDC doesn’t estimate how many people a given condition will kill annually, it does track how many die from it each year. Dementia deaths in 2020 show a notable increase over 2019.

How could the Covid-19 pandemic cause a spike in dementia-related deaths? Researchers can only speculate without examining each case. But it’s likely a result of disrupted access to care.

“Individuals with Alzheimer’s disease and related dementias are the most vulnerable people in society,” says Miguel Arce Rentería, a clinical neuropsychologist and associate research scientist at Columbia University Medical Center in New York. People with dementia are highly reliant on caregivers, whether they’re living at home or in an assisted living facility.

While a death certificate that cites dementia may mean the person died as a result of neurodegeneration, it’s more often because another health issue was exacerbated by their inability to access care. Pneumonia doesn’t get caught in time; medication never gets taken; a fall causes a severe bone break that leads to fatal complications.

The pandemic dramatically disrupted dementia care. Nursing homes struggled with staffing and adequate PPE for employees. The atmosphere was tense—a factor that could put residents at a higher risk of dying on its own. Routine checkups were foregone, or conducted over the phone or computer—an imperfect medium new to both patients and providers.

Restrictions on visitors to stop the spread of Covid-19 may have also played a role in the increase in dementia-related deaths. Loneliness has been correlated with increased risk of developing dementia in healthy adults, and may exacerbate its progression.

And just like Covid-19 has disproportionately impacted communities of color across the country, it’s likely that structural racism has harmed people of color living with dementia. Black and Hispanic populations in the US are more likely to develop dementia than white people to begin with, and tend to be diagnosed later, worsening outcomes. Add in a pandemic, says Arce Rentería, and “the disparities are just magnified 10 times.”

The pandemic isn’t just a respiratory illness. By straining resources and access to healthcare, it has indirectly killed thousands. As the US health care system continues to battle Covid-19, it will have to pay attention to the gaps and inequalities revealed by all the pandemic’s impacts.

Correction (Oct. 19): This story has been updated to reflect Miguel Arce Rentería’s full last name; a previous version of the story omitted part of it. 

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