LOS ANGELES (KABC) -- Can't find your phone or remember where you parked your car? It's not always a sign of aging.
New findings show aging is only a small part of what causes cognitive decline.
Ten million new cases of dementia are diagnosed every year, but you might be surprised what other risk factors, besides aging, play a role.
New findings in the Public Library Science Journal found age only explained 23% of cognitive decline in those 54 to 85.
In the remaining 77%, other factors, like personal and parental education levels, race, income and occupation, played a greater role. Understanding these causes gives scientists insight into the differing degrees of cognitive decline in diseases such dementia and Alzheimer's.
"The hard thing about Alzheimer's is that ... it's a years' long decline," said Dr. Sarah Kremen, a Behavioral Neurologist with Cedars-Sinai's Jona Goldrich Center for Alzheimer's and Memory Disorders. "For some people, it may be five or eight years, for some, it could be 20."
Case Western Reserve University researchers found for every 1,000 seniors with COVID-19, seven will be diagnosed with Alzheimer's within a year.
This is slightly above the 5 in 1,000-diagnosis rate for seniors who did not have coronavirus.
University of Missouri researchers found patients with COVID-related pneumonia had a higher risk of developing dementia.
However, COVID is not the only surprising risk factor.
"Two-thirds of Alzheimer's patients here in the U.S. are women," noted Dr. Sepi Shokouhi, an Assistant Professor of Psychiatry and Behavioral Science with the Vanderbilt Center for Cognitive Medicine.
Scientists say it's not just because women live longer than men. Researchers found an abnormal protein linked to dementia was more widespread in women's brains.
"I can predict that sex will be more strongly integrated in future precision medicine in Alzheimer's disease," said Shokouhi.
Plus, studies show taking an anticholinergic medication, such as Benadryl or clozapine, for three years or more was associated with a 54% higher dementia risk.
Other factors contributing to cognitive decline include obesity, smoking and chronic disease. There are things you can do to lower your risk that have a lot of impact.
Simply walking can lower your risk for dementia.
Researchers found that walking 4,000 steps a day lowers your dementia risk by 25%, while reaching 10,000 steps a day lowers it by 50%.