More than 121,000 Hoosiers over 65 have Alzheimer's

An estimated 11% of adults aged 65 or older in Indiana — about 121,300 people — have Alzheimer's disease, per a new study.

Why it matters: It's critical for public health officials, policymakers and others to have a clear look at the number of Alzheimer's cases in a given area, the authors say — in part because caring for those with the disease cost an estimated $321 billion nationwide last year, much of which came via Medicare and Medicaid.

Details: The study, published in the journal Alzheimer's & Dementia, estimated the rates of Alzheimer's disease among adults ages 65 or older in a given area based on demographic risk factors, including age, sex and race/ethnicity.

• Researchers used data from the Chicago Health and Aging Project (a population-based study examining Alzheimer's risk factors), plus population estimates from the CDC's National Center for Health Statistics.

Zoom in: Marion County had the second highest rate in the state, at 12.3%. Lake County tops the state at 12.9%.

The intrigue: The IU School of Medicine hosts the Indiana Alzheimer's Disease Research Center, one of a few dozen centers in the country solely committed to Alzheimer's research.

• The center reports it has received more than 450 brain donations since its founding in 1991.

By the numbers: According to the Alzheimer's Association, 216,000 family caregivers in Indiana bear the burden of 321 million hours of unpaid care for those with the disease.

• That care is valued at $5.1 billion — and costs an estimated $1 billion for the state Medicaid program.

The big picture: The eastern and southeastern U.S. have the country's highest rates of Alzheimer's disease, according to the study.

• Maryland (12.9%), New York (12.7%) and Mississippi (12.5%) topped the list of U.S. states ranked by estimated number of Alzheimer's cases.

Yes, but: The researchers caution that their approach is incomplete, as demographic-based risk factors can only tell part of the picture.

• Other risk factors — including cardiovascular health and lifestyle — also play a role, but "such data are unavailable at the county level, and we cannot incorporate them into our estimates," they write.