David Rein
Senior Fellow
NORC at the University of Chicago
October 2026
State rankings give a broad picture and county rankings a local one, but most Americans live in metropolitan areas, so we ranked metropolitan statistical areas (MSAs). An MSA is a Census Bureau unit made up of one or more counties: an urban core of at least 50,000 people plus the surrounding counties tied to it by commuting. It is the closest thing in public data to a city as people actually experience it. We used the July 2023 delineations, with Connecticut’s metros built from its legacy counties because our data still use them.
These rankings come from our new pooled 2020-2022 public use file, which combines three years of Medicare data into one set of counts. Pooling is important for anyone working below the state level. Small counties and small demographic groups are often suppressed in a single year because their counts fall under disclosure limits; three years of counts clear those limits more often. For example, in the 2022 single-year file, 62 percent of county-level cells for the Highly Likely or Likely definition display a value as compared to 71 percent in the pooled file. For Black and Hispanic beneficiaries at the county level, the share rises from 38 percent in the single-year file to 51 percent in the pooled file. Pooled counts are three-year sums, so rates built from them are three-year averages, which also steadies estimates for medium-sized areas.
Like everything else on our site so far, the rates in this post are rates of diagnosed dementia in Medicare claims. A metro with a high rate may have more disease, more diagnosis, or both, and these data alone cannot separate the two.
Among the 64 MSAs with at least 150,000 Medicare beneficiaries ages 65 and older, these 20 had the highest age-adjusted Highly Likely or Likely prevalence. Age adjustment recalculates each metro’s rate as if its beneficiaries had the national Medicare age mix, so a metro full of 85-year-olds and a metro full of 67-year-olds can be compared on the same terms. The chart shows both the crude rate (open circle) and the age-adjusted rate (filled circle), ranked by the adjusted value.
San Juan-Bayamón-Caguas, Puerto Rico, and Miami-Fort Lauderdale-West Palm Beach, Florida, had diagnosis rates far above the national average of 9.7 percent, and they remain above it even after age adjustment. The large MSAs with the lowest age-adjusted prevalence were Minneapolis-St. Paul-Bloomington, Minnesota-Wisconsin (7.8 percent), Albuquerque, New Mexico (7.9 percent), San Diego-Chula Vista-Carlsbad, California (7.9 percent), Tucson, Arizona (8.1 percent), Pittsburgh, Pennsylvania (8.1 percent), North Port-Bradenton-Sarasota, Florida (8.3 percent), Cape Coral-Fort Myers, Florida (8.3 percent), Rochester, New York (8.4 percent), Albany-Schenectady-Troy, New York (8.5 percent), and San Jose-Sunnyvale-Santa Clara, California (8.5 percent).
Everything we post comes from our system’s public use file, which can be accessed freely via our data request form. If you notice a finding or pattern you think is important, we would love to hear about it. Find us at Dementiadatahub@norc.org.
The Dementia DataHub is funded by the National Institute on Aging and led by NORC at the University of Chicago with partners at George Washington University’s Milken Institute School of Public Health and KPMG LLP.
