What is the incidence of dementia with Lewy bodies (DLB) and Parkinson’s disease dementia (PDD)? According to a new analysis from the 15-year population-based study of residents in Olmsted County, MN, the incidence rate for DLB was 3.5 per 100,000 years overall and 2.5 per 100,000 years overall, for PDD, and rates for both conditions increased steeply with age.
The findings were reported by Walter Rocca, MD, of the Mayo Clinic in Rochester, MN, and colleagues in the Sept. 16 online edition of JAMA Neurology.
Dr. Rocca and co-authors used the medical records linkage system of the Rochester Epidemiology Project to identify any individuals who developed parkinsonism and DLB or PDD.
Over the 15-year period, the investigators reported 542 cases of incident parkinsonism—64 of these individuals had DLB, and 46 had PDD. To put this number into context, Dr. Rocca and colleagues wrote, “Parkinson disease incidence was 4-fold higher, with an incidence rate of 14.2 cases per 100 000 person-years.”
Those individuals who developed DLB were younger at symptom onset than those patients who developed PDD, and they experienced more hallucinations and cognitive fluctuations. Men also had a higher incidence of DLB than women, regardless of age.
Despite the fact that DLB is presumed to be the second leading cause of neurodegenerative dementia after Alzheimer’s disease, the authors noted that there was a dearth of information about its incidence.
These findings may prompt new studies and guide health care planning, Dr. Rocca and co-authors wrote.
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