Prevalence of amyloid pathology differs across dementia type and age

The prevalence of amyloid pathology on PET imaging varies according to what type of dementia the patient has, patient age, and apolipoprotein E epsilon-4 (APOE e4) allele status, according to a report published online May 19 in JAMA.

“To correctly interpret the clinical significance of amyloid PET results, clinicians need to understand the prevalence of amyloid positivity across different types of dementia and how this is associated with demographic, genetic, and cognitive factors. Most amyloid PET studies to date come from single centers with modest sample sizes. Therefore, we conducted an individual participant meta-analysis to estimate the prevalence of amyloid positivity in a large sample encompassing a variety of dementia syndromes,” said Rik Ossenkoppele, Ph.D., of the department of neurology and the Alzheimer Center at V.U. University Medical Center, Amsterdam, and his associates (JAMA 2015;313:1939-49).

The investigators pooled data from 29 cohorts involving 1,897 participants with clinical diagnoses of Alzheimer’s disease (1,359 patients), frontotemporal dementia (288), dementia with Lewy bodies (51), vascular dementia (138), and corticobasal syndrome (61), as well as 1,849 healthy control subjects. They found that the prevalence of amyloid pathology on PET decreased with advancing age in Alzheimer’s disease, from 93% at age 50 to 79% at age 90. However, the prevalence of amyloid pathology increased with advancing age in the other dementias.

This suggests that amyloid PET “might have the potential to be most helpful for differential diagnosis in early-onset dementia, particularly if the goal is to rule in AD dementia,” they said.

The Amyloid PET Study was funded by the National Institute on Aging, the National Institute of Biomedical Imaging and Bioengineering, the Alzheimer’s Association, and numerous other organizations and industry sources.

The prevalence of amyloid pathology on PET imaging varies according to what type of dementia the patient has, patient age, and apolipoprotein E epsilon-4 (APOE e4) allele status, according to a report published online May 19 in JAMA.

“To correctly interpret the clinical significance of amyloid PET results, clinicians need to understand the prevalence of amyloid positivity across different types of dementia and how this is associated with demographic, genetic, and cognitive factors. Most amyloid PET studies to date come from single centers with modest sample sizes. Therefore, we conducted an individual participant meta-analysis to estimate the prevalence of amyloid positivity in a large sample encompassing a variety of dementia syndromes,” said Rik Ossenkoppele, Ph.D., of the department of neurology and the Alzheimer Center at V.U. University Medical Center, Amsterdam, and his associates (JAMA 2015;313:1939-49).

The investigators pooled data from 29 cohorts involving 1,897 participants with clinical diagnoses of Alzheimer’s disease (1,359 patients), frontotemporal dementia (288), dementia with Lewy bodies (51), vascular dementia (138), and corticobasal syndrome (61), as well as 1,849 healthy control subjects. They found that the prevalence of amyloid pathology on PET decreased with advancing age in Alzheimer’s disease, from 93% at age 50 to 79% at age 90. However, the prevalence of amyloid pathology increased with advancing age in the other dementias.

This suggests that amyloid PET “might have the potential to be most helpful for differential diagnosis in early-onset dementia, particularly if the goal is to rule in AD dementia,” they said.

The Amyloid PET Study was funded by the National Institute on Aging, the National Institute of Biomedical Imaging and Bioengineering, the Alzheimer’s Association, and numerous other organizations and industry sources.

The prevalence of amyloid pathology on PET imaging varies according to what type of dementia the patient has, patient age, and apolipoprotein E epsilon-4 (APOE e4) allele status, according to a report published online May 19 in JAMA.

“To correctly interpret the clinical significance of amyloid PET results, clinicians need to understand the prevalence of amyloid positivity across different types of dementia and how this is associated with demographic, genetic, and cognitive factors. Most amyloid PET studies to date come from single centers with modest sample sizes. Therefore, we conducted an individual participant meta-analysis to estimate the prevalence of amyloid positivity in a large sample encompassing a variety of dementia syndromes,” said Rik Ossenkoppele, Ph.D., of the department of neurology and the Alzheimer Center at V.U. University Medical Center, Amsterdam, and his associates (JAMA 2015;313:1939-49).

The investigators pooled data from 29 cohorts involving 1,897 participants with clinical diagnoses of Alzheimer’s disease (1,359 patients), frontotemporal dementia (288), dementia with Lewy bodies (51), vascular dementia (138), and corticobasal syndrome (61), as well as 1,849 healthy control subjects. They found that the prevalence of amyloid pathology on PET decreased with advancing age in Alzheimer’s disease, from 93% at age 50 to 79% at age 90. However, the prevalence of amyloid pathology increased with advancing age in the other dementias.

This suggests that amyloid PET “might have the potential to be most helpful for differential diagnosis in early-onset dementia, particularly if the goal is to rule in AD dementia,” they said.

The Amyloid PET Study was funded by the National Institute on Aging, the National Institute of Biomedical Imaging and Bioengineering, the Alzheimer’s Association, and numerous other organizations and industry sources.