### Abstract

OBJECTIVE: To estimate the prevalence of elevated brain amyloid and reduced cortical thickness (as a marker for neurodegeneration) in a defined population.

METHODS: Mayo Clinic Study of Aging participants underwent MRI to assess a composite Alzheimer disease (AD) signature cortical thickness measure and PET to assess brain amyloid accumulation. Participants were characterized as having elevated amyloid (A+/A-), reduced cortical thickness (N+/N-), and A+N+, A+N-, A-N+, or A-N-. The prevalence of AD biomarkers was derived by adjusting for nonparticipation and standardizing to the Olmsted County, Minnesota, population.

RESULTS: Among 1,646 participants without dementia (mean age 70.8 years; 53.2% men), the prevalence (95% confidence interval) of amyloidosis was 21.1% (19.1%-23.2%): women, 24.3%; men, 17.5%. The prevalence of reduced cortical thickness was 28.9% (26.4%-31.5%): women, 27.9%; men, 30.2%. The prevalence estimates of biomarker categories were as follows: A-N-: 61.4%; A+N-: 9.7%; A-N+: 17.4%; and A+N+: 11.5%, and varied by sex and by APOE ε4 carrier status. In men, prevalence estimates were as follows: A-N-: 62.6%; A+N-: 7.3%; A-N+: 19.9%; and A+N+: 10.2%. In women, prevalence estimates were as follows: A-N-: 60.4%; A+N-: 11.7%; A-N+: 15.3%; and A+N+: 12.6%. In ε4 carriers, prevalence estimates were as follows: A-N-: 54.6%; A+N-: 16.6%; A-N+: 12.4%; and A+N+: 16.4%. In non-ε4 carriers, prevalence estimates were as follows: A-N-: 63.3%; A+N-: 6.9%; A-N+: 19.9%; and A+N+: 10.0%.

CONCLUSIONS: These prevalence estimates are important for understanding age-related trends in amyloid positivity and AD signature cortical thickness in the population, and for potentially projecting the future burden of biomarkers in elderly persons.

Original language | English (US) |
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Pages (from-to) | 2039-2048 |

Number of pages | 10 |

Journal | Neurology |

Volume | 89 |

Issue number | 20 |

DOIs | |

State | Published - Nov 14 2017 |

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### ASJC Scopus subject areas

- Clinical Neurology

### Cite this

*Neurology*,

*89*(20), 2039-2048. https://doi.org/10.1212/WNL.0000000000004652

**Weighting and standardization of frequencies to determine prevalence of AD imaging biomarkers.** / Roberts, Rosebud O; Knopman, David S; Syrjanen, Jeremy A.; Aakre, Jeremiah A.; Vassilaki, Maria; Kremers, Walter K; Mielke, Michelle M; Machulda, Mary Margaret; Graff-Radford, Jonathan; Geda, Yonas Endale; Vemuri, Prashanthi D; Lowe, Val; Jack, Clifford R Jr.; Petersen, Ronald Carl.

Research output: Contribution to journal › Article

*Neurology*, vol. 89, no. 20, pp. 2039-2048. https://doi.org/10.1212/WNL.0000000000004652

}

TY - JOUR

T1 - Weighting and standardization of frequencies to determine prevalence of AD imaging biomarkers

AU - Roberts, Rosebud O

AU - Knopman, David S

AU - Syrjanen, Jeremy A.

AU - Aakre, Jeremiah A.

AU - Vassilaki, Maria

AU - Kremers, Walter K

AU - Mielke, Michelle M

AU - Machulda, Mary Margaret

AU - Graff-Radford, Jonathan

AU - Geda, Yonas Endale

AU - Vemuri, Prashanthi D

AU - Lowe, Val

AU - Jack, Clifford R Jr.

AU - Petersen, Ronald Carl

PY - 2017/11/14

Y1 - 2017/11/14

N2 - OBJECTIVE: To estimate the prevalence of elevated brain amyloid and reduced cortical thickness (as a marker for neurodegeneration) in a defined population.METHODS: Mayo Clinic Study of Aging participants underwent MRI to assess a composite Alzheimer disease (AD) signature cortical thickness measure and PET to assess brain amyloid accumulation. Participants were characterized as having elevated amyloid (A+/A-), reduced cortical thickness (N+/N-), and A+N+, A+N-, A-N+, or A-N-. The prevalence of AD biomarkers was derived by adjusting for nonparticipation and standardizing to the Olmsted County, Minnesota, population.RESULTS: Among 1,646 participants without dementia (mean age 70.8 years; 53.2% men), the prevalence (95% confidence interval) of amyloidosis was 21.1% (19.1%-23.2%): women, 24.3%; men, 17.5%. The prevalence of reduced cortical thickness was 28.9% (26.4%-31.5%): women, 27.9%; men, 30.2%. The prevalence estimates of biomarker categories were as follows: A-N-: 61.4%; A+N-: 9.7%; A-N+: 17.4%; and A+N+: 11.5%, and varied by sex and by APOE ε4 carrier status. In men, prevalence estimates were as follows: A-N-: 62.6%; A+N-: 7.3%; A-N+: 19.9%; and A+N+: 10.2%. In women, prevalence estimates were as follows: A-N-: 60.4%; A+N-: 11.7%; A-N+: 15.3%; and A+N+: 12.6%. In ε4 carriers, prevalence estimates were as follows: A-N-: 54.6%; A+N-: 16.6%; A-N+: 12.4%; and A+N+: 16.4%. In non-ε4 carriers, prevalence estimates were as follows: A-N-: 63.3%; A+N-: 6.9%; A-N+: 19.9%; and A+N+: 10.0%.CONCLUSIONS: These prevalence estimates are important for understanding age-related trends in amyloid positivity and AD signature cortical thickness in the population, and for potentially projecting the future burden of biomarkers in elderly persons.

AB - OBJECTIVE: To estimate the prevalence of elevated brain amyloid and reduced cortical thickness (as a marker for neurodegeneration) in a defined population.METHODS: Mayo Clinic Study of Aging participants underwent MRI to assess a composite Alzheimer disease (AD) signature cortical thickness measure and PET to assess brain amyloid accumulation. Participants were characterized as having elevated amyloid (A+/A-), reduced cortical thickness (N+/N-), and A+N+, A+N-, A-N+, or A-N-. The prevalence of AD biomarkers was derived by adjusting for nonparticipation and standardizing to the Olmsted County, Minnesota, population.RESULTS: Among 1,646 participants without dementia (mean age 70.8 years; 53.2% men), the prevalence (95% confidence interval) of amyloidosis was 21.1% (19.1%-23.2%): women, 24.3%; men, 17.5%. The prevalence of reduced cortical thickness was 28.9% (26.4%-31.5%): women, 27.9%; men, 30.2%. The prevalence estimates of biomarker categories were as follows: A-N-: 61.4%; A+N-: 9.7%; A-N+: 17.4%; and A+N+: 11.5%, and varied by sex and by APOE ε4 carrier status. In men, prevalence estimates were as follows: A-N-: 62.6%; A+N-: 7.3%; A-N+: 19.9%; and A+N+: 10.2%. In women, prevalence estimates were as follows: A-N-: 60.4%; A+N-: 11.7%; A-N+: 15.3%; and A+N+: 12.6%. In ε4 carriers, prevalence estimates were as follows: A-N-: 54.6%; A+N-: 16.6%; A-N+: 12.4%; and A+N+: 16.4%. In non-ε4 carriers, prevalence estimates were as follows: A-N-: 63.3%; A+N-: 6.9%; A-N+: 19.9%; and A+N+: 10.0%.CONCLUSIONS: These prevalence estimates are important for understanding age-related trends in amyloid positivity and AD signature cortical thickness in the population, and for potentially projecting the future burden of biomarkers in elderly persons.

UR - http://www.scopus.com/inward/record.url?scp=85037714814&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85037714814&partnerID=8YFLogxK

U2 - 10.1212/WNL.0000000000004652

DO - 10.1212/WNL.0000000000004652

M3 - Article

VL - 89

SP - 2039

EP - 2048

JO - Neurology

JF - Neurology

SN - 0028-3878

IS - 20

ER -