Resumen de Association between functional performance and Alzheimer's disease biomarkers in individuals without dementia

Maria Vassilaki, Jeremiah A. Aakre, Walter K. Kremers, Michelle M. Mielke, Yonas E. Geda, Mary M. Machulda, David S. Knopman, Preciosa M. Coloma, Barbara Schauble, Prashanthi Vemuri, Val J. Lowe, Clifford R. Jack, Ronald C. Petersen, Rosebud O. Roberts

• Objectives To examine the cross‐sectional association between functional performance and Alzheimer's disease (AD) neuroimaging biomarkers in individuals without dementia (cognitively unimpaired (CU), and those with mild cognitive impairment (MCI)).

  Design Cross‐sectional.

  Setting Olmsted County, Minnesota.

  Participants Population‐based Mayo Clinic Study of Aging (MCSA) participants (aged ≥ 50, mean age 71.3 ± 10.2; 53.4% male; 28.3% apolipoprotein (APO)E ε4 allele carriers, 1,578 CU, 204 MCI) who underwent 11C‐Pittsburgh compound B (11C‐PiB) positron emission tomography (PET) (N=1,782).

  Measurements We defined an abnormal (high) 11C‐PiB‐PET retention ratio as a standardized uptake value ratio greater than 1.42 (high amyloid; A+), abnormal (reduced) AD signature cortical thickness (neurodegeneration; N+) as less than 2.67 mm (MRI measurement), and biomarker groups according to the combination of abnormality (or not) for amyloid accumulation (A+/A–) and neurodegeneration (N+/N–). Functional performance was assessed using the Clinical Dementia Rating (CDR) Sum of Boxes (SOB) for functional domains and the Functional Activities Questionnaire (FAQ).

  Results Participants with a CDR‐SOB (functional) score greater than 0 were almost 4 times as likely to have N + (odds ratio (OR)=3.92, 95% confidence interval (CI)=1.77–8.67, adjusting for age, sex, education, global cognitive z‐score, and APOE ε4 allele status; p<.001) and those with a FAQ score greater than 0 were 1.5 times as likely to have A + (OR=1.48, 95% CI=1.04–2.11, p=.03). Higher FAQ scores were associated with greater odds of A+N + and A–N + in CU participants.

  Conclusion The findings of this cross‐sectional study supplement limited available information that supports an association between functional performance and AD neuroimaging biomarkers very early in the dementia pathophysiology. The associations should be validated in longitudinal studies. J Am Geriatr Soc 66:2274–2281, 2018.