Table 2.
Association between Neuroimaging Biomarkers and Impaired Odor Identification in Cognitively Normal Individuals - the Mayo Clinic Study of Aging.
| Impaired Olfaction | ||||||
|---|---|---|---|---|---|---|
|
| ||||||
| Anosmia vs. normosmiaa | Hyposmia vs. normosmiaa | |||||
|
| ||||||
| Imaging Biomarkers | No. Abn /All | OR (95%CI)b | p | No. Abn /All | OR (95%CI) | p |
| Basic modelc | ||||||
| Abnormal 11C-PiB PETd | 28/130 | 2.74 (1.12, 6.66) | .03 | 176/278 | 1.25 (.74, 2.12) | .40 |
| Abnormal 18F-FDG PETe | 28/130 | .99 (.38, 2.55) | .98 | 175/277 | 1.06 (.59, 1.91) | .84 |
| Abnormal AD Sig. CTf | 78/326 | 2.20 (1.25, 3.86) | <.01 | 500/748 | 1.34 (.92, 1.94) | .13 |
| Abnormal HVag | 78/326 | 2.45 (1.21, 4.94) | .01 | 495/743 | 1.61 (.95, 2.72) | .08 |
| Basic model adjusted also for APOE ε4 carrier status | ||||||
| Abnormal 11C-PiB PET | 28/130 | 2.78 (1.11, 7.01) | .03 | 176/278 | 1.23 (.72, 2.12) | .45 |
| Abnormal 18F-FDG PET | 28/130 | .97 (.38, 2.50) | .95 | 175/277 | 1.05 (.58, 1.89) | .86 |
| Abnormal AD Sig. CT | 78/326 | 2.21 (1.25, 3.89) | <.01 | 500/748 | 1.33 (0.91, 1.93) | .14 |
| Abnormal HVa | 78/326 | 2.47 (1.22, 5.00) | .01 | 495/743 | 1.60 (.94, 2.71) | .08 |
| Basic model adjusted also for the Boston Naming Testh | ||||||
| Abnormal 11C-PiB PET | 26/126 | 2.70 (1.08, 6.78) | .03 | 173/273 | 1.24 (.73, 2.11) | .42 |
| Abnormal 18F-FDG PET | 26/126 | .98 (.37, 2.62) | .97 | 172/272 | 1.09 (.60, 1.97) | .78 |
| Abnormal AD Sig. CT | 75/319 | 2.05 (1.15, 3.66) | .01 | 485/729 | 1.29 (.88, 1.88) | .19 |
| Abnormal HVa | 75/319 | 2.30 (1.12, 4.69) | .02 | 480/724 | 1.56 (.92, 2.65) | .10 |
| Basic model adjusted also for UPDRS | ||||||
| Abnormal 11C-PiB PET | 28/130 | 2.80 (1.14, 6.86) | .02 | 176/278 | 1.25 (.74, 2.12) | .40 |
| Abnormal 18F-FDG PET | 28/130 | .96 (.37, 2.49) | .94 | 175/277 | 1.05 (.59, 1.89) | .86 |
| Abnormal AD Sig. CT | 78/326 | 2.15 (1.22, 3.79) | <.01 | 500/748 | 1.32 (.91, 1.92) | .14 |
| Abnormal HVa | 78/326 | 2.43 (1.20, 4.90) | .01 | 495/743 | 1.60 (.94, 2.71) | .08 |
| Basic model adjusted also for history of head traumai | ||||||
| Abnormal 11C-PiB PET | 27/102 | 2.65 (1.04, 6.72) | .04 | 144/219 | 1.12 (.63, 2.02) | .70 |
| Abnormal 18F-FDG PET | 27/102 | .98 (.37, 2.59) | .97 | 143/218 | .97 (.51, 1.85) | .93 |
| Abnormal AD Sig. CT | 75/285 | 2.22 (1.24, 3.98) | <.01 | 454/664 | 1.31 (.88, 1.95) | .18 |
| Abnormal HVa | 75/285 | 2.20 (1.08, 4.49) | .03 | 451/661 | 1.45 (.85, 2.47) | .18 |
Osmia categories were defined based on the Brief Smell Identification Test (B-SIT) score as follows: anosmia (score <6), hyposmia (men 6–10, women 6–10.25), normosmia (men 10.25–12; women 10.5–12).
OR (95% CI) retained from multinomial logistic regression. Separate models were run for each neuroimaging biomarker, represented by one row in the table, having osmia as the outcome variable.
Basic model is adjusted for age, education, sex.
Abnormal 11C-PiB PET (elevated amyloid) was defined as standardized uptake value ratio (SUVR)>1.40.
Abnormal 18F-FDG PET (hypometabolism) was defined as SUVR <1.32.
Abnormal (reduced) AD Sig. CT was defined as <2.74 mm.
Abnormal (reduced) hippocampal volume was defined as <−2.40 cm3 (adjusted for total intracranial volume).
Kaplan EGH, Weintraub S. The Boston Naming Test, 2nd ed. Boston, MA: Lea & Fabiger, 1978.
History of head trauma: “Have you ever experienced any head injuries that led you to see a doctor, stay in the hospital, lose your memory, or become unconscious”.
No. Abn. - the number of persons with abnormal B-SIT; All - participants with and without abnormal biomarker in the specific analysis strata; OR – odds ratio; CI – confidence interval. 11C-PiB PET - Pittsburgh compound B positron emission tomography; 18F-FDG PET - 18fluorodeoxyglucose PET; AD Sig. CT - Alzheimer’s Disease signature cortical thickness; HVa: hippocampal volume adjusted for total intracranial volume; UPDRS - Unified Parkinson’s Disease Rating Scale.