Table 1.
Characteristics of Participants - the Mayo Clinic Study of Aging.
| Characteristics | Normosmiaa (N=248) |
Hyposmia (N=503) |
Anosmia (N=78) |
pb |
|---|---|---|---|---|
| Age (years) at time of B-SIT, mean (SD) | 77.7 (4.7) | 79.7 (5.2) | 81.3 (5.4) | <0.001 |
| Female | 145 (58.5) | 227 (45.1) | 30 (38.5) | <0.001 |
| Education (years), mean (SD) | 14.6 (2.7) | 14.2 (2.9) | 14.9 (2.8) | 0.037 |
| Ever Smoker (at time of B-SIT) | 113 (45.6) | 238 (47.3) | 42 (53.8) | 0.441 |
| APOE ε24/ε34/ε44 | 61 (24.6) | 134 (26.6) | 15 (19.2) | 0.357 |
| Depressive symptoms BDI (>=13) (at time of B-SIT) | 8 (3.2) | 32 (6.4) | 4 (5.1) | 0.196 |
| History of diabetes mellitus II (definite/probable) | 33 (13.3) | 104 (20.7) | 9 (11.5) | 0.015 |
| History of stroke | 7 (2.8) | 18 (3.6) | 6 (7.7) | 0.135 |
| History of hypertension | 178 (71.8) | 387 (76.9) | 60 (76.9) | 0.287 |
| History of self-reported alcohol problems | 7 (2.8) | 20 (4.0) | 2 (2.6) | 0.645 |
| Continuous B-SIT score, mean (SD) | 11.4 (0.5) | 8.7 (1.3) | 3.9 (1.2) | <0.001 |
| Abnormal 11C-PiB PETc | 33 (32.4) | 69 (39.2) | 17 (60.7) | 0.024 |
| Abnormal 18F-FDG PETd | 26 (25.5) | 54 (30.9) | 10 (35.7) | 0.481 |
| Abnormal AD Sig. CTe | 54 (21.8) | 159 (31.8) | 36 (46.2) | <0.001 |
| Abnormal HVaf | 21 (8.5) | 85 (17.2) | 22 (28.2) | <0.001 |
| Imaging Biomarker Groupg | 0.016 | |||
| A−/N− | 47 (46.1) | 68 (39.5) | 8 (28.6) | |
| A+/N− | 24 (23.5) | 37 (21.5) | 6 (21.4) | |
| A−/N+ | 22 (21.6) | 36 (20.9) | 3 (10.7) | |
| A+/N+ | 9 (8.8) | 31 (18.0) | 11 (39.3) |
N (%) unless otherwise noted.
Osmia categories were defined as follows based on the B-SIT score: anosmia (score <6), hyposmia (men 6–10, women 6–10.25), normosmia (men 10.25–12; women 10.5–12).
Chi-squared test for categorical variables or Wilcoxon rank sum test for continuous variables.
Abnormal 11C-PiB PET (elevated amyloid) was defined as standardized uptake value ratio (SUVR)>1.40; 306 participants had 11C-PiB PET.
Abnormal 18F-FDG PET (hypometabolism) was defined as SUVR <1.32; 305 participants had 18F-FDG PET.
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).
Imaging biomarker groups defined by the combination of abnormality for amyloid (A+/A−) and neurodegeneration (N+/N−).
B-SIT = Brief Smell Identification Test; APOE = apolipoprotein E; BDI = Beck depression inventory; 11C-PiB PET = Pittsburgh compound B positron emission tomography; 18F-FDG = 18fluorodeoxyglucose; AD Sig. CT = Alzheimer’s Disease signature cortical thickness; HVa = hippocampal volume adjusted for total intracranial volume.