Association between olfactory function and cognitive impairment in dementia‐free older adults in Taiwan: A longitudinal cohort study
Bibliographic record
Abstract
Abstract Background The olfactory impairment could be one of the earliest signs of cognitive impairment. However, limited studies have evaluated olfactory function and cognitive domains in Asian older adults. This study aimed to relate olfaction with global and domain‐specific cognition in Taiwan’s community‐dwelling, non‐demented older adults. Method This cohort study is part of the Taiwan Initiative for Geriatric Epidemiological Research, including 310 non‐demented older adults between 2015‐2019 with two repeated measures on cognitive function. Global and domain‐specific (memory, executive function, attention, and language) cognition were assessed by the Taiwanese version of Montreal Cognitive Assessment (MoCA‐T) and a battery of neuropsychological tests, respectively. The Sniffin' Sticks‐Odor Identification Test (SS‐OIT) was utilized to identify impaired olfaction. The generalized linear mixed model was used to examine the association of SS‐OIT with cognitive function over time, after adjustment for age, sex, years of education, apolipoprotein E ε4 status, presence of depression, sleep quality, chronic respiratory diseases, smoking, practice effect and follow‐up time. Subgroup analyses were also conducted. Result Better olfactory identification ability (i.e., increased SS‐OIT score) was associated with better performance of global cognition (MoCA‐T: β = 0.14, 95% confidence interval = 0.05‐0.24), memory (logical memory ‐ immediate and delayed theme and free recall: β = 0.06 to 0.09), executive function (trail making test‐A: β = 0.05 for baseline, ‐0.03 for interaction with follow‐up years), and verbal fluency (β = 0.08). Anosmia (SS‐OIT score ≦8) was associated with impaired memory [the lowest tertile (T1) vs. higher tertiles (T2+T3), adjusted odds ratio (aOR): 2.40 to 3.06], and verbal fluency (T1 vs. T2+T3, aOR = 2.39). After stratified analyses, the associations above remained significant in apolipoprotein E ε4 non‐carriers (MoCA‐T: β = 0.19; memory: β = 0.08 to 0.11; verbal fluency: β = 0.08), older adults without respiratory diseases (MoCA‐T: β = 0.14; memory: β = 0.06 to 0.10; verbal fluency: β = 0.10), and older adults without depression (MoCA‐T: β = 0.14; memory: β = 0.06 to 0.09; trail making test‐A: β = 0.04 for baseline, ‐0.02 for interaction with follow‐up years; verbal fluency: β = 0.09). Conclusion Impaired olfactory identification is associated with poor global or domain‐specific cognition in non‐demented older adults. Further research is required to validate our findings and clarify the underlying mechanism between anosmia and cognitive impairment.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.001 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".