Olfactory Dysfunction and High Blood Pressure Serve as Early Markers of Cognitive Decline in Older Adults

Author(s): Masato Okuda, Akiko Noda

Introduction: Olfactory dysfunction is recognized as an early sign of dementia. Hypertension is a risk factor for dementia in midlife, but it is less clear in old age.

 Materials and methods: Fifty-two consecutive volunteers aged ≥ 60 years (mean age, 71.0 ± 4.8 years) were enrolled in this study. We performed the Odor Stick Identification Test for the Japan (OSIT-J) as the olfactory test. Cognitive function was evaluated with the Revised Hasegawa’s Dementia Scale (HDS-R), Mini-Mental State Examination (MMSE), Trail Making Test B (TMT-B), and Touch Panel-type Dementia Assessment Scale (TDAS). The systolic blood pressure (SBP), diastolic BP (DBP), and heart rate (HR) were measured using plethysmography.

 Results: The TMT-B score was significantly correlated with the HR and OSIT-J score (HR: r = 0.306, p = 0.028; OSIT-J score: r = 0.279, p = 0.045), and HR and OSIT-J score were the significant factors of TMT-B score (HR: β = 0.295, p = 0.033; OSIT-J score: β = 0.281, p = 0.039). The TDAS score was significantly correlated with SBP and DBP (SBP: r = 0.293, p = 0.035; DBP: r = 0.302, p = 0.029). The SBP and DBP were higher in participants with TDAS scores ≥ 7 than those with TDAS scores < 7 (SBP: 155.6 ± 23.1 mmHg vs. 140.3 ± 16.1 mmHg, p = 0.017; DBP: 90.8 ± 10.3 mmHg vs. 80.9 ± 9.9 mmHg, p = 0.006).

 Conclusions: Decreased olfactory function, high BP, and increased HR were all associated with cognitive decline in older adults.