Differences in Odor Identification in Early-Onset and Late-Onset Depression.

Yuping Ning,Qiang Wang,Qi Peng,Gaohong Lin,Zhangying Wu,Le Hou,Xiaomei Zhong,Si Zhang,Min Zhang,Meiling Liu,Huarong Zhou,Ben Chen,Minfeng Yang

doi:10.3390/brainsci12020276

Yuping Ning, Qiang Wang + Show 11 more

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https://doi.org/10.3390/brainsci12020276

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Abstract

(1) Background: Odor identification (OI) dysfunction is a potential predictor of developing dementia in late life depression (LLD). However, it is not clear whether patients with early onset depression (EOD) and late onset depression (LOD) may exhibit different OI dysfunctions. The aim of this study was to compare OI between EOD patients and LOD patients and its relationship with cognitive function. (2) Methods: A total of 179 patients with LLD and 189 normal controls were recruited. Participants underwent clinical assessment, olfactory testing, and comprehensive neuropsychological assessment. The OI scores of EOD patients and LOD patients were compared, and correlation analyses and mediation analyses were used to explore the relationship between OI and cognition. (3) Result: LOD patients exhibited lower OI scores than EOD patients and normal controls (NCs). Additionally, the LOD patients exhibited a higher percentage of OI dysfunction than the EOD patients. Moreover, OI scores were associated with global cognition, memory, language, and visuospatial ability in the EOD group (p < 0.05) but were not associated with any cognitive score in the LOD patients (p > 0.05). Finally, the scores of the Auditory Verbal Learning Test Immediate recall and Boston Naming Test exhibited a partially mediating effect on the difference in OI scores between the EOD and LOD patients. (4) Conclusions: LOD patients exhibited worse OI than EOD patients, and their difference in OI was mediated by their memory and language function.

Highlights

Late life depression (LLD) is one of the leading risks of disability and dementia in the geriatric population [1], with approximately 3.68–4.60% of older adults being diagnosed with depression each year [2]
Our previous studies suggested that compared with LLD patients with intact Odor identification (OI), LLD patients with OI dysfunction exhibited more severe cognitive impairment and structural and functional brain abnormalities, which suggested that OI impairment may serve as a marker for predicting the conversion from LLD to dementia [24–26]
There were fewer males in the early-onset depression (EOD) patients than in the normal controls (NCs) group, the EOD patients were younger than the NC group, and the late-onset depression (LOD) patients were older than the NC group

Summary

Introduction

Late life depression (LLD) is one of the leading risks of disability and dementia in the geriatric population [1], with approximately 3.68–4.60% of older adults being diagnosed with depression each year [2]. Our previous studies suggested that compared with LLD patients with intact OI, LLD patients with OI dysfunction exhibited more severe cognitive impairment and structural and functional brain abnormalities, which suggested that OI impairment may serve as a marker for predicting the conversion from LLD to dementia [24–26]. It is not clear whether patients with EOD and LOD may exhibit different OI, which is extremely important for the rational use of olfaction to predict dementia risk

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