Amyloid imaging with [¹⁸F]florbetapir in geriatric depression: Early-onset versus late-onset

Background We examined patients with mild cognitive impairment (MCI) with a history of geriatric depression (GD) and healthy controls (HC) to evaluate the effect of beta-amyloid (Aβ) pathology on the pathology of GD by using [¹⁸F]florbetapir PET. Methods Thirty-three elderly patients (76.7-±-4.2-years) and 22 healthy controls (HC; 72.0-±-4.5-years, average-±-SD) were examined by [¹⁸F]florbetapir positron emission tomography (PET) to quantify the standard uptake value ratio (SUVR) as the degree of amyloid accumulation, by MRI to determine the degree of atrophy, by Mini-Mental State Examination for cognitive functions, and by Geriatric Depression Scale for the severity of depression, and by Clinical Dementia Rating for activity of daily living (ADL). The cut-off value of 1.08 for SUVR was defined as Aβ-positive. Results Of the patients and HC, 39.4% and 27.3%, respectively, were beta-amyloid-positive. The onset age of GD was significantly correlated with SUVR (r-=-0.44, p-<-0.01). Compared to patients without Aβ (GD-Aβ), patients with Aβ (GD-+-Aβ) did not differ in terms of age, cognitive function, severity of depression and ADL, and brain atrophy. GD-+-Aβ had significantly older average-±-SD age at onset of GD (73.6-±-7.1 versus 58.7-±-17.8, p-<-0.01) and significantly shorter average-±-SD time between onset of GD and PET scan day (3.1-±-5.2-years versus 18.1-±-18.6-years, p-<-0.001) than GD-Aβ. Conclusions Our results showed that the rate of Aβ positivity was higher in late-onset GD and that onset-age was associated with SUVR, suggesting that the later the onset of GD, the more Aβ pathology affected its onset.