Cognitively unimpaired persons with raised amyloid beta deposition mild cognitive impairment (MCI), suggests a new study. persons with clinical anxiety are particularly at higher risk.

The study included 1440 subjects, aged ≥50 years, from the Mayo Clinic Study of Aging. They had no cognitive impairment at the time of their recruitment. Men comprised more than half of the study population. All the participants underwent Beck Depression Inventory-II (BDI-II) and Beck Anxiety Inventory (BAI) and Pittsburgh compound B positron emission tomography (PiB-PET) imaging to look for amyloid deposition.

Seventy-three out of the 1440 subjects had BAI scores ≥10 indicative of clinical anxiety, while 79 were found to have clinical depression with BDI-II scores ≥ 13. On PET scan, raised cortical amyloid deposits were seen in 379 people (median age 77). Compared to other participants, they had one more medical comorbidity and 1 year less education. During the follow-up period (5.5 years median), 206 persons had new onset of MCI. Presence of raised amyloid alone was associated with increased risk of incident MCI. However, a significant additive effect for MCI was noted between amyloid and anxiety with a hazard ratio of 6.77 for joint effect. But no such association was observed for depression and amyloid deposition.

This prospective study published in the journal Alzheimer’s & Dementia has shown that amyloid deposition in older adults is associated with increased risk for new-onset MCI. Alzheimer’s disease can now be diagnosed before it presents clinically. Early intervention in at-risk individuals raises the odds of improved outcomes. Hence, the preclinical state of Alzheimer’s disease is now a subject of ongoing research.

Based on their findings the study authors suggest that anxiety should be considered in adults in the very early stages of Alzheimer’s i.e., those who are not yet cognitively impaired. They write, “anxiety could be a very early marker of AD. Thus, assessing anxiety could be an important tool to identify patients at high risk of AD even before cognitive decline occurs.” Managing anxiety may reduce the risk of progression to MCI in persons with amyloid-positive scans.

Reference

1. Pink A, et al. A longitudinal investigation of Aβ, anxiety, depression, and mild cognitive impairment. Alzheimers Dement. 2021 Dec 8. doi: 10.1002/alz.12504.