A recent study published in the Alzheimer's Association supports a synergistic interaction between anxiety and Aβ in increasing the risk of cognitive decline.
Amyloid beta (Aβ) deposition may precede clinical symptoms of Alzheimer's disease (AD) by about 15 to 20 years. The field of AD and brain ageing has made substantial advances in biomarker measurements such that in living persons, cortical Aβ deposition can be visualized by amyloid brain imaging using various types of tracers.
A group of researchers investigated the longitudinal relationship between cortical amyloid deposition, anxiety, and depression and the risk of incident mild cognitive impairment (MCI).
The researchers followed 1440 community-dwelling, cognitively unimpaired individuals aged ≥ 50 years for a median of 5.5 years. Clinical anxiety and depression were assessed using Beck Anxiety and Depression Inventories (BAI, BDI-II). Cortical amyloid-beta (Aβ) was measured by Pittsburgh compound B positron emission tomography (PiB-PET) and elevated deposition (PiB+) was defined as standardized uptake value ratio ≥ 1.48. We calculated Cox proportional hazards models with age as the time scale, adjusted for sex, education, and medical comorbidity.
Cortical Aβ deposition (PiB+) independent of anxiety (BAI ≥ 10) or depression (BDI-II ≥ 13) increased the risk of MCI. There was a significant additive interaction between PiB+ and anxiety (joint effect hazard ratio 6.77; 95% confidence interval 3.58–12.79; P = .031) that is, being PiB+ and having anxiety further amplified the risk of MCI.
Thus, the researchers concluded that the current study mostly supports a synergistic interaction between anxiety and Aβ in increasing the risk of cognitive decline.
In summary, the researchers expand upon the previous literature by showing that clinical anxiety in community-dwelling individuals during the preclinical phase of AD increases the risk of incident MCI. Therefore, 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 a cognitive decline occurs.
Reference:
A longitudinal investigation of Aβ, anxiety, depression, and mild cognitive impairment by Anna Pink, et al. published in the Alzheimer's Association.
https://alz-journals.onlinelibrary.wiley.com/doi/10.1002/alz.12504