New research published August 4, 2021 in the journal Neurology has shown an association of midlife plasma amyloid-β (Aβ) levels with cognitive impairment in late life.

A subsample of 2284 participants in the Atherosclerosis Risk in Communities (ARIC) cohort study, who had normal cognition in midlife was analysed to look at the relationship of plasma Aβ42, Aβ40, and Aβ42:Aβ40 ratio measured in midlife, late-life and the change from midlife to late-life, to risk of mild cognitive impairment (MCI), dementia and combined MCI/dementia outcomes in late-life. The study participants were followed up for more than 25 years.

Analysis of data over 25 years showed that 22% (n=502) of the study participants had developed dementia, 36% (n=832) had MCI, while 38% (n=859) had normal cognition. The midlife plasma Aβ levels in cognitively normal people were found to be linked to the risk of dementia or MCI in old age. Higher levels of plasma Aβ40 (67 pg/mL) at midlife were associated with increased risk of late-life MCI or dementia by 15%, whereas increase in plasma midlife plasma Aβ42 (10 pg/mL) levels was associated with 13% lower risk of later MCI or dementia. A 37% reduced risk of MCI or dementia in late life was seen with each doubling of the Aβ42/Aβ40 ratio at midlife.

Based on their findings, the researchers suggested that the midlife plasma Aβ levels can be considered as a potential biomarker to evaluate the risk of future cognitive impairment. Screening of younger individuals can help prevent the onset of dementia.

Alzheimer’s disease, the most common cause of dementia, is considered a disease of old age. An article published in Alzheimers & Dementia, the journal of the Alzheimers Association has hypothesised that “it is not a disease of the elderly but rather a clinically silent pathology of midlife (approximately 40–65 years or even younger), whose terminal phase is characterized by dementia. If this were so, then on the broadest social level AD would no longer be considered a disease of end-of-life but rather a disease of the young. The clinical consequences of such a change would also be significant, reorientating disease management away from palliative care to active prevention strategies in younger, healthier individuals.” (Alzheimers Dement (N Y). 2015 Sep; 1(2): 122–130) This study is a step in this direction.

(Source: Medpage Today August 4, 2021 & Neurology. 2021 Aug 4; doi: 10.1212/WNL.0000000000012482)

Dr Veena Aggarwal

Consultant Womens’ Health

CMD and Editor-in-Chief, IJCP Group & Medtalks

Trustee, Dr KK’s Heart Care Foundation of India