Amyloid β42 and Total Tau Levels in Cerebrospinal Fluid Associate with Survival in an 85-Year-Old Population-Based Cohort Followed until Death

Abstract

Background: Dementia of Alzheimer’s type (AD) is related to decreased survival. It is not clear whether also biological markers of AD are related to mortality. Low levels of amyloid beta-42 (Aβ42) and high levels of total tau (T-tau) protein in cerebrospinal fluid (CSF) are established biomarkers for AD. Objective: Our aim was to investigate whether levels of Aβ42 and T-tau are associated with survival among octogenarians independently of dementia status. Methods: Sixty-five 85-year-olds underwent lumbar puncture and were followed with repeated neuropsychiatric examinations until death. Results: Lower CSF Aβ42 (p = 0.010) and higher CSF T-tau (p = 0.005) at the age of 85 were associated with lower survival independently of dementia status at baseline and follow-up. Low CSF Aβ42 and high CSF T-tau were also related to baseline dementia at the age of 85 years, and lower CSF Aβ42 with increased dementia incidence during the first 3 years of follow-up. Conclusions: Biological markers of AD are associated with mortality in octogenarians. The reason for this needs further study. Our findings highlight the importance to consider the competing risk of death when evaluating biological markers of AD in the very old.

Association between ATN profiles and mortality in a clinical cohort of patients with cognitive disorders

“…Studies that examined the association between individual CSF biomarkers of AD and mortality have shown contrasting results; some have reported an association with CSF tau [ 18 , 27 ] and hyperphosphorylated tau [ 17 ], while others did not find an association [ 18 , 27 , 28 ]. As in the present study, most studies found a lower level of CSF Aβ42 to be associated with a higher risk of mortality [ 18 , 28 , 29 ].…”

Review of Risk Factors Associated With Biomarkers for Alzheimer Disease

“…Older adults are at a greater risk for abnormal Aβ and tau. Memory declines in older adults without dementia, and deposition of Aβ and tau normally increases with age 4. In addition, Ribbe et al4 reported that the life span of people 85 years or older with abnormal Aβ and tau levels was shortened by 1 year.…”

“…Older adults are at a greater risk for abnormal Aβ and tau. Memory declines in older adults without dementia, 4 In addition, Ribbe et al 4 reported that the life span of people 85 years or older with abnormal Aβ and tau levels was shortened by 1 year. Improved Aβ and tau levels have been reported with consumption of green tea more than 3 times each week, 18 an effect more pronounced in people between the ages of 65 and 74 years.…”

“…Many biomarkers have been implicated in AD, such as total tau (t-tau), phosphorylated tau (p-tau), amyloid-β (Aβ; nerve cell biomarkers), and APOE ε4 (a fat metabolism biomarker). High levels of t-tau and low levels of Aβ are well known biomarkers for AD 4…”

“…High levels of t-tau and low levels of Aβ are well known biomarkers for AD. 4 Amyloid-β and tau can be measured in a number of ways. They can be detected through blood, cerebrospinal fluid (CSF), magnetic resonance imaging, and positron emission tomography.…”