Adulthood cognitive trajectories over 26 years and brain health at 70 years of age: findings from the 1946 British Birth Cohort

Abstract

Few studies can address how adulthood cognitive trajectories relate to brain health in 70-year-olds. Participants (n = 468, 49% female) from the 1946 British birth cohort underwent 18F-Florbetapir PET/MRI. Cognitive function was measured in childhood (age 8 years) and across adulthood (ages 43, 53, 60-64 and 69 years) and was examined in relation to brain health markers of β-amyloid (Aβ) status, whole brain and hippocampal volume, and white matter hyperintensity volume (WMHV). Taking into account key contributors of adult cognitive decline including childhood cognition, those with greater Aβ and WMHV at age 70 years had greater decline in word-list learning memory in the preceding 26 years, particularly after age 60. In contrast, those with smaller whole brain and hippocampal volume at age 70 years had greater decline in processing search speed, subtly manifest from age 50 years. Subtle changes in memory and processing speed spanning 26 years of adulthood were associated with markers of brain health at 70 years of age, consistent with detectable prodromal cognitive effects in early older age.

Keywords: Amyloid; Brain health; Brain volume; Cognition; Cognitive decline; Life course.

Fig. 1

Associations betweencognitive trajectories of word learning test and search speed measures between 43 and 69 years of age that are associated with brain health measures at 70 years of age, including Aβ status (A) brain volume (B) hippocampal volume (C) white matter hyperintensity volume (D) and Aβ and hippocampal groups (E) at age 70. WLT=word learning test; A-H-=PET amyloid negative and hippocampal volume not in smallest decile (2) A+H-= PET amyloid positive and hippocampal volume not in smallest decile (3) A-H+= PET amyloid negative and hippocampal volume in smallest decile (4) A+H+= PET amyloid positive and hippocampal volume in smallest decile. NB: Continuous variables are illustrated as the 10th and 90th percentiles for graphical representation. Models adjust for sex, age at scan, childhood cognition, childhood and adulthood SEP and educational attainment. (For interpretation of the references to color in this figure legend, the reader is referred to the Web version of this article.)

Fig. 2

Associations of the relationships between specific cognitive change periods in adulthood and brain health measures at 70 years of age, including odds ratios for Aβ status (A), beta coefficient difference in brain volume (B) and hippocampal volume (C), and relative difference in white matter hyperintensity volume (D). Models adjust for sex, age at scan, childhood cognition, childhood and adult SEO and educational attainment. WMH, white matter hyperintensity volume; Yrs, years of age. Cognitive change, conditional on earlier measurements, was calculated as the residual from the regression of each cognitive measure on the earlier measure. Change unit represent declining change in cognition that differed from changes expected on average given the earlier cognition. Residuals were standardized, allowing comparisons between periods. (For interpretation of the references to color in this figure legend, the reader is referred to the Web version of this article.)