Statistical significance was set at p<0♰5. Using brain-PAD values as outcomes, statistical analysis was undertaken in R 4.1.0.
Insight 46 is a substudy of the NSHD where, at the age of approximately 70 years, 502 members of the cohort were recruited to a longitudinal study incorporating amyloid β-PET and multimodal MRI (PET-MRI) on a single scanner, detailed cognitive assessments, physical examination, and measurement of blood-based biomarkers. Alongside effectively controlling for chronological age, members of this cohort have been extensively studied since birth, with 24 prospective waves of data collection over the life course. The Medical Research Council National Survey of Health and Development (NSHD), also known as the 1946 British Birth Cohort, is the world's longest continuously running birth cohort and provides the opportunity to assess relationships among biological contributors to ageing. Many studies investigating biological variability in ageing are limited by the variability of chronological age among participants, a dependence on retrospective data collection, and heterogeneity in image acquisition and processing. Combining 12 metrics in a hierarchical partitioning model explained 33% of the variance in brain-PAD. Early-life factors did not relate to brain-PAD. Higher brain-PAD was associated with future hippocampal atrophy over the subsequent 2 years (0♰03 mL/year per 5-year increment in brain-PAD). An increase in brain-PAD was associated with increased cardiovascular risk at age 36 years (β=2♳ ) and 69 years (β=2♶ ) increased cerebrovascular disease burden (1♹ ) lower cognitive performance (–1♳ ) and increased serum neurofilament light concentration (1♲ ). Female sex was associated with a 5♴-year (95% CI 4♱ to 6♸) younger brain-PAD than male sex. The mean brain-predicted age was 67♹ years (8♲, 46♳ to 94♳). We included 456 participants (225 female), with a mean chronological age of 70♷ years (SD 0♷ range 69♲ to 71♹). The Lancet Regional Health - Western Pacificīetween May 28, 2015, and Jan 10, 2018, 502 individuals were assessed as part of Insight 46.The Lancet Regional Health – Southeast Asia.The Lancet Gastroenterology & Hepatology.