Two-thirds of people over 90 have Alzheimer's brain changes, study shows
A major Norwegian study reveals that Alzheimer's disease pathology is far more common than previously thought, affecting nearly two-thirds of those over 90 and one-quarter of cognitively healthy older adults. The findings, based on blood tests in 11,486 people, have significant implications for healthcare planning, pharmaceutical development, and how societies prepare for aging populations.
Originaltitel: Prevalence of Alzheimer's disease pathology in the community
The prevalence of Alzheimer's disease neuropathological changes (ADNCs), the leading cause of cognitive impairment, remains uncertain. Recent blood-based biomarkers enable scalable assessment of ADNCs1. Here we measured phosphorylated tau at threonine 217 in 11,486 plasma samples from a Norwegian population-based cohort of individuals over 57 years of age as a surrogate marker for ADNCs. The estimated prevalence of ADNCs increased with age, from less than 8% in people 58-69.9 years of age to 65.2% in those over 90 years of age. Among participants aged 70 years or older, 10% had preclinical Alzheimer's disease, 10.4% had prodromal Alzheimer's disease and 9.8% had Alzheimer's disease dementia. Furthermore, among those 70 years of age or older, ADNCs were present in 60% of people with dementia, in 32.6% of those with mild cognitive impairment and in 23.5% of the cognitively unimpaired group. Our findings suggest a higher prevalence of Alzheimer's disease dementia in older individuals and a lower prevalence of preclinical Alzheimer's disease in younger groups than previously estimated2.