Estimation of lifetime risks of Alzheimer's disease dementia using biomarkers for preclinical disease.

INTRODUCTION: Lifetime risks are the probabilities of progressing to Alzheimer's disease (AD) dementia during one's lifespan. Here, we report the first estimates of the lifetime and ten-year risks of AD dementia based on age, gender, and biomarker tests for preclinical disease.

METHODS: We used a multistate model for the disease process together with US death rates.

RESULTS: Lifetime risks of AD dementia vary considerably by age, gender, and the preclinical or clinical disease state of the individual. For example, the lifetime risks for a female with only amyloidosis are 8.4% for a 90-year old and 29.3% for a 65-year old. Persons younger than 85 years with mild cognitive impairment, amyloidosis, and neurodegeneration have lifetime risks of AD dementia greater than 50%.

DISCUSSION: Most persons with preclinical AD will not develop AD dementia during their lifetimes. Lifetime risks help interpret the clinical significance of biomarker screening tests for AD.