Vermunt L, et al. - In this investigation, researchers projected the age-specific duration of the preclinical, prodromal, and dementia stages of Alzheimer's disease (AD) and how disease duration was impacted by sex, setting, apolipoprotein E (APOE) genotype, and cerebrospinal fluid tau. In a combined sample of six cohorts (n=3,268), multistate modelling was performed with death as the end stage. They also approximated the duration of the preclinical, prodromal, and dementia stages. Findings revealed that the duration of AD overall varied from 24 (age 60) to 15 (age 80) years. For those with preclinical AD, 70 years of age, the estimated duration of preclinical AD was 10 years, 4 years of prodromal AD and 6 years of dementia. Duration estimates of AD disease become more precise if consideration is given to age, gender, setting, APOE, and cerebrospinal fluid tau. For clinical practice and trial design, this will be relevant.