45 The probability of a cognitive impairment in a longitudinal cohort of aged adults.

Oregon Convention Center 

We determined how family history and/or the number of APOE4 carrier alleles affect the probability of incurring a serious cognitive impairment within the ten years given a person's entry age while accounting for the competing risk of a premature death or drop out. A serious cognitive impairment is defined by a clinical diagnosis of dementia or a mild cognitive impairment as verified by an informant. During annual follow-up a participant can either be in a normal cognitive state or display some transient or permanent cognitive deficit. Given an entry age in the range 75-90 the probability of a serious cognitive impairment within ten years of follow-up is low (range 9-18%) in the presence of no risks but increases by a factor of 1.7 with one risk and 2.4 with two or more risks. This is based on longitudinal data from the BRAiNS (Biologically Resilient Adults in Neurological Studies) cohort which recruited participants having mean entry age 75.2 ± 7.3, 48% with no risks, 37% with 1 risk and 15% with two or more risks and having as much as 31 years of follow-up. These results have implications for recruiting participants to a longitudinal study of cognitive changes in the elderly.

cognitive impairment

dementia

mild cognitive impairment

ten year follow-up

family history

APOE4 

Section on Statistics in Epidemiology