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P3‐267: Comparison of statistical models estimating rate of decline in a population‐based cohort of persons with Alzheimer's disease: The Cache County study
Author(s) -
Tripodis Yorghos,
Mielke Michelle,
Sherva Richard,
Corcoran Christopher,
Tschanz JoAnn,
Lyketsos Constantine,
Hendrix Suzanne,
Green Robert
Publication year - 2011
Publication title -
alzheimer's and dementia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.713
H-Index - 118
eISSN - 1552-5279
pISSN - 1552-5260
DOI - 10.1016/j.jalz.2011.05.1708
Subject(s) - statistics , mathematics , random effects model , population , linear model , dementia , mixed model , demography , analysis of variance , medicine , disease , sociology , meta analysis
tor for the development of Alzheimer’s disease (AD). However, the association between APOE genotype and rate of progression in patients with AD remains controversial. Some studies suggest that presence of APOE e4 leads to faster cognitive decline, slower decline, or even that APOE genotype is not associated with decline. Methods: Among incident cases of AD in the population-based Cache County Dementia Progression study, APOE genotype was examined as a predictor of both preand post-AD trajectories of MMSE. Mixed effect models were estimated to assess this relationship, treating subject-specific intercepts and linear change with time as random effects.Results:MMSEtrajectories from 335 incident cases (65.6% female; 45.1% APOE E4 carriers)were analyzed. While there was no association of APOE e4 status with cognitive decline at the pre-dementia onset phase of the disease, there was significant association during the post-onset phase. This relationship depended on gender and time from reported onset of symptoms. At the early post-onset phase of the disease, men who were e4 carriers declined faster than men whowere non-carriers; women whowere carriers decline slower than women who were non-carriers. As the disease progressed, differences in the rate of decline by gender and APOE genotypewere no longer significant. For example,1 year after an AD diagnosis, the rate of decline of women e4 carriers was significantly different from both men and women who are non-carriers. However, five years after an AD diagnosis, the only statistically significant difference in the rate of declineis between women non-carriers and men carriers. After 8 years, all differences in rate of decline among carriers and non-carriers of both genders have disappeared. Conclusions: These findings demonstrate that the effect of APOE genotype on the rate of cognitive decline has a complex structure and depends on gender and also on the duration following the onset of AD. These results may help explain the differences in the literature regarding the effect of APOE on the rate of decline.