Apolipoprotein E ε4 is superior to apolipoprotein E ε2 in predicting cognitive scores over 30 months

Abstract

Background

The purpose of this study was to compare apolipoprotein E ε4 (Apo E ε4) and apolipoprotein E ε2 (Apo E ε2) as predictors of cognitive and functional trajectories over 30 months.

Methods

This prospective cohort study included 287 community-dwelling memory clinic patients with dementia, mild cognitive impairment, or no cognitive impairment. The Addenbrooke Cognitive Examination, Mini-Mental State Examination, Montreal Cognitive Assessment, Delirium Index, and Nottingham Instrumental Activities of Daily Living tests were administered to each subject.

Results

One hundred and nine subjects (40%) carried Apo E ε4 and 48 (16.7%) carried Apo E ε2. One hundred and nine ε4-positive subjects differed significantly from 178 ε4-negative subjects in 19/52 comparisons (36.5%), whereas 46 Apo E ε2-positive subjects had 0/52 significant differences from 239 ε2-negative subjects (P < 0.0001). The variables most affected by ε4 were the Delirium Index and Mini-Mental State Examination. Instrumental Activities of Daily Living score and residence were unrelated to Apo E ε4 or ε2.

Conclusion

Apo E ε4 positivity predicted four cognitive scores measured every 6 months over 30 months. Apo E ε2 scores predicted none of 52 comparisons.

Keywords:

• apolipoprotein E genotype
• dementia
• mild cognitive impairment

Acknowledgments

We thank Judy Warren-Smith and Jenny Delbridge, the medical librarians at Wyong Hospital, for their tireless work searching for articles on delirium and dementia.

Disclosure

The authors report no potential conflicts of interest in this work.