Odor identification impairment in carriers of ApoE-ε4 is independent of clinical dementia

The ApoE acme is expressed in olfactory brain structures and is believed to play a role in neuronal regenerative processes as well as in development of Alzheimer's disease (AD), the most common form of dementia The epsilon 4 allele lots been reported to be associated with compromised odor identification ability in the elderly, and this deficit has been interpreted as a sign of pre-diagnostic AD However, because it has not been demonstrated that the relationship between the epsilon 4 allele and odor identification is mediated by dementia, it is possible that the epsilon 4 allele may have an effect on odor identification over and above any effects of dementia. The present study investigated effects of ApoE-status on odor identification in a lame, population-based sample (n =1236) of adults (45-80 years), who were assessed for dementia at time of testing and 5 years later The results showed that the epsilon 4 allele was associated with an odor identification deficit among, elderly participants (75-80) Critically. this effect remained after current and pre-diagnostic dementia, vocabulary, global cognitive status and health variables were partialled out The present results suggest that the ApoE gene plays a role in olfactory functioning that is independent of dementia conversion within 5 years (C) 2008 Elsevier Inc All rights reserved