AUTHOR=Fujiwara Yoshinori , Ihara Kazushige , Hachisu Mitsugu , Suzuki Hiroyuki , Kawai Hisashi , Sakurai Ryota , Hirano Hirohiko , Chaves Paulo H. M. , Hashizume Masahiro , Obuchi Shuichi 

TITLE=Higher Serum Brain-Derived Neurotrophic Factor Levels Are Associated With a Lower Risk of Cognitive Decline: A 2-Year Follow Up Study in Community-Dwelling Older Adults

JOURNAL=Frontiers in Behavioral Neuroscience

VOLUME=Volume 15 - 2021

YEAR=2021

URL=https://www.frontiersin.org/journals/behavioral-neuroscience/articles/10.3389/fnbeh.2021.641608

DOI=10.3389/fnbeh.2021.641608

ISSN=1662-5153

ABSTRACT=Objective: To examine the relationship  of serum brain-derived neurotrophic factor (BDNF) levels with subsequent short-term decline  in  cognitive functioning of community-dwelling older adults.
Design: Two-year prospective, observational study 
Setting and Participants: Four hundred five adults aged 65-84 years, living in an urban city (Tokyo, Japan). 
Methods: Participants free of a dementia diagnosis underwent  health assessments at baseline (2011) and follow-up (2013). Serum BDNF levels and scores from the Montreal Cognitive Assessment-Japanese version (MoCA-J) were measured systematically. Logistic regression was used to assess the odds of cognitive decline between baseline and follow-up visitsin the full MoCA-J scale (operationally defined as a decrease of 2 or more points), as well as in MoCA-J subscales (decline of 1 or more points in a specific subscale), as a function of serum BDNF level, adjusting for baseline demographics, prevalent chronic diseases, and baseline cognitive scores.  .  
Results: Among individuals who performed worse on the full MoCA-J at baseline (i.e., scores in the bottom quartile [≤21], which is consistent with a mild cognitive impairment status), but not among those who performed better (top 3 quartiles), those with highest baseline serum BDNF levels (top quartile) had lower odds of subsequent decline in the full MoCa-J scale than those with lowest (bottom quartile); i.e., OR): .10 (95% CI: .02-.62; p=.013). Regarding MoCA-J subscales, adjusted odds of decline in the executive function subscale, but not in the other 5 subscales, were substantially lower among those with highest baseline serum BDNF levels (top quartile), as compared to those with lowest (bottom quartile); i.e., odds ratio (OR): .27 (95% confidence interval [CI]: .13-.60; p<.001). 
Conclusions and Implications: Higher serum BDNF levels were associated with lower risk of decline in cognitive function in a sample of community-dwelling older Japanese adults. Risk varied among cognitive subdomains and according to baseline cognition. Research seeking to evaluate the added-value of serum BDNF in health promotion initiatives directed towards cognitive decline prevention in community-dwelling older adults is warranted.