THE ASSOCIATION BETWEEN BDNF POLYMORPHISM AND BIOMARKERS OF STRESS IN MIDDLE AGED AND OLDER ADULTS
Bibliographic record
Abstract
Stress exposure over the lifespan is robustly associated with accelerated cognitive decline in late life. Researchers continue to investigate factors that determine individual differences in stress physiology. Brain derived neurotrophic factor is found to associate with cognitive trajectory in late life, and the Met allele of the functional Val66Met BDNF gene has been found to associate with poorer episodic memory and executive functioning in late life. The objective of this study was to evaluate the association between BDNF polymorphism and indices of stress among adults aged 50+. Community dwelling middle aged and older adults provided a blood sample for BDNF genotyping. Participants also sampled their saliva five times a day over three consecutive days for measurement of diurnal cortisol and underwent the Trier Social Stress Test (TSST) for measurement of stress reactivity. Among 120 adults aged 50–67 (83% female, 89% Caucasian), 73 participants were Val/Val carriers and 47 carried one copy of the Met allele (45 Val/Met, 2 Met/Met carriers). Val/Val and Met carriers did not differ on any demographic factors. Repeated measures analyses did not reveal an association between BDNF genotype and diurnal salivary cortisol (p=.63); however, analyses revealed that Met carriers displayed a blunted cortisol response to the TSST compared with Val/Val carriers, F(9, 936)=2.09, p=.03. This is the first study to evaluate the role of BDNF polymorphism in stress physiology among middle-aged and older adults. Future studies are needed to evaluate lifespan interconnections between BDNF, stress physiology and cognitive function.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".