Association between BDNF polymorphism and hypothalamic-pituitary-adrenal activity in later adulthood

<p>Stress exposure over the lifespan is robustly associated with accelerated cognitive decline in later life. Brain-derived neurotrophic factor (BDNF) is shown to regulate activity of the hypothalamic-pituitary-adrenal axis. The objective of this study was to evaluate the association betweenthe <em>BDNF</em> polymorphism and indices of stress among adults aged 50+. Community-dwelling middle-aged and older adults provided a blood sample for <em>BDNF</em> genotyping. Participants also sampled their saliva 5 times/day for 3 consecutive days for the measurement of diurnal cortisol and underwent the Trier Social Stress Test (TSST) for the measurement of stress reactivity. Among 121 adults aged 50–67 years (78% female; 89% Caucasian), 74 participants were Val/Val carriers and 47 carried 1 copy of the Met allele. Repeated-measures analyses did not reveal an association between BDNF genotype and diurnal salivary cortisol (<em>p</em> = 0.63); however, analyses revealed that Met+ carriers displayed lower levels of cortisol secretion in response to the TSST compared with Val/Val carriers; <em>F</em>(4.43, 496.238) = 2.57, <em>p</em> = 0.032. This is the first study to evaluate the role of the <em>BDNF</em> polymorphism in stress physiology among older adults. Future studies are needed to evaluate the lifespan interconnections between <em>BDNF</em> and stress physiology.</p> <p> </p>