The BDNF Val66Met Polymorphism, Regular Exercise, and Cognition: A Systematic Review

Effects of a 6-month dual-task, power-based exercise program on cognitive function, neurological and inflammatory markers in older adults: secondary analysis of a cluster randomised controlled trial

Functional power-based exercise training can improve physical performance in older adults and cognitive training can improve measures of cognition, but their combined effects on cognition and related risk factors (neurological and inflammatory markers) remains uncertain. This 6-month cluster randomised controlled trial evaluated the effectiveness of dual-task functional power training (DT-FPT) on cognition and circulating neurological and inflammatory markers in older adults at increased falls risk, and whether intervention responses varied by apolipoprotein-E (ApoE) and brain derived neurotrophic factor (BDNF) polymorphisms. Three hundred residents aged ≥ 65 years at increased falls risk residing in 22 independent-living retirement communities, were randomised by village, to DT-FPT (n = 156, 11 villages) involving a multi-component power-based training program performed simultaneously with cognitive and/or motor tasks (45-60 min, 2/week), or a usual care control (CON) group (n = 144, 11 villages). Cognition (computerized CogState battery), inflammatory cytokines, BDNF, insulin-like growth factor-1, vascular endothelial growth factor, amyloid β (1-40) and (1-42) were assessed at baseline and 6-months. Overall, 233 (78%) participants completed the intervention and adherence averaged 50.1%. DT-FPT led to a net 0.18-0.20 SD benefit versus CON in psychomotor ability/attention and reaction time/attention (both P < 0.05). There were no significant intervention effects on circulating markers, except for a net 10.5% benefit in amyloid β (1-40) in DT-FPT versus CON (P < 0.05). Responses were not influenced by APOE or BDNF genotype. In conclusion, DT-FPT in older adults at increased falls risk can provide some cognitive benefits, but these were not related to corresponding changes in inflammatory or neurological markers or influenced by genotype. Australian New Zealand Clinical Trials Registry (ACTRN12613001161718). http://www.anzctr.org.au/ This project was funded by a grant from the National Health and Medical Research Council (NHMRC) Project (APP1046267).

A longitudinal study of polygenic score and cognitive function decline considering baseline cognitive function, lifestyle behaviors, and diabetes among middle-aged and older US adults

BACKGROUND

Genomic study of cognition decline while considering baseline cognition and lifestyle behaviors is scarce. We aimed to evaluate the impact of a polygenic score for general cognition on cognition decline rate, while considering baseline cognition and lifestyle behaviors, among the general population and people with diabetes, a patient group commonly affected by cognition impairment.

METHODS

We tested associations of the polygenic score for general cognition with annual changing rates of cognition measures in 8 years of follow-up among 12,090 White and 3100 Black participants of the Health and Retirement Study (HRS), a nationally representative sample of adults aged 50 years and older in the USA. Cognition measures including word recall, mental status, and total cognitive score were measured biannually. To maximize sample size and length of follow-up, we treated the 2010 wave of survey as baseline, and follow-up data until 2018 were analyzed. Baseline lifestyle behaviors, APOE status, and measured cognition were sequentially adjusted. Given racial differences in polygenic score, all analyses were conducted by race.

RESULTS

The polygenic score was significantly associated with annual changing rates of all cognition measures independent of lifestyle behaviors and APOE status. Together with age and sex, the polygenic score explained 29.9%, 15.9%, and 26.5% variances of annual changing rates of word recall, mental status, and total cognitive scores among Whites and explained 17.2%, 13.9%, and 18.7% variance of the three traits among Blacks. Among both White and Black participants, those in the top quartile of polygenic score had the three cognition measures increased annually, while those in the bottom quartile had the three cognition measures decreased annually. After further adjusting for the average cognition assessed in 3 visits around baseline, the polygenic score was still positively associated with annual changing rates of all cognition measures for White (P ≤ 2.89E - 19) but not for Black (P ≥ 0.07) participants. In addition, among participants with diabetes, physical activity offset the genetic susceptibility to decline of mental status (interaction P ≤ 0.01) and total cognitive scores (interaction P = 0.03).

CONCLUSIONS

Polygenic score predicted cognition changes in addition to measured cognition. Physical activity offset genetic risk for cognition decline among diabetes patients.

Correlation between nocturnal intermittent hypoxemia and mild cognitive impairment in the older adult and the role of BDNF Val66Met polymorphism: a hospital-based cross-sectional study

PURPOSE

To explore the prevalence of nocturnal intermittent hypoxemia (NIH) in a tertiary hospital geriatric department and the relationship between NIH and mild cognitive impairment (MCI) in older adults, and to examine the role of brain-derived neurotrophic factor (BDNF) Val66Met polymorphism.

METHODS

Older adults aged ≥ 60 were enrolled. NIH and cognitive assessments were conducted. BDNF concentrations and BDNF Val66Met polymorphism were detected for a preliminary exploration of the possible mechanism of the process.

RESULTS

Of 325 older adults enrolled, 157 (48%) had NIH and were further divided into mild, moderate, and severe NIH groups according to their oxygen desaturation of ≥ 4% per hour of sleep (ODI4). MCI detection rate in the four groups gradually increased, and the differences were statistically significant (chi-square = 4.457, P = 0.035). ODI4 was negatively correlated with MoCA score in all participants (r =  - 0.115, P = 0.039) and patients with NIH (r =  - 0.199, P = 0.012). After adjusting for sex, age, and cardiovascular risk factors, NIH and MCI remained independently associated (OR = 3.13, 95% CI 1.03-9.53, P = 0.045). BDNF levels were positively correlated with MoCA score (r = 0.169, P = 0.028) and negatively correlated with nocturnal average oxygen saturation in patients with NIH (r =  - 0.288, P = 0.008). Older adults with different BDNF Val66Met genotypes did not show significant differences in MCI rate and BDNF levels (P > 0.05).

CONCLUSION

The older adults with NIH have a higher MCI detection rate. BDNF levels may be a potential biomarker for cognitive dysfunction in patients with NIH.

The efficacy of physical exercise interventions on mental health, cognitive function, and ADHD symptoms in children and adolescents with ADHD: an umbrella review

Background

A considerable number of published reviews have addressed the effects of physical exercise on mental health, cognitive function, or attention-deficit hyperactivity (ADHD) symptoms as outcomes in children and adolescents with ADHD. Their findings have often conflicted, therefore, there is an urgent need to synthesise a hierarchy of the evidence and examine the credibility of previous meta-analyses. To establish the robustness of these findings, we conducted an additional meta-analysis on a number of individual studies that were not covered in previous reviews but were suitable for inclusion in our own study.

Methods

Three reviewers independently searched Web of Science, Psych INFO, Embase, Cochrane Library, PubMed, SPORTDiscus, and Cumulative Index to Nursing and Allied Health Literature (CINAHL) for meta-analyses published between database inceptions to December 1, 2022. The individual studies were also screened from 1 January 2015 to 1 December 2022. We included meta-analyses and eligible individual studies that addressed the effects of exercise on at least one outcome of mental health, cognitive function, or ADHD symptoms in children and adolescents with ADHD. We excluded systematic reviews and articles that lacked sufficient data for a meaningful second analysis. The effect estimates (Hedges' g), 95% confidence interval (95% CI), 95% prediction interval (95% PI), small study effects, and excess significance bias were calculated. Finally, we categorised the meta-analyses based on the credibility of the evidence criteria and their quality using a Measurement Tool to Assess Systematic Reviews 2 checklist. This umbrella review was registered with PROSPERO, CRD42022361331.

Findings

Of 181 listed review articles and 60 individual papers, 10 reviews and 12 individual articles were included in the meta-analyses. This yielded 37 meta-analyses based on 106 study estimates. Evidence was highly suggestive for the effectiveness of exercise (class II) for improving inattention (G = 0.92, 95% CI: 0.44-1.39, 95%), inhibitory control (G = 0.82, 95% CI: 0.52-1.13), and cognitive flexibility (G = 0.52, 95% CI: 0.32-0.72). However, evidence for the effectiveness of exercise on emotional, social, and working memory outcomes was weak, and these results were not significant for hyperactivity and behavioural functioning.

Interpretation

Improvement of cognitive flexibility, inhibitory control, and inattention in children and adolescents with ADHD was highly suggested by exercise interventions. However, results were weak for other outcomes (emotional functioning, social functioning, and working memory). Further high-quality randomised controlled trials are, therefore, warranted to determine the effectiveness of exercise on weak outcomes.

Funding

None.

Are COMT Val158Met (rs4680), DRD2 TaqIA (rs1800497), and BDNF Val66Met (rs6265) polymorphisms associated with executive functions performance at rest and during physical exercise?

Executive functions (EFs) encompass a wide array of cognitive processes, which appear to be influenced by genetic variants of the COMT, DRD2/ANKK1, and BDNF polymorphisms. The present study aimed to investigate whether COMT Val158Met (rs4680), DRD2/ANKK1 (rs1800497), and BDNF Val66Met (rs6265) polymorphisms were associated with EFs assessed at rest and during moderate acute physical exercise. Sixty physically active individuals underwent four laboratory visits. First, they filled out the pre-exercise survey, researchers collected their anthropometric data, and then performed a maximal cardiopulmonary exercise test. In the second and third sessions, participants performed EFs test in a randomized order: while the individual was seated on a cycle ergometer without pedaling (i.e., rest condition); and during physical exercise (pedaling for 30 minutes at moderate intensity before starting the EFs test during exercising). On the fourth day, blood samples were drawn. Our results showed that the response time of the COMT Val homozygotes group was significantly shorter than the COMT Met-carrier group [t(39.78) = 2.13, p = .039,d = 0.56] at rest condition. No significant association was found for the other analyses (DRD2/ANKK1 and BDNF). In conclusion, the present study suggests that COMT Val158Met (rs4680) polymorphisms may be associated with EFs at rest condition. However, further studies are needed to validate this association.

Interaction Effect between Physical Activity and the BDNF Val66Met Polymorphism on Depression in Women from the PISMA-ep Study

The relationship between depression and the Val66Met polymorphism at the brain-derived neurotrophic factor gene (BDNF), has been largely studied. It has also been related to physical activity, although the results remain inconclusive. The aim of this study is to investigate the relationship between this polymorphism, depression and physical activity in a thoroughly characterised sample of community-based individuals from the PISMA-ep study. A total of 3123 participants from the PISMA-ep study were genotyped for the BDNF Val66Met polymorphism, of which 209 had depression. Our results are in line with previous studies reporting a protective effect of physical activity on depression, specifically in light intensity. Interestingly, we report a gene-environment interaction effect in which Met allele carriers of the BDNF Val66Met polymorphism who reported more hours of physical activity showed a decreased prevalence of depression. This effect was observed in the total sample (OR = 0.95, 95%CI = 0.90–0.99, p = 0.027) and was strengthened in women (OR = 0.93, 95%CI = 0.87–0.98, p = 0.019). These results highlight the potential role of physical activity as a promising therapeutic strategy for preventing and adjuvant treatment of depression and suggest molecular and genetic particularities of depression between sexes.

Physical Activity, Fitness, and Executive Functions in Youth: Effects, Moderators, and Mechanisms

Over the last decade, a growing body of research has examined the link between physical activity, fitness, and cognitive function in children and adolescents. Physical activity experimental research conducted with children and adolescents has identified selectively greater effects for tasks requiring higher order executive functions. As such, the primary aim of our chapter is to provide an overview of findings from systematic reviews and meta-analyses that have examined the effects of physical activity on measures of executive function in child and adolescent populations. We begin our chapter with definitions of key concepts associated with physical activity, fitness and cognitive function. We then provide a synthesis of systematic reviews and meta-analyses that have examined the acute and chronic effect of physical activity on EFs. Following this, we discuss the quantitative (e.g., time, intensity) and qualitative (e.g., type) characteristics of physical activity that may moderate effects. The next section focuses on the neurobiological, psychosocial and behavioral mechanisms responsible for the effect of physical activity on executive functions. We conclude by highlighting the limitations of the existing evidence base and providing recommendations for future research.

FEASibility testing a randomized controlled trial of an exercise program to improve cognition for T2DM patients (the FEAST trial): A study protocol

While cognitive dysfunction is an important concern in persons with type 2 diabetes mellitus (T2DM), it has received little attention in the T2DM literature. Although it often remains unrecognized, cognitive dysfunction associated with T2DM can lead to severe consequences. Prior research studies have consistently shown that aerobic exercise enhances cognitive function among healthy subjects. However, very few studies have examined the effects of aerobic exercise on cognitive function in persons with T2DM. In addition, one important single-nucleotide polymorphism that influences cognition in humans is the brain-derived neurotrophic factor (BDNF) Val66Met variant. Despite strong evidence suggesting aerobic exercise has a beneficial effect on cognitive function, there is significant variability in individual response to exercise programs on cognitive outcomes among Val/Val versus Met carriers. However, the evidence on how the BDNF Val66Met variant influences cognitive outcomes following an aerobic exercise intervention among individuals with T2DM is currently lacking. Therefore, the purpose of this randomized controlled trial is to pilot-test a 3-month supervised exercise program to improve plasma BDNF levels and cognition, overall and according to genotypes of the BDNF Val66Met variant. A total of 81 patients with T2DM will be randomly assigned to either aerobic exercise group (n = 54) or attention control group (n = 27) for 3 months. Outcomes of interest include postintervention changes in plasma BDNF levels, fasting blood glucose, hemoglobin A1c, body mass index, executive function, memory, and processing speed. This study will provide further evidence on use of exercise as a non-pharmaceutical, low-cost intervention to improve cognition in this population.

High-intensity exercise and cognitive function in cognitively normal older adults: a pilot randomised clinical trial

BACKGROUND

Physical inactivity has been consistently linked to increased risk of cognitive decline; however, studies examining the impact of exercise interventions on cognition have produced inconsistent findings. Some observational studies suggest exercise intensity may be important for inducing cognitive improvements; however, this has yet to be thoroughly examined in older adult cohorts. The objective of the current study was to evaluate the effect of systematically manipulated high-intensity and moderate-intensity exercise interventions on cognition.

METHODS

This multi-arm pilot randomised clinical trial investigated the effects of 6 months of high-intensity exercise and moderate-intensity exercise, compared with an inactive control, on cognition. Outcome measures were assessed at pre- (baseline), post- (6 months), and 12 months post-intervention. Ninety-nine cognitively normal men and women (aged 60-80 years) were enrolled from October 2016 to November 2017. Participants that were allocated to an exercise group (i.e. high-intensity or moderate-intensity) engaged in cycle-based exercise two times per week for 6 months. Cognition was assessed using a comprehensive neuropsychological test battery. Cardiorespiratory fitness was evaluated by a graded exercise test.

RESULTS

There was a dose-dependent effect of exercise intensity on cardiorespiratory fitness, whereby the high-intensity group experienced greater increases in fitness than the moderate-intensity and control groups. However, there was no direct effect of exercise on cognition.

CONCLUSIONS

We did not observe a direct effect of exercise on cognition. Future work in this field should be appropriately designed and powered to examine factors that may contribute to individual variability in response to intervention.

TRIAL REGISTRATION

This study is registered with the Australian New Zealand Clinical Trials Registry (ACTRN12617000643370). Registered on 3 May 2017-retrospectively registered. https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=372780.

The Influence of the BDNF Val66Met Polymorphism on the Association of Regular Physical Activity With Cognition Among Individuals With Diabetes

INTRODUCTION

Diabetes is associated with cognitive dysfunction that comes with substantial lifetime consequences, such as interference with diabetes self-management and reduced quality of life. Although regular physical activity has been consistently shown to enhance cognitive function among healthy subjects, significant interpersonal differences in exercise-induced cognitive outcomes have been reported among brain-derived neurotrophic factor (BDNF) Val/Val vs. Met carriers. However, the evidence on how the BDNF Val66Met variant influences the relationship between regular physical activity and cognition among individuals with diabetes is currently lacking.

METHODS

A total of 3,040 individuals with diabetes were included in this analysis using data from the Health and Retirement Study. Associations among moderate and vigorous physical activities (MVPA) and measures of cognitive function were evaluated using multivariable linear regression models within each stratum of the Val66Met genotypes.

RESULTS

MVPA was more strongly associated with total cognitive score, mental status, and words recall among Met/Met carriers, compared to Val/Val and Val/Met carriers.

CONCLUSIONS

This study provided preliminary findings on how BDNF variants may modulate the exercise-induced cognitive benefits among mid-aged and older adults with diabetes. Given the limitations of the current study, it is necessary for randomized controlled trials to stratify by BDNF genotypes to more conclusively determine whether Met carriers benefit more from increased physical activity. In addition, future research is needed to examine how the interplay of BDNF Val66Met variants, DNA methylation, and physical activity may have an impact on cognitive function among adults with diabetes.