Forever young(er): potential age-defying effects of long-term meditation on gray matter atrophy

While overall life expectancy has been increasing, the human brain still begins deteriorating after the first two decades of life and continues degrading further with increasing age. Thus, techniques that diminish the negative impact of aging on the brain are desirable. Existing research, although scarce, suggests meditation to be an attractive candidate in the quest for an accessible and inexpensive, efficacious remedy. Here, we examined the link between age and cerebral gray matter re-analyzing a large sample (n = 100) of long-term meditators and control subjects aged between 24 and 77 years. When correlating global and local gray matter with age, we detected negative correlations within both controls and meditators, suggesting a decline over time. However, the slopes of the regression lines were steeper and the correlation coefficients were stronger in controls than in meditators. Moreover, the age-affected brain regions were much more extended in controls than in meditators, with significant group-by-age interactions in numerous clusters throughout the brain. Altogether, these findings seem to suggest less age-related gray matter atrophy in long-term meditation practitioners.Nicolas Cherbuin is funded by Australian Research Council fellowship number 120100227

Intraindividual variability is a fundamental phenomenon of aging: Evidence from an 8-year longitudinal study across young, middle and older adulthood

Moment-to-moment intraindividual variability (IIV) in cognitive speed is a sensitive behavioural indicator of the integrity of the aging brain and brain damage, but little information is known about how IIV changes from being relatively low in young adulthood to substantially higher in older adulthood. We evaluated possible age group, sex, and task differences in IIV across adulthood using a large, neurologically normal, population-based sample evaluated thrice over 8 years. Multilevel modeling controlling for education, diabetes, hypertension, and anxiety and depressive symptoms showed expected age group differences in baseline IIV across the adult lifespan. Increase in IIV was not found until older adulthood on simple tasks, but was apparent even in the 40s on a more complex task. Females were more variable than males, but only at baseline. IIV in cognitive speed is a fundamental behavioural characteristic associated with growing older, even among healthy adults

Sugar in mind: Untangling a sweet and sour relationship beyond type 2 diabetes

It is widely recognised that type 2 diabetes (T2D) represents a major disease burden but it is only recently that its role in neurodegeneration has attracted more attention. This research has shown that T2D is associated with impaired cerebral health, cognitive decline and dementia. However, the impact on the brain of progressive metabolic changes associated with the pre-clinical development of the disease is less clear. The aim of this review is to comprehensively summarise how the emergence of risk factors and co-morbid conditions linked to the development of T2D impact cerebral health. Particular attention is directed at characterising how normal but elevated blood glucose levels in individuals without T2D contribute to neurodegenerative processes, and how the main risk factors for T2D including obesity, physical activity and diet modulate these effects. Where available, evidence from the animal and human literature is contrasted, and sex differences in risk and outcomes are highlighted.The research was supported by the Australian National Health and Medical Research Council grant 1063907

DRD4-exonIII-VNTR moderates the effect of childhood adversities on emotional resilience in young-adults

Most individuals successfully maintain psychological well-being even when exposed to trauma or adversity. Emotional resilience or the ability to thrive in the face of adversity is determined by complex interactions between genetic makeup, previous exposure to stress, personality, coping style, availability of social support, etc. Recent studies have demonstrated that childhood trauma diminishes resilience in adults and affects mental health. The Dopamine receptor D4 (DRD4) exon III variable number tandem repeat (VNTR) polymorphism was reported to moderate the impact of adverse childhood environment on behaviour, mood and other health-related outcomes. In this study we investigated whether DRD4-exIII-VNTR genotype moderates the effect of childhood adversities (CA) on resilience. In a representative population sample (n = 1148) aged 30-34 years, we observed an interactive effect of DRD4 genotype and CA (β = 0.132; p = 0.003) on resilience despite no main effect of the genotype when effects of age, gender and education were controlled for. The 7-repeat allele appears to protect against the adverse effect of CA since the decline in resilience associated with increased adversity was evident only in individuals without the 7-repeat allele. Resilience was also significantly associated with approach-/avoidance-related personality measures (behavioural inhibition/activation system; BIS/BAS) measures and an interactive effect of DRD4-exIII-VNTR genotype and CA on BAS was observed. Hence it is possible that approach-related personality traits could be mediating the effect of the DRD4 gene and childhood environment interaction on resilience such that when stressors are present, the 7-repeat allele influences the development of personality in a way that provides protection against adverse outcomes.The study was supported by NHMRC of Australia Unit Grant No. 973302. DD is funded by NHMRC Capacity Building Grant No. 418020 in Population Health Research. NC is funded by NHMRC Research Fellowship No. 471501. KA is funded by NHMRC Research Fellowship No. 366756

Dementia risk estimates associated with measures of depression: A systematic review and meta-analysis

Late-life depression is consistently and similarly associated with a twofold increased risk of dementia. The precise risk estimates produced in this study for specific instruments at specified thresholds will assist evidence-based medicine and inform policy on this important population health issue

The impact of aging on subregions of the hippocampal complex in healthy adults

The hippocampal complex, an anatomical composite of several subregions, is known to decrease in size with increasing age. However, studies investigating which subregions are particularly prone to age-related tissue loss revealed conflicting findings. Possible reasons for such inconsistencies may reflect differences between studies in terms of the cohorts examined or techniques applied to define and measure hippocampal subregions. In the present study, we enhanced conventional MR-based information with microscopically defined cytoarchitectonic probabilities to investigate aging effects on the hippocampal complex in a carefully selected sample of 96 healthy subjects (48 males/48 females) aged 18-69 years. We observed significant negative correlations between age and volumes of the cornu ammonis, fascia dentata, subiculum, and hippocampal-amygdaloid transition area, but not the entorhinal cortex. The estimated age-related annual atrophy rates were most pronounced in the left and right subiculum with -0.23% and -0.22%, respectively. These findings suggest age-related atrophy of the hippocampal complex overall, but with differential effects in its subregions. If confirmed in future studies, such region-specific information may prove useful for the assessment of diseases and disorders known to modulate age-related hippocampal volume loss.NC is funded by Australian Research Council Future fellowship number 120100227. EL is funded by the Eunice Kennedy Shriver National Institute of Child Health & Human Development of the National Institutes of Health under award number R01HD081720 and further supported by the Cousins Center for Psychoneuroimmunology at the University of California, Los Angeles (UCLA)

Cognitive Deficits Are Associated with Frontal and Temporal Lobe White Matter Lesions in Middle-Aged Adults Living in the Community

BACKGROUND The association between brain white matter lesions and cognitive impairment in old age is well established. However, little is known about this association in midlife. As this information will inform policy for early preventative healthcare initiatives, we investigated non-periventricular frontal, temporal, parietal and occipital lobe white matter hyperintensities (WMH) in relation to cognitive function in 428 (232 women) community-dwelling adults aged 44 to 48 years. RESULTS Frontal white matter lesions were significantly associated with greater intraindividual RT variability in women, while temporal WMH were associated with face recognition deficits in men. Parietal and occipital lobe lesions were unrelated to cognitive performance. These findings did not differ when education and a range of health variables, including vascular risk factors, were taken into account. CONCLUSION Gender differences in WMH-cognition associations are discussed, and we conclude that small vessel disease is present in midlife and has functional consequences which are generally not recognized. Preventative strategies should, therefore, begin early in life.David Bunce's collaboration in this work was supported by the Leverhulme Trust and the British Academy. The study was funded by NHMRC of Australia Unit Grant No. 973302, Program Grant No. 179805, NHMRC project grant No. 157125, grants from the Australian Rotary Health Research Fund and the Australian Brewers Foundation. Nicolas Cherbuin is funded by NHMRC Research Fellowship No. 471501. Kaarin Anstey is funded by NHMRC Research Fellowship No. 366756. The funders had no role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript

A Systematic Review and Meta-analysis of the Socioeconomic, Lifestyle, and Environmental Factors Associated with Healthy Ageing in Low and Lower-Middle-Income Countries

Population ageing is a growing social and health issue in low and lower-middle-income countries (LLMIC). It will have an impact on rising healthcare costs, unaffordable pension liabilities, and changing healthcare demands. The health systems of many LLMICs are unprepared to meet these challenges and highlighting the modifiable factors that may help decrease these pressures is important. This review assessed the prevalence of healthy ageing and the modifiable factors that may promote/inhibit healthy ageing among older people in LLMIC. A systematic search of all articles published from 2000 to June 2022 was conducted in Scopus, PubMed (MEDLINE), and Web of Science. All observational studies reporting the prevalence of healthy ageing and its associations with socio-demographic, lifestyle, psychological, and social factors were examined. Random-effect models were used to estimate the pooled prevalence of healthy ageing, and meta-analyses were conducted to assess the risk/benefit of modifiable factors. From 3,376 records, 13 studies (n = 81,144; 53% of females; age ≥ 60 years) met the inclusion criteria. The pooled prevalence of healthy ageing ranged from 24.7% to 56.5% with lower prevalence for a multi-dimensional model and higher prevalence for single global self-rated measures. Factors positively associated with healthy ageing included education, income, and physical activity. Being underweight was negatively associated with healthy ageing. Almost half of older people in LLMIC were found to meet healthy ageing criteria, but this estimate varied substantially depending on the healthy ageing measures utilized (multi-dimensional = 24.7%; single indicator = 56.5%). The healthy ageing prevalences for both measures are lower compared to that in high-income countries. Developing health policies and educative interventions aimed at increasing physical exercise, social support, and improving socio-economic status and nutrition will be important to promote the healthy ageing of older people in LLMIC in sustainable ways.</p

Cerebral atrophy in mild cognitive impairment:A systematic review with meta-analysis

Introduction: Although mild cognitive impairment (MCI) diagnosis is mainly based on cognitive assessment, reliable estimates of structural changes in specific brain regions, that could be contrasted against normal brain aging and inform diagnosis, are lacking. This study aimed to systematically review the literature reporting on MCI-related brain changes. Methods: The MEDLINE database was searched for studies investigating longitudinal structural changes in MCI. Studies with compatible data were included in the meta-analyses. A qualitative review was conducted for studies excluded from meta-analyses. Results: The analyses revealed a 2.2-fold higher volume loss in the hippocampus, 1.8-fold in the whole brain, and 1.5-fold in the entorhinal cortex in MCI participants. Conclusion: Although the medial temporal lobe is likely to be more vulnerable to MCI pathology, atrophy in this brain area represents a relatively small proportion of whole brain loss, suggesting that future investigations are needed to identify the source of unaccounted volume loss in MCI.</p

Attention deficit/hyperactivity disorder symptoms and cognitive abilities in the late-life cohort of the PATH Through Life Study

Attention Deficit/Hyperactivity Disorder (ADHD) is a common neuropsychiatric disorder that has not been well studied in older adults. In this study we examined relationships between ADHD symptoms and cognitive ability and compared them between middle-age (MA; 48-52 years) and older-age (OA; 68-74 years) adults sampled from the same population. ADHD, mood disorder symptoms and cognitive abilities were assessed in a large population-based sample (n = 3443; 50% male). We measured current ADHD symptoms using the adult ADHD Self-Report Scale (ASRS), which we found to have the same underlying structure in both cohorts. Older adults reported significantly lower levels of ADHD symptoms and 2.2% of the OA cohort scored equal or above the ASRS cut-off score of 14 (which has been previously associated with ADHD diagnosis) compared with 6.2% of MA adults. Symptom levels were not significantly different between males and females. Using multigroup structural equation modelling we compared ADHD symptom-cognitive performance relationships between the two age groups. Generally higher ADHD symptoms were associated with poorer cognitive performance in the MA cohort. However, higher levels of inattention symptoms were associated with better verbal ability in both cohorts. Surprisingly, greater hyperactivity was associated with better task-switching abilities in older adults. In the OA cohort ADHD symptom-cognition relationships are indirect, mediated largely through the strong association between depression symptoms and cognition. Our results suggest that ADHD symptoms decrease with age and that their relationships with co-occurring mood disorders and cognitive performance also change. Although symptoms of depression are lower in older adults, they are much stronger predictors of cognitive performance and likely mediate the effect of ADHD symptoms on cognition in this age group. These results highlight the need for age-appropriate diagnosis and treatment of comorbid ADHD and mood disorders