Academic literature on the topic 'Structural MRI, Alcohol Dependence, Sex differences'

AbstractIndividuals diagnosed with alcohol-related neurodevelopmental disorder (ARND) exhibit difficulty on hippocampally mediated memory tasks and show reduced hippocampal size. However inconsistencies exist regarding the affected memory functions and where within the hippocampi effects occur. Given recent studies showing anterior and posterior segments support distinct memory functions and sex dimorphisms in hippocampal function, we asked whether these factors influence memory performance in youth with ARND (n= 18) and typically developing controls (n= 17). Participants received a battery of memory tests and a structural MRI scan. Right and left hippocampi were manually traced; anterior and posterior segments were delineated at the uncus. Measured were intracranial volumes (ICV) and right and left hippocampi and hippocampal segments. Volumes were adjusted for ICV. Relative to controls, the ARND group had lower IQs and memory performance on most tasks and marginally smaller ICVs. Left and right hippocampal volumes and posterior segments were smaller in the ARND group. Although no sex differences were observed between groups, females overall had larger anterior hippocampi than males. Positive and negative associations between hippocampal and selective memory indices were found in the ARND group only. These findings are the first to suggest that posterior hippocampal development may be compromised in youth with ARND. (JINS, 2014,20, 181–191)

Background: Cognitive reserve aims to explain individual differences in the susceptibility to the functional impact of dementia in the presence of equal amount of neuropathological damage. It is thought to be shaped by a combination of innate individual differences and lifetime exposures. Which determinants are associated with cognitive reserve remains unknown. Objective: The objective of this study was to investigate the associations of sociodemographic, lifestyle, physical, and psychosocial determinants with cognitive reserve, and potential sex differences. Methods: This cross-sectional study included 4,309 participants from the Rotterdam Study (mean age 63.9±10.7) between 2006–2016. Participants completed five cognitive tests and a brain MRI-scan. Cognitive reserve was defined as a latent variable that captures variance common across five cognitive tests, while adjusting for demographic and MRI-inferred neuropathological factors. The associations of potential determinants and cognitive reserve, adjusted for relevant confounders, were assessed with structural equation models. Results: Current smoking (adjusted mean difference: –0.31, 95%confidence interval –0.42; –0.19), diabetes mellitus (–0.25, –0.40; –0.10) and depressive symptoms (–0.07/SD, –0.12; –0.03) were associated with a lower cognitive reserve whereas alcohol use (0.07/SD, 0.03; 0.12) was associated with higher cognitive reserve. Only smoking was associated with cognitive reserve in both men and women. Employment, alcohol use, diabetes, history of cancer, COPD, and depressive symptoms were only associated with cognitive reserve in women. Conclusion: Our study found that current smoking, diabetes mellitus, and depressive symptoms were associated with a lower cognitive reserve, whereas more alcohol use was associated with a higher cognitive reserve, but with clear differences between men and women.

Objective:To examine the association between the American Heart Association (AHA) Life's Simple 7 (LS7) metric and brain structure.Methods:We determined cardiovascular health (CVH) according to the AHA LS7, assigning 0, 1, or 2 points for meeting poor, intermediate, or ideal criteria for the 7 components (range 0–14) at baseline (aged 18–30 years in 1985–1986) and year 25 follow-up examination for 518 participants of the Coronary Artery Risk Development in Young Adults (CARDIA) brain MRI substudy. Visit-based CVH score and average score was assessed in relation to percent of intracranial volume of normal tissue of the whole brain, gray matter, and white matter, and abnormal tissue volume of white matter at year 25 using multivariable linear, logistic, and quantile regression, after adjustment for age, sex, race, field center, educational attainment, and alcohol consumption.Results:Mean percentage of whole brain volume, normal gray matter, and normal white matter was 81.3% (±2.5), 42.9% (±2.0), and 38.4% (±2.0). Greater CVH score at baseline (per each additional point at year 0: 0.1%, 95% confidence limits 0.01–0.3; p < 0.05) and average CVH score were associated with greater percentage of whole brain volume (per each additional point in average score: 0.2%, 95% confidence limits 0.04–0.3; p < 0.05). Visit-based or average CVH score was not significantly associated with normal gray or white matter volume or abnormal white matter volume.Conclusions:Maintaining ideal levels of cardiovascular health, determined by the LS7, in young adulthood is associated with greater whole brain volume in middle age but not regional differences in structure.

Objective: Addiction is a chronic relapsing brain disease. Brain structural abnormalities may constitute an abnormal neural network that underlies the risk of drug dependence. We hypothesized that individuals with Betel Quid Dependence (BQD) have functional connectivity alterations that can be described by long- and short-range functional connectivity density(FCD) maps. Methods: We tested this hypothesis using functional magnetic resonance imaging (fMRI) data from subjects of the Han ethnic group in Hainan, China. Here, we examined BQD individuals (n = 33) and age-, sex-, and education-matched healthy controls (HCs) (n = 32) in a rs-fMRI study to observe FCD alterations associated with the severity of BQD. Results: Compared with HCs, long-range FCD was decreased in the right anterior cingulate cortex (ACC) and increased in the left cerebellum posterior lobe (CPL) and bilateral inferior parietal lobule (IPL) in the BQD group. Short-range FCD was reduced in the right ACC and left dorsolateral prefrontal cortex (dlPFC), and increased in the left CPL. The short-range FCD alteration in the right ACC displayed a negative correlation with the Betel Quid Dependence Scale (BQDS) (r=-0.432, P=0.012), and the long-range FCD alteration of left IPL showed a positive correlation with the duration of BQD(r=0.519, P=0.002) in BQD individuals. Conclusions: fMRI revealed differences in long- and short- range FCD in BQD individuals, and these alterations might be due to BQ chewing, BQ dependency, or risk factors for developing BQD.

AbstractLifestyle may be one source of unexplained variance in the great interindividual variability of the brain in age-related structural differences. While physical and social activity may protect against structural decline, other lifestyle behaviors may be accelerating factors. We examined whether riskier lifestyle correlates with accelerated brain aging using the BrainAGE score in 622 older adults from the 1000BRAINS cohort. Lifestyle was measured using a combined lifestyle risk score, composed of risk (smoking, alcohol intake) and protective variables (social integration and physical activity). We estimated individual BrainAGE from T1-weighted MRI data indicating accelerated brain atrophy by higher values. Then, the effect of combined lifestyle risk and individual lifestyle variables was regressed against BrainAGE. One unit increase in combined lifestyle risk predicted 5.04 months of additional BrainAGE. This prediction was driven by smoking (0.6 additional months of BrainAGE per pack-year) and physical activity (0.55 less months in BrainAGE per metabolic equivalent). Stratification by sex revealed a stronger association between physical activity and BrainAGE in males than females. Overall, our observations may be helpful with regard to lifestyle-related tailored prevention measures that slow changes in brain structure in older adults.

ObjectiveTo investigate the independent associations of social isolation and loneliness with incident dementia and to explore the potential neurobiological mechanisms.MethodsWe utilized the UK Biobank cohort to establish Cox proportional hazard models with social isolation and loneliness as separate exposures. Demographic (sex, age and ethnicity), socioeconomic (education level, household income and Townsend deprivation index), biological (BMI, APOE genotype, diabetes, cancer, cardiovascular disease and other disabilities), cognitive (speed of processing and visual memory), behavioral (current smoker, alcohol intake and physical activity), and psychological (social isolation or loneliness, depressive symptoms and neuroticism) factors measured at baseline were adjusted. Then, voxel-wise brain-wide association analyses were used to identify gray matter volumes (GMV) associated with social isolation and with loneliness. Partial least squares regression was performed to test the spatial correlation of GMV differences and gene expression using the Allen Human Brain Atlas.ResultsWe included 462,619 participants (mean age at baseline 57.0 years [SD 8.1]). With a mean follow-up of 11.7 years (SD 1.7), 4,998 developed all-cause dementia. Social isolation was associated with a 1.26-fold increased risk of dementia (95% CI, 1.15-1.37) independently of various risk factors including loneliness and depression (i.e., full adjustment). However, the fully adjusted hazard ratio for dementia related to loneliness was 1.04 (95% CI, 0.94-1.16); and 75% of this relationship was attributable to depressive symptoms. Structural MRI data were obtained from 32,263 participants (mean age 63.5 years [SD 7.5]). Socially isolated individuals had lower GMVs in temporal, frontal and other (e.g., hippocampal) regions. Mediation analysis showed that the identified GMVs partly mediated the association between social isolation at baseline and cognitive function at follow-up. Social isolation-related lower GMVs were related to under-expression of genes that are down-regulated in Alzheimer’s disease and to genes that are involved in mitochondrial dysfunction and oxidative phosphorylation.ConclusionSocial isolation is a risk factor for dementia that is independent of loneliness and many other covariates. Social isolation-related brain structural differences coupled with different molecular functions also support the associations of social isolation with cognition and dementia. Social isolation may thus be an early indicator of an increased risk of dementia.