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Objectives It is well known that low educational attainment is associated with cognitive function decline in older age. Childhood book availability may help to preserve cognitive function in older adults with low education. The study objective was to examine the association between childhood book availability and cognitive function among older adults with low educational attainment, and to investigate the mediating effect of the volume of reading-related brain regions (e.g. superior temporal cortex). Methods A cross-sectional study of community-dwelling older Japanese adults aged 65–84 years was conducted (n  = 474). Cognitive function was assessed using the Mini-Mental State Examination (MMSE). Childhood book availability was assessed using a retrospective questionnaire. Brain region volume was measured using magnetic resonance imaging. Multivariate regression modeling and structural equation modeling were used for analysis. Results Both high educational attainment and childhood book availability were independently associated with high MMSE score. Stratification of educational level showed that childhood book availability was positively associated with MMSE score among participants with low educational attainment (coefficient = 1.48, 95% confidence interval [CI]: 0.31 to 2.66), but not among those with moderate or high educational attainment (coefficient = −0.01, 95% CI: −1.44 to 1.42 and −1.21, 95% CI: −3.85 to 1.42, respectively). Among participants with low educational attainment, left superior temporal cortex volume mediated the association between childhood book availability and MMSE score. Discussion The availability of books in childhood helps to preserve cognitive function in older adults with low education via left superior temporal cortex volume. Further research is needed to replicate these findings. [ABSTRACT FROM AUTHOR]

Background: The noradrenergic systems in the brain maintain cognitive functions including attention/concentration and establishment of long‐term memory. In addition, hypofunction of noradrenergic systems is supposed to be involved in the pathophysiology of Alzheimer's disease. In this study, we tried to examine the possible associations of concentrations of basal salivary 3‐methoxy‐4‐hydroxyphenylglycol (sMHPG), a major metabolite of noradrenaline, and brain volume changes during 4 years in elderly people living in a rural community. Methods: The survey was conducted twice in Kurokawa‐cho, Imari, Saga Prefecture, Japan, among people aged 65 years and older. We collected data from 226 residents. Measurements of sMHPG and brain MRIs were collected at Time 1 (2005–2007). Follow‐up brain MRIs were taken at Time 2 (2009–2011). A total of 70 participants (18 men, mean age 71.9 ± 4.8 years; 52 women, mean age 72.0 ± 4.3 years) completed this survey. Concentrations of sMHPG at baseline were divided into two groups using the mean value (12.83 ng/ml). We compared the brain volumes between groups with higher and lower sMHPG concentrations over time using voxel‐based morphometry implemented with statistical parametric mapping. Results: In participants with higher sMHPG concentrations at baseline, brain volumes including right precuneus were significantly larger 4 years after baseline than those with lower sMHPG concentrations at baseline. No interaction between sMHPG concentration and MRI acquisition interval was found. Conclusion: Our results suggest that higher sMHPG concentrations in elderly people might be associated with maintenance of brain volume, especially in brain regions closely related to cognitive function. [ABSTRACT FROM AUTHOR]

The detrimental effects of high-level mercury exposure on the central nervous system as well as effects of low-level exposure during early development have been established. However, no previous studies have investigated the effects of mercury level on brain morphometry using advance imaging techniques in young adults. Here, utilizing hair analysis which has been advocated as a method for biological monitoring, data of regional gray matter volume (rGMV), regional white matter volume (rWMV), fractional anisotropy (FA) and mean diffusivity (MD), cognitive functions, and depression among 920 healthy young adults in Japan, we showed that greater hair mercury levels were weakly but significantly associated with diminished cognitive performance, particularly on tasks requiring rapid processing (speed measures), lower depressive tendency, lower rGMV in areas of the thalamus and hippocampus, lower rWMV in widespread areas, greater FA in bilaterally distributed white matter areas overlapping with areas of significant rWMV reductions and lower MD of the widely distributed gray and white matter areas particularly in the bilateral frontal lobe and the right basal ganglia. These results suggest that even normal mercury exposure levels in Japan are weakly associated with differences of brain structures and lower neurobehavioral performance and altered mood among young adults. An analysis of cognitive and brain structural data from over 900 Japanese participants reveals a relationship between increased hair mercury levels and reduced cognitive performance and reductions in gray and white matter volume. [ABSTRACT FROM AUTHOR]