IC-P-191: The relationship between insulin resistance and white matter integrity in middle-aged and older adults

Tai Chi Chuan (TCC) exercise has been shown to improve cognitive task-switching performance in older adults, but the extent of this positive effect varies among individuals. Past research also shows that brain white matter integrity could predict behavioral gains of cognitive and motor learning. Therefore, in this randomized controlled trial (NCT02270320), we examined whether baseline integrity of three target white matter tract groups was predictive of task-switching improvement after 12-week TCC training in middle-aged and older adults. Thirty-eight eligible participants were randomly assigned to a TCC group (n = 19) and a control group (n = 19). Cognitive task-switching and physical performances were collected before and after training. Brain diffusion spectrum MR images were acquired before training and the general fractional anisotropy (GFA) of each target white matter tract group was calculated to indicate baseline white matter integrity of that group. Correlation and regression analyses between these GFAs and post-training task-switching improvement were analyzed using adjusted p-values. After 12 weeks, significant task-switching and physical performance improvements were found only in the TCC group. Moreover, higher baseline GFA of the prefronto-striato-thalamo-prefrontal loop fibers (r = −0.63, p = 0.009), but not of the prefronto-parietal/occipital (r = −0.55, p = 0.026) and callosal (r = −0.35, p = 0.189) fiber groups, was associated with greater reductions of task-switching errors after the TCC training. Multiple regression analysis revealed that baseline GFA of the prefronto-striato-thalamo-prefrontal loop fibers was the only independent white matter integrity predictor of task-switching error reductions after TCC training (β = −0.620, adjusted R2 change = 0.265, p = 0.009). These findings not only highlight the important role of baseline integrity of the prefronto-striatal circuits in influencing the extent of positive cognitive task-switching effects from short-term TCC training, but also implicate that preserving good white matter integrity in the aging process may be crucial in order to gain the best cognitive effects of exercise interventions.

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Effect of older adults in the family on the sandwich generation's pursuit of entrepreneurship: evidence from China

Ageing and Society ◽

10.1017/s0144686x21001033 ◽

2021 ◽

pp. 1-20

Author(s):

Yiwei Liu ◽

Wenjing Wang ◽

Zhen Cong ◽

Zhirui Chen

Keyword(s):

Older Adults ◽

Family Members ◽

Mediating Effect ◽

Entrepreneurial Activity ◽

Basic Unit ◽

Instrumental Support ◽

Middle Aged ◽

Social Wellbeing ◽

The Relationship ◽

Elderly Family

Abstract Household entrepreneurship is a basic unit of entrepreneurial activity, and a crucial aspect of connecting personal and social wellbeing. This study examines the relationship between the proportion of elderly family members and household entrepreneurship. This study also assesses the mediating effect of the middle-aged generation's support to their parents and the moderating effect of the parents’ support with respect to the proportion of elderly family members and entrepreneurship. We use data from the China Family Panel Studies. We adopt the instrumental variable method to deal with endogeneity, robustness and credibility of the estimation results. The results show that a higher proportion of elderly family members impedes household entrepreneurship. Moreover, the financial and instrumental support provided by the middle-aged generation to their parents significantly mediates the relationship between the proportion of elderly family members and household entrepreneurship. In turn, parents’ financial support to the middle-aged generation moderates the focal relationship; however, parents’ instrumental support does not moderate the focal relationship. These findings emphasise the need to develop a comprehensive social security network for older adults that will indirectly promote household entrepreneurship, and improve personal and social wellbeing.

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Prediction of white matter integrity pattern in overweight and obese adults

Proceedings of The Nutrition Society ◽

10.1017/s0029665120001378 ◽

2020 ◽

Vol 79 (OCE2) ◽

Author(s):

Sussanne Reyes ◽

Patricio Peirano ◽

Betsy Lozoff ◽

Cecilia Algarin

Keyword(s):

White Matter ◽

Cognitive Flexibility ◽

Diffusion Tensor ◽

Brain Regions ◽

Normal Weight ◽

White Matter Integrity ◽

School Age ◽

Loss Avoidance ◽

Neurocognitive Tasks ◽

The Relationship

Abstract IntroductionObesity has been associated with lower white matter integrity (WMI) in limbic brain regions, including the fornix. Both early decrease of WMI in the fornix (WMIf) and midlife obesity have been related to dementia incidence with advancing age. No studies have explored early cognitive predictors of WMIf in overweight-obese (OO) adults. Aim of this study was to compare OO and normal-weight (NW) participants with respect to (a) WMIf in adulthood and (b) the relationship between cognitive performance at school-age and in adolescence with WMIf in adulthood.MethodsParticipants were part of a cohort followed since infancy who underwent magnetic resonance imaging studies in adulthood (22.3 ± 1.3 years). Diffusion tensor imaging was performed and Tract Based Spatial Statistics (TBSS) was used to obtain fractional anisotropy (FA) skeleton; increased FA relates to greater WMI. A mask for the fornix was created (JHU-ICBM DTI-81 Atlas) and then used to extract the average FA for each individual. Participants also performed neurocognitive tasks: (a) school-age (10.3 ± 1.0 years): the trail making test comprises two conditions and time difference between conditions reflects cognitive flexibility; (b) adolescence (15.6 ± 0.5 years): incentive task that test the effect of incentives (reward, loss avoidance or neutral) on inhibitory control performance (correct responses latency). In adulthood, BMI was categorized as NW (≥ 18.5 to < 25.0 kg/m2) and OO (≥ 25.0 kg/m2) groups. A t-test and univariate GLM were conducted. Analysis were adjusted by sex and age-specific BMI z-scores.ResultsParticipants were 27 NW (41% female) and 41 OO (49% female). Compared to NW, OO participants showed decreased FA in the fornix (0.585 vs. 0.618, p < 0.05), i.e. lower WMIf. Differences were apparent in the relationship between cognitive flexibility at school-age (F = 2.9, p = 0.06) and loss avoidance latency in adolescence (F = 3.5, p < 0.05) with FA in the fornix in adulthood. Increased cognitive flexibility at school-age (β = 0.335, p < 0.05) and decreased loss avoidance latency in adolescence (β = -0.581, p < 0.001) were related to higher FA in the fornix in OO adults. No relationship resulted significant in NW adults.DiscussionPerformance in neurocognitive tasks at earlier developmental stages were related with WMIf only in OO adults, group characterized by decreased WMIf. Our results provide evidence regarding specific neurocognitive tasks with predictive value for WMIf alterations. Further, they could contribute to the understanding of neural mechanisms underlying obesity and also provide insight relative to neurodegenerative risk with advancing age.SupportFondecyt 11160671 and NIH HD33487.

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