Regional Brain Volumes Moderate, but Do Not Mediate, the Effects of Group-Based Exercise Training on Reductions in Loneliness in Older Adults.
Regional Brain Volumes Moderate, but Do Not Mediate, the Effects of Group-Based Exercise Training on Reductions in Loneliness in Older Adults.
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DOI：
10.3389/fnagi.2017.00110
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发表时间：
2017
影响因子：
4.8
通讯作者：
McAuley E
中科院分区：
文献类型：
--
作者：
Ehlers DK;Daugherty AM;Burzynska AZ;Fanning J;Awick EA;Chaddock-Heyman L;Kramer AF;McAuley E
引言：尽管老年人感知到的孤独普遍存在且对健康有负面影响，但很少有研究考察行为、心理社会和神经机制之间的相互作用。研究表明，身体活动以及感知到的社会支持的改善和压力的减轻与孤独感的降低有关。然而，大脑结构对这些变化的影响尚不清楚。本研究考察了在运动干预后，局部脑容量的变化是否介导了社会支持和压力的变化对感知孤独变化的影响。我们还考察了基线脑容量在多大程度上调节了社会支持、压力和孤独变化之间的关系。
方法：参与者为247名老年人（年龄65.4 ± 4.6岁），他们参加了一项为期6个月的随机对照试验，该试验包括四种运动条件：舞蹈（n = 69）、力量/拉伸/稳定性（n = 70）、步行（n = 54）和步行加强版（n = 54）。所有小组每周会面3次，每次1小时。参与者在基线和干预后完成了评估感知社会支持、压力和孤独的问卷调查。干预前后的局部脑容量（杏仁核、前额叶皮质[PFC]、海马体）通过对每位参与者的T1加权结构磁共振成像进行自动分割来测量。数据在潜在模型框架中进行分析。
结果：在干预过程中，感知到的社会支持增加（p = 0.003），而压力（p < 0.001）和孤独（p = 0.001）降低。社会支持的增加直接（-0.63，p < 0.01）以及通过压力的降低间接（-0.10，p = 0.02）预测了孤独感的降低。杏仁核、PFC和海马体体积的变化与心理社会变量的变化无关（所有p ≥ 0.44）。然而，基线杏仁核较大的个体由于压力降低幅度更大，孤独感降低幅度也更大（0.35，p = 0.02）。此外，基线PFC体积较大的个体由于社会支持增加幅度更大，压力降低幅度也更大（-0.47，p = 0.02）。在这些途径中未观察到组间差异。
结论：社会支持环境以及由此导致的压力降低，而非运动模式，可能是改善老年人感知孤独的运动项目的重要特征。由于杏仁核体积与焦虑、抑郁以及PFC中的认知控制过程受损有关，调节作用的研究结果表明有必要在该领域进行进一步调查。
试验注册：ClinicalTrials.gov标识符NCT01472744（https://clinicaltrials.gov/ct2/show/NCT01472744?term=NCT01472744&rank=1）
Introduction: Despite the prevalence of and negative health consequences associated with perceived loneliness in older adults, few studies have examined interactions among behavioral, psychosocial, and neural mechanisms. Research suggests that physical activity and improvements in perceived social support and stress are related to reductions in loneliness. Yet, the influence of brain structure on these changes is unknown. The present study examined whether change in regional brain volume mediated the effects of changes in social support and stress on change in perceived loneliness after an exercise intervention. We also examined the extent to which baseline brain volumes moderated the relationship between changes in social support, stress, and loneliness. Methods: Participants were 247 older adults (65.4 ± 4.6 years-old) enrolled in a 6-month randomized controlled trial comprised of four exercise conditions: Dance (n = 69), Strength/Stretching/Stability (n = 70), Walk (n = 54), and Walk Plus (n = 54). All groups met for 1 h, three times weekly. Participants completed questionnaires assessing perceived social support, stress, and loneliness at baseline and post-intervention. Regional brain volumes (amygdala, prefrontal cortex [PFC], hippocampus) before and after intervention were measured with automatic segmentation of each participant's T1-weighted structural MRI. Data were analyzed in a latent modeling framework. Results: Perceived social support increased (p = 0.003), while stress (p < 0.001), and loneliness (p = 0.001) decreased over the intervention. Increased social support directly (−0.63, p < 0.01) and indirectly, through decreased stress (−0.10, p = 0.02), predicted decreased loneliness. Changes in amygdala, PFC, and hippocampus volumes were unrelated to change in psychosocial variables (all p ≥ 0.44). However, individuals with larger baseline amygdalae experienced greater decreases in loneliness due to greater reductions in stress (0.35, p = 0.02). Further, individuals with larger baseline PFC volumes experienced greater reductions in stress due to greater increases in social support (−0.47, p = 0.02). No group differences in these pathways were observed. Conclusions: The social support environment and resulting reductions in stress, as opposed to exercise mode, may represent important features of exercise programs for improving older adults' perceived loneliness. As amygdala volume has been linked to anxiety, depression and impaired cognitive control processes in the PFC, moderation findings suggest further investigation in this area is warranted. Trial Registration: ClinicalTrials.gov identifier NCT01472744 (https://clinicaltrials.gov/ct2/show/NCT01472744?term=NCT01472744&rank=1).