Supplementary Material for: Which Social Network or Support Factors are Associated with Cognitive Abilities in Old Age?

<b><i>Background:</i></b> Social networks and support have been proposed as cognitively protective in old age. As studies often consider these social factors in isolation the question of which characteristics of the social environment are beneficial remains. <b><i>Objective:</i></b> The current study examined associations between measures of social networks (including contact with friends/family, marital status and living arrangement), feelings of loneliness and social support, and a range of cognitive outcomes. <b><i>Methods:</i></b> Social network, loneliness and support data were available in the Lothian Birth Cohort 1936 (LBC1936, n = 1,091) at age 70. Participants completed a battery of cognitive tests, and factor scores were available for general cognitive ability, and the cognitive domains of processing speed and memory. Childhood cognitive ability data from age 11 were also available. <b><i>Results:</i></b> When examined in separate ANCOVAs, lower loneliness and more social support were significantly associated with better cognitive abilities at age 70, though not memory (independently of age, sex, childhood cognitive ability and social class), accounting for about 0.5-1.5% of the variance. When the social factors were considered simultaneously, higher loneliness remained associated with lower general cognitive ability (η_p² = 0.005, p = 0.046), and those living alone (η_p² = 0.007, p = 0.014) or with less social support (η_p² = 0.007, p = 0.016) had slower processing speed. When these final models were repeated including a depression symptoms score as a covariate, the associations between loneliness and general cognitive ability, and social support and processing speed, were no longer significant. However, the association between living alone and processing speed remained (η_p² = 0.006, p = 0.031). <b><i>Conclusions:</i></b> Of the social factors considered, loneliness, social support and living arrangement were most consistently associated with aspects of cognitive ability in older people, and these associations appeared to be partly, though not wholly, accounted for by symptoms of depression. Although longitudinal follow-up is required to examine the causal direction of the effects more definitively, it may be beneficial to promote the development of interventions to reduce loneliness and social isolation, and to increase social support.

<b><i>背景：</i></b> 既往研究提出，社交网络与社会支持对老年群体具有认知保护作用。由于现有研究多孤立地考量此类社会因素，社交环境的哪些特征能够发挥认知益处这一问题仍有待明确。
<b><i>研究目的：</i></b> 本研究旨在探讨社交网络指标（包括与亲友的接触频率、婚姻状况及居住安排）、孤独感与社会支持，与一系列认知结局之间的关联。
<b><i>研究方法：</i></b> 1936年洛锡安出生队列（Lothian Birth Cohort 1936, LBC1936, n=1091）的70岁研究对象提供了社交网络、孤独感及社会支持相关数据。所有参与者完成了一套认知测试，研究者可获取一般认知能力、加工速度与记忆等认知领域的因子得分；同时还收集了参与者11岁时的儿童期认知能力数据。
<b><i>研究结果：</i></b> 单独开展协方差分析（ANCOVA）时，较低的孤独感水平与更高的社会支持，均与70岁时更佳的认知能力显著相关，但与记忆能力无关（校正年龄、性别、儿童期认知能力及社会阶层等混杂因素），此类关联可解释约0.5%~1.5%的变异量。当同时纳入所有社会因素进行分析时，更高的孤独感仍与较低的一般认知能力显著相关（偏η²=0.005, p=0.046）；独居者（偏η²=0.007, p=0.014）或社会支持水平较低者（偏η²=0.007, p=0.016）的加工速度更慢。在后续重复上述最终模型并加入抑郁症状得分作为协变量后，孤独感与一般认知能力、社会支持与加工速度之间的关联不再显著，但独居与加工速度较慢之间的关联仍保持显著（偏η²=0.006, p=0.031）。
<b><i>研究结论：</i></b> 在本次研究纳入的社会因素中，孤独感、社会支持及居住安排与老年人群的认知能力维度关联最为一致；此类关联部分（但非全部）可由抑郁症状来解释。尽管需开展纵向追踪研究以更明确地验证效应的因果方向，但推广旨在降低孤独感与社会隔离、提升社会支持的干预措施或具有积极意义。