Research Team for Social Participation and Community Health, Tokyo Metropolitan Institute of Gerontology, Japan.
J Gerontol B Psychol Sci Soc Sci. 2021 Aug 13;76(7):1441-1451. doi: 10.1093/geronb/gbaa226.
This study aimed to assess the relationship between social isolation and cognitive functioning.
Data were retrieved from the National Survey of the Japanese Elderly, a nationally representative sample of Japanese adults, aged 60 years or older. We estimated a social isolation index to incorporate variables, such as social interactions, social engagement, and social support, with perceived social isolation, for a comprehensive measurement. The association of social isolation with cognitive functioning was assessed using a panel data fixed-effects model, controlling for age, socioeconomic status, health-related variables, and time-invariant heterogeneity. Moreover, we conducted analyses using the System Generalized Method of Moments (GMM) to address the dynamic relationship of cognitive functioning and potential endogeneity.
For both men and women, the association between social isolation and cognitive functioning was significant, particularly among those aged 75 or older, as a 1% increase in social isolation was associated with decreased cognitive functioning (24% decrease for men and 20% decrease for women). However, this association was not confirmed by the System GMM, after addressing endogeneity.
Our findings potentially suggest that the association between social relationship and cognitive functioning reported in previous studies was biased, due to endogeneity. Although we did not observe causal impacts, this does not necessarily mean that social isolation does not have a negative impact on health, as both positive and negative consequences of social relationships may exist. Further research is needed to reveal the causal relationship, as well as the detailed mechanisms of health effects of social relationships.
本研究旨在评估社会隔离与认知功能之间的关系。
数据来自日本老年人全国调查，这是一项针对日本 60 岁及以上成年人的全国代表性样本。我们构建了一个社会隔离指数，纳入了社交互动、社交参与和社会支持等变量以及感知到的社会隔离，以进行全面测量。使用面板数据固定效应模型评估社会隔离与认知功能之间的关联，同时控制年龄、社会经济地位、与健康相关的变量和时不变异质性。此外，我们还使用系统广义矩法（GMM）进行分析，以解决认知功能的动态关系和潜在的内生性问题。
对于男性和女性而言，社会隔离与认知功能之间存在显著关联，特别是对于 75 岁及以上的人群，社会隔离增加 1%与认知功能下降相关（男性下降 24%，女性下降 20%）。然而，在解决内生性问题后，系统 GMM 并未证实这种关联。
我们的研究结果表明，之前研究报告的社会关系与认知功能之间的关联可能存在偏倚，这是由于内生性问题所致。尽管我们没有观察到因果影响，但这并不一定意味着社会隔离对健康没有负面影响，因为社会关系可能同时存在积极和消极的后果。需要进一步的研究来揭示因果关系以及社会关系对健康影响的详细机制。
