Del Pozo Cruz Borja, Perales Francisco, Alfonso-Rosa Rosa M, Del Pozo-Cruz Jesus
Centre for Active and Healthy Ageing, Department of Sports Science and Clinical Biomechanics, University of Southern Denmark, Odense,Denmark.
Epidemiology of Physical Activity and Fitness Across the Lifespan (EPAFit) Research Group, Faculty of Education, University of Seville, Spain.
J Gerontol A Biol Sci Med Sci. 2021 Oct 13;76(11):1977-1980. doi: 10.1093/gerona/glab110.
Previous studies examining unidirectional relationships between social isolation and physical functioning among older adults may be biased due to reverse causality. This study leveraged data from a US national sample of older adults and a novel estimation method to identify bidirectional associations between these 2 phenomena and their associated temporal dynamics.
The analyses were based on 9 waves of panel data from a sample of adults aged 65 and older from the US National Health and Aging Trends Study (n = 12 427 individuals) and a cross-lagged panel model. Social isolation was measured using the Social Isolation Index (SII) and physical functioning through the Short Physical Performance Battery (SPPB).
One SD increase in the SPPB was associated with a -0.013 SD decrease (95% confidence interval [CI]: -0.023 to -0.004) in the SII a year later, whereas 1 SD increase in the SII was associated with a larger -0.058 SD decrease (95% CI: -0.069 to -0.046) in the SPPB a year later. The SII→SPPB effect lasted for approximately 5 years, whereas the SPPB→SII lasted for approximately 3 years.
This study confirmed the existence of statistically significant bidirectional associations between social isolation and physical functioning among older adults in the United States, net of reverse causation. Because the effect of social isolation dominates, the findings indicate that public health strategies to promote successful aging should prioritize interventions that enrich older adults' social networks. Furthermore, the effect time horizons yielded by the model point to the optimal timing for the re-delivery of interventions.
以往关于老年人社会隔离与身体机能之间单向关系的研究可能因反向因果关系而存在偏差。本研究利用来自美国老年人全国样本的数据和一种新颖的估计方法，以确定这两种现象之间的双向关联及其相关的时间动态。
分析基于美国国家健康与老龄化趋势研究中65岁及以上成年人样本的9轮面板数据（n = 12427人）以及交叉滞后面板模型。使用社会隔离指数（SII）测量社会隔离，通过简短身体机能测试电池（SPPB）测量身体机能。
SPPB增加1个标准差与一年后SII降低0.013个标准差相关（95%置信区间[CI]：-0.023至-0.004），而SII增加1个标准差与一年后SPPB更大幅度降低0.058个标准差相关（95%CI：-0.069至-0.046）。SII→SPPB效应持续约5年，而SPPB→SII效应持续约3年。
本研究证实了在美国老年人中，排除反向因果关系后，社会隔离与身体机能之间存在具有统计学意义的双向关联。由于社会隔离的影响占主导，研究结果表明，促进成功老龄化的公共卫生策略应优先考虑丰富老年人社交网络的干预措施。此外，模型得出的效应时间范围指出了再次实施干预措施的最佳时机。
