ABSTRACT

Depression and social isolation increase risk for executive function declines and are among the top five modifiable risk factors for dementia. However, the interrelationships between depression, social isolation and executive function are not well established. Further evidence is needed to inform strategies to promote executive function and independence in older age. We examined whether social isolation mediated the association between depression and executive function in community-dwelling middle-aged and older adults and whether this association was modified by age and sex. Adults aged 45 to 85 years from the Canadian Longitudinal Study on Aging (CLSA) Comprehensive cohort were followed over three years (complete case analysis, n = 14,133). Baseline depressive symptoms, a history of clinical depression, and functional social isolation (perceived lack of social support) were self-reported. Executive function at follow-up was a composite measure of five cognitive tests. Conditional process analysis assessed the mediating effects of functional social isolation across age group and sex, adjusted for sociodemographic and health covariates. Functional social isolation significantly mediated the association of depressive symptoms (proportion mediated [P_M] = 8.0%) or clinical depression (P_M = 17.5%) with executive function only among women aged 75+ years. Functional social isolation explains a proportion of the total effect of depressive symptoms or clinical depression on executive function in women aged 75 and older. Although reverse causation cannot be ruled out, our findings suggest that interventions that reduce functional social isolation or depression in older women may promote executive function.

摘要

抑郁和社会孤立会增加执行功能下降的风险，并且是痴呆症的前五个可改变的风险因素之一。然而，抑郁、社会孤立和执行功能之间的相互关系尚未明确。需要进一步的证据来制定促进老年执行功能和独立性的策略。我们研究了社会隔离是否介导了社区中老年人抑郁与执行功能之间的关联，以及这种关联是否会因年龄和性别而改变。对加拿大老龄化纵向研究 (CLSA) 综合队列中 45 至 85 岁的成年人进行了三年多的随访（完整的病例分析，n = 14,133）。自我报告基线抑郁症状、临床抑郁病史和功能性社会隔离（感知缺乏社会支持）。随访时的执行功能是五项认知测试的综合衡量标准。条件过程分析评估了跨年龄组和性别的功能性社会隔离的中介效应，并根据社会人口统计和健康协变量进行了调整。_{功能性社会隔离显着介导抑郁症状（介导的}比例[ PM ] = 8.0%）或临床抑郁症（PM = 17.5%）仅在 75 岁以上的女性中具有执行功能。功能性社会隔离解释了抑郁症状或临床抑郁症对 75 岁及以上女性执行功能的总体影响的一部分。尽管不能排除反向因果关系，但我们的研究结果表明，减少老年女性功能性社会孤立或抑郁的干预措施可能会促进执行功能。