Background the course of depression is variable, but it is unknown how this variability over time affects long-term cognitive decline. Objective to examine the relationship of different trajectories of depressive symptoms on rates of subsequent cognitive decline in older adults. Design population-based cohort study. Setting communities in the USA and England. Subjects 17,556 older adults from the Health and Retirement Study and the English Longitudinal Study of Ageing. Methods depressive symptoms were assessed using the Center for Epidemiologic Studies Depression Scale, and trajectories were calculated using group-based trajectory modelling. Global cognitive function and three cognitive domains of memory, executive function and temporal orientation were assessed for up to 18 years. Results five trajectories of depressive symptoms were identified. Compared with the ‘non-depressed’ trajectory, the ‘worsening depressive symptoms’ trajectory (pooled β = −0.016 standard deviation (SD)/year, 95% confidence interval (CI): −0.021 to −0.010), ‘persistent depressive symptoms’ trajectory (pooled β = −0.016 SD/year, 95% CI: −0.024 to −0.008), and ‘mild depressive symptoms’ trajectory (pooled β = −0.008 SD/year, 95% CI: −0.014 to −0.003) were associated with faster rates of cognitive decline, while no such association was found for the ‘improving depressive symptoms’ trajectory (pooled β = 0.001 SD/year, 95% CI: −0.010 to 0.012). Conclusions subthreshold depressive symptoms are associated with an increased rate of cognitive decline, while individuals who show improving depressive symptoms do not exhibit accelerated cognitive decline. These findings raise the possibility that maintaining depressive symptoms as low as possible and ignoring the clinical threshold, might mitigate cognitive decline in older adults.

中文翻译：

---

老年人抑郁症状和随后认知能力下降的轨迹：两个纵向队列的汇总分析

背景 抑郁症的病程是可变的，但尚不清楚这种随时间的变化如何影响长期的认知能力下降。目的检查抑郁症状的不同轨迹与老年人随后的认知能力下降率之间的关系。设计基于人群的队列研究。在美国和英国设置社区。受试者来自健康与退休研究和英国老龄化纵向研究的 17,556 名老年人。方法 使用流行病学研究中心抑郁量表评估抑郁症状，并使用基于组的轨迹建模计算轨迹。对全球认知功能和记忆、执行功能和时间方向的三个认知领域进行了长达 18 年的评估。结果 确定了抑郁症状的五种轨迹。与“非抑郁”轨迹相比，“抑郁症状恶化”轨迹（合并 β = -0.016 标准差 (SD)/年，95% 置信区间 (CI)：-0.021 至 -0.010），“持续性抑郁症状'轨迹（合并 β = -0.016 SD/年，95% CI：-0.024 至 -0.008）和“轻度抑郁症状”轨迹（合并 β = -0.008 SD/年，95% CI：-0.014 至 -0.003）与更快的认知衰退率相关，而“改善抑郁症状”轨迹没有发现这种关联（合并 β = 0.001 SD/年，95% CI：-0.010 至 0.012）。结论 阈下抑郁症状与认知衰退率增加有关，而抑郁症状改善的个体并未表现出认知衰退加速。