Ho Rainbow T H, Fong Ted C T, Yau Joshua C Y, Chan Wai Chi, Kwan Joseph S K, Chiu Patrick K C, Lam Linda C W
Centre on Behavioral Health, The University of Hong Kong, Pok Fu Lam, Hong Kong.
Department of Social Work and Social Administration, The University of Hong Kong, Pok Fu Lam, Hong Kong.
Front Aging Neurosci. 2020 Feb 21;12:35. doi: 10.3389/fnagi.2020.00035. eCollection 2020.
Memory deficits are linked to dysfunctional HPA axis activity and negative affect in older adults. This study evaluated the mediating effect of the diurnal cortisol pattern on the relationship between affect and memory in older people with mild cognitive impairment (MCI).
This longitudinal study recruited 189 Chinese older adults with MCI from elderly centers in Hong Kong. The participants completed assessments of affect, salivary cortisol, and digit spans at baseline; neurocognitive assessments on verbal fluency, memory retrieval, and digit spans at 6-month follow-up; and instrumental activities of daily living (IADL) at 1-year follow-up. Structural equation modeling examined the direct and indirect effects of negative affect on memory and IADL via diurnal cortisol pattern.
Controlling for covariates, negative affect significantly predicted flattened diurnal cortisol slopes (β = 0.17, < 0.05) but not memory or IADL ( = 0.23 - 0.91) directly. Diurnal cortisol slopes negatively predicted memory retrieval (β = -0.20, < 0.05), which in turn positively predicted IADL (β = 0.22, < 0.01). The indirect effect from negative affect to IADL via cortisol slope and memory retrieval was significant and negative (αβγ = -0.05, 95% bootstrapped CI = -0.248 to -0.001).
The present study established certain temporal linkages among affect and cortisol slopes at baseline, memory retrieval at 6 months, and functional decline 1 year later in older adults with MCI. Flattened diurnal cortisol slopes might mediate the detrimental effects of negative affect on memory retrieval and functioning across 1 year.
记忆缺陷与老年人下丘脑-垂体-肾上腺（HPA）轴功能失调及消极情绪有关。本研究评估了昼夜皮质醇模式在轻度认知障碍（MCI）老年人的情绪与记忆关系中的中介作用。
这项纵向研究从香港的老年中心招募了189名患有MCI的中国老年人。参与者在基线时完成了情绪、唾液皮质醇和数字广度的评估；在6个月随访时进行了言语流畅性、记忆提取和数字广度的神经认知评估；在1年随访时进行了日常生活活动能力（IADL）评估。结构方程模型研究了消极情绪通过昼夜皮质醇模式对记忆和IADL的直接和间接影响。
在控制协变量后，消极情绪显著预测了昼夜皮质醇斜率变平（β = 0.17，P < 0.05），但未直接预测记忆或IADL（P = 0.23 - 0.91）。昼夜皮质醇斜率负向预测记忆提取（β = -0.20，P < 0.05），而记忆提取又正向预测IADL（β = 0.22，P < 0.01）。消极情绪通过皮质醇斜率和记忆提取对IADL的间接效应显著且为负（αβγ = -0.05，95% 自抽样置信区间 = -0.248至-0.001）。
本研究在患有MCI的老年人中建立了基线时的情绪与皮质醇斜率、6个月时的记忆提取以及1年后的功能衰退之间的特定时间联系。昼夜皮质醇斜率变平可能介导了消极情绪对1年内记忆提取和功能的有害影响。
