Petersen Inge, McGue Matt, Tan Qihua, Christensen Kaare, Christiansen Lene
The Danish Twin Registry,Unit of Epidemiology,Biostatistics and Biodemography,Institute of Public Health,University of Southern Denmark,Odense,Denmark.
Twin Res Hum Genet. 2016 Apr;19(2):104-11. doi: 10.1017/thg.2016.3. Epub 2016 Feb 16.
A complex interrelation exists between change in depression symptomatology and cognitive decline. Studies indicate either that depression is a direct risk factor for cognitive change over time, or vice versa. Longitudinal twin studies provide the possibility to unravel cause and effect of correlated traits. Here, we have applied twin modeling approaches to shed light on the genetic correlation between both level and change of depression symptomatology and cognitive functioning, and to further explore the bidirectionality of any such correlation using assessments of both phenotypes at two occasions 10 years apart. The study included 2,866 Danish twins with a mean age of 56.8 years at intake (range: 45-68 years). Of these, 1,267 were intact pairs. A total number of 1,582 twins (55%), of whom 557 were intact pairs, participated in the follow-up survey. We found stable cross-sectional heritability estimates of approximately 60% for general cognitive abilities and 30% for affective depressive symptoms. There was a considerable decline in the mean cognitive performance over 10 years, whereas the mean affective depression symptoms score was stable and with no genetic contribution to any individual change. Additionally, we saw a small but significant cross-trait correlation at both occasions (-0.11 and -0.09, respectively), but cross-trait cross-occasion analysis revealed no evidence that either of the two traits predicts the other over a 10-year interval. Thus, our study was not able to detect any causal association between change in depressive symptomatology and cognitive decline in middle-aged and elderly people over a 10-year interval.
抑郁症状变化与认知衰退之间存在复杂的相互关系。研究表明，抑郁要么是认知随时间变化的直接风险因素，反之亦然。纵向双胞胎研究为揭示相关性状的因果关系提供了可能。在此，我们应用双胞胎建模方法来阐明抑郁症状水平及变化与认知功能之间的遗传相关性，并通过对相隔10年的两个时间点的两种表型进行评估，进一步探究这种相关性的双向性。该研究纳入了2866名丹麦双胞胎，入组时的平均年龄为56.8岁（范围：45 - 68岁）。其中，1267对为完整双胞胎对。共有1582名双胞胎（55%）参与了随访调查，其中557对为完整双胞胎对。我们发现，一般认知能力的稳定横断面遗传度估计约为60%，情感性抑郁症状的遗传度估计约为30%。在10年期间，平均认知表现有相当程度的下降，而平均情感性抑郁症状评分保持稳定，且个体变化无遗传因素影响。此外，在两个时间点我们均观察到了较小但显著的跨性状相关性（分别为 -0.11和 -0.09），但跨性状跨时间点分析未发现证据表明这两种性状中的任何一种在10年间隔内可预测另一种性状。因此，我们的研究未能检测到中年及老年人在10年间隔内抑郁症状变化与认知衰退之间存在任何因果关联。
