Center for Clinical Research and Prevention, Bispebjerg and Frederiksberg Hospital, Frederiksberg, Denmark.
Department of Epidemiology, Biostatistics, and Biodemography, Institute of Public Health, University of Southern Denmark, Odense, Denmark.
Acta Psychiatr Scand. 2020 Dec;142(6):446-455. doi: 10.1111/acps.13238. Epub 2020 Oct 19.
Familial and genetic factors seem to contribute to the development of depression but whether this varies with age at diagnosis remains unclear. We examined the influence of familial factors on the risk of depression by age at first diagnosis.
We included 23 498 monozygotic and 39 540 same-sex dizygotic twins from the population-based Danish Twin Registry, followed from 1977 through 2011 in nationwide registers. We used time-to-event analyses accounting for censoring and competing risk of death to estimate cumulative incidence, casewise concordance, relative recurrence risk, and heritability of first depression by age using monozygotic and same-sex dizygotic twin pairs.
During follow-up, a total of 1545 twins were diagnosed with depression. For twins at age 35 or younger at first depression, heritability was estimated to be 24.8% (95% confidence interval [CI], 4.6-43.1%), whereas at age 90 it was 14.7% (95% CI, 3.1-26.3%). The relative recurrence risk was higher at younger ages: At age 35, the risk was 27.7-fold (95% CI, 20.0-35.5) and 6.9-fold (95% CI, 3.9-9.8) higher than the population risk for monozygotic and same-sex dizygotic twins, respectively, while the corresponding numbers were 3.0 (95% CI, 2.3-3.6) and 1.8 (95% CI, 1.3-2.2) at age 90. Heritability seemed similar for male and female twins.
Familial risk of depression, caused either by genes or shared environment, seemed to slightly decrease with age at diagnosis and an elevated concordance risk for monozygotic over same-sex dizygotic pairs suggested a genetic contribution to the development of depression.
家族和遗传因素似乎与抑郁症的发生有关，但这种关联是否因诊断时的年龄而异尚不清楚。我们通过首次诊断时的年龄来研究家族因素对抑郁症风险的影响。
我们纳入了来自丹麦双胞胎登记处的 23498 对同卵双胞胎和 39540 对同性别异卵双胞胎，这些双胞胎从 1977 年开始到 2011 年在全国登记册中进行随访。我们使用考虑删失和死亡竞争风险的生存时间分析来估计首次抑郁症的累积发病率、病例一致性、相对复发风险和遗传度，使用同卵双胞胎和同性别异卵双胞胎对来估计年龄。
在随访期间，共有 1545 对双胞胎被诊断为抑郁症。对于首次抑郁症发生在 35 岁或更年轻的双胞胎，遗传度估计为 24.8%（95%置信区间[CI]，4.6-43.1%），而在 90 岁时为 14.7%（95% CI，3.1-26.3%）。相对复发风险在较年轻时更高：在 35 岁时，风险分别比普通人群的同卵双胞胎和同性别异卵双胞胎高 27.7 倍（95% CI，20.0-35.5）和 6.9 倍（95% CI，3.9-9.8），而在 90 岁时，相应的数字分别为 3.0（95% CI，2.3-3.6）和 1.8（95% CI，1.3-2.2）。遗传度似乎在男性和女性双胞胎中相似。
由基因或共享环境引起的抑郁症家族风险似乎随着诊断时的年龄而略有降低，同卵双胞胎比同性别异卵双胞胎的一致性风险升高提示遗传因素对抑郁症的发生有一定贡献。
