de Jong Frank Jan, den Heijer Tom, Visser Theo J, de Rijke Yolanda B, Drexhage Hemmo A, Hofman Albert, Breteler Monique M B
Department of Epidemiology and Biostatistics, Erasmus Medical Center, 3000 DR Rotterdam, The Netherlands.
J Clin Endocrinol Metab. 2006 Jul;91(7):2569-73. doi: 10.1210/jc.2006-0449. Epub 2006 Apr 24.
Thyroid function has been related to Alzheimer disease (AD), but it remains unclear whether thyroid dysfunction results from or contributes to developing AD.
The objective of the study was to determine the association between thyroid function and both medial temporal lobe atrophy on brain magnetic resonance imaging (MRI) as putative early sign of AD and risk of dementia.
This was a population-based cohort study among 1077 elderly subjects aged 60-90 yr and dementia free at baseline (1995-1996).
Nonfasting serum levels of TSH, free T(4) (fT(4)), T(3), and rT(3) were available in 1025 subjects followed up for incident dementia until 2005. In a subset of 489 nondemented elderly, we assessed volumes of the hippocampus and amygdala on brain MRI. Subjects using thyroid medication were excluded.
During 5657 person-years of follow-up (mean 5.5 yr), 63 subjects were diagnosed with dementia (46 with AD). TSH and thyroid hormones were not associated with risk of dementia or AD. TSH and T(3) were also not related to brain atrophy, whereas nondemented subjects with higher fT(4) levels had more hippocampal and amygdalar atrophy on MRI. Similar associations were found for rT(3). Excluding subjects with thyroid disorders or incipient AD did not change the results.
In our study, TSH was related neither to risk of AD nor with early MRI markers thereof, arguing against an important role of thyroid function in the development of AD. Whether the association of higher fT(4) and rT(3) levels with brain atrophy on MRI has functional significance remains to be elucidated.
甲状腺功能与阿尔茨海默病（AD）相关，但甲状腺功能障碍是由AD导致还是促成AD的发生仍不清楚。
本研究的目的是确定甲状腺功能与脑磁共振成像（MRI）显示的内侧颞叶萎缩（作为AD的假定早期征象）以及痴呆风险之间的关联。
这是一项基于人群的队列研究，研究对象为1077名年龄在60 - 90岁之间且在基线时（1995 - 1996年）无痴呆的老年人。
1025名随访至2005年以观察痴呆发病情况的受试者提供了非空腹血清促甲状腺激素（TSH）、游离甲状腺素（fT4）、三碘甲状腺原氨酸（T3）和反三碘甲状腺原氨酸（rT3）水平。在489名非痴呆老年人的亚组中，我们通过脑MRI评估了海马体和杏仁核的体积。使用甲状腺药物的受试者被排除。
在5657人年的随访期间（平均5.5年），63名受试者被诊断为痴呆（46名患有AD）。TSH和甲状腺激素与痴呆或AD的风险无关。TSH和T3也与脑萎缩无关，而fT4水平较高的非痴呆受试者在MRI上有更多的海马体和杏仁核萎缩。rT3也有类似的关联。排除患有甲状腺疾病或早期AD的受试者后结果未改变。
在我们的研究中，TSH与AD风险及其早期MRI标志物均无关，这表明甲状腺功能在AD发生过程中不起重要作用。较高的fT4和rT3水平与MRI上脑萎缩的关联是否具有功能意义仍有待阐明。
