维生素D作为一种免疫调节剂，可能影响自身免疫性甲状腺疾病。既往研究显示维生素D通过减少促甲状腺激素（TSH）刺激的碘摄取和抑制细胞生长直接影响甲状腺细胞。然而，基于人群的维生素D和TSH的关系尚不清楚。

泰国玛希隆大学Ramathibodi医院医学部La-or chailurkit教授等人进行了一项研究，该研究结果发表在2013年1月底23卷《甲状腺》（Thyroid）杂志上。作者发现年轻个体高维生素D状态与血清TSH水平降低相关。

该研究从泰国第四次国家健康调查样本中按地区随机抽取2582例年龄15–98岁的成年人，平均年龄为55.0±0.4岁。按照试验设计，男女均等。所有入选个体均测量血清25（OH）D、TSH、TPOAb、TgAb。

研究结果表明，TgAb阳性个体的血清TSH水平较高，而总体25（OH）D水平较低。此外，无论VitD缺乏的切点定在20ng/ml还是30ng/ml，TgAb阳性个体VitD缺乏的患病率显著高于TPOAb和TgAb阴性的个体，分别为：8.3% vs 5.6%，P＜0.05和47.6% vs 42.0%，P＜0.05。然而，在校正年龄和性别后，VitD状态与TPOAb及TgAb阳性无相关关系。为了探讨VitD和年龄对血清TSH的可能影响，根据年龄分为3组展开分析，研究发现仅在低年龄组个体中，高25（OH）D与低TSH独立相关。

该研究发现，年轻个体高VitD状态与血循环TSH降低相关。

Background: Vitamin D is an immunomodulator and may affect autoimmune thyroid diseases. Vitamin D has also been shown to influence thyrocytes directly by attenuating thyrotropin (TSH)-stimulated iodide uptake and cell growth. However, it is unclear how vitamin D status is related to TSH at the population level. The goal of the present study was to investigate the relationship between vitamin D status and TSH levels according to thyroid autoantibodies in a population-based health survey in Thailand.

Methods: A total of 2582 adults, aged 15–98 years, were randomly selected according to the geographical region from the Thailand 4th National Health Examination Survey sample. By study design, the sexes were equally represented. Serum levels of 25-hydroxyvitamin D [25(OH)D], TSH, the thyroid peroxidase antibody (TPOAb), and the thyroglobulin antibody (TgAb) were measured in all subjects.

Results: The mean age was 55.0±0.4 (SE) years. In subjects positive for serum TgAb, serum TSH levels were higher, whereas total serum 25(OH)D levels were lower. In addition, the prevalence of vitamin D insufficiency in TgAb-positive subjects was significantly higher than that observed in TPOAb- and TgAb-negative subjects, whether based on cutoff values of 20 or 30?ng/mL: 8.3% vs. 5.6%, p<0.05; or 47.6% vs. 42.0%, p<0.05, respectively. However, vitamin D status was not associated with positive TPOAb and/or TgAb after controlling for sex and age. To explore the probable interaction between vitamin D status and age on serum TSH, analyses were performed according to age tertiles; it was found that higher 25(OH)D levels were independently associated with lower TSH, but only in subjects in the lowest age tertile.

Conclusions: This population-based study showed that high vitamin D status in younger individuals is associated with low circulating TSH.