維生素D作為一種免疫調(diào)節(jié)劑，可能影響自身免疫性甲狀腺疾病。既往研究顯示維生素D通過(guò)減少促甲狀腺激素（TSH）刺激的碘攝取和抑制細(xì)胞生長(zhǎng)直接影響甲狀腺細(xì)胞。然而，基于人群的維生素D和TSH的關(guān)系尚不清楚。

泰國(guó)瑪希隆大學(xué)Ramathibodi醫(yī)院醫(yī)學(xué)部La-or chailurkit教授等人進(jìn)行了一項(xiàng)研究，該研究結(jié)果發(fā)表在2013年1月底23卷《甲狀腺》（Thyroid）雜志上。作者發(fā)現(xiàn)年輕個(gè)體高維生素D狀態(tài)與血清TSH水平降低相關(guān)。

該研究從泰國(guó)第四次國(guó)家健康調(diào)查樣本中按地區(qū)隨機(jī)抽取2582例年齡15–98歲的成年人，平均年齡為55.0±0.4歲。按照試驗(yàn)設(shè)計(jì)，男女均等。所有入選個(gè)體均測(cè)量血清25（OH）D、TSH、TPOAb、TgAb。

研究結(jié)果表明，TgAb陽(yáng)性個(gè)體的血清TSH水平較高，而總體25（OH）D水平較低。此外，無(wú)論VitD缺乏的切點(diǎn)定在20ng/ml還是30ng/ml，TgAb陽(yáng)性個(gè)體VitD缺乏的患病率顯著高于TPOAb和TgAb陰性的個(gè)體，分別為：8.3% vs 5.6%，P＜0.05和47.6% vs 42.0%，P＜0.05。然而，在校正年齡和性別后，VitD狀態(tài)與TPOAb及TgAb陽(yáng)性無(wú)相關(guān)關(guān)系。為了探討VitD和年齡對(duì)血清TSH的可能影響，根據(jù)年齡分為3組展開(kāi)分析，研究發(fā)現(xiàn)僅在低年齡組個(gè)體中，高25（OH）D與低TSH獨(dú)立相關(guān)。

該研究發(fā)現(xiàn)，年輕個(gè)體高VitD狀態(tài)與血循環(huán)TSH降低相關(guān)。

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.