Neven Kristof Y, Cox Bianca, Cosemans Charlotte, Gyselaers Wilfried, Penders Joris, Plusquin Michelle, Roels Harry A, Vrijens Karen, Ruttens Ann, Nawrot Tim S
Centre for Environmental Sciences, Hasselt University, Diepenbeek, Belgium.
Department of Obstetrics, East-Limburg Hospital, Genk, Belgium.
BMC Med. 2021 Feb 19;19(1):47. doi: 10.1186/s12916-021-01919-4.
The micronutrient iodine is essential for a healthy intrauterine environment and is required for optimal fetal growth and neurodevelopment. Evidence linking urinary iodine concentrations, which mainly reflects short-term iodine intake, to gestational diabetes mellitus (GDM) is inconclusive. Although the placental concentrations would better reflect the long-term gestational iodine status, no studies to date have investigated the association between the placental iodine load and the risk at GDM. Moreover, evidence is lacking whether placental iodine could play a role in biomarkers of insulin resistance and β-cell activity.
We assessed the incidence of GDM between weeks 24 and 28 of gestation for 471 mother-neonate pairs from the ENVIRONAGE birth cohort. In placentas, we determined the iodine concentrations. In maternal and cord blood, we measured the insulin concentrations, the Homeostasis Model Assessment (HOMA) for insulin resistance (IR) index, and β-cell activity. Logistic regression was used to estimate the odds ratios (OR) of GDM, and the population attributable factor (PAF) was calculated. Generalized linear models estimated the changes in insulin, HOMA-IR, and β-cell activity for a 5 μg/kg increase in placental iodine.
Higher placental iodine concentrations decreased the risk at GDM (OR = 0.82; 95%CI 0.72 to 0.93; p = 0.003). According to the PAF, 54.2% (95%CI 11.4 to 82.3%; p = 0.0006) of the GDM cases could be prevented if the mothers of the lowest tertile of placental iodine would have placental iodine levels as those belonging to the highest tertile. In cord blood, the plasma insulin concentration was inversely associated with the placental iodine load (β = - 4.8%; 95%CI - 8.9 to - 0.6%; p = 0.026).
Higher concentrations of placental iodine are linked with a lower incidence of GDM. Moreover, a lower placental iodine load is associated with an altered plasma insulin concentration, HOMA-IR index, and β-cell activity. These findings postulate that a mild-to-moderate iodine deficiency could be linked with subclinical and early-onset alterations in the normal insulin homeostasis in healthy pregnant women. Nevertheless, the functional link between gestational iodine status and GDM warrants further research.
微量营养素碘对于健康的子宫内环境至关重要，是胎儿最佳生长和神经发育所必需的。将主要反映短期碘摄入量的尿碘浓度与妊娠期糖尿病（GDM）联系起来的证据尚无定论。尽管胎盘碘浓度能更好地反映妊娠期长期碘状态，但迄今为止尚无研究调查胎盘碘负荷与GDM风险之间的关联。此外，缺乏胎盘碘是否在胰岛素抵抗和β细胞活性生物标志物中起作用的证据。
我们评估了来自ENVIRONAGE出生队列的471对母婴在妊娠24至28周之间的GDM发病率。在胎盘中，我们测定了碘浓度。在母体和脐带血中，我们测量了胰岛素浓度、胰岛素抵抗稳态模型评估（HOMA）指数和β细胞活性。采用逻辑回归估计GDM的比值比（OR），并计算人群归因分数（PAF）。广义线性模型估计胎盘碘每增加5μg/kg时胰岛素、HOMA-IR和β细胞活性的变化。
胎盘碘浓度较高可降低GDM风险（OR = 0.82；95%CI 0.72至0.93；p = 0.003）。根据PAF，如果胎盘碘处于最低三分位数的母亲的胎盘碘水平与最高三分位数的母亲相同，则54.2%（95%CI 11.4至82.3%；p = 0.0006）的GDM病例可以预防。在脐带血中，血浆胰岛素浓度与胎盘碘负荷呈负相关（β = -4.8%；95%CI -8.9至-0.6%；p = 0.026）。
胎盘碘浓度较高与GDM发病率较低有关。此外，较低的胎盘碘负荷与血浆胰岛素浓度、HOMA-IR指数和β细胞活性改变有关。这些发现表明，轻度至中度碘缺乏可能与健康孕妇正常胰岛素稳态的亚临床和早发性改变有关。然而，妊娠期碘状态与GDM之间的功能联系值得进一步研究。
