Anna M E Noten, Eva M Loomans, Tanja G M Vrijkotte, Peter M van de Ven, A S Paul van Trotsenburg, Joost Rotteveel, Manon van Eijsden and Martijn J J Finken
Overt hypothyroidism in pregnant women is associated with a lower intelligence quotient in their children. More recently, subtle decreases in maternal thyroid function have also been associated with neurodevelopmental impairment in offspring. We tested the effect of hypothyroxinaemia during early pregnancy on school performance.
This was a longitudinal study that included the data of 1196 mother-child pairs from the Amsterdam Born Children and Their Development study.
Maternal serum free thyroxine (T4) and TSH were obtained at a median gestational age of 12.9 (interquartile range: 11.9–14.3) weeks. School performance was assessed at age 5 years and based on scores obtained in arithmetic and language tests from the national monitoring and evaluation system. Poor school performance was defined as a test result <25th percentile and subnormal school performance as a result <50th percentile of the norm population. To estimate the impact of possible non-response bias, we conducted inverse-probability weighted analyses.
Maternal hypothyroxinaemia (i.e., a maternal free T4 in the lowest 10% of distribution) was associated with a 1.61 (95% CI: 1.05–2.47) -fold increased odds of subnormal arithmetic performance after adjustment for confounders (P=0.03). However, the odds ratio dropped to 1.48 (95% CI: 0.94–2.32) after inverse-probability weighting (P=0.09). No such relations were found with TSH.
Maternal hypothyroxinaemia at the end of the first trimester was associated with reduced performance in an arithmetic test, but not in a language test, in 5-year-old offspring. However, our results should be interpreted carefully because of possible non-response bias.
Nitash Zwaveling-Soonawala, M Emma Witteveen, Jan Pieter Marchal, Femke C C Klouwer, Nadine A Ikelaar, Anne M J B Smets, Rick R van Rijn, Erik Endert, Eric Fliers and A S Paul van Trotsenburg
The hypothalamus–pituitary–thyroid (HPT) axis set point develops during the fetal period and first two years of life. We hypothesized that thyroxine treatment during these first two years, in the context of a randomized controlled trial (RCT) in children with Down syndrome, may have influenced the HPT axis set point and may also have influenced the development of Down syndrome-associated autoimmune thyroiditis.
We included 123 children with Down syndrome 8.7 years after the end of an RCT comparing thyroxine treatment vs placebo and performed thyroid function tests and thyroid ultrasound. We analyzed TSH and FT4 concentrations in the subgroup of 71 children who were currently not on thyroid medication and had no evidence of autoimmune thyroiditis.
TSH concentrations did not differ, but FT4 was significantly higher in the thyroxine-treated group than that in the placebo group (14.1 vs 13.0 pmol/L; P = 0.02). There was an increase in anti-TPO positivity, from 1% at age 12 months to 6% at age 24 months and 25% at age 10.7 years with a greater percentage of children with anti-TPO positivity in the placebo group (32%) compared with the thyroxine-treated group (18.5%) (P = 0.12). Thyroid volume at age 10.7 years (mean: 3.4 mL; range: 0.5–7.5 mL) was significantly lower (P < 0.01) compared with reference values (5.5 mL; range: 3–9 mL) and was similar in the thyroxine and placebo group.
Thyroxine treatment during the first two years of life led to a mild increase in FT4 almost 9 years later on and may point to an interesting new mechanism influencing the maturing HPT axis set point. Furthermore, there was a trend toward less development of thyroid autoimmunity in the thyroxine treatment group, suggesting a protective effect of the early thyroxine treatment. Lastly, thyroid volume was low possibly reflecting Down-specific thyroid hypoplasia.
Charlotte A Heinen, Zhi Zhang, Lars P Klieverik, Tim C de Wit, Edwin Poel, Maqsood Yaqub, Anita Boelen, Andries Kalsbeek, Peter H Bisschop, A S Paul van Trotsenburg, Hein J Verberne, Jan Booij and Eric Fliers
Brown adipose tissue (BAT) activity in humans is stimulated by cold and by a limited number of pharmacological agents, including β3-adrenergic agonists and bile acids. Although thyrotropin-releasing hormone (TRH) is known to activate BAT in several mammals, this has not been reported in humans.
A randomized, placebo-controlled, double-blind, cross-over trial.
We investigated the effects of intravenous bolus administration of 400 µg TRH or 2 mL saline on BAT activity in healthy, lean men. BAT activity was measured as standardized 18F-fluorodeoxyglucose (18F-FDG) uptake and glucose metabolic rate (MRglu) using dynamic PET/CT imaging. The first six individuals were studied at room temperature, while subsequently nine were exposed to mild cold (17°C ± 1°C) for 60 min before imaging. During the dynamic scan, blood was withdrawn for measurement of thyroid hormone and catecholamine concentrations. This trial is registered with The Netherlands National Trial Register (number NTR5512).
Sixteen participants were recruited. Six men studied at room temperature showed no visible BAT activity during either session. After exposure to mild cold, four of nine men (44.4%) showed clear increase of 18F-FDG uptake after TRH administration compared to placebo. Maximal standardized 18F-FDG uptake showed a trend toward increase after TRH compared to placebo (P = 0.066). MRglu showed a significant increase after TRH administration (P = 0.014). The increase in 18F-FDG uptake was not paralleled by changes in plasma thyroid hormone or catecholamine concentrations.
Systemic TRH administration can increase the activity of cold-stimulated BAT in adult men. These findings may assist developing pharmacological strategies for modulating BAT activity in the management of obesity.
Kevin Stroek, Annemieke C Heijboer, Marelle J Bouva, Catharina P B van der Ploeg, Marie-Louise A Heijnen, Gert Weijman, Annet M Bosch, Robert de Jonge, Peter C J I Schielen, A S Paul van Trotsenburg and Anita Boelen
Congenital hypothyroidism (CH) is defined as thyroid hormone deficiency at birth due to disorders of the thyroid gland (thyroidal CH, CH-T), or the hypothalamus or pituitary (central CH, CH-C). The Dutch Newborn Screening (NBS) strategy is primarily based on determination of thyroxine (T4) concentrations in dried blood spots followed, if necessary, by thyroid-stimulating hormone (TSH) and thyroxine-binding globulin (TBG) measurement enabling detection of both CH-T and CH-C. A calculated T4/TBG ratio serves as an indirect measure for free T4. A T4/TBG ratio ≤ 17 in a second heel puncture is suggestive of CH-C.
Design and methods:
In the present study, we evaluated 11 years of Dutch CH NBS using a database of referred cases by assessing the contribution of each criterion in the unique stepwise T4-TSH-TBG NBS algorithm.
Between 2007 and the end of 2017, 1 963 465 newborns were screened in the Netherlands. Use of the stepwise algorithm led to 3044 referrals and the identification of 612 CH cases, consisting of 496 CH-T, 86 CH-C, and 30 CH of unknown origin diagnoses. We detected 62.8% of CH-C cases by the T4/TBG ratio in the second heel puncture. The positive predictive value (PPV) of the stepwise T4-TSH-TBG NBS algorithm was 21.0%.
This evaluation shows that the Dutch stepwise T4-TSH-TBG NBS algorithm with a calculated T4/TBG ratio is of great value for the detection of both CH-T and CH-C in the Netherlands, at the cost of a lower PPV compared to TSH-based NBS strategies.