Seasonal Variation Of Vitamin D And Serum Thyrotropin Levels And Its Relationship In A Euthyroid Caucasian Population

Das, Gautam; Taylor, Peter; Javaid, Heather; Tennant, Brian P.; Geen, John; Aldridge, Andrew; Okosieme, Onyebuchi

doi:10.4158/ep-2017-0058

Cited by 15 publications

(15 citation statements)

References 33 publications

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“…Another possible explanation is the relationship between maternal vitamin D and fetal TSH levels. Barchetta et al ( 33 ) and Das et al ( 34 ) have reported that TSH is higher in winter and inversely correlated with vitamin D levels in euthyroid adults, offering a mechanism to explain TSH seasonality.…”

Section: Discussionmentioning

confidence: 98%

A Detailed Analysis of the Factors Influencing Neonatal TSH: Results From a 6-Year Congenital Hypothyroidism Screening Program

et al. 2020

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Background: Neonatal thyrotropin (TSH) on dried blood spot (DBS), the most common screening strategy for primary congenital hypothyroidism (CH), is influenced by numerous factors that may hinder a true CH diagnosis. A second test can thus be performed to clarify the initial findings, although its application varies among screening programs. Objectives: The aim of this study was to evaluate the effect of maternal and neonatal factors on neonatal TSH levels and offer practical screening recommendations. Methods: We retrospectively analyzed screening data of 62,132 neonates born in Abruzzo, an Italian region considered mildly iodine deficient, between 2011 and 2016. We then performed a multiple linear regression to model the relationship between TSH (the dependent variable) and 13 independent variables extracted from blood collection cards. Results: Most neonates (53,551 of 62,132, 86%) had normal TSH and no clinical indications for a second screening. A minority (1,423, 2.3%) had elevated TSH in the initial DBS, which was confirmed in 97 cases (7%) on a second screen. The remaining neonates (6,594, 10.6%) had a normal initial TSH but underwent a second test in accordance with screening protocols, and were found to have delayed TSH elevation in 23 cases (0.4%). Those 120 newborns (97 + 23), considered highly suspicious for primary CH, were referred to a pediatrician for confirmatory testing and excluded from subsequent analysis of factors influencing TSH levels. Sex (β regression coefficient, β = 1.11 female to male, 95% CI 1.09, 1.12) and age at collection (β = 0.78 day 5 to days 2-3, 95% CI 0.74, 0.83) affected neonatal TSH, suggesting the utility of specific nomograms. In addition, prematurity (β = 0.85 term to preterm, 95% CI 0.80, 0.91), dopamine use (β = 0.71, 95% CI 0.62, 0.81), and birth weight (β = 1.40 normal vs. very low, 95% CI 1.05, 1.89) strongly influenced neonatal TSH. Conclusions: Neonatal TSH is influenced by several factors supporting the delineation of local sex-and age-adjusted TSH cutoffs, and the universal adoption of a second TSH test in neonates at risk of missed primary CH diagnosis.

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Section: Discussionmentioning

confidence: 98%

A Detailed Analysis of the Factors Influencing Neonatal TSH: Results From a 6-Year Congenital Hypothyroidism Screening Program

et al. 2020

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“…TSH values follow a seasonal pattern, decreasing during the summer, and then increasing during the winter. These annual variations in TSH secretion should be considered for the interpretation of results [30,31]. In addition, there is a robust circadian variation in TSH secretion [32,33].…”

Section: Discussionmentioning

confidence: 99%

Effect of Weight Loss after Bariatric Surgery on Thyroid-Stimulating Hormone Levels in Euthyroid Patients with Morbid Obesity

et al. 2019

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Obesity is associated with several endocrine abnormalities, including thyroid dysfunction. The objective of this study was to investigate the effect of weight loss after bariatric surgery on thyroid-stimulating hormone (TSH) levels in euthyroid patients with morbid obesity. We performed an observational study, evaluating patients with morbid obesity submitted to bariatric surgery. We included 129 patients (92 women) and 31 controls (21 women). Clinical, anthropometric, biochemical, and hormonal parameters were evaluated. The primary endpoint was circulating TSH (µU/mL). Fasting TSH levels were higher in the obese group (3.3 ± 0.2) than in the control group (2.1 ± 0.2). The mean excessive body mass index (BMI) loss (EBMIL) 12 months after bariatric surgery was 72.7 ± 2.1%. TSH levels significantly decreased in the obese patients after surgery; 3.3 ± 0.2 vs. 2.1 ± 0.2 before and 12 months after surgery, respectively. Free thyroxine (T4) (ng/dL) levels significantly decreased in the obese patients after surgery; 1.47 ± 0.02 vs. 1.12 ± 0.02 before and 12 months after surgery, respectively. TSH decreased significantly over time, and the decrement was associated with the EBMIL. In euthyroid patients with morbid obesity, weight loss induced by bariatric surgery promotes a significant decline of the increased TSH levels. This decrement of TSH is progressive over time after surgery and significantly associated with excess BMI loss.

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“…The peaks in nTSH in the current study were seen in late spring as opposed to the summer months so this was slightly unexpected. A further mechanism may involve seasonal vitamin D metabolism affecting the hypothalamic‐pituitary‐thyroid axis with recent studies indicating an inverse relationship between vitamin D levels and TSH …”

Section: Discussionmentioning

confidence: 99%

“…A further mechanism may involve seasonal vitamin D metabolism affecting the hypothalamic-pituitary-thyroid axis with recent studies indicating an inverse relationship between vitamin D levels and TSH. 28,29 This article is the first publication of its kind from Northern trigger to re-evaluate the population with urinary iodine concentrations. Seasonal variation in neonatal TSH has also been demonstrated and may reflect a population at the borderline of iodine sufficiency and therefore vulnerable to seasonal environmental and husbandry shifts.…”

Section: Discussionmentioning

confidence: 99%

Neonatal TSH levels in Northern Ireland from 2003 to 2014 as a measure of population iodine status

Mullan

Patterson

Doolan

et al. 2018

Clinical Endocrinology

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The neonatal TSH database suggests iodine sufficiency in the NI population. However, the rising frequency of results >2 mIU/L may indicate an emerging mild iodine deficiency. This is one of the largest and longest studies of its kind in the UK and the first carried out in NI. The summer months may be a time of increased risk of iodine deficiency in our pregnant women whose requirements are increased and who are not currently targeted by any iodine fortification programme in the UK.

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Seasonal Variation Of Vitamin D And Serum Thyrotropin Levels And Its Relationship In A Euthyroid Caucasian Population

Cited by 15 publications

References 33 publications

A Detailed Analysis of the Factors Influencing Neonatal TSH: Results From a 6-Year Congenital Hypothyroidism Screening Program

A Detailed Analysis of the Factors Influencing Neonatal TSH: Results From a 6-Year Congenital Hypothyroidism Screening Program

Effect of Weight Loss after Bariatric Surgery on Thyroid-Stimulating Hormone Levels in Euthyroid Patients with Morbid Obesity

Neonatal TSH levels in Northern Ireland from 2003 to 2014 as a measure of population iodine status

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