The Effect of Vitamin D Supplementation on Hypothyroidism in the Randomized Controlled D-Health Trial.
In: Thyroid, Jg. 33 (2023-11-01), Heft 11, S. 1302-1310
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Zugriff:
Background: Hypothyroidism is common, and in iodine-sufficient areas, it is primarily caused by autoimmune destruction of the thyroid gland. Observational studies have consistently shown an inverse association between serum 25-hydroxyvitamin D concentration and autoimmune diseases; however, there is a lack of evidence from randomized controlled trials to support a benefit of vitamin D supplementation, particularly for autoimmune thyroid diseases. We, therefore, aimed to assess the effect of vitamin D supplementation on the incidence of hypothyroidism. Methods: We analyzed data from the D-Health Trial (n = 21,315), a randomized double-blind placebo-controlled trial of 60,000 international units per month of supplemental vitamin D3 among Australians aged 60 years and over. Hypothyroidism, a tertiary outcome of the D-Health Trial, was defined by treatment with levothyroxine, ascertained through linkage with the Australian Pharmaceutical Benefits Scheme. The outcome was time to first prescription of levothyroxine. We began follow-up at 12 months after randomization; people who had died or who had been dispensed levothyroxine during the first year were excluded. Flexible parametric survival models were used to assess the effect of vitamin D supplementation on hypothyroidism, overall and within strata defined by age, sex, body mass index, and predicted baseline vitamin D status. Results: We included 17,851 participants in the main analysis (vitamin D = 8939; placebo = 8912). During a median follow-up of 4.1 years (interquartile range 4.1–4.1), 293 participants developed hypothyroidism (vitamin D = 138 [1.5%]; placebo = 155 [1.7%]). Vitamin D supplementation did not significantly reduce the incidence of hypothyroidism (overall hazard ratio [HR] 0.89; 95% confidence interval [CI] 0.71–1.12). There was some suggestion of an effect in females (overall HR 0.78; CI 0.58–1.06) but not in males (overall HR 1.06; CI 0.74–1.50; p interaction 0.20). Conclusions: Vitamin D supplementation did not reduce the incidence of hypothyroidism overall; however, the possible beneficial effect observed in females warrants further investigation. Clinical Trial Registration: Australian New Zealand Clinical Trials Registry: ACTRN12613000743763. [ABSTRACT FROM AUTHOR]
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The Effect of Vitamin D Supplementation on Hypothyroidism in the Randomized Controlled D-Health Trial.
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Autor/in / Beteiligte Person: | Waterhouse, Mary ; Pham, Hai ; Rahman, Sabbir T. ; Baxter, Catherine ; Duarte Romero, Briony ; Armstrong, Bruce K. ; Ebeling, Peter R. ; English, Dallas R. ; Hartel, Gunter ; van der Pols, Jolieke C. ; Venn, Alison J. ; Webb, Penelope M. ; Whiteman, David C. ; McLeod, Donald S. A. ; Neale, Rachel E. |
Zeitschrift: | Thyroid, Jg. 33 (2023-11-01), Heft 11, S. 1302-1310 |
Veröffentlichung: | 2023 |
Medientyp: | academicJournal |
ISSN: | 1050-7256 (print) |
DOI: | 10.1089/thy.2023.0317 |
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