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Endocrine Abstracts (2019) 63 GP80 | DOI: 10.1530/endoabs.63.GP80

ECE2019 Guided Posters Thyroid Autoimmune Disorders (12 abstracts)

Effect of nine months of vitamin D supplementation on muscle performance in Graves’ disease: a double-blinded, randomized clinical trial

Diana Grove-Laugesen 1 , Sofie Malmstrom 1 , Eva Ebbehoj 1 , Anne Lene Riis 2 , Torquil Watt 3 , Klavs Würgler Hansen 4 & Lars Rejnmark 1


1Aarhus University Hospital, Aarhus, Denmark; 2Regional Hospital Horsens, Horsens, Denmark; 3Gentofte Hospital, Gentofte, Denmark; 4Regional Hospital Silkeborg, Silkeborg, Denmark.


Background: Vitamin D deficiency has been proposed to play a role in development and course of Graves’ disease (GD). Muscle weakness and fatigue are shared features of GD and vitamin D deficiency. We aimed to investigate whether vitamin D supplementation would improve restoration of muscle performance and thyroid-related quality of life (QoL) in GD.

Methods: In a double-blinded clinical trial, hyperthyroid patients with a first time diagnosis of GD were randomized to vitamin D 70 mcg/day or matching placebo as add-on to standard antithyroid medication (ATD). At baseline and after three and nine months of intervention, we assessed isometric muscle strength, muscle function tests, postural stability, body composition, and self-reported ThyPRO Tiredness and Impaired Daily Life (0–100, higher score worse). Differences in change between groups were analyzed using linear mixed modelling. (The DAGMAR study clinicaltrials.gov ID NCT02384668).

Results: Nine months of vitamin D supplementation caused a reduced muscle strength increase at all muscle groups investigated, although only significant at knee extension 60° with a 7% (95% CI:0.3;13) lower increase in muscle strength compared with placebo. Vitamin D supplementation showed a trend towards reduced gain of lean body mass (−3.1% (95% CI:−6.5;0.4)). There was no significant difference in Tiredness or Impaired Daily Life, but improvement of Impaired Daily Life tended to be lower in the vitamin D group (10 points (95% CI:−2;22)). In the entire group of patients, all measures improved significantly in response to nine months of ATD with an improvement of 21–37% in muscle strength at the different muscle groups (Pall<0.001) and of 11% (95% CI:9;13) in lean body mass. Furthermore, performance of the repeated chair stand test and the time-up-and-go test improved by 15% (95% CI:12;18) and 2% (95% CI:0.4;5). Postural stability improved by 26–54% Pall<0.001. Large changes was observed in Tiredness and Impaired Daily Life with improvements of 22 (95% CI:19;26) and 36 (95% CI:28;45) points. In general, improvements were most marked during the first three months of ATD, but the recovery continued from three to nine months.

Conclusion: Nine months of vitamin D supplementation 70 mcg/day caused unfavorable effects on restoration of muscle performance. In contrast, ATD treatment was associated with marked improvement in all measures of muscle performance and thyroid-related QoL. In patients with newly diagnosed GD, high dose vitamin D supplementation should not be recommended to improve muscle function, but ATD therapy seems to be of major importance to alleviate muscle impairment.

Volume 63

21st European Congress of Endocrinology

Lyon, France
18 May 2019 - 21 May 2019

European Society of Endocrinology 

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