Elsevier

Growth Hormone & IGF Research

Review article

Vitamin D across growth hormone (GH) disorders: From GH deficiency to GH excess

Highlights

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The interplay between vitamin D and the growth hormone (GH)/insulin-like growth factor (IGF)-I system to date is not fully understood.

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In GHD patients the vitamin D insufficiency or deficiency may worsen the already known cardiovascular and metabolic risk of GHD patients.

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GH treatment seems to be able to improve vitamin D levels in the majority of the studies available.

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In acromegaly vitamin D levels are commonly higher than controls and both medical and surgical treatment seem to be able to reduce vitamin D levels.

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Vitamin D seems to be a marker of integrity of the GH/IGF-I axis and it should be included among the evaluations to be performed in these conditions.

Abstract

The interplay between vitamin D and the growth hormone (GH)/insulin-like growth factor (IGF)-I system is very complex and to date it is not fully understood. GH directly regulates renal 1 alpha-hydroxylase activity, although the action of GH in modulating vitamin D metabolism may also be IGF-I mediated. On the other hand, vitamin D increases circulating IGF-I and the vitamin D deficiency should be normalized before measurement of IGF-I concentrations to obtain reliable and unbiased IGF-I values. Indeed, linear growth after treatment of nutritional vitamin D deficiency seems to be mediated through activation of the GH/IGF-I axis and it suggests an important role of vitamin D as a link between the proliferating cartilage cells of the growth plate and GH/IGF-I secretion.

Vitamin D levels are commonly lower in patients with GH deficiency (GHD) than in controls, with a variable prevalence of insufficiency or deficiency, and this condition may worsen the already known cardiovascular and metabolic risk of GHD, although this finding is not common to all studies. In addition, data on the impact of GH treatment on vitamin D levels in GHD patients are quite conflicting. Conversely, in active acromegaly, a condition characterized by a chronic GH excess, both increased and decreased vitamin D levels have been highlighted, and the interplay between vitamin D and the GH/IGF-I axis becomes even more complicated when we consider the acromegaly treatment, both medical and surgical.

The current review summarizes the available data on vitamin D in the main disorders of the GH/IGF-I axis, providing an overview of the current state of the art.

Abbreviations

GHT

growth hormone treatment

GHD

growth hormone deficiency

Keywords

Growth hormone

Growth hormone deficiency

Acromegaly

Vitamin D

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