NHS « Shine on Scotland

Press release from Great Ormond Street Hospital

With thanks to The Lancet

A new study published online first, and in an upcoming Lancet, shows that genetic factors affect the risk of a person having vitamin D insufficiency. The article is written by Prof Tim Spector, King’s College, London, London, UK, Dr Elina Hyppönen, UCL Institute of Child Health , London, UK, and Dr Thomas J Wang, Massachusetts General Hospital, Boston, USA, and international colleagues from the SUNLIGHT consortium.

Vitamin D is crucial for maintenance of musculoskeletal health, and might also have a role in extraskeletal tissues. Determinants of circulating vitamin D concentrations include sun exposure and diet, but previous work showing clustering of low vitamin D concentrations within families and twins suggests that genetic factors also play a part. In this study, the authors aimed to identify common genetic variants affecting vitamin D concentrations and risk of insufficiency.
The authors did a genome-wide association study of almost 34,000 white people of European descent from 15 studies. A range of conventional techniques, including radioimmunoassay and mass spectrometry, were used to determine serum vitamin D concentrations. Vitamin D insufficiency was defined as concentrations lower than 75 nmol/L or 50 nmol/L.

Variants at three genetic sites or ‘loci’ were significantly associated with vitamin D concentrations. These loci were near genes involved in cholesterol synthesis, vitamin D metabolism, and vitamin D transport. Participants with a genotype score (combining the three confirmed variants) in the highest quartile (the 25% at greatest risk) were at two-and-a-half times increased risk of having vitamin D concentrations lower than 75 nmol compared with those in the lowest quartile (The 25% at lowest risk).

The authors conclude: “Our findings establish a role for common genetic variants in regulation of circulating vitamin D concentrations. The presence of harmful alleles at the three confirmed loci more than doubled the risk of vitamin D insufficiency. These findings improve our understanding of vitamin D regulation and could assist identification of a subgroup of the white population who are most at risk of vitamin D insufficiency and who may need extra levels of supplementation.*”

They add:  “We studied only white individuals of European descent. Whether the genetic variants we identified affect vitamin D status in other racial or ethnic groups is unknown and warrants further study.”

In an accompanying comment, Dr Roger Bouillon, Katholieke Universiteit Leuven, Belgium, says: “Today’s results only partly explain the wide variability of vitamin D status, and whether these genetically based variations modify the health outcomes in vitamin D deficiency is not known. Therefore the battle against vitamin D deficiency will probably not be modified by these new findings. We need additional studies to explain the mechanisms underlying the pandemic of vitamin D deficiency and, above all, we need a strategy to correct this serious worldwide deficiency.”

http://press.thelancet.com/vitamind.pdf

Notes to editors:

Great Ormond Street Hospital for Children NHS Trust is the country’s leading centre for treating sick children, with the widest range of specialists under one roof.

With the UCL Institute of Child Health, we are the largest centre for paediatric research outside the US and play a key role in training children’s health specialists for the future.

Our charity needs to raise £50 million every year to help rebuild and refurbish Great Ormond Street Hospital, buy vital equipment and fund pioneering research. With your help we provide world class care to our very ill children and their families.