Vitamin D insufficiency? EU-funded researchers say genes matter,
Genetic factors, sun exposure and diet all play a role in a person's risk of suffering from vitamin D insufficiency, researchers find. Their genome-wide association study, which was partly funded by the EU, uncovers three genetic sites linked to vitamin D concentrations. The findings are published online by The Lancet journal. Support for this work came from the EU-funded ENGAGE ('European network for genetic and genomic epidemiology'), GEFOS ('Genetic factors for osteoporosis'), TREAT-OA ('Translational research in Europe - applied technologies for osteoarthritis') and GENOMEUTWIN ('Genome-wide analyses of European twin and population cohorts to identify genes in common diseases') projects. While the first three received funding to the tune of EUR 12 million, EUR 2.9 million and EUR 11.9 million respectively under the Health Theme of the Seventh Framework Programme (FP7), GENOMEUTWIN was funded by the Life Quality Programme of the Fifth Framework Programme (FP5) with EUR 13.7 million. Analysing vitamin D levels in the blood serum of nearly 34,000 people of European descent, the researchers identified genetic sites (loci) involved with cholesterol synthesis, vitamin D metabolism and vitamin D transport. Test subjects that showed harmful genetic variants (alleles) in all of those places at the same time were 2.5 times more likely to have vitamin D concentrations lower than 75 nanomole per litre (nmol/L). Normal concentrations were defined as being above this value for this study. 'Our findings establish a role for common genetic variants in regulation of circulating vitamin D concentrations,' the paper reads. '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.' The scientists stress that their study focused exclusively on one subgroup of the general population: '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.' '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,' comments Dr Roger Bouillon of Katholieke Universiteit Leuven in Belgium. '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.' Vitamin D deficiency is a highly common disorder and probably affects more than 1 billion people around the globe. Since vitamin D is key to healthy muscles and bones, insufficient levels can lead to impaired bone mineralisation and ultimately bone softening (rickets) and osteoporosis. Lack of vitamin D has also been implicated in a range of other disorders including cancer, and immune and cardiovascular diseases.
Countries
Belgium, United Kingdom