Vitamin D deficiency: health at risk for many Europeans

13% of the population of the European Union, regardless of age and ethnicity, suffers from vitamin D deficiency. A percentage that represents a true pandemic and highlights a serious public health problem; vitamin D is essential to prevent bone deformities, such as rickets in children and osteomalacia in adults.

These are some of the data reported by a project, funded by the European Union and published last month in the American Journal of Clinical Nutrition, which involved several research centers from different countries on the old continent.

Vitamin D, an indispensable hormone for health

The actions of vitamin D are attributed to its active metabolite, namely 1,25- dihydroxycholecalciferol [1,25(OH)2 D3] or calcitriol. The main source of vitamin D is, in humans, skin exposure to sunlight, but it can also be introduced through the diet. Few foods, however, naturally contain it and they are: oily fish, dried mushrooms, whole milk derivatives, and eggs. Vitamin D hypovitaminosis is currently estimated to be extremely prevalent worldwide. 

Recent data indicate that, like many other industrialized nations, this deficiency affects about 70-80% of the elderly Italian population. 25(OH)D is the main circulating metabolite of vitamin D, and although assay techniques are not yet adequately standardized, its determination is the most accurate method for estimating the vitamin's reserve status in the body. Furthermore, while there is general agreement on the importance of preventing vitamin D deficiency, there is more heterogeneity on what level of 25(OH)D defines hypovitaminosis. In contrast, it is almost universally agreed that 25 (OH) D concentration below 25-30 nanomoles per liter is a sign of vitamin D deficiency and a risk signal for metabolic bone disease.

Thousands of individuals in Europe suffer from vitamin D deficiency

The data collected in this study are part of the four-year project, called ODIN, which began in late 2013. The project represents a multidisciplinary approach involving a team of experts from 19 countries in the European Union. The study revealed that regardless of age and ethnicity, 13 percent of the 55,844 European individuals, included in the research, have average vitamin D levels below 30 nanomoles per liter, throughout the year. This percentage increased from October to March by 17.7 percent and decreased, in the period from April to November to 8.3 percent. 

In dark-skinned ethnic subgroups, the prevalence of 25(OH) D levels below 30 nmol/L was 3 to 71 times higher than in light-skinned populations, depending on the country examined. In the case of deficiency defined as 25 (OH) D concentration below 50 nmol/L, the overall prevalence was found to rise to 40.4 percent. Vitamin D deficiency in Europe can be described as a pandemic, but the distribution of data on blood levels of 25(OH) D in the European Union are of highly variable quality.

A study using a standardized protocol

Previous surveys of vitamin D status in Europe have used different methods of data analysis, resulting in differences in results. Instead, this latest report uses a specific protocol: the VDSP program, which the researchers themselves described as "a solid platform on which to build public health" in Europe. This protocol made it possible, for the first time, to obtain internationally comparable data and to reanalyze the results of numerous population studies. All values were combined with those from 4 previously standardized studies, is provided data from a population of more than 54,000 European citizens of all ages.

Vitamin D hypovitaminosis: a widespread problem

Vitamin D, over the past 15 years, has captured the attention of scientific and medical communities, regulatory agencies, the food industry, and citizens. This is evidenced by the increase in scientific literature, the demand for medical tests to determine vitamin D status, a series of reevaluations of dietary recommendations, the Promo of supplements, and the increase in the number of food products with added vitamin D placed on the market. 

In 1975 there were about 250 scientific articles about the vitamin but 30 years later, in 2007, this number had risen to around 1600, and in 2013 to 3774. Strategies to counter vitamin D deficiency have been discussed in several countries in Europe over the decades. Lately, Sweden has expanded its list of foods undergoing fortification to help address the problem, largely due to low levels of sunshine in the nation. Meanwhile, an increase in rickets cases in the United Kingdom has highlighted the need for similar initiatives on a mandatory or voluntary basis.

A deficit that requires public health interventions

The findings from the project show that vitamin D deficiency is indisputable throughout Europe, with prevalence rates that require intervention from a public health perspective. According to the researchers who conducted the study, these data are firm evidence of vitamin D deficiency and that European policy strategies should aim to ensure vitamin D consumption to protect the majority of the population. 

Source: K. D. Cashman et al. "Vitamin D deficiency in Europe: pandemic?" American Journal of Clinical Nutrition 2016 Apr;103(4):1033-44.