New results from the HELENA study show that vitamin D deficiency is a highly prevalent condition in European adolescents.
HELENA (Healthy Lifestyle in Europe by Nutrition in Adolescence) is a wide-ranging project financially supported by the European Union, which is designed to understand and enhance nutritional and lifestyle habits of adolescents in Europe. The nutritional aspects that are assessed include:
- Dietary intake, nutrition knowledge and eating attitudes
- Food choices and preferences
- Body composition
- Plasma lipids and metabolic profile
- Vitamin status
- Immune function related to nutritional status
- Physical activity and fitness
- Genotype (to analyse gene-nutrient and gene-environment interactions)
In particular, assessment of vitamin D concentrations was included in the study as comparable data on the European level were lacking.
Fasting blood samples were obtained from a sample of 1006 adolescents with an age range of 12·5-17·5 years, selected in the nine European countries participating in this cross-sectional study. The samples were analysed for calcifediol (25-hydroxycholecalciferol (25(OH)D)), a major transport form of vitamin D. Median 25(OH)D levels for the whole population were 57·1nmol/l (5th percentile 24·3nmol/l, 95th percentile 99·05nmol/l).
Vitamin D status was classified into four groups according to international guidelines:
- Sufficiency/optimal levels ≥ 75nmol/l;
- Insufficiency 50-75nmol/l;
- Deficiency 27·5-49·99nmol/l and s
- Severe deficiency < 27·5nmol/l).
80% of European adolescents have suboptimal levels of vitamin D
About 80% of the sample had suboptimal levels of vitamin D. Among these, 39% had insufficient levels, 27% deficient and 15% severely deficient levels (see Figure 1).
Vitamin D concentrations increased with age (P < 0·01) and tended to decrease according to BMI.
An adequate vitamin D status is essential during childhood and adolescence, for its important role in cell growth, skeletal structure and development. It also reduces the risk of conditions such as CVD, osteoporosis, diabetes mellitus, infections and autoimmune disease. The authors concluded that their finding of a highly prevalent deficiency in vitamin D in European adolescent should be a matter of concern for public health authorities.
González-Gross M, Valtueña J, Breidenassel C, t al. Vitamin D status among adolescents in Europe: the Healthy Lifestyle in Europe by Nutrition in Adolescence study. Br J Nutr. 2011 Aug 17:1-10.