Due to reported variations in vitamin D deficiency, researchers determine the most important factors of vitamin D deficiency in school children.
Vitamin D has been shown to be one of the key nutrients that helps in the development and maintenance of bone health. Vitamin D essentially helps promote skeletal growth and development from early on in life. Much attention has shifted towards vitamin D over the course of the past decade due to new research findings that have implicated vitamin D on health outcomes even beyond bone health.
The prevalence of vitamin D deficiency is widespread throughout the world. It seems that this is dependent on many things, ranging from latitude, seasonality, the population, vitamin D food policy in the country, and how the country defines vitamin D deficiency. Due to all these factors, European populations have shown lots of variability in the prevalence of vitamin D deficiency.
According to data, there seems to be a higher prevalence of low vitamin D status in children and youth from southern European countries compared to other European regions. There are some recent findings that show, for example, that children and youth from Italy had very comparable or higher prevalence of vitamin D deficiency compared to same age groups in Netherlands and Great Britain. The tests used to measure the levels of vitamin D were completed using different methods in those separate studies. This suggests that there may be variations in values for vitamin D depending on the test method that is used. In light of these findings, one research group wanted to determine vitamin D deficiency in different populations across a southern European country using a standard method.
Yannis Manois and his research team recently published their findings, in the British Journal of Nutrition, on the prevalence of vitamin D deficiency in schoolchildren across different populations in Greece. They used a large-scale and cross-sectional study design that lasted over two years and involved 2,386 children who lived in four different districts of Greece. The participants were aged between 9-13 years of age and were scattered throughout distinct Greek territories that covered northern, central, western and southern areas of Greece. The sampling was random, multistage, and it was divided by parents’ education level. Different measurements were used throughout the study including socio-economic and demographic indices, dietary intake, physical activity levels, and physical exams among others. Blood samples were taken to look into biochemical composition and indices. Vitamin D levels were standardized and categorized into the following: levels that put you at risk of vitamin D deficiency, levels that indicate vitamin D insufficiency, and sufficient vitamin D levels.
They found that girls had a higher prevalence of vitamin D deficiency and insufficiency compared to boys. The highest rates of vitamin D deficiency and insufficiency were found to be during the spring and the lowest during the fall. The prevalence of vitamin D insufficiency was found to be higher in urban regions compared to rural regions.
In conclusion, this group found that females, urban dwellers, and spring seasonality were all associated with a higher prevalence of vitamin D deficiency or insufficiency. Furthermore, despite the fact that Greece is a southern European country, the prevalence of low vitamin D status in children and youth is comparable to those of other recorded European countries.
This research highlights the fact that, in any population, there are sub-populations who will be at greater risk of vitamin D deficiency. With this in mind, it would be beneficial to set up effective initiatives, where reasonable, to help support those sub-populations who are known to be at risk for vitamin D deficiency.
Written by Ingrid Qemo, BSc
Reference: Manios, Y., Moschonis, G., Hulshof, T., Bourhis, A., Hull, G.L.J., Dowling, K.G., Kiely, M., and Cashman, K.D. 2017. Prevalence of vitamin D deficiency and insufficiency among schoolchildren in Greece: the role of sex, degree of urbanisation and seasonality. British Journal of Nutrition. 118(7):550-558