Bone Abstracts

Introduction: The importance of vitamin D in metabolism, bone growth and functioning of many organs and systems (the plejotropic effect) has been broadly discussed in the literature recently. The systemic deficiency of vitamin D connected with the lower sunlight exposure and the decreased diet supply favours to bone mineral density lowering and the bone structure disorganization. More and more often the common vitamin deficiency in children and adolescents has been observed. It is universally known that even temporary shortage of vitamin D during the rapid growth may hamper the correct peak bone mass acquistion.

The aim of the study was to determine the vitamin D supply in schoolchildren from the different regions of Poland.

Patients and methods: The study comprised research centers from the six cities in Poland: Łódź (coordinator), Białystok, Katowice, Szczecin, Lublin, Poznań. The healthy schoolchildren at the age of 9–11, 99 were examined. In every child the liver metabolite of vitamin D was detected twice (first after the winter season, secondly after the summer). The serum was analysed in the laboratory with the international certificate in the Department of Biochemistry and Experimental Medicine in The Children’s Memorial Health Institute in Warsow. The serum concentration of vitamin D (25OHD) was detected with the immunochemiluminescence method with the DEQAS international control system. The sufficient 25 OHD serum concentration was recognized at range of 20–100 ng/ml. The concentration at the range of 10–20 ng/ml was recognized as vitamin D insufficiency and below 10 ng/ml as vitamin D deficiency.

The results: The 715 of children were examined. The greatest vitamin D shortages were observed in Szczecin and Białystok – in 95 and in 90% of children (insufficiency in 64 and 67% and deficiency in 31 and 23%). In Katowice and Lublin the lower vitamin D concentration was detected in 89 and 88% of children (insufficiency in 73 and 68% and deficiency in 16 and 20%). The lower shortages were revealed in children from Łódź and Poznań- in 77 and 74% (insufficiency in 57 and 59% and deficiency in 20 and 15%). The results of the vitamin D in the same children proved considerable improvement after the summer. The greatest shortages were obtained in Poznań and Szczecin – in 52.9 and 42.1% (insufficiency in 52.2 and 42.1% and deficiency in 0.7 and 0%). On the other hand in Łódź the decreased 25OHD concentration was observed in 41.5% of children and it was the insufficiency only. The lowest shortages were revealed in Lublin, Białystok and Katowice- in 28, 26.3 and 26.3% of children and again it was the insufficiency only.

Conclusions: 1. The lower concentration of liver metabolite of vitamin D in as many of examined children indicates on adverse diet and climatic conditions which may influence on bone mineralization in children.

2. The results of this study confirm the neccesity of the prophylaxis of vitamin D deficiency in schoolchildren in Poland.

3. The considerable improvement of the 25OHD serum concentration in the majority of children after the summer may provide favourable influence of the sun exposure.