Programme no. 439-OP
Vitamin D status of Icelandic children and its influence on bone accrual
Haukur Heidar Hauksson*1, Kristjan Thor Magnusson2, Erlingur Johannsson3, Hannes Hrafnkelsson4, Emil L. Sigurdsson5
1Solvangur Health Care Center,Hafnarfjordur,Iceland, 2Center for Research in Sport and Health Sciences, School of Education,University of Iceland,Reykjavik,Iceland, 3Center for Research in Sport and Health Sciences, School of Education,University of Iceland,Reykjavik,Iceland, 4Seltjarnarnes Health Care Center,Seltjarnarnes,Iceland;Center for Research in Sport and Health Sciences, School of Education,University of Iceland,Reykjavik,Iceland, 5Department of Family Medicine,University of Iceland,Reykjavik ,Iceland;Solvangur Health Care Center,Hafnarfjordur,Iceland
* = Presenting author
The main objective of this study was to assess the vitamin D status of Icelandic children at the age of 7, and again at 9 years of age, and the association of vitamin D status with bone mineral content and bone accrual over two years.
The importance of vitamin D on children’s bone-health has been well established, with long-lasting and severe deficiency causing rickets. The effects of less severe deficiency are not fully known and have been linked to various conditions.
At age seven 65% of the children had vitamin D concentrations under 50 nmol/L, and at age nine this figure was 60%. At age seven 43% of the children had insufficient amounts of vitamin D (from 37.5 to 50 nmol/L), and 22% had a vitamin D deficiency (under 37.5 nmol/L). Of the children that had vitamin D concentrations less than 50 nmol/L at age 9, 58% of them had also been under 50 nmol/L at age seven.
In linear regression analysis no association was found between vitamin D and bone mineral content. Furthermore, there was no significant difference in bone accrual over two years for the children with insufficient or deficient vitamin D at both ages, compared to those having over 50 nmol/L at both time points.
In 2006 321 children were invited to this study and 267 (83%) took part. 211 (79%) underwent a DXA scan in 2006, and 164 were again scanned two years later. 159 (60%) vitamin D samples were measured in 2006, and 119 (75%) were measured again in 2008.
Conclusion: Over 60% of Icelandic children have inadequate concentrations of vitamin D in serum repeatedly over a two-year interval. However, vitamin D in the range measured in this study did not have a significant effect on bone mineral content or accrual at ages 7 and 9.
Points for discussion: The results of our study regarding vitamin D status show a higher prevalence of low vitamin D status in Iceland than previous studies in other Nordic countries have shown. Although our study did not show any association between vitamin D concentrations and BMC or bone mineral accrual, other studies have had different results. Thus, it is clear that more research on this topic is necessary, and randomized controlled trials could help eliminate potential confounding factors, both known and unknown.