Background: The importance of vitamin D for skeletal health is well established and many recent reports indicate that vitamin D deficiency is linked to chronic diseases. Vitamin D status is defined by serum 25-hydroxyvitamin D (25(OH)D), and although there is no consensus on optimal levels of 25(OH)D concentrations of 50 nmol/l (20 ng/ml) meet the requirements in 97.5% of the population. In Sweden, sun cannot synthesize vitamin D during the winter, therefore supplementation is recommended in Sweden during infancy.
Objective and hypotheses: Will increased indoor activities and obesity during the three last decades contribute to decreased vitamin D levels in children?
Method: We analysed serum collected 19822013 at GP-GRC from 2048 Swedish children (mean age±S.D., 8.59±3.68 years; 1197 boys). 25(OH)D was determined with the IDS-iSYS 25-hydroxy vitamin DS automated chemiluminescence immunoassay. Studies of decades-old sera have revealed that 25(OH)D is stable.
Results: A median (10th90th percentile) of 58 (2996) was found and 704 (34.4%) subjects had serum 25(OH)D levels below the recommended level of 50 nmol/l over the 32 years study period. Interestingly, only 3.1% of the children had 25(OH)D levels below 25 nmol/l defined as vitamin D deficiency. We found that younger children had higher levels of 25(OH)D, possibly due to the general supplementation in infants.
Conclusion: In this unique study over 30 years in a large group of children, there was no trend for decreased vitamin D levels. Information that will be of high value for future costbenefit analyses in preventive health care.
Funding: These investigator-initiated and sponsored studies (TRN 88-080; TRN 88-177; TRN 89-071; and TRN 98-0198-003) were supported by unrestricted research grants from Pharmacia/Pfizer, the Swedish Research Council grant number 7509, the Foundation Växthuset for Children, Sahlgrenska University Hospital (ALF), West Sweden Region (VGR) grants, and the County Council of Östergötland.
01 - 03 Oct 2015
European Society for Paediatric Endocrinology