Serum 25-hydroxyvitamin D Concentrations (25OHD)
Conditions
Keywords
Vitamin D, Serum 25-hydroxyvitamin D (25OHD), Dietary supplement, Ethnicity, Immigrant
Brief summary
Insufficient intake of vitamin D is a public health problem, affecting about 40% of the Finnish population in the winter. Vitamin D has a wide range of health effects: in addition to its effect on bone, it is known to affect inflammatory response among other things. The sources of vitamin D are the synthesis in the skin as well as diet and dietary supplements. In Finland and in Northern Europe vitamin D is formed in the skin only from March to October. This alone is not sufficient to cover the need for year-round, because vitamin D storage is used in a few months. During the winter months the only sources of vitamin D are diet and vitamin preparations. Current vitamin D recommendations are usually based on studies in white population. However, there can be a difference in the need of vitamin D and in vitamin D metabolism between different population groups. More research evidence is needed from the northern countries. The aim of this study is to evaluate the vitamin D need in Somali immigrant population and in original Finnish population. The hypothesis is that the Somalis need more vitamin D to exceed the serum 25(OH)D concentration of 50 nmol/L than the original Finnish population.
Interventions
DIETARY_SUPPLEMENTVitamin D3
Sponsors
University College Cork
Technical University of Denmark
Finnish Institute for Health and Welfare
University of Helsinki
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
PREVENTION
Masking
DOUBLE (Subject, Investigator)
Eligibility
Sex/Gender
FEMALE
Age
21 Years to 66 Years
Healthy volunteers
Yes
Inclusion criteria
* woman between 21-66 years of age * belongs to original Finnish population or to Somali immigrant population * healthy (= no disease requiring medication) * lives in the metropolitan area
Exclusion criteria
* pregnant or breastfeeding * has traveled to a sunny destination or destination near the equator during the previous month * plans to travel to a sunny destination or destination near the equator in the next 6 months * has used a tanning bed during the previous month * plans to use a tanning bed in the next 6 months * the subject's blood 25-hydroxy-vitamin D level (25 (OH) D), exceeds 100 nmol / L or is less than 30 nmol / L at baseline in the screening phase.
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Serum 25-hydroxyvitamin D (25(OH)D) concentrations | Change from baseline in serum 25(OH)D concentration at 3 and 6 months | The effect of ethnicity on the serum 25(OH)D concentration response to vitamin D supplementation will be investigated. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Serum calcium concentration | Change from baseline in serum calcium concentration at 3 and 6 months | Markers of calcium metabolism, which are affected by vitamin D, will be measured |
| Serum parathyroid hormone (PTH) concentration | Change from baseline in serum PTH concentration at 3 and 6 months | Markers of calcium metabolism, which are affected by vitamin D, will be measured |
Other
| Measure | Time frame | Description |
|---|---|---|
| Polymorphisms in genes involved in the transport and metabolism of vitamin D | Baseline | Genomic DNA will be isolated and single nucleotide polymorphisms (SNPs) for key genes involved in vitamin D transport and metabolism will be measured to investigate the ethnic variation in the genes. |
Countries
Finland
Outcome results
None listed