Comparing Different Amounts of Vitamin D Supplementation to Preschool Children Living in Northern and Southern Sweden

Vitamin D Deficiency Clinical Trial

— Dvisum  

Clinical Trial Details — Status: Completed

Administrative data

• NCT number: NCT01741324
• Other study ID #: Dvisum
• Status: Completed
• Phase: N/A
• First received: November 26, 2012
• Last updated: October 31, 2016
• Start date: November 2012
• Est. completion date: July 2013

Study information

• Verified date: October 2016
• Source: Umeå University
• Contact: n/a
• Is FDA regulated: No
• Health authority: Sweden: The National Board of Health and Welfare
• Study type: Interventional

Clinical Trial Summary

Vitamin D has a range of biological effects of public health relevance. Vitamin D status is assessed on levels of its metabolite 25-hydroxyvitamin D [25(OH)D], where levels < 50 nmol/L indicate insufficiency. Despite studies indicating that the vitamin D intake among Swedish children are significantly below recommendations, little is known of their vitamin D status. The investigators have recently found inadequate vitamin D status in pre-school children living in northern Sweden, especially in dark-skinned children and during the winter months despite vitamin D intakes meeting the recommendations. Overall, 25% of the light skinned and 40% of the dark skinned children had S-25(OH) D <50 nmol/L (Öhlund I, unpublished data). The aim is to examine which amount of vitamin D is needed to maintain or increase S-25(OH)D to ≥50 nmol/L among 97.5% of the participants regardless of skin color or geographic location (northern or southern Sweden). Furthermore the investigators will examine if vitamin D status affects on health markers as bone density, blood pressure, serum lipids, fatty acids, inflammatory and immunological markers and mental wellbeing.

Children aged 5-8 years living either northern (Umeå) or southern Sweden (Malmö) will be recruited to this trial during November-December 2012. They will be randomized to a vitamin D supplement of either 10 or 25 g per day, or in Malmö also placebo to be used for three months. The randomization will be stratified according to skin color (light or dark) according to a method using visual inspection and interviews of parents/guardians. The investigators will use a 2×2×2 factorial design to investigate the effects of two different doses of vitamin D (10 µg and 25 µg) in children with dark and light skin color, living in northern (Umeå) and southern (Malmö), Sweden. In order to achieve a moderate difference between groups (effect size 0.25) 20 children per group are required (power> 87%, alpha = 0.05). With an estimated dropout of 10%, a total of 220 children will be included.

At baseline, the participants will undergo blood sampling for S-25(OH)D and other biomarkers, blood pressure and anthropometrical measurements, including bone densitometry and body composition using air displacement pletysmography, and the parents will answer a questionnaire on behavioral and emotional problems in the participating child using the Child Behavior Checklist. These measurements will be repeated at follow-up in February-March 2013.

Description:

Vitamin D has a range of biological effects of public health relevance (Prentice et al, 2008). Besides its well known role in mineralization of bone and teeth, vitamin D also play important roles in metabolic functions, the pathogenesis of certain diseases, e.g. type 1 diabetes, celiac disease, asthma and allergies, as well as in the prevention of cancer (Holick, 2008).

Vitamin D status is assessed on plasma or serum levels of its metabolite 25-hydroxyvitamin D [25(OH)D, calcidiol] as it reflects the sum of vitamin D converted in the skin through sunlight exposure and from dietary sources. Several reports advocate that levels <37 nmol/L denote severe vitamin D deficiency; levels <50 nmol/L insufficient; 50-75 nmol/L suboptimal levels and ≥75nmol/L optimal levels (Dawson-Hughes et al, 2005, Huh et al, 2008, Yetley, 2008). In children, most suggested cut-off values for adequate levels of 25(OH)D are based on the absence of rickets, increased measures of bone mineralization and maximal suppression of parathyroid hormone (PTH) levels (Greer, 2009).

The major source of vitamin D is dermal biosynthesis catalyzed by ultraviolet B sunlight (Cashman et al, 2011). However, during winter, northern Sweden has limited hours of daylight leading to reduced sun exposure. Consequently, the dietary source of vitamin D is of specific importance in this region (Brustad et al, 2007, Edvardsen et al, 2007). Fatty fish, eggs, vitamin D fortified milk and margarines are the main sources, mainly supplying the most active form D3. These are important basic foods which also contain common food allergens. Thus, children with food allergies to milk, fish, and egg can be at increased risk of vitamin D deficiency. Several dairy products are fortified with vitamin D, but in some products in the form of D2 which is not as bioactive as D3.

Skin color affects the capacity to form vitamin D3 as children with dark complexion need 5-10 times more sun exposure to generate the same amount of vitamin D3 compared to fair-skinned children, and therefore are at increased risk of vitamin D deficiency when exposure to sun is limited (Holick, 2005). Recently the recommendations on protecting the skin from sunshine to reduce the risk of skin cancer later in life has been debated as it may increase the risk of vitamin D deficiency (Stechschulte et al, 2011). Obesity in children might be another risk factor for vitamin D deficiency, since an increased proportion of available vitamin D may be stored in adipose tissue thus lowering the S-25(OH)D (Prentice, 2008).

Despite studies indicating that the vitamin D intake among Swedish children and adolescents are significantly below recommendations, little is known of their vitamin D status (Garemo et al, 2007, Enghardt et al, 2006, Öhlund et al, 2010). Furthermore there is a paucity of studies investigating vitamin D intake and status in food-allergic adolescents who may be at increased risk of vitamin D insufficiency due to strict avoidance of vitamin D containing foods.

Recently the investigators of Dvisum assessed Vitamin D status in pre-school children (n=90; mean age 54+/-7.1 mo), all living in northern Sweden (latitude 63°) and half of them with fair skin, half with darker complexion. The study group was examined first in August-September (late summer) and then the following January-February (winter). Skin type, vitamin D intake, anthropometrics, S-25(OH) D and parathyroid hormone (S-PTH) were assessed. The investigators found inadequate vitamin D status in these children living in northern Sweden, especially in dark-skinned children and during the winter despite vitamin D intakes meeting the recommendations, prompting strategies to improve intake of vitamin D in this population. Overall, 25% and 40% of the light and dark skinned had S-25(OH) D <50 nmol/L.

The aim is to examine which amount of vitamin D is needed to maintain or increase S-25(OH)D to ≥50 nmol/L among 97.5% of the participants regardless of skin color or geographic location (northern or southern Sweden). Furthermore the investigators will examine if vitamin D status affects health markers such as bone density, blood pressure, serum lipids, fatty acids and inflammatory and immunological markers and mental wellbeing.

In order to identify whether there are differences depending on the latitude within Sweden, children will be recruited both from northern Sweden (Umeå) and from southern Sweden (Malmo). As it is unclear what levels of the serological marker 25 (OH) D that affect the health of children, different markers of health will be examined before and after the intervention. Children aged 5-8 years, 50% fair-skin 50 % darker skin, in northern Sweden (Umeå) and southern Sweden (Malmö) will be included in a longitudinal, randomized trial. The children are first examined in November-December and randomized to a vitamin D supplement of either 10 or 25 g per day, to be used for three months. At the follow up in February-March all examinations will be repeated.

The investigators will use a 2 × 2 × 2 factorial design to investigate the effects of two different doses of vitamin D (10 µg and 25 µg) in children with dark and light skin color, living in northern (Umeå) and southern (Malmö), Sweden. In order to achieve a moderate difference between groups (effect size 0.25) requires 20 children per group (power>87%, alpha = 0.05). With this group size, we can see a group difference in the S-25 (OH) D of 3.75 nmol/L, S-PTH of 0.35 mmol/L and bone mineral density in the lumbar region of 0.075 g/cm2. In Skåne, but not Umeå also a placebo group will participate. With an estimated dropout of 10%, a total of 220 children will be included.

The study include sampling for analysis of S-25 (OH) D, calcium, phosphate, alkaline phosphatase (ALP), magnesium, PTH and osteocalcin, serum lipids (total cholesterol, HDL cholesterol, LDL cholesterol. ApoA1 and ApoB lipoprotein) and fatty acids as well as inflammatory and immunological markers (CRP, interleukin (IL) -1 and 2, IL-4, IL-6, I-10, Il-17, CD40 ligand, TNF and IFNγ, fibrinogen and antisecretory factor). Before sampling, the children receive a topical anesthetic (EMLA).

Measurements of blood pressure and anthropometric measurements of length, weight, waist circumference and bone densitometry (DEXA) and body composition (fat mass% and fat free mass) using a Air Displacement Plethysmography ( BOD POD) Questions about diet, vitamin supplements, foreign travel, how much time the children spend time outdoors and the use of sunscreen as well as questions about the child's health and family situation will be answered by the parents through a questionnaire. To investigate the possible association between vitamin D status and mental well-being, the investigators will use the Child Behaviour Checklist (CBCL).

This study is national with a multicultural perspective, it is expected to provide knowledge about the needs of vitamin D to prevent vitamin D deficiency. The study is also expected to provide a better understanding of association between vitamin D status and various markers of health among children.

By preventing vitamin D deficiency, poor bone development, susceptibility to infections, and perhaps prone to autoimmune diseases and cardiovascular risk factors could be reduced, and hopefully the mental well-being improved, which reduces costs to both society and the individual, and reduces unnecessary suffering of individuals.

Recruitment information / eligibility

• Status: Completed
• Enrollment: 220
• Est. completion date: July 2013
• Est. primary completion date: April 2013
• Accepts healthy volunteers: Accepts Healthy Volunteers
• Gender: Both
• Age group: 5 Years to 7 Years

Eligibility

Inclusion Criteria:

• 5-7 years of age

• Healthy

Exclusion Criteria:

• Chronic illness, including coeliac disease or other chronic gastrointestinal disorders

• Drugs that can affect bone health or vitamin D uptake

• Cow's milk allergy

Study Design

Allocation: Randomized, Endpoint Classification: Efficacy Study, Intervention Model: Factorial Assignment, Masking: Double Blind (Subject, Caregiver, Investigator, Outcomes Assessor), Primary Purpose: Prevention

Related Conditions & MeSH terms

• Vitamin D Deficiency

Intervention

Dietary Supplement:
• Vitamin D 25 microg/d
The vitamin D supplement will be provided as a milk drink taken daily.
• Vitamin D 10 microg/d
The vitamin D supplement will be provided as a milk drink taken daily.
• No extra vitamin D
Milk drink with no extra vitamin D (placebo)

Locations

Country	Name	City	State
Sweden	Department of Pediatrics, University hospital Malmö	Malmö	Skåne
Sweden	Pediatrics, Department of Clinical Sciences, Umeå University	Umeå	Västerbotten

Sponsors (2)

Lead Sponsor	Collaborator
Umeå University	Region Skane

Country where clinical trial is conducted

Sweden, 

References & Publications (15)

Brustad M, Edvardsen K, Wilsgaard T, Engelsen O, Aksnes L, Lund E. Seasonality of UV-radiation and vitamin D status at 69 degrees north. Photochem Photobiol Sci. 2007 Aug;6(8):903-8. — View Citation

Cashman KD, FitzGerald AP, Viljakainen HT, Jakobsen J, Michaelsen KF, Lamberg-Allardt C, Mølgaard C. Estimation of the dietary requirement for vitamin D in healthy adolescent white girls. Am J Clin Nutr. 2011 Mar;93(3):549-55. doi: 10.3945/ajcn.110.006577. — View Citation

Dawson-Hughes B, Heaney RP, Holick MF, Lips P, Meunier PJ, Vieth R. Estimates of optimal vitamin D status. Osteoporos Int. 2005 Jul;16(7):713-6. — View Citation

Edvardsen K, Brustad M, Engelsen O, Aksnes L. The solar UV radiation level needed for cutaneous production of vitamin D3 in the face. A study conducted among subjects living at a high latitude (68 degrees N). Photochem Photobiol Sci. 2007 Jan;6(1):57-62. — View Citation

Enghardt B, Pearson M, Becker W. Dietary habits and nutrient intake in Swedish children 4 years old and school children in grade 2 and 5 (Riksmaten - barn 2003). Uppsala: National Food Administration (Livsmedelsverket), Uppsala, Sweden; 2006.

Garemo M, Lenner RA, Strandvik B. Swedish pre-school children eat too much junk food and sucrose. Acta Paediatr. 2007 Feb;96(2):266-72. — View Citation

Greer FR. Defining vitamin D deficiency in children: beyond 25-OH vitamin D serum concentrations. Pediatrics. 2009 Nov;124(5):1471-3. doi: 10.1542/peds.2009-2307. — View Citation

Holick MF. The vitamin D deficiency pandemic and consequences for nonskeletal health: mechanisms of action. Mol Aspects Med. 2008 Dec;29(6):361-8. doi: 10.1016/j.mam.2008.08.008. Review. — View Citation

Holick MF. The vitamin D epidemic and its health consequences. J Nutr. 2005 Nov;135(11):2739S-48S. — View Citation

Huh SY, Gordon CM. Vitamin D deficiency in children and adolescents: epidemiology, impact and treatment. Rev Endocr Metab Disord. 2008 Jun;9(2):161-70. doi: 10.1007/s11154-007-9072-y. Review. — View Citation

Ohlund K, Olsson C, Hernell O, Ohlund I. Dietary shortcomings in children on a gluten-free diet. J Hum Nutr Diet. 2010 Jun;23(3):294-300. doi: 10.1111/j.1365-277X.2010.01060.x. — View Citation

Prentice A, Goldberg GR, Schoenmakers I. Vitamin D across the lifecycle: physiology and biomarkers. Am J Clin Nutr. 2008 Aug;88(2):500S-506S. Review. — View Citation

Prentice A. Vitamin D deficiency: a global perspective. Nutr Rev. 2008 Oct;66(10 Suppl 2):S153-64. doi: 10.1111/j.1753-4887.2008.00100.x. Review. — View Citation

Stechschulte SA, Kirsner RS, Federman DG. Sunscreens for non-dermatologists: what you should know when counseling patients. Postgrad Med. 2011 Jul;123(4):160-7. doi: 10.3810/pgm.2011.07.2315. Review. — View Citation

Yetley EA. Assessing the vitamin D status of the US population. Am J Clin Nutr. 2008 Aug;88(2):558S-564S. Review. — View Citation

* Note: There are 15 references in all — Click here to view all references

Outcome

Type	Measure	Description	Time frame	Safety issue
Other	Inflammatory and immunological markers	CRP, interleukin (IL) -1 and 2, IL-4, IL-6, I-10, Il-17, CD40 ligand, TNF-alfa, IFN?, fibrinogen and antisecretory factor	90 days after start of treatment	No
Other	Behavioral and emotional well-being	Parental assessment using Child Behavioral Checklist	90 days after start of treatment	No
Primary	Serum 25OH-vitamin D levels		90 days after start of treatment	No
Secondary	Bone mineralisation	Bone mineralisation will be measured with DXA-scan, serum PTH and serum osteocalcin	120 days after start of treatment	No