Introduction
• > 100 ng/mL (> 250 nmol/L): intoxication | |
• 20–100 ng/mL (50–250 nmol/L): target area | |
• 12–20 ng/mL (30–50 nmol/L): subnormal | |
• < 12 ng/mL (< 30 nmol/L): deficiency |
Physiology of vitamin D metabolism
Laboratory assessment of vitamin D
Vitamin D supply in Germany
Interpretation of serum vitamin D levels
• Exclusively breastfed infants without vitamin D prophylaxis | |
• Infants, children, and adolescents with: | |
• Malabsorption or maldigestion disorders (e.g., celiac disease, Crohn’s disease, cystic fibrosis) | |
• Chronic inflammatory diseases (e.g., inflammatory bowel disease) | |
• Chronic kidney disease | |
• Chronic liver disease | |
• On permanent medication with substances that affect calcium or vitamin D metabolism (e.g., antiepileptic drugs, antiviral medication, fungicides, or high dose glucocorticoid therapy which inhibits intestinal calcium absorption and stimulates tubular calcium excretion) | |
• With very low sun exposure, for example, chronically immobilized children and adolescents | |
• With a migrant background (through the influence of pigmentation, nutrition, and sun exposure) |
Vitamin D and skeletal diseases
Vitamin D and extraskeletal diseases
References | Effect of vitamin D supplementation from RCTs | |
---|---|---|
Diseases of the upper airway | + and − | |
Asthma bronchiale | + and − | |
Attention-deficit/hyperactivity disorder | − | |
Type I diabetes mellitus | No RCT performed | |
Type II diabetes mellitus | + and − | |
High blood pressure | − | |
Cardiac insufficiency | − | |
Obesity | No RCT performed | |
Multiple sclerosis | + and −* |
Conclusions and recommendations
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During childhood and adolescence, adequate vitamin D status is desirable to promote enteral calcium absorption and thus bone health.
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In addition to the vitamin D provided in breast milk or infant formula, an oral vitamin D3 supplement (400–500 IU/day) is recommended for all infants in Germany until their second early summer. Depending on the time of their birth, vitamin D supplementation is recommended for a period of one to one and a half years, since during summer, increased ultra violet exposure and vitamin D self-synthesis occurs. A combined supplement comprised of vitamin D and fluoride prophylaxis should be given.
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The total daily intake of vitamin D for premature infants weighing less than 1500 g at birth is 800–1000 IU/day in the first few months of life.
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A desirable total vitamin D intake (from sunlight-dependent, endogenous synthesis and enteral intake) for children older than 1 year, adolescents, and adults is 600–800 IU/day.
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Regular outdoor activities for children not only improve vitamin D synthesis, but also lead to further positive health effects. Exposure to sunlight improves vitamin D status while exercise increases bone mass development. Exposure to sunlight between April and September, at least twice a week between 10:00 am and 3:00 pm for 5 to 30 min is the most effective form of improving vitamin D status. Playing outside with an uncovered head, arms, and legs is adequate for vitamin D production in children and adolescents with skin types II and III. Care should be taken to avoid sunburn.
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Children and adolescents should regularly (once or twice a week) consume fish rich in vitamin D. Fish consumption is desirable for various reasons and contributes to vitamin D intakes.
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There are indications that vitamin D supplementation has possible preventive effects on the risk for infections. However, these effects are not proven beyond doubt.
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Untargeted testing of vitamin D serum concentrations in healthy children without risk factors for vitamin D deficiency is not recommended. Groups at high risk of vitamin D deficiency include children and adolescents with certain chronic diseases and risk factors (Table 2). In these cases, prophylactic vitamin D supplementation (500–1000 IU/day) may be useful, especially in the winter months.
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A 25-hydroxy-vitamin D serum concentration (< 20 ng/ml) does not constitute an indication for vitamin D supplementation unless there are additional risk factors (Table 2).