=colecalciferol. Essential for bone health.
Obtained from sun exposure to the skin. Only a few dietary sources – oily fish, cheese, egg yolk, fortified cereals. Diet more important for calcium, of course. Once you apply sun screen, you don’t make vitamin D any more so there is a conflict with the potential for skin solar damage including cancer.
Children under 5 considered a high risk group, along with pregnant, pigmented skin, northern latitudes, wearing concealing clothing, being housebound etc.
2021 Scottish government advice is that everyone consider taking a Vitamin D supplement, particularly between October and March, but that all year round supplementation should be taken by:
- all pregnant and breastfeeding women
- all infants and children under 5 years old
- people who have low or no exposure to the sun, for example those who cover their skin for cultural reasons, are housebound, confined indoors for long periods or live in an institution
- people from minority ethnic groups with dark skin such as those of African, African-Caribbean and south Asian origin, who require more sun exposure to make as much vitamin D
2017 chief medical officer (CMO) advice – all babies from birth up to one-year-of-age should be given a daily supplement of 8.5 to 10μg vitamin D with Healthy Start vitamin drops being the recommended choice of vitamin, other than babies who are formula fed getting at least 500ml per day, as infant formula already has added vitamin D.
Nonetheless, breastfeeding is preferred – supplementation needed for breastfed infants given lack of sunlight in the UK (probably only useful sun exposure in Scotland between April and September, and between 11 and 3pm).
Children aged 1-4 years old should be given a daily supplement containing 10mcg of vitamin D.
“Healthy Start” vitamins preferred – made for NHS, available free to those on income support, contains recommended dose (approx 300 units) .
Standard prevention dose is 300-400u (10mcg) (neonates), between 400u and 1000u (over 1/12) per day. Over the counter multivitamins often contain surprisingly little Vitamin D. Drops, tablets, sprays all available.
Many vitamin D preparations around this dose contain calcium, which may improve efficacy in fracture prevention, but some people won’t like. Fultium D3 capsules have 800u (20μg) vit D and no calcium.
Symptoms
Aches and pains, delayed walking, seizures and tetany, genu valgum/varum, muscle weakness (incl cardiomyopathy). The classic features of rickets are bowed legs, rachitic rosary (expanded costochondral junctions), pectus carinatum, curvature of the spine, expansion of the metaphyses at the wrist/ankle, poor dentition.
Testing
Historically deficiency defined as 25hydroxyVitaminD below 25nmol/L. But debated what is optimal. Current practice in the UK, uses this figure, and defines ‘insufficiency’ as between 25 and 50 nmol/L.
Treatment
For treatment of deficiency, with symptoms, dose is substantially higher – 2000u for <6/12 of age, 6000u for kids up to 12yrs, 10 000u over 12yr. Treat for 4-8 weeks, check that adequate calcium in diet. After that, to standard prevention dose as above.
Colecaciferol liquid available (3000u/ml), tablets come in 1000u doses and higher. The combined VitD/Cal tablets tend to have lower doses and may not be well tolerated.
Weekly doses, or single megadoses (30x daily dose) have been recommended where compliance a concern. Intramuscular ergocalciferol 7.5mg (300,000 units, 1ml) can be given in special situations.
Alfacalcidol is used in chronic kidney disease, needs specialist advice and careful monitoring.
Monitoring
Repeat measurement of serum 25 OH vitamin D is not usually necessary, and certainly not within 3 months of starting treatment unless agreed with the duty biochemist. Check compliance eg empty bottles?
Continue supplementation until child has stopped growing.
[RCPCH guidance, 2013]