Vitamin D deficiency


  • Statewide logo

    This guideline has been adapted for statewide use with the support of the Victorian Paediatric Clinical Network

  • See also 

    Background 

    • Vitamin D is essential for bone, muscle and other aspects in health.
    • Sunlight (UVB) is the most important source of vitamin D (>90%);
    • Only small amounts are available from diet. The main natural food source is fish. Breastmilk, despite its other benefits, contains almost no vitamin D. Infant formula is fortified with Vitamin D.
    • D3 synthesis in the skin varies due to:
      • Skin colour: Adults with dark skin (Fitzpatrick types V and VI) require 3-6 times the amount of UVB compared to people with light skin.
      • Skin exposure/clothing.
      • Season/UVB available - there may not be enough UVB during winter months in Victoria to maintain adequate vitamin D levels
      • Note: Sunscreens do not result in low vitamin D.
    • In the absence of sun exposure, recommended dietary allowances are:
      • 0-12 months old: 400 IU daily
      • 1 - 18 years old: 400-600 IU daily

    Assessment  

    Risk factors: 

    • Lack of skin exposure to sunlight
    • Dark skin
    • Medical conditions/medications: obesity, liver failure, renal disease, malabsorption (incl. cystic fibrosis, celiac disease, inflammatory bowel disease) medications (incl. isoniazid, rifampicin, anticonvulsants)
    • In infants: maternal vitamin D deficiency and exclusive breastfeeding combined with at least one other risk factor. 

    History: 

    • Non-specific bone / muscular pain; fatigue with exercise
    • Symptoms of low calcium: muscle cramps, tetany, seizures (rare beyond 6 months of age)
    • Time outdoors 
    • Dairy intake
    • Previous vitamin D levels, previous/current treatments - to reduce risk of over-dosing
    • Family understanding of Vitamin D

    Exam: 

    • Signs of Rickets (deformity in growing bones)
    • Delayed dentition, delayed anterior fontanelle closure 

    InvestigationsInfants:

    Infants:
    • Exclusively breastfed infants with at least one other risk factor without symptoms/signs - usually appropriate to start supplements without investigations.
    • Infants with symptoms/signs need urgent specialist review (see Management)

    In children with one or more risk factors for low vitamin D:

    • Measure vitamin D, Ca, PO4 and ALP
    • In those with symptoms/signs of deficiency: also measure parathyroid hormone
    • In children with rickets: also measure UECr. Perform X-ray wrist and clinical photography

    Definitions of vitamin D status: 

    The laboratory test of Vitamin D is 25-hydroxy vitamin D - 25(OH)D.
    The recommended level is > 50 nmol/L.
    (Note: Some laboratories report levels with a different range)

    Severe deficiency

    < 12.5 nmol/L

    Moderate deficiency

    12.5 - 29 nmol/L

    Mild deficiency

    30 - 49 nmol/L

    Sufficient

    > 50 nmol/L

    Elevated

    > 250 nmol/L


    Management

    Vitamin D deficiency is a common condition requiring long-term management.
    It is ideally self-managed or managed in community health settings.
    Children with clinical rickets or abnormal serum calcium require urgent specialist assessment and management.


    Initial management:

    Children and adolescents with low vitamin D 
    • Aim to restore and maintain Vitamin D levels in the normal range (≥ 50 nmol/L)
    • Options are either daily low-dose supplements or high-dose intermittent therapy (≥50,000IU/dose). See Dosing Table
    • Multiple low-dose supplements are commercially available.
    • Ensure adequate Calcium Intake
      • Cheese, yoghurt and fortified soy dairy are useful sources of calcium in children who dislike cow milk. Consider supplements if poor intake.
    • Treatment should be paired with health education about sun protection/sun exposure and encouraging outside activity. Children/young people with dark skin can tolerate intermittent sun exposure without sunscreen. Hats/sunglasses are still recommended. See also:Sun Exposure recommendations and Sunsmart handouts

    Infants: 

    • There is inadequate evidence to support high dose treatments in infants aged < 3 months.
    • Exclusively breastfed infants of mothers with Vitamin D deficiency, with at least one other Risk Factor should be given 400 IU daily for at least the first 12 months of life. Monitor adherence.
    • Infants on full formula feeds should receive adequate vitamin D from this source. Those on mixed feeds or solids may have inadequate intake: consider checking levels or adding daily supplements in babies with risk factors.
    • Note: Current practice in Victoria varies widely. Some hospitals treat infants born to deficient mothers with 50,000 IU at birth. Sometimes a sticker is placed in the Green child health book.

    Dosing tables: 

    Age

    Deficiency level

    Treatment (oral doses D3) 

    Maintenance/prevention in children with ongoing risk factors

    Preterm

    Mild

    200 IU/kg/day, maximum 400 IU/day

    200 IU/kg/day, max. 400 IU/day

    Moderate or severe

    800 IU/day, review after 1 month

    < 3 months 
    (term)

    Mild

    400 IU/day for 3 months

    400 IU daily

    Moderate or severe

    1,000 IU/day daily for 3 months

    3 - 12 months

    Mild

    400 IU/day for 3 months

    400 IU daily

    Moderate or severe

    1,000 IU/day for 3 months,
    OR 50,000 IU stat and review after 1 month (consider repeating dose)

    1 - 18 years

    Mild deficiency

    1,000-2,000 IU/day for 3 months,
    OR 150,000 IU stat

    400 IU daily,
    OR 150,000 IU at start of Autumn

    Moderate or severe

    1,000 - 2,000 IU daily for 6 months,
    OR 3,000 - 4,000 IU daily for 3 months,
    OR 150,000 IU stat and repeat at 6 weeks


    Notes: There is a wide range of commercially available tablets, capsules and liquid supplements.
    See Supplements photoboard

    Ongoing management and monitoring:

    • In moderate/severe deficiency, repeat bloods: 25(OH)D, Ca, PO4, ALP (and PTH if previously elevated) three months after initial diagnosis/treatment (one month in infants). Further treatment may be required if 25(OH)D is still low.
    • In mild deficiency, it is usually not necessary to recheck for response to treatment. 
    • Avoid very frequent testing  in patients with known deficiency and stable risk factors
      • One practical approach is to test yearly or second-yearly at the end of Summer (peak annual levels of Vitamin D).
      • Children with ongoing risk factors need a plan to maintain levels through Winter/Spring; this can either be through annual dosing (e.g. in Autumn), or daily supplements over the cooler months (e.g. April - September). Children with multiple risk factors and/or severe deficiency may require high dose treatments more than once a year. 
    • If high dose treatments are required:
      • Liaise with your local community health centre (many GPs are high-dose prescribers) 
      • Refer to your local General Paediatric outpatients. 

    Consider admission/specialist consultation: 

    • Admission: symptomatic hypocalcaemia (incl. tetany, stridor, seizures)
    • Specialist review:
      • clinical rickets
      • abnormal serum calcium
      • not responding to high-dose vitamin D supplements

    Consider transfer when: 

    • Children requiring care above the level of comfort of the local hospital.

      For emergency advice and paediatric or neonatal ICU transfers, call the Paediatric Infant Perinatal Emergency Retrieval (PIPER) Service: 1300 137 650.

    Information sheets:  

    Appendices: