See also 

Immigrant health guideline - Low Vitamin D 
Contains detailed information and background, especially for at-risk migrant and refugee populations

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 

• 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)

Management

Initial management:

• 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.
  • Drops designed for adults are up to 50 times more concentrated, leading to risk of overdosing.  
  • See photoboard of supplements and give clear instructions
• 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

• 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: 

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. 

• Medical Practitioners can obtain TGA authorisation to treat patients with high dose Vitamin D (usually 50,000IU D3 capsules).
• Further information and authorised prescriber form.
• List of pharmacies stocking high dose vitamin D 

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:  

• Vitamin D factsheets (English and translated versions)
• Vitamin D and UV radiation (SunSmart) 

Appendices:

• Vitamin D supplements photo board