Immigrant Health Service

Low Vitamin D

  • Dosing tables        Measurement of vitamin D       Pharmacies stocking high dose vitamin D   Supplements photoboard

    Medicare guidelines for vitamin D testing
    From 1 November 2014 - the Medicare item for 25 hydroxy vitamin D testing changed to item number 66883. Vitamin D testing only attracts a Medicare benefit if the patient meets one or more of the 11 criteria below. The RCH laboratory will not perform vitamin D testing unless the patient meets (any of) these criteria - now included on EPIC.
    Criteria
    (a) signs or symptoms of osteoporosis or osteomalacia
    (b) increased alkaline phosphatase and otherwise normal liver function tests
    (c) hyperparathyroidism, hypo or hypercalcaemia, or hypophosphataemia
    (d) malabsorption (e.g. cystic fibrosis, short bowel syndrome, inflammatory bowel disease or untreated coeliac disease, previous bariatric surgery)
    (e) deeply pigmented skin, or chronic and severe lack of sun exposure for cultural, medical, occupational or residential reasons
    (f) on medication that decreases 25OHD levels (e.g. anticonvulsants)
    (g) chronic renal failure or renal transplant recipient
    (h) less than 16 years of age and has signs or symptoms of rickets
    (i) infant whose mother has established vitamin D deficiency
    (j) exclusively breastfed baby and has at least one other risk factor mentioned in a paragraph in this item
    (k) sibling who is less than 16 years of age and has vitamin D deficiency

     

    This guideline was developed for the RCH Immigrant health clinic, and is the basis for the RCH Clinical Practice Guidelines. This version contains additional detail, directed to clinicians providing care for refugee-background and migrant communities. The content is congruent with the 2013 Australian and New Zealand position statement on 'Vitamin D and health in pregnancy, infants, children and adolescents in Australia and New Zealand'.

    Background

    Vitamin D is essential for bone and muscle health, and there is evidence it is important in other aspects of health.

    • Vitamin D refers to both D3 (cholecalciferol) and D2 (ergocalciferol)
      • D3 is produced in the skin through the action of UVB in sunlight, it is also the most common form in food and the form available in supplements. Small amounts of D2 are found in some plant-based foods
    • Sunlight is the most important source of vitamin D, and is estimated to provide 90% of vitamin D in humans[1]
      • The amount of UVB available for skin synthesis varies with latitude, season, time of day, shade, and skin exposure (e.g. clothing). Window glass blocks UVB
      • Adults with dark skin require 2 - 7 times the amount of UVB compared to people with light skin to produce similar vitamin D levels[2]
      • There may not be enough UVB during winter months in the Southern states to maintain adequate vitamin D levels
      • There are no data on skin synthesis in children
      • Sunscreens do not result in low vitamin D with normal use in adults[2]
      • See the updated 2016 Cancer Council Australia Position statement on sun exposure and vitamin D
    • Dietis usually a poor source of vitamin D; most Australians only get around 10% of their vitamin D from dietary sources[3]
      • Vitamin D is found naturally in few foods (some fatty fish, liver, small amount in eggs). Some dairy products are fortified with Vitamin D (some milk, all margarine). Meat, normal dairy and fruit are not sources of vitamin D
      • Breastmilk contains almost no vitamin D (25 IU/L). Infant formula is fortified with D3 (360 - 520 IU/L)
    • In the absence of sun exposure, recommended dietary allowances are[4]:
      • Age < 12 months - AI 400 IU daily
      • 1 - 18 years - EAR 400 IU daily and RDA 600 IU daily
    • 25-hydroxy vitamin D (25(OH)D) is used to measure vitamin D status
    • The recommended level for 25(OH)D is >= 50 nmol/L at all ages and during pregnancy/lactation
    Definitions of vitamin D status
    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
     Notes:
    Vitamin D 1 mcg = 40 IU. To convert ng/ml to nmol/L multiply by 2.5.
    Adequate Intake (AI), used when no EAR/RDA available
    Estimated Average Requirement (EAR), reflects estimated median requirements
    Recommended Daily Allowance (RDA) meets/exceeds the needs of 97.5% of the population

    Risk factors for low vitamin D

    • Lack of skin exposure to UVB in sunlight (time inside, chronic illness/hospitalisation, complex disability, covering clothing, southerly latitude)
    • Dark skin (Fitzpatrick types V and VI)
    • Medical conditions or medications affecting vitamin D metabolism (obesity, liver failure, renal failure, malabsorption, medications e.g. isoniazid, rifampicin, anticonvulsants)
    • In infants: maternal vitamin D deficiency (cord levels ~ 65% maternal levels) [5] and exclusive breastfeeding combined with at least one other risk factor.

    Prevalence

    Refugee-background communities may have multiple risk factors for low vitamin D e.g. dark skin, covering clothing and limited time outside.

    • 61 - 100% in African refugees in Melbourne, Adelaide and Sydney have low vitamin D (< 50 nmol/L) [6-11]
    • Two large Australian case series of rickets found almost all children had ethno-cultural risk factors (dark skin, maternal covering clothing) [12,13]
    • Low vitamin D is also seen commonly in other refugee cohorts wearing covering clothing (Afghani, Iraqi), and has been found in 33% of Karen refugees.[14]

    Assessment

    History

    • Non-specific bony and/or muscular pain; fatigue with exercise
    • Irritability, delayed motor milestones (young children)
    • Dairy intake, symptoms of low calcium (muscle cramps)
      • Hypocalcaemic seizures are rare beyond 6-12 months of age
    • Sunscreen use, time outside  
    • Previous vitamin D levels, previous/current treatment (especially with the availability of newer forms of supplementation) see photo board
    • Family understanding

    Exam

    • Rickets - deformity in growing bones due to failure of mineralisation of osteoid. Peak incidence during infancy, although deformity reflects age/growth (and can be in any direction). Consider other causes if asymmetrical
      • Long bone deformity, splaying (wrists, ankles), bossing, delayed fontanel closure (normally closed by 18 months, 100% by 23 - 26 months), rosary
    • Other - delayed dentition (no teeth by 9 months, no molars by 14 months), enamel hypoplasia

    Screening

    • Screen children/adolescents with one or more risk factors for low vitamin D
      • Measure vitamin D, calcium, phosphate and ALP
      • Also measure parathyroid hormone in those with low calcium intake, symptoms/signs or multiple risk factors
      • In exclusively breastfed infants with at least one other risk factor it is usually more practical to start supplements without screening (see below)
    • Children with rickets require the above investigations and additional investigations (CUE, X-ray wrist, clinical photos, consider Mg, 1,25 dihydroxy vitamin D and urinary Ca/P/Creatinine)
    • In recent arrivals: if the initial vitamin D level is normal, repeat at the end of the first winter in Australia
    • Levels at the start and end of winter can be useful to make a clinical judgment on dosing
    • Clinical photography is useful to monitor bony deformity (nutritional rickets usually corrects after treatment of low vitamin D provided the child has adequate calcium and phosphate intake).

    Measurement of vitamin D

    25(OH)D is used to measure vitamin D status.
    RCH uses a chemiluminescence immunoassay which measures total 25(OH)D. This measures both 25(OH)D3 (98%) and 25(OH)D2 (82%)
    The volume of blood required is 1 ml (around 200 mcL serum)
    The coefficient of variation is 10%
    See  Specimen collection handbook for details

    Management

    • Admission/specialist assessment
      • Symptomatic rickets/hypocalcaemia (including tetany, stridor, seizures) requires hospital admission for intravenous calcium infusion with cardiac monitoring and vitamin D, do not give Vitamin D in the outpatient setting to this group
      • Children with clinical rickets or abnormal serum calcium require specialist assessment
    • Children with low vitamin D should be treated to restore their levels to the normal range with either daily dosing or high dose therapy.
      • There is inadequate evidence to support high dose therapy in children age < 3 months
      • D3 is the only form currently available in supplements.
      • RCH uses cholecalciferol (D3) 100,000 IU/ml in olive oil. The solution is light and temperature sensitive and degrades to inactive vitamin D. The shelf life is only 3 months if not kept in the fridge (with reduced potency at this time). It should be 90% potent at 3 months if stored < 4 degrees Celsius, but olive oil consolidates at this temperature. Similar solutions are used at the following hospitals: Monash, Dandenong, Sunshine, Warnambool, and Ballarat.
      • Dosing tables
    • Ensure adequate calcium intake, children/young people may need calcium supplements if dietary intake is poor (< 2 serves dairy daily)
      • 1 cup cow milk contains ~ 300 mg calcium. One Caltrate [TM] tablet contains 600 mg calcium
      • RDA for calcium by age
      • Cheese, yoghurt and fortified soy dairy are useful sources of calcium in children who dislike cow milk
    • Treatment should be paired with health education and advice about sun protection/sun exposure; encouraging outside play/activity. Children/young people with dark skin can tolerate intermittent sun exposure without sunscreen. Hats/sunglasses are still recommended
    • Follow-up bloods at 3 months (earlier - at 1 month - in infants with moderate - severe deficiency)
      • Follow-up bloods should include 25(OH)D, Ca, PO4 and ALP; and PTH if elevated initially. Further management may be required if 25(OH)D is still low
      • Children/young people with ongoing risk factors for low vitamin D need to understand this is a long-term issue: they require ongoing monitoring and a plan to maintain vitamin D and calcium status through behavioural change where possible, and supplementation where this is inadequate. They may require high dose vitamin D more than once a year. Avoid very frequent testing
    • Breastfed babies with at least one other risk factor for low vitamin D should be given 400 IU daily for at least the first 12 months of life. Babies on full formula feeds should receive adequate vitamin D from this source. Consider checking levels or adding daily supplements in babies with risk factors for low vitamin D with mixed feeds or who have appropriately reduced their formula intake after starting solids
    • Pregnancy guidelines (RWH 2017) are available
    • Vic Department of Health key health messages (August 2012) and pharmacies stocking high dose vitamin D
    • Translated handouts on vitamin D (includes English versions)

    Dosing table: Management of low vitamin D

    Age
    Level
     
    Treatment
    (oral doses D3)
     
    Maintenance/prevention in children with ongoing risk factors
    Preterm
    Mild deficiency
    30 - 49 nmol/L
    200 IU/kg/d
    Maximum 400 IU/d
    200 IU/kg/d
    Maximum 400 IU/d
    Moderate or severe deficiency
    < 30 nmol/L
    800 IU/d, review after 1 month
    200 IU/kg/d
    Maximum 400 IU/d
    < 3 months
    (term)
    Mild deficiency
    30 - 49 nmol/L
    400 IU daily for 3 months
    400 IU daily
    Moderate or severe deficiency < 30 nmol/L
    1,000 IU daily for 3 months
    400 IU daily
    3 - 12 months
    Mild deficiency
    30 - 49 nmol/L
    400 IU daily for 3 months
    400 IU daily
    Moderate or severe deficiency
    < 30 nmol/L
    1,000 IU daily for 3 months or 50,000 IU and review after 1 month, consider repeating dose
    400 IU daily
    1 - 18 years
    Mild deficiency
    30 - 49 nmol/L
    1,000 - 2,000 IU daily for 3 months or 150,000 IU stat
    400 IU daily or 150,000 IU at the start of Autumn
    Moderate or severe deficiency
    < 30 nmol/L
    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
    400 IU daily or 150,000 IU at the start of Autumn

    Calcium [4]

    Age
    AI
    EAR
    RDA
    0 - 6 months
    200 mg
     
     
    6 - 12 months
    260 mg
     
     
    1 - 3 years
     
    500 mg
    700 mg
    4 - 8 years
     
    800 mg
    1000 mg
    9 - 18 years
     
    1100 mg
    1300 mg

    Sun exposure

    Skin colour
    Light to olive skin
    Fitzpatrick type I - IV
    Naturally dark skin
    Fitzpatrick type V - VI
     
     
     
    Infants, children, adolescents
     
    Summer or UV index >= 3
    Avoid sunburn, full sun protection with sunscreen/hat/clothing/shade and sunglasses recommended
    Avoid sunburn, able to tolerate intermittent sun exposure without sunscreen, hat and sunglasses still recommended
    Encourage active outside play or physical activity during and after school/preschool
     
     
    Winter
    Sun protection recommendations vary with latitude/UV index. If UV index < 3, sun protection not required unless in alpine regions, outside for extended periods or near highly reflective surfaces such as snow/water
    Sunscreen not needed in Southern states/New Zealand unless near highly reflective surfaces such as snow or water. It may not be possible to maintain vitamin D levels through sun exposure alone in southern states of Australia/New Zealand
    Encourage active outside play or physical activity during and after school/preschool
     
     
    Pregnancy/
    Adults
     
    Summer
    6 - 7 minutes with arms (or equivalent area) exposed mid-morning or mid-afternoon most days of the week, avoid sunburn,
    full sun protection with sunscreen/hat/clothing/shade and sunglasses recommended
    15 - 50 minutes with arms (or equivalent area) exposed mid-morning or mid-afternoon most days of the week, 
    avoid sunburn, 
    intermittent sun exposure without sunscreen can be tolerated but hat and sunglasses still recommended
     
    Winter
    7 - 40 minutes exposure (depending on latitude) with face arms, and hands exposed at lunchtime most days of the week. If UV index < 3, sunscreen not required 
    unless in alpine regions, outside for extended periods or near highly reflective surfaces such as snow/water
    Depends on latitude. 
    Sunscreen not needed in Southern states/New Zealand unless near highly reflective surfaces such as snow or water. 
    It may not be possible to maintain vitamin D levels through sun exposure alone in southern states of Australia/New Zealand

    References

    Immigrant health clinic protocols. Author: Georgie Paxton, updated March 2015, reviewed Feb 2018. Contact georgia.paxton@rch.org.au