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Caring for kids new to Canada

A guide for health professionals working with immigrant and refugee children and youth

Vitamin D Deficiency

Key points

  • Vitamin D deficiency is prevalent among refugee children.
  • Causes of vitamin D deficiency include dietary insufficiency, malabsorption, reduced sun exposure, and prolonged breastfeeding without supplementation.
  • Health risks include hyperparathyroidism and impaired bone development.
  • Vitamin D deficiency should be suspected in young newcomers to Canada who are at risk and present with pain, irritability and poor growth or skeletal deformity, or rickets and (rarely) hypocalcemic seizures.
  • Vitamin D deficiency can be treated with supplementation and dietary modification.

Prevalence

Vitamin D deficiency has been found to be common in refugee children.1,2 One study found the prevalence among refugees treated at Australian health centres to be between 40% and 80%.3

Definition

The best indicator of vitamin D status is serum concentration of 25-hydroxy-vitamin-D (25OHD).4 Current Canadian Paediatric Society (CPS) definitions of 25OHD status are provided in Table 1.5  There is controversy, however, over the levels classified as deficient and insufficient.6

Table 1: Current definitions of 25OHD status
25(OH)D level ng/mL nmol/L
Deficient <10 <25
Insufficient 10-30 25-75
Optimal 30-90 75-225
Pharmacological (potential adverse effects) >90 >225
Potentially toxic >200 >500
Source: Canadian Paediatric Society. Vitamin D supplementation: Recommendations for Canadian mothers and infants. Paediatr Child Health 2007;12(7):583-9.

Etiology

In addition to inadequate dietary intake or malabsorption of vitamin D, deficiency can also be related to:

  • limited sun exposure (causes include not just climate but cultural traditions such as protective or religious clothing or keeping babies indoors),
  • low vitamin D levels in pregnancy, and
  • prolonged breastfeeding without supplementation.1,7

Refugee children from conflict zones may lack sun exposure due to hiding.1 Deficiency is also more common in females and people with darker skin.8

Consequences

Vitamin D deficiency may cause secondary hyperparathyroidism and affect bone development, the most serious consequence of which is rickets.

A recent study9 has associated vitamin D deficiency with multiple health risks, including increased severity of infectious disease and long-term risk of cardiovascular disease and cancer, but further research into long-term effects is needed.

Diagnosis

Vitamin D deficiency should be suspected in young newcomers at risk who present with pain, irritability and poor growth or skeletal deformity, rickets or (rarely) hypocalcemic seizures.

Diagnosis can be confirmed using a blood test for the measurement of serum 25-OHD as well as levels of phosphate and alkaline phosphatase.10 Rickets can be diagnosed using radiological criteria.

Treatment

The CPS5 and Health Canada4 recommend vitamin D supplementation for Canadian infants who are breastfed. The doses may need to be modified or increased for newcomer children based on risk, and there is some controversy over optimal dosage. The recommendations from the CPS on supplementation are below. Children with clinical vitamin D deficiency (rickets or osteomalacia) will require therapeutic doses of vitamin D.

In babies 1 year of age and older, children and youth, vitamin D deficiency can also be addressed by giving a vitamin D supplementation and dietary modifications.

For infants under 1 year of age, the CPS recommends the following:5

  • Breastfed babies should be given a supplement of 400 IU (international units) per day.
  • Babies in northern communities (north of 55° latitude, which is about the level of Edmonton) or who have other risk factors (such as dark skin) should get 800 IU per day between October and April, when there is less sunlight.
  • Since vitamin D is already added to formula, most full-term babies who are formula-fed won’t need a supplement. However, formula-fed babies in northern communities should receive a supplement of 400 IU per day from October to April to ensure they have enough vitamin D.

Information on recommended daily intake of vitamin D for all older groups is available from Health Canada.

Selected resources

Information for parents and caregivers

Canadian Paediatric Society, Vitamin D. 

References

  1. Sheikh M, Wang S, Pal A, et al. Vitamin D deficiency in refugee children from conflict zones. J Immigr Minor Health 2011;13(1):87-93.
  2. Aucoin, M, Weaver, R, Thomas, R, Jones, L. Vitamin D status of refugees arriving in Canada: Findings from the Calgary Refugee Health Program. Can Fam Physician 2013; 59:e188-194.
  3. Benson J, Skull S. Hiding from the sun—vitamin D deficiency in refugees. Aust Fam Physician 2007;36(5):355-7.
  4. Health Canada. Vitamin D and calcium: Updated dietary reference intakes.
  5. Canadian Paediatric Society. Vitamin D supplementation: Recommendations for Canadian mothers and infants. Paediatr Child Health 2007;12(7):583-9.
  6. Institute of Medicine of the National Academies, Food and Nutrition Board, 2010, 2011.
    Consensus report: Dietary reference intakes for calcium and vitamin D.
  7. U.S. Department of Health and Human Services, Centers for Disease Control and Prevention, National Center for Emerging and Zoonotic Infectious Diseases. Guidelines for evaluation of the nutritional status and growth in refugee children during the domestic medical screening process. Bethesda, MD: CDC, April 2012.
  8. Wishart HD, Reeve AM, Grant CC. Vitamin D deficiency in a multinational refugee population. Intern Med J 2007;37(12):792-7.
  9. Holick MF. Vitamin D deficiency. N Engl J Med 2007;357(3):266-81.
  10. Pearce SH, Cheetham TD. Diagnosis and management of vitamin D deficiency. BMJ 2010;340:b5664.

Reviewer(s)

  • Anna Banerji, MD
  • Andrea Hunter, MD

Last updated: July, 2016