Vitamin A Deficiency
- Vitamin A deficiency is common in low-resource countries, especially among refugees.
- Vitamin A deficiency can affect vision, in a range from reduced night vision to blindness.
- Causes include dietary insufficiency, malabsorption, or increased utilization or excretion due to common illnesses.
- Stressors such as diarrhea, measles and pneumonia can decrease vitamin A levels and lead to disease.
Vitamin A deficiency is common in low-resource countries, particularly among refugees. For example, one-third of adolescent refugees in Nepal and up to two-thirds of African refugee children have been reported to have vitamin A deficiency.1,2
Vitamin A status can be identified by measuring serum retinol concentrations to assess levels. Table 1 helps define degrees of deficiency. With the high prevalence of vitamin A deficiency, however, this testing is not usually done if patients are asymptomatic.
|Serum retinol (micrograms/dL)||Serum retinol (micromols/L)||WHO definition|
|20 or above||0.7 or above||None|
|Source: Adapted from Centers for Disease Control and Prevention, World Food Programme. A Manual: Measuring and interpreting malnutrition and mortality. Rome: WFP, 2005:28.|
Vitamin A deficiency can be caused by low dietary intake, malabsorption and increased utilization or excretion associated with common illnesses.3 Despite established policies for supplementing and fortifying foods supplied at refugee camps, high rates of vitamin A deficiency persist. Refugee numbers, pressures on food supply and difficult logistics make implementation a challenge in many regions.
While most cases of vitamin A deficiency are not severe enough to have definite, observable symptoms, stressors such as measles, pneumonia or diarrhea can decrease levels further and result in serious disease. Vitamin A deficiency can affect vision, in a range from poor night vision to blindness,4 and there is an increased risk of death after measles, diarrhea or pneumonia.
The prevalence of blindness in children in Sudanese refugee camps has been estimated at 1.4 per 1000 children, with 40% of cases due to corneal opacities attributed mainly to vitamin A deficiency.5 Additional consequences include impaired bone growth, weakened immune response and increased risk of mortality.4
If a deficiency is suspected, clinicians should have vitamin A levels tested in a newcomer child or youth.
Vitamin A deficiency in young newcomers can be treated with supplementation and dietary modifications.
The recommended daily intake of vitamin A for all age groups, including infants, children and adolescents, are available from Health Canada.
- Centers for Disease Control and Prevention. Immigrant and refugee health.
- Health Canada, 2007. Eating well with Canada’s food guide is available in multiple languages.
- 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.
- Seal AJ, Creeke PI, Mirghani Z, et al. Iron and vitamin A deficiency in long-term African refugees. J Nutr 2005;135(4):808-13.
- Woodruff BA, Blanck HM, Slutsker L, et al. Anaemia, iron status and vitamin A deficiency among adolescent refugees in Kenya and Nepal. Public Health Nutr 2006;9(1):26-34.
- WHO. World Health Report 2002 – Reducing risks, promoting healthy life. Geneva, Switzerland: WHO, 2002.
- Centers for Disease Control and Prevention. Guidelines for evaluation of the nutritional status and growth in refugee children during the domestic medical screening examination. Bethesda, MD: CDC, 2012.
- Zeidan Z, Hashim K, Muhit MA, et al. Prevalence and causes of childhood blindness in camps for displaced persons in Khartoum: Results of a household survey. East Mediterr Health J 2007;13(3):580-5.
- Anna Banerji, MD
- Andrea Hunter, MD
Last updated: April, 2013