Due to the many approaches by which vitamin A status has been assessed, there is large variability in the prevalence estimates for vitamin A deficiency.[1][2] However, vitamin A deficiency is most common in infants/children living in low- and middle-income countries,[3][4][5] in whom prevalence of vitamin A deficiency is approximately 30%.[6][2]
Some conditions also increase a person’s risk of developing vitamin A deficiency. These include chronic alcohol intake, liver cirrhosis, intestinal absorption disorders like Crohn’s disease, and conditions that affect the exocrine pancreas (e.g., chronic pancreatitis).[7]