Prevalence of sub-clinical vitamin A deficiency in 2-5-year-old children in Tehran.

To determine vitamin A status using conjunctival impression cytology (CIC) in children aged 2-5 years, we assessed 1257 randomly selected children in urban and rural areas of Tehran. History of using supplemental vitamin A, respiratory or diarrhoeal infection in the previous 6 months, residential location, parents' education, family economic status, and child's age, sex and weight were recorded. Sub-clinical vitamin A deficiency (defined as abnormal CIC) was found in 23.6% of the sample, a rate classified as a moderate public health problem. There was a statistically significant relationship between sex and age and abnormal CIC (P < 0.05).