Global prevalence of Vitamin A Deficiency

Micronutrient Deficiency Information System Working Paper No. 2

World Health Organization, United Nations Childrens Fund


Vitamin A deficiency (VAD) is the single most important cause of childhood blindness in developing countries. It also contributes significantly, even at subclinical levels, to morbidity and mortality from common childhood infections. VAD is the result of two primary factors: persistent inadequate intake of vitamin A that is frequently exacerbated by others dietary circumstances, and a high frequency of infections. An estimated 2.8 million preschool-age children are at risk of blindness from VAD, and the health and survival of 251 million others are seriously compromised.

Heightened awareness of the role of vitamin A in human health has led to an international effort to eliminate vitamin A deficiency and its consequences as a public health problem by the year 2000. This is among the important end-of-decade micronutrient goals endorsed by the World Summit for Children (1990), the International Conference on Nutrition (1992), and the World Health Assembly (1993).

This document provides a baseline which national and international health authorities can use to track progress achieved towards the virtual elimination of VAD as a public health problem. It is divided into four sections. The first describes the nature of VAD and reviews the epidemiological issues involved in measuring and interpreting VAD prevalence studies. The second section presents summary tables of the most recent prevalence data, by country and WHO region. The third section presents more detailed sub-national prevalence data by WHO region. The fourth section provides complete bibliographic information for all data sources presented.