Indicators for assessing vitamin A deficiency and their application in monitoring and evaluating intervention programmes
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 is intended primarily for managers of national programmes for the prevention and control of micronutrient malnutrition, particularly vitamin A deficiency. It provides principles governing the use of biological indicators for vitamin A deficiency (VAD) surveillance, provides the rationale behind each indicator and its limitations and cut-off points for interpretation in terms of public health significance. For the first time, a series of non-biological indicators useful to identify high risk areas are provided and cut-off points for their interpretation suggested. Also included are indicators for monitoring progress toward achieving the goal of elimination of VAD as a significant public health problem by the year 2000.