IDENTIFYING AREAS WITH VITAMIN-A-DEFICIENCY - THE VALIDITY OF A SEMIQUANTITATIVE FOOD FREQUENCY METHOD

Objectives. The prevalence of vitamin A deficiency has traditionally b een assessed through xerophthalmia or biochemical surveys. The cost an d complexity of implementing these methods limits the ability of nonre search organizations to identify vitamin A deficiency. This study exam ined the validity of a simple, inexpensive food frequency method to id entify areas with a high prevalence of vitamin A deficiency. Methods. The validity of the method was tested in 15 communities, 5 each from t he Philippines, Guatemala, and Tanzania. Serum retinol concentrations of less than 20 mu g/dL defined vitamin A deficiency. Results. Weighte d measures of vitamin A intake six or fewer times per week and unweigh ted measures of consumption of animal sources of vitamin A four or few er times per week correctly classified seven of eight communities as h aving a high prevalence of vitamin A deficiency (i.e., 15% or more of preschool-aged children in the community had the deficiency) (sensitiv ity = 87.5%) and four of seven communities as having a low prevalence (specificity = 57.1%). Conclusions. This method correctly classified t he vitamin A deficiency status of 73.3% of the communities but demonst rated a high false-positive rate (42.9%).