Mass distribution of vitamin A

This paper reviews the origin, rationale, and effectiveness of this strategy. The efficacy of oral vitamin A administration is examined in terms of: (1) the efficiency of absorption of vitamin A as an ester and as an alcohol, and in either water-miscible or oil-soluble preparations, given the health status of the recipient; (2) the retention of oil-soluble physiologic and massive dosages; and (3) the protective period provided against low serum retinol levels and xerophthalmia. Means of evaluating the effectiveness of the massive-dose intervention strategy are then examined; specific attention is given to measures of postintervention reduction of xerophthalmia, to comparisons of intervention and control populations, to the slope test for age-prevalence association, and to mathematical estimates of expected xerophthalmic prevalence or incidence reduction. Finally, it is noted that effectiveness evaluations that used pre/post-intervention measures have shown that mass distribution of vitamin A can reduce the incidence of mild xerophthalmia. Tables and graphs derived from intervention evaluations provide supporting data. A 79-item bibliography (1935-82) is provided.