Assessment of the vitamin A status of preschool and school age Senegalese children during a cross-sectional study.

The increasing concern about vitamin A deficiency in even its mild subclinical form has created the need for a mass screening test. Various clinical, biochemical and cytological methods for assessing the vitamin A status have been widely used but all are unsatisfactory for technical, ethical or public health reasons. The two prevalence criteria defined by the World Health Organization (WHO) for a vitamin A deficiency problem of public health significance are xerophthalmia and serum retinol concentrations. Recently we proposed a prevalence criterion for impression cytology with transfer (ICT) at the level of 50% of ICT results being abnormal. We conducted a cross-sectional survey of the prevalence of vitamin A deficiency and also undernutrition during the dry season in a random sample of 1,259 children (n = 442 for the 2-6 years and n = 817 for the 7-14 years) from a rural area in Senegal. Prevalence was 0 times and 4.2 times the WHO criteria for xerophthalmia and deficient serum retinol levels, respectively in preschool children. Abnormal ICT results were more frequent in preschool than in school children (53.4% versus 21.0%). There was an association between abnormal ICT results and stunting. Vitamin A deficiency was a public health problem in preschool children as assessed by the biochemical criterion (20.9% of serum retinol values under 0.35 mumol/l) or the cytological cut-off (53.4% of abnormal ICT results) but was also found in school children (21.0% of abnormal ICT results).