Conjunctival impression cytology with transfer (CICT) to detect pre-clinical vitamin A deficiency among slum children in India

Impact of disease on markers of micronutrient status

“…Filteau et al (1993) have reported correlations between plasma retinol and a,-acid glycoprotein ( r -0.35) and retinol and serum amyloid A ( r -0.20). Sensitivity and specificity, however, were not as good as CIC when compared with the results of Chowdhury et al (1996), but, of course, acute-phase proteins are synthesized in response to a stress. Different stresses undoubtedly influence different proteins in different ways and it is probably unlikely that any acute-phase protein will behave exactly like RBP.…”

“…Ocular abnormalities have been demonstrated using conjunctival impression cytology (CIC) and results obtained by CIC have been compared with plasma retinol levels to assess sensitivity and specificity of CIC to measure vitamin A status. While some workers report good agreement between the two methods (Chowdhury et al 1996;Table 3), other workers in different environments have not obtained good agreement (Natadisastra et al 1988;Gadomski et al 1989;Carlier et al 1991Carlier et al , 1992Stolzfus et al 1993; Table 3). The probable reason for the lack of agreement is that while plasma retinol responds very rapidly to changes in vitamin A intake, the re-appearance of goblet cells in the ocular epithelium may take 3-8 weeks (Wittpenn et al 1986).…”

“…In Third World situations where people are living in unhygienic conditions and food is frequently contaminated with pathogens, disease is common and consequently levels of circulating retinol may be dangerously low for long periods. Low levels of retinol are probably responsible for the abnormalities in ocular epithelium which have been reported by many workers (Carlier et al 1992;Nathanail & Powers, 1992;Stolzfus et al 1993;Chowdhury et al 1996). Ocular abnormalities have been demonstrated using conjunctival impression cytology (CIC) and results obtained by CIC have been compared with plasma retinol levels to assess sensitivity and specificity of CIC to measure vitamin A status.…”

“…CIC is a relatively non-invasive technique but it involves a certain amount of subjectivity and it is difficult to perform in young children (Nathanail & Powers, 1992;Chowdhury et al 1996). In contrast, the fact that the level of retinol is determined by the disease activity raises the possibility that retinol may be evaluated by comparison with an independent disease marker, i.e.…”

Optimal nutrition: vitamin A and the carotenoids

“…In contrast, those subjects starting with low plasma retinol ended up with plasma levels in the 'risk' category for vitamin A deficiency. It is generally accepted that individuals with concentrations of retinol below 0·7 µmol/l are more likely to have impaired epithelial structure and integrity in the eye (Chowdhury et al 1996) and recent findings suggest this situation may also be the same in the gut (Northrop-Clewes et al 1998). In addition, con-centrations of plasma retinol between 0·7 and 1·6 µmol/l will not be optimal in the presence of infection.…”