Prevalence of infant Vitamin A deficiency and undernutrition in the Republic of Congo

Objectives: A representative sample of 5722 pre-school children living in rural and urban areas of the Congo was examined between July and September 1999 for assessing Vitamin A deficiency. Methods: Using a randomized two-level cluster sampling method, 190 clusters of 30 children aged from 6 months to 6 years were selected in order to assess the prevalence of active xerophthalmia (night blindness and/or Bitot spots). Concurrently, the children's height and weight were determined. A semi-quantitative seven-day dietary questionnaire was applied to the mothers of 5722 children to estimate the latter's consumption of Vitamin A rich foodstuffs. The prevalence of biochemical deficiency was assessed based on the serum retinol concentrations analyzed in dried blood spots from a sub-sample of 300 children living in the Pointe-Noire area. Results: Among the 5722 children studied, 0.7% were found to suffer from night blindness and 7.7% had Bitot spots. The weekly intake of Vitamin A rich foods was estimated in 5722 children. Our data suggest that Vitamin A rich food consumption was lower in rural zones than in urban area according to the food frequency method threshold values. The serum retinol levels were lower than 10 mu g/dl in 18% (95% confidence interval [C.I.]: 13.7, 22.3) [8.04 +/- 2.87 mu g/dl] and less than 20 mu g/dl in 49% (95% C.I.: 43.4, 54.6) [15.05 +/- 2.76 mu g/dl] of the 300 studied children. We have established a significant relation between mean serum retinol levels and high rate of Vitamin A food intake (chi-square = 59.64, 2 d.d.l., p < 0.05) in the sample studied. The mean serum retinol concentrations did not differ significantly between the various Z-scores of weight for age (W/A) and height for age (H/A) patterns. But children with a weight for height (W/H) ratio below -2 standard deviation (S.D.) had significantly lower serum retinol values [9.33 +/- 1.3 mu g/dl] than those with a W/H ratio greater than or equal to -2S.D. [10.82 +/- 4.84 mu g/dl]. Conclusion: These data suggest that Vitamin A deficiency is still a serious public health problem in rural areas of the Congo in which this study was carried out. (c) 2006 Elsevier B.V. All rights reserved.