URINARY IODINE EXCRETION IN MOTHERS AND THEIR BREAST-FED CHILDREN IN RELATION TO OTHER CHILDHOOD NUTRITIONAL PARAMETERS

Objective: There is currently no coordinated policy on the epidemiolog y and control of iodine deficiency disorders (IDD) in many parts of Af rica even where these disorders are endemic. Assessment of the urinary iodine excretion is believed to give the best index of the prevalence of IDD in the community. This study aimed to establish whether: (i) t he breast-fed child of an iodine replete mother was protected from IDD and, (ii) infants at risk of IDD and in need of immediate iodine supp lementation could easily be identified through simple screening method s. Design: Randomized, cross-sectional study. Setting: A tertiary care infant welfare clinic in Ibadan, South-western Nigeria, a geographica l area recognised to be outside Nigeria's endemic goitre belt (goitre prevalence < 5.0%). Subjects: 68 healthy mother-child pairs. The child ren were all aged 9-18 months and breast-fed almost exclusively. Inter ventions: Nil. Methods: The relationships of anthropometric, iodine st atus (casual urinary iodine (I) and iodine/creatinine ratio (I/Cr)) an d nutritional indices (weights, haematocrits) of the mothers with thos e of their breast-fed children were assessed, as well as how these par ameters differed between the children classified on the basis of their mid-upper arm circumference, MUAC, as: (A) borderline malnourished, M UAC < 13.5 cm and, (B) well nourished, MUAC > 13.5 cm. Results: The ma ternal values for I and I/Cr were significantly (p < 0.001) greater th an those of their breast-fed infants, although the respective mother-c hild pair values correlated positively (I, r 0.47; I/Cr, 0.21; both p < 0.05). There was thus a gradient in iodine status between the mother and her breast-fed infant that is unfavourable to the growing child; the latter may thus require iodine supplementation in spite of the fac t that the mother is iodine replete. Among the children, those conside red well nourished (Group B) had similar iodine status parameters as t hose considered poorly nourished (Group A) suggesting that malnutritio n alone should not be the determinant of the prioritization (or otherw ise) of iodine supplementation in a population with coexistent iodine deficiency and malnutrition. Mean values for (I) in all the children ( 9.9 mu g/dl) fell in the iodine deficiency range ( < 10 mu g/dL), alth ough all the mothers were iodine replete (mean urinary (I) 14.5 mu g/d L), despite the fact that all resided in a non iodine deficient area. Conclusion: The study suggests that: (i) the breast-fed child of an io dine replete mother resident in a non-iodine deficient area may be iod ine deficient and in need of iodine supplementation; (ii) malnutrition , as defined by the simple community screening method of measuring the MUAC, will not accurately identify those infants in immediate need of iodine supplementation. These observations have important implication s for planning IDD control programmes in Africa.