During the last two years, a severe selenium deficiency has been documented in Northern Zaire, in an area already characterised by a severe iodine deficiency. It is associated to a peculiarly elevated (1% to 7%) prevalence of myxedematous cretinism as compared to other endemic goiter areas (Latin America, Asia, New Guinea) where neurological cretinism is the predominant form. During a selenium supplementation trial, a drop of serum T4 was observed after two months in initially iodine-& selenium-deficient subjects of Northern zaire. The drop of serum T4 is likely related to the recent biochemical finding that the enzyme converting the prohormone T4 to the active hormone T3 contains selenium at its active site. Iodine deficiency must, thus, be corrected before selenium supplementation. we intend to determine more precisely the link between iodine and selenium deficiency. A first approach is to pursue the determination of the geographical map of iodine and selenium status in different areas of Zaire and in other countries (Tanzania, people's Republic of China). To determine whether the correction of selenium deficiency, in addition to iodine supplementation brings clinical benefits to the general wellbeing of the population, 2000 pregnant women are supplemented with iodine +/- selenium from the first prenatal visit until the sixth month after delivery clinical parameters (neonatal mortality, birthweight, child growth, neurological development), iodine and selenium status (thyroid function parameters, serum selenium, serum and erythrocyte glutathione peroxidase) are assessed during and after the end of selenium supplementation. The effect of selenium deficiency on thyroid hormone metabolism and on clinical thyroid state in subjects who are not iodine deficient is not known. The thyroid function parameters (thyroid hormones, TSH, lipid metabolism parameters, cardiac function tests, TSH response to TRH stimulation) are compared before and 2 months after selenium or placebo supplementation in 160 subjects already treated with iodised oil. The recent development of a device diffusing iodine in drinking water (Rhodiffuse Iodé, Rhône poulenc, France) offers an interesting alternative to iodised 0il in order to supplement villages with iodine. It is proposed to analyse the theoretical aspects of adding also selenium to water by this system.
Funding SchemeCSC - Cost-sharing contracts
SE1 9RT London