An epidemiological investigation of maternal and neonatal indicators of iodine status in Bangladesh

Abstract

This research was done to investigate the iodine status of mothers, their neonates and women of child bearing age (WCBA) in districts with differing severity of iodine deficiency (ID) and the inter-relationships between the various indicators used. This study also aimed to rank the commonly used indicators of ID in order of their practical merits and demerits. Deficiency of iodine continues to threaten the health and well-being, social and economic productivity and advancement of about one billion people of the world. Most of the 'at risk' people are in the developing countries. Recent evidence indicates that the disorders resulting from ID affect 20% of the world population, about 710 million people are 'at risk' in Asia, and 287 million in Africa and Latin America, and some 20-30 million in Europe. Recent evidence from country-by-country counts indicates that the total number of people 'at risk' of IDD exceeds 1,570 million (29% of the world's population). In absolute terms, Southeast Asia (which includes India, Bangladesh, Indonesia etc.) and the Western Pacific (which also includes China) together account for more than 50% of the world's total population 'at risk' of IDD. Globally, the prevalence of goitre is estimated to be 12% and at least 110 countries are known to have an IDD problem. Some of the consequences of ID are not reversible, but virtually all can be completely prevented by easily available techniques of iodine supplementation. Researchers are investigating the relationship between mother and neonate, using different indicators of iodine status within and across increasing severities of ID. A cross-sectional study was carried out in this study in four districts of Bangladesh during 1991 - 1992. Out of a total of 2221 subjects, 1554 were adult woman of 15 to 35 years of age and 667 were neonates. The major proxy and direct indicators of iodine status used were serum T4, serum TSH, urinary iodide and goitre. The indicators of iodine status showed significant association with the indicators of socioeconomic status. Income was significantly (PO.OOl) and inversely associated with goitre. Effects of ID on outcome of pregnancy were also studied. Gestational age and birth weight were significantly lower (PO.OOl) in neonates of mothers with ID and showed direct association with increasing severity of environmental iodine deficiency. However it was not possible to analyse the possible confounding effects of parity, or of anaemia in pregnancy between districts. The conclusion is that foetal growth as revealed by birth weight is significantly and inversely related to maternal ID. ........