Salt intake and iodine status around the world

• Main Author: Ji, Chen
• Published: University of Warwick 2013
• Subjects: 610; QP Physiology
• Online Access: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.582443

Background: Salt reduction and universal salt iodisation programmes are implemented worldwide to prevent cardiovascular disease and iodine deficiency disorders, respectively. Concerns have been raised regarding the potential policy conflicts, and a programme coalition is proposed by the World Health Organization to optimise salt and iodine intakes at population level. This study aimed 1) to estimate population salt intake and iodine status in index countries; 2) to investigate the association between salt and iodine intakes; 3) to assess the impact of salt intake modification on iodine status; 4) to estimate the determinants of and potential geographical variation in salt and iodine intakes where data are available; and 5) to provide suggestions to policy makers. Data and Methods: In the ecological analysis, national estimations of salt and iodine intakes were extracted from international organisation databases and published papers. Three case studies used population level data obtained from the Kumasi Salt Reduction Study in Ghana, the Third United States National Health and Nutrition Examination Survey (NHANES III) and the 2000-01 UK National Diet and Nutrition Survey 19-64 years (NDNS). Linear regression was used in the Kumasi analysis, and Bayesian geo-additive models were used in the other two analyses by accounting for the spatial effect and important linear and nonlinear risk factors. Results: Salt intake varied between countries, with Kumasi lower than the western countries. Iodine status also varied by country, but with no consistent association with salt intake. A moderate salt reduction programme is unlikely to have a major impact on iodine status in countries committed to universal salt iodisation, provided that iodine concentration is titrated to actual salt intake, maximum coverage is achieved as in China and iodised salt becomes part of food processing. At least in Britain, high salt intake is associated with low socioeconomic status, irrespective of geographic location. Conclusions: Policy-makers may therefore need to adjust iodine content in salt in accordance with each country’s context. The Bayesian geo-additive models are useful for monitoring and evaluating salt reduction and iodine supplementation.