Iodine fortification of foods and condiments, other than salt, for preventing iodine deficiency disorders

Iodine deficiency disorders (IDD) affect close to 1.9 billion people worldwide, and are amajor public health concern inmany countries. Among children, iodine deficiency is the main cause of potentially preventable deficits of central nervous system development and impairment of cognitive function, as well as goitre and hypothyroidism in people of all ages. Salt iodisation is the preferred strategy for IDDprevention and control, however, in some instances where salt is not themajor condiment, alternate vehicles for iodine fortification have been considered. Objectives To assess the effects of fortifying foods, beverages, condiments, or seasonings other than salt with iodine alone or in conjunction with other micronutrients, on iodine status and health-related outcomes in all populations. Search methods Studies were identified through systematic searches of the following databases from their start date to January 2018: Cochrane Public Health Group Specialised Register; CENTRAL; MEDLINE; MEDLINE in Process; Embase;Web of Science; CINAHL; POPLINE; AGRICOLA; BIOSIS; Food Science and Technology Abstracts; OpenGrey; Bibliomap and TRoPHI; AGRIS; IBECS; Scielo; Global IndexMedicus-AFRO and EMRO; LILACS; PAHO;WHOLIS; WPRO; IMSEAR; IndMED; and Native Health Research Database. We also searched reference list of relevant articles, conference proceedings, and databases of ongoing trials, and contacted experts and relevant organisations to identify any unpublished work. We applied no language or date restrictions. Selection criteria Studies were eligible if they were randomised or quasi-randomised controlled trials (RCT) with randomisation at either the individual or cluster level (including cross-over trials), non-randomised RCTs, or prospective observational studies with a control group, such as cohort studies, controlled before-and-after studies, and interrupted time series. We included studies that examined the effects of fortification of food, beverage, condiment, or seasoning with iodine alone, or in combination with other micronutrients versus the same unfortified food, or no intervention. We considered the following measures: death (all-cause), goitre, physical development, mental development, cognitive function and motor skill development, cretinism, hypothyroidism, adverse effects (any reported by trialists), urinary iodine concentration, thyroid-stimulating hormone (TSH) concentration, and serum thyroglobulin concentration. We included all populations, including pregnant women, from any country.