Percent of women living in households using adequately iodized salt
The percent of women who live in households using salt that has been fortified with iodine according to recommended standards. ‘Adequately iodized salt’ is defined as salt containing ≥15 ppm of iodine.
This indicator is calculated as:
(Number of women who live in households with salt containing ≥15 ppm iodine / Total number of women surveyed) x 100
Results of testing household salt used for cooking and/or as table salt. For accurate testing, household samples of salt should be sent to laboratories for titration testing that can determine concentration levels (WHO, 2001). Rapid test kits have been designed for screening and can indicate if iodine is present in a sample, but do not give a reliable measure of concentration. The rapid test kits lack the necessary sensitivity and specificity for calculating this indicator (Gorstein, et al., 2007). Household salt iodine levels can be categorized as adequate or inadequate and, where found, as excessive. Household surveys also can collect data on brand names, dates of expiration, and the presence or absence of iodization labeling (ACC/SCN, 2007). Where available, data can be disaggregated by geographic/ecological zone and relevant socioeconomic and demographic factors such as education, income, and urban/rural residence
Population-based household surveys; the testing of households using iodized salt is part of the core questionnaire in the DHS and UNICEF-MICS.
This indicator serves as a proxy measure for the number of women who may be receiving adequate amounts of iodine. Iodine deficiency disorders (IDD) are prevalent throughout the world and an estimated two billion people have inadequate iodine intake (Gorstein et al., 2007). The most at-risk populations for low iodine intake live in remote inland areas where no marine foods are eaten. IDD interventions often focus on women of reproductive age because of their increased need for iodine during pregnancy. Iodine deficiency in pregnancy can cause extreme and irreversible mental and physical retardation known as cretinism. Even milder, subclinical deficiencies can impair fetal motor and mental development and are associated with miscarriage, fetal growth restriction, stillbirth (ACC/SCN, 2007; Black et al., 2008; WHO, 2010). Mild deficiency among children and adults is very common and can cause loss of learning ability and goiter (an enlargement of the thyroid gland). Iodine deficiency alone was found to lower mean IQ scores by 13.5 points (Bleichrodt and Born, 1994). For pregnant women with severe deficiencies, iodine supplementation by the second trimester can improve neurological and cognitive development of the infant (Black et al., 2008). This indicator relates to achieving Millennium Development Goals: #4. Reduce child mortality; and #5. Improve maternal health.
This indicator can be used to evaluate the availability of adequately iodized salt in households for a given population. The coverage indicator for the ‘proportion of households having access to iodized salt’ is included in the DHS core survey, UNICEF–MICS, and is used for surveillance in the Vitamin and Mineral Nutrient Indicator (VMNIS) database. WHO and UNICEF have recommended universal salt iodization (USI) as a safe, cost-effective and sustainable approach to ensure sufficient iodine intake and reduce the burden of disease associated with iodine deficiency (ACC/SCN, 2007).
Additionally, this indicator can be a proxy for iodine status, however, the primary indicator for measuring iodine status and determining IDD is urinary iodine concentration (UI). For pregnant women, UI levels below 150 mcg/L are considered inadequate and above 500 mcg/L are considered excessive. An additional adequacy criterion is that not more than 20 percent of UI samples from children and non-pregnant women are below 50 mcg/L of iodine. More details on indicators for iodine coverage and status can be found in these resources: WHO (2010); Gorstein et al. (2007); and WHO/UNICEF/ICCIDD, (2001).
In measuring household availability of iodized salt for women in the sample, the indicator does not reflect the women’s actual intake of iodine or their physiologic iodine status. Households’ salt supplies may be from varying sources, some of which are iodized and others not, or the salt processing facilities may not be consistent in the levels of iodine added. For women with severe IDD, household availability of iodized salt may not provide sufficient iodine needed during pregnancy and supplementation may be needed.
Accurate testing for iodine levels is costly and requires sending samples to a laboratory. The rapid test kits can detect the presence of iodine in salt but do not provide information on the level and whether it is adequate or excessive.
nutrition, adolescent, safe motherhood (SM)
ACC/SCN, 2007, ‘Universal Salt Iodization,’ SCN News; No. 35, Geneva: WHO.
Black, RE, Allen, LH, Bhutta, ZA, Caufield LE, de Onis, M, Ezzati, M, Mathers, C, Rivera, J,, “Maternal and child undernutrition: global and regional exposures and health consequences,” Lancet 2008; 371: 243-260.
Bleichrodt, N., and M. Born. 1994. “A Meta-Analysis of Research into Iodine and Its Relationship to Cognitive Development.” In The Damaged Brain of Iodine Deficiency, ed. J. B. Stanbury, 195-200. New York: Communication Corporation.
Gorstein J, Sullivan KM, Parvanta I, Begin F. Indicators and Methods for Cross-Sectional Surveys of Vitamin and Mineral Status of Populations. The Micronutrient Initiative (Ottawa) and the Centers for Disease Control and Prevention (Atlanta), May 2007. http://www.who.int/vmnis/toolkit/mcn-micronutrient-surveys.pdf
WHO, UNICEF, International Council for the Control of Iodine Deficiency Disorders (ICCIDD), 2001, Assessment of iodine deficiency disorders and monitoring their elimination, WHO/NHD/01.01 , Geneva:WHO.
WHO, 2010, Nutrition Landscape Information System (NLIS), Country Profile Indicators Interpretation Guide, Geneva: WHO. http://whqlibdoc.who.int/publications/2010/9789241599955_eng.pdf
WHO, Vitamin and Mineral Information System (VMNIS), Department for Health and Development (NHD), Geneva, Switzerland. Online database at http://www.who.int/vmnis/en/