National and Sub-National Estimates of Household Coverage of Iodized Salt and Urinary Iodine Status among Women of Reproductive Age in India: Insights from the India Iodine Survey, 2018-19

Abstract

Background: Iodine deficiency is a significant public health problem for many populations worldwide, including India, particularly during the "first 1000 days" of life. Though Universal Salt iodization (USI) is mandatory in India, prior to 2018-19, there was no state-wide survey with estimates of iodine concentrations in salt using iodometric titration. Taking cognizance of this fact, Nutrition International commissioned the first-of-its-kind national-level survey in India, titled the India Iodine Survey 2018-19.

Objectives: The study was conducted across the country to provide national and subnational estimates of iodine concentrations in household salt using iodometric titration and iodine nutrition status among women of reproductive age (15-49 y).

Methods: The survey adopted a multi-stage randomcluster probability proportional to size sampling design, covering 21,406 households in all the states and union territories (UTs) of India.

Results: At the national level, the household coverage of edible salt with adequate iodine (content ≥15 parts/million) was 76.3%. At the sub-national level, the coverage varied, with 10 states and 3 UTs achieving USI and 11 states and 2 UTs falling below the national average, with the highest among all the states and UTs, being Jammu and Kashmir and the lowest being Tamil Nadu. At the national level, the median urinary iodine concentration for pregnant women was 173.4 μg/L, for lactating women was 172.8 μg/L, and for non-pregnant, non-lactating women, it was 178.0 μg/L, which is within the adequate iodine nutrition range according to the WHO guidelines.

Conclusions: The survey results can be widely used by various stakeholders, including government, academia, and industry, to understand the iodine nutrition status of the population, enable the scale-up of sustained efforts toward consolidating gains and achieving USI, leading to the reduction and elimination of Iodine Deficiency Disorders.

Keywords: India Iodine Survey; iodometric titration test; median urinary iodine concentration; universal salt iodization; women of reproductive age.