Iodine Deficiency Persists in Rural Communities Despite Salt Iodization, Suggests Study
A recent cross-sectional study published in the Indian Journal of Endocrinology and Metabolism in June 2026 reveals that over a quarter of the rural population remains biochemically iodine deficient, with a median urinary iodine concentration (MUIC) under 100 micrograms per liter. This critical public health gap is fueled by an alarming 31% of households consuming salt with inadequate or entirely absent iodization.
Although universal salt iodization was established to eradicate iodine deficiency disorders (IDD), Tamil Nadu exhibits India's lowest household coverage of adequately iodized salt at 61.9%, with clinical gaps persisting due to improper storage and poor awareness. To address this, Gayathri Gopakumar and colleagues from the Sri Ramachandra Institute of Higher Education and Research conducted a cross-sectional study to quantify household salt iodization, dietary iodine consumption, and MUIC while analyzing their association with storage and cooking habits.
Therefore, the cross-sectional study evaluated salt iodization, daily iodine intake, and urinary iodine levels among 630 rural adults in Tamil Nadu, excluding those storing salt over two months. Utilizing spot-testing kits, dietary recalls, and urinary assays, researchers correlated these clinical endpoints with sociodemographic factors and household practices.
Key clinical findings from the study include:
Deficient Urinary Iodine Levels: Researchers reported that 27.2% of participants had biochemical iodine deficiency—comprising 21% severe, 29% moderate, and 50% mild—despite an overall cohort MUIC of 163.2 micrograms per liter.
Inadequate and Excess Salt Iodization: Researchers revealed that 31% of households used uniodized or inadequately iodized salt, 31% used excessively iodized salt (>30 ppm), and only 38% had adequately iodized salt (15 ppm).
Substantial Knowledge and Awareness Deficits: The researchers indicated that 40% of the population was unaware of iodized salt, 50.4% deemed its consumption unimportant, and only 16% knew the clinical consequences of IDD.
Elevated Daily Salt Consumption: Researchers demonstrated a daily per capita salt intake of 13.35 grams, which is substantially higher than the World Health Organization (WHO) standard of under 5 grams and the national 8.0 grams baseline.
Key Demographic and Clinical Correlations: They identified that MUIC differed significantly by age and hypertension status but showed no statistical association with the iodization level of the salt consumed.
The results suggest that a significant proportion of the rural population remains vulnerable to thyroid disorders due to improper iodine intake, as 27.2% of individuals exhibit deficient MUIC levels and 31% use inadequately iodized salt. This underscores a public health challenge where deficient and excessive iodization coexist, highlighting the need for robust monitoring to harmonize domestic salt quality.
Thus, the study concludes healthcare professionals are encouraged to counsel patients on optimal salt storage and cooking practices to prevent iodine degradation, while remaining aware that both deficient and excessive dietary iodine can precipitate thyroid auto-immunity or dysfunction in susceptible individuals.
Although the study is limited by its regional focus, a female-predominant sample, and unassessed salt iodization in 8% of households, these findings pave the way for future large-scale research to investigate the long-term thyroid health outcomes of concurrent high daily salt intake and excessive salt iodization.
Reference
Gopakumar G, Shriraam V, Jasmine A, Mahadevan S, Prabhu SR. Iodized salt consumption practices and iodine status in the rural adult population near Chennai, India. Indian J Endocr Metab 2026;30:246-50.
