Cross sectional study on the prevalence and associated factors of iodine status in the population of Lausanne

TL;DR

This study found that about a third of people in Lausanne had iodine deficiency, with women, older adults, and those with hypertension being more affected.

Contribution

The study identifies demographic and health factors associated with iodine deficiency in a Swiss population.

Findings

Approximately 29.5% of participants had some level of iodine deficiency.

Women, older age, and hypertension were positively associated with iodine deficiency.

Higher BMI, smoking, and thyroid hormone supplementation were negatively associated with iodine deficiency.

Abstract

To assess iodine status and factors associated with iodine deficiency. Cross-sectional study conducted between 2003 and 2006 including 6,341 community dwellers, aged 35–75 years old, from a population-based sample from the city of Lausanne, Switzerland. Urinary iodine concentration (UIC) was used to assess iodine status. Iodine status was considered as adequate for UIC ≥ 100 mcg/L, mild deficiency if 50 ≤ UIC ≤ 99 mcg/L, moderate deficiency if 20 ≤ UIC ≤ 49 mcg/L, and severe deficiency if UIC < 20 mcg/L. A further categorization into adequate and deficient (UIC < 100 mcg/L) was performed. Overall, 70.5% of the participants presented with adequate iodine status, 23.0% with mild, 6.0% with moderate and 0.5% with severe iodine deficiency. After multivariable analysis, being a woman (odds ratio (95% confidence interval): 1.64 (1.45 ; 1.85)), hypertension 1.41 (1.24 ; 1.60) and increasing age (p for trend < 0.001) were associated with iodine deficiency. Conversely, increasing body mass index (p for trend < 0.001), current smoking 0.86 (0.75 ; 0.99) and thyroid hormone supplementation 0.48 (0.33 ; 0.70) were negatively associated with iodine deficiency. A positive correlation was found between UIC and urinary sodium concentration: 0.277, p < 0.001. In Lausanne, approximately one third of participants presented with iodine deficiency. Factors such as older age, being a woman or presenting with hypertension are associated with iodine deficiency, making those groups the main targets for further preventive interventions.

The online version contains supplementary material available at 10.1038/s41598-025-24318-8.

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