Iodine status in Danish pregnant women after an increase in iodine fortification

Objective Iodine fortification programmes are implemented in many countries and often associated with an increase in population iodine intake. However, the initial attempt may not be sufficient and in Denmark the level of iodine added to salt was increased in 2019. Sparse evidence is available on the impact of such modification in iodine fortification. The aim of this study was to evaluate iodine status in Danish pregnant women in 2021 after this increase in iodine fortification and compare to iodine status in 2012. Design Cross-sectional study. Patients Pregnant women in the North Denmark Region referred for routine obstetric ultrasound in 2021. Measurements Participants filled out a questionnaire and delivered a spot urine. Median urinary iodine concentration (UIC) was calculated and assessed according to the recommended range in pregnancy (150-249 mu g/L). Results Altogether 147 pregnant women were included and 88% used iodine-containing supplements. Median UIC was overall 77 mu g/L [95% confidence interval (CI): 61-96 mu g/L], which was lower than in 2012 (101 mu g/L [95% CI: 89-111 mu g/L]) (p < 0.001). Considering sources of iodine intake in pregnancy, lower daily intake of dairy products (p = 0.008) and bread (p < 0.001) and a lower content of iodine in the supplement used (p < 0.001) was seen in 2021 compared to 2012. Conclusion Despite an increase in iodine fortification and frequent use of iodine-containing supplements, iodine status in pregnant women in the North Denmark Region was insufficient. Results call for continued monitoring and attention to ensure adequate iodine status during pregnancy in Denmark.

Automated summary

This study evaluated iodine status in Danish pregnant women and found that despite iodine fortification programs and supplement use, iodine intake was insufficient.