Iodine status of pregnant women in a population changing from high to lower fish and milk consumption.

OBJECTIVES: Pregnancy is one of the most critical periods for iodine deficiency. The aim of the present study was to assess the iodine status and dietary intake of pregnant women in a population changing from high to lower consumption of milk and fish. DESIGN: Cross-sectional observational study. Urine samples were collected for measuring urinary iodine concentration (UIC) and creatinine, and blood samples for measuring serum thyroid-stimulating hormone (TSH). Frequency of consumption of selected food and beverages was obtained through a semi-quantitative validated FFQ. The difference in the distribution of UIC, ratio of iodine to creatinine (I:Cr) and TSH between groups following recommendations on fish and dairy product intake or not (fish ≥2 times/week as a main meal, diary products ≥2 portions/d) was assessed. SETTING: Primary Health Care of the Capital Area, Reykjavik, Iceland. SUBJECTS: Randomly selected pregnant women (19-43 years old, n 162). RESULTS: The median UIC was 180 μg/l, I:Cr 173 μg/g and TSH 1·5 mmol/l. Women who did not consume fish ≥2 times/week and also did not consume dairy products in line with the recommended intake level of ≥2 portions/d had median UIC of 160 μg/l (I:Cr 149 μg/g) compared with 220 μg/l (I:Cr 190 μg/g) in the group following both the recommendations for fish and those for dairy products. Use of dietary supplements in the two groups was similar. CONCLUSIONS: Iodine status in the population studied was within the optimal range (150-249 μg/d) defined by the WHO.