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 mu g/l, I: Cr 173 mu g/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 mu g/l (I: Cr 149 mu g/g) compared with 220 mu g/l (I: Cr 190 mu g/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 mu g/d) defined by the WHO.