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.