Iodine intake and status in a group of pregnant women in Norway

Abstract

BACKGROUND: Iodine deficiency is a worldwide problem known to have adverse effects on growth and development in humans. Pregnant women are exceptionally vulnerable to iodine deficiency as the need of iodine is increased during pregnancy. The Mother and Child Cohort Study showed that pregnant women in Norway could be at risk of suboptimal iodine intake. OBJECTIVE: The main objective was to describe iodine status in a group of pregnant women in Norway. METHOD: A cross-sectional study was performed among 40 pregnant women (22-47 years) from Norway. Two samples of morning spot urine were collected from each participant for assessment of urinary iodine concentrations and urinary creatinine concentrations. Two-day food diary was recorded to calculate iodine intake from food, including iodine from supplement (total iodine intake). A control group of 26 non-pregnant women in childbearing age (22-48 years) was included in the study. RESULTS: The median iodine intake from food was 124 μg/day and the median total iodine intake (food and supplement) was 170 μg/day in the pregnant women. Intake of iodinecontaining supplements was reported by 25% of the women. The median urinary iodine concentration was 80 μg/L. After adjusting for creatinine the iodine/creatinine ratio was 80 μg/g creatinine and the adjusted age- and sex iodine/creatinine ratio was 87 μg/day. Total iodine intake (food and supplement) correlated well with urinary iodine concentration (rs = 0.54, p< 0.001). There was a significant difference in total iodine intake (food and supplement) between the pregnant women and the control group (p=0.014). CONCLUSION: The findings from the present study indicate mild-to-moderate iodine deficiency in the group of pregnant women in Norway, shown through low intake of iodine from food and a low median urinary iodine concentration. A nationally representative study on iodine status in pregnant women in Norway is needed to confirm the findings.