Impact of Dietary Habit, Iodine Supplementation and Smoking Habit on Urinary Iodine Concentration During Pregnancy in a Catalonia Population

Abstract

(1) Background: The nutritional status of women during pregnancy can have a considerable effect on maternal and fetal health, and on the perinatal outcome. Aim: to assess the changes occurring in dietary iodine intake, potassium iodide supplementation, and smoking habit, and the impact of these changes on the urinary iodine concentration (UIC) during pregnancy in a population of women in Catalonia (Spain). (2) Methods: Between 2009–2011, an observational study included a cohort of women whose pregnancies were monitored in the public health system in the Central and North Metropolitan areas of Catalonia. Women received individual educational counseling, a dietary questionnaire was completed, and a urine sample was collected for iodine determination at each trimester visit. (3) Results: 633 (67.9%) women answered the questionnaire at all 3 visits. The percentage of women with a desirable UIC (≥150 μg/L) increased from the first to the second trimester and remained stable in the third (57.3%, 68.9%, 68%; p < 0.001). Analysis of the relationship between UIC≥150 μg/L and the women’s dietary habits showed that the percentage with UIC ≥150 μg/L increased with greater consumption of milk in the first trimester, and the same was true for iodized salt use in all three trimesters and iodine supplementation in all three. (4) Conclusion: During pregnancy, increased intake of milk, iodized salt, and iodine supplements were associated with an increase in the UIC.

The effect of sodium restriction on iodine prophylaxis: a review

“…Of note, iodine excess can be also found, mostly due to high iodine content in tap water [48][49][50][51]. In many countries (Continental Europe, the UK and the US), the primary sources of iodine are dairy products and fortified table salt [52][53][54][55][56][57]. Elsewhere, especially in the Middle East, dietary iodine mainly comes from fortified flour and salt [58].…”

HPLC Analysis of the Urinary Iodine Concentration in Pregnant Women

“…In recent years, several studies have assessed UIC in pregnant women. Most of them showed low median UIC, suggesting insufficient iodine status in pregnancy [25,[41][42][43][44][45][46][47][48].…”

Report of the Scientific Committee of the Spanish Agency for Food Safety and Nutrition (AESAN) on the nutritional status of women of childbearing age, during pregnancy and lactation with respect to adequate iodine intake

“…A recent study carried out by Torres et al (2020) shows how, independently, milk, iodized salt and iodine supplements favourably impact ioduria. Other studies report how iodized salt alone is able to achieve adequate ioduria levels (Santiago et al, 2013) (Menéndez et al, 2014) (Torres et al, 2017) (González-Martínez et al, 2021.…”

“…This involves a marked decrease in iodine uptake by the mammary gland, with a subsequent decrease in its concentration in breast milk (Andersen, 2015). Smoking has not been found to increase the risk of iodine deficiency during pregnancy (Torres et al, 2020); however, it is recommended that pregnant women do not smoke or stay in environments with tobacco smoke (passive smoking).…”

“…There is no recent information on the situation of breastfeeding women. A study conducted in Catalonia reported a significant increase in the use of iodized salt from the first to the third trimester (from 35.7 % to 87.6 %) when midwives were involved in education (Torres et al, 2020). If changes are made during pregnancy, they are likely to persist after delivery.…”