Iodine deficiency during pregnancy: a national cross-sectional survey in Latvia

Abstract

Objective: Low iodine intake during pregnancy may cause thyroid dysfunction, which results in inadequate fetal brain development. In the absence of a universal salt iodization programme, we conducted a nationwide survey of iodine deficiency in pregnant women in Latvia. Design: A countrywide twenty-cluster survey, with at least twenty women per cluster. Participants completed a questionnaire on dietary habits concerning iodine intake (n 739). Thyroid function (thyroid-stimulating hormone, free thyroxine and thyroperoxidase antibodies) was measured (n 550). Urinary iodine was measured using the ammonium persulfate method (n 696). Setting: The survey was performed in all regions of Latvia during the spring and autumn seasons in 2013. Subjects: Pregnant women (n 829). Results: The median creatinine (Cr)-standardized urinary iodine concentration (UIC) was 80·8 (interquartile range (IQR) 46·1-130·6) µg/g Cr or 69·4 (IQR 53·9-92·6) µg/l during pregnancy, and 81 % of pregnant women had UIC levels below the WHO recommended range of 150-250 µg/g Cr. The UIC was lowest during the first trimester of pregnancy, 56·0 (IQR 36·4-100·6) µg/g Cr, reaching higher concentrations of 87·5 (IQR 46·4-141·7) µg/g Cr and 86·9 (IQR 53·8-140·6) µg/g Cr in the second and third trimesters, respectively. Women taking supplements containing ≥150 µg iodine (6·8 % of respondents) had non-significantly higher UIC than did women without supplementation (96·2 v. 80·3 µg/g Cr, respectively, P = NS). Thyroperoxidase antibody concentration did not correlate significantly with UIC: Spearman's ρ = − 0·012, P = 0·78. Conclusions: The median UIC indicates iodine deficiency in pregnant women in Latvia. Iodine supplementation (150 µg daily) and regular UIC monitoring should be suggested to overcome iodine deficiency and to reach the recommended levels without inducing autoimmune processes.

Iodine Deficiency in Latvia: Current Status and Need for National Recommendations

“…The median UIC was significantly higher in the second and third trimesters, which was attributed to the intake of iodine-containing supplements (Konrade et al, 2015). Contrary to the finding of no seasonality effect in the UIC values, the elevated TPO-Ab concentration was approximately two times higher in spring than in autumn (Konrade et al, 2015). In addition, we did not observe any association between UIC and elevated TPO-Ab values.…”

“…Our studies revealed that less than 20% of pregnant women reported the use of iodine-containing supplements, and only 6.8 % used supplements with an iodine content of ³ 150 µg; this supplementation resulted in a slightly higher median UIC compared with those of the group of women who did not use iodine-containing supplements and those who used supplements with an iodine content of < 100 µg (Konrade et al, 2015). These findings indicate that iodine-containing supplements, dairy products and iodised salt are the most important iodine sources in Latvia.…”

“…However, a larger sample size would be necessary to verify these results. Nevertheless, our recent study showed that the median UIC was significantly lower in women who reported only rare milk product consumption than in women who consumed approximately three servings of milk products daily (Konrade et al, 2015).…”

“…A study of pregnant women in Latvia found a median UIC of 80.8 µg/g Cr, indicating substantial iodine deficiency, and the data supported the notion that iodine deficiency already existed before pregnancy (Konrade et al, 2015). The median UIC was significantly higher in the second and third trimesters, which was attributed to the intake of iodine-containing supplements (Konrade et al, 2015).…”

Knowledge of the Importance of Iodine in Nutrition among Adults in Latvia

“…Data published in 2015 showed deficiency for pregnant women in Latvia (Konrade et al, 2015). Mild iodine deficiency among schoolchildren was found in 2000 and again in 2010/2011 when results from urinary iodine concentration (UIC) data showed that 31.6% school-aged children had mild, 11.9% -moderate and 2.8% -severe iodine deficiency (Selga et al, 2000;Konrade et al, 2014).…”