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Thesis (Master's)

University of Iceland > Heilbrigðisvísindasvið > Meistaraprófsritgerðir - Heilbrigðisvísindasvið >

Please use this identifier to cite or link to this item: http://hdl.handle.net/1946/33107

Title: 
  • Iodine status of pregnant women in Iceland: A cross-sectional study of women from 11-14 weeks gestation
  • Title is in Icelandic Jóðhagur barnshafandi kvenna á Íslandi
Degree: 
  • Master's
Abstract: 
  • Introduction: Iodine is an essential constituent of thyroid hormone, thus plays a key role in numerous developmental and metabolic processes. Adequate iodine consumption during pregnancy is pivotal to ensure proper growth of the developing fetus. Iceland has historically been considered an iodine sufficient nation due to high fish and dairy consumption, however, changes in dietary habits may be contributing to an arising public health issue.
    Objective: To reassess the iodine status of the population of pregnant women in Iceland and determine those most at risk for deficiency.
    Methods: Cross-sectional study of women attending their first sonar appointment in gestational weeks 11-14 at National University Hospital in the period from October 2017 – March 2018. Spot urine samples were collected to determine urinary iodine concentration (UIC) and the ratio of iodine to creatinine (I:Cr) was calculated. Results on UIC were compared with the optimal range defined by WHO (median UIC of 150-249 μg/L in pregnancy and not more than 20% of the population below 50 g/L). The results are presented as median UIC (mUIC) with 95% confidence interval (95% CI). A food frequency questionnaire (FFQ) was completed to assess dietary consumption of the main sources of iodine in the Icelandic diet (dairy and fish), and evaluated the percent of women following dietary guidelines for fish and dairy consumption (fish ≥2 times/week, dairy products ≥2 portions/day).
    Results: Of the 1,350 women eligible to participate in the presents study,1,015 signed informed consent forms (75%).Urine samples collected from 983 participants (73%). The median UIC was 89 (42-141) μg/L and 30% of the sample population had UIC below 50 μg/L. Only 35% of women reported following dietary recommendations for fish, 19% followed recommendations for dairy, and 7.5% followed both. Those who avoided dairy products (n=40) had mUIC of 65 (11-85) μg/L compared to mUIC of 91 (38-158) μg/L of the group that did not avoid dairy products (p=.01). The group of women who avoided fish (n=18) had a mUIC of 50 (5-66) μg/L compared to mUIC of 90 (38- 157) μg/L in the group that did not (p=.07). A positive relationship was seen with increased dairy consumption and higher mUIC with the highest mUIC seen in women consuming more than two dairy portions a day (mUIC 124 (98-290) μg/L).
    Conclusion: Iodine status was below optimal range defined by the WHO. Dairy consumption was a strong indicator of iodine excretion. More attention is needed to address iodine status during pregnancy to limit adverse effects of suboptimal iodine intake during prenatal development.

  • Abstract is in Icelandic

    Inngangur: Joð er mikilvægur hluti skjaldkirtilshorm na og gegnir efnið þannig hlutverki meðal annars við efnaskipti, v xt og þroska. Viðunandi joðhagur mæðra meðg ngu er þar af leiðandi mikilvægur fyrir f sturþroska og þroska barnsins eftir fæðingu þess. s gulegu samhengi hefur joðhagur sland verið talinn g ður, vegna mikillar neyslu fisk- og mj lkurafurða. Ranns kn joðhag barnshafandi kvenna slandi sem gerð var fyrir 10 rum s ðan s ndi að miðgildi joðstyrks þvagi (180 μg/L) var innan þeirra marka sem Alþj ðaheilbrigðism lastofnunin (WHO) telur sættanlegt (miðgildi 150-249 mg/L og að h marki 20% undir 50 μg/L). Breytingar matarvenjum gætu þ hafa haft hrif joðhag þj ðarinnar.
    Markmið: Að meta joðhag barnshafandi kvenna slandi og að kanna hvort hægt s að skilgreina h pa sem eru mestri hættu joðskorti með þv að spyrja einfaldra spurninga um fæðuval upphafi meðg ngu.
    Aðferðir: Þversniðsranns kn meðal kvenna sem mættu mskoðun Landsp tala við 11.-14. viku meðg ngu t mabilinu okt ber 2017 til mars 2018. Þvags num var safnað til að kvarða styrk joðs (urine iodine concentration; UIC) og creatinins þvagi. Niðurst ður eru birtar sem miðgildi UIC (mUIC) og 95% ryggism rk (CI). Fæðuskimunarlisti var lagðar fyrir þ tttakendur til að meta neyslu mj lkurv rum og fiski. Hlutfall kvenna sem fylgir r ðeggingum um neyslu fiski (≥ tvisvar viku) og mj lkurv rum (tveir skammtar dag) var kannað.
    Niðurst ður: Af þeim 1350 konum sem boðin var þ tttaka ranns kninni skrifuðu 1015 undir samþykkisyfirl singu (75%). Þar af skiluðu 983 þ tttakendur þvags ni (73%). Miðgildi UIC var 89 (42- 141) μg/L og 30% tilfella var UIC undir 50 μg/L. Alls s gðust 35% þ tttakenda borða fisk að minnsta kosti tvisvar viku, en 19% neytti að minnsta kosti tveggja skammta af mj lkurv rum dag. Aðeins 7,5% fylgdi bæði r ðleggingum um fisk og mj lkurneyslu. Miðgildi joðstyrks þvagi kvenna sem s gðust forðastu mj lkurafurðir (n=40) var 65 (11-85) μg/L, samanborið við 91 (38-158) μg/L meðal þeirra sem ekki s gðust forðast mj lkurafurðir (p=0,01). Miðgildi UIC hj konum sem s gðust forðastu fisk (n=18) var 50
    (5-66) μg/L, samanborið við 90 (38-157) μg/L hj þeim sem ekki s gðust forðast fisk (p= 0,07). Styrkur joðs þvagi j kst samhliða aukinni mj lkurv runeyslu og var mUIC 124 (98-290) μg/L hj þeim h pi kvenna sem neytti að minnsta kosti tveggja skammta af mj lkurv rum ( n osta) dag.
    lyktun: Miðgildi joðstyrks þvagi hefur lækkað umtalsvert fr fyrri ranns kn og er undir viðmiðum WHO. Sv r við einf ldum spurningum um neyslu mj lkurvara tengjast joðstyrk þvagi. Joðskorti er h r l st fyrsta sinn slandi og benda niðurst ðurnar til þess að nauðsynlegt s að leita leiða til að bæta joðhag kvenna barnsburðaraldri.

Sponsor: 
  • The work presented in this thesis was carried out at the Unit for Research, Faculty of Food Science and Nutrition, University of Iceland and Landspitali National University Hospital in cooperation with the sonar department. Recruitment and sample collection for PREWICE II (the larger study that this research is part of) was funded by the University of Iceland Research Fund and Science Fund of Landspitali National University Hospital. Shipment of samples and part of the iodine analysis in THL, Helsinki Finland was funded by the EUthyroid project.
Accepted: 
  • May 20, 2019
URI: 
  • http://hdl.handle.net/1946/33107


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