Mustafa ÖZBEK, Erman ÇAKAL, Bekir UÇAN, Mahmut APAYDIN, Özden ÖZDEMİR BAŞER, Taner DEMİRCİ

The effects of salt consumption habits on iodine status and thyroid functions during pregnancy

Background/aim: Iodine is the basic substrate for thyroid hormone synthesis and is vital for the general population and especially pregnant women. Iodine deficiency may cause severe health problems for a foetus. This study aimed to determine the relationship, if any, between iodine level and thyroid function tests, and to determine the relationship between consumption of salt types and its effects on thyroid function tests in the first trimester of pregnancy. Materials and methods: Three hundred and six pregnant women in the first trimester of pregnancy, who had known no thyroid disease history and had not received iodine supportive therapy, were included in the study. All patients were questioned for their preferred table salt or rock salt in daily use and urine iodine concentrations (UICs) were analysed in spot urine. The results were evaluated statistically according to salt usage preferences. Results: The median age of patients in the study was 27.8 (± 5.4). In terms of salt consumption habits, 235 (76.8%) of patients reported using table salt, and 71 (23.2%) reported using rock salt. Iodine deficiency was found in 75.81% (n = 232) of all cases according to urinalysis. Median UICs of table salt group were significantly higher than rock salt group (123.7 μg/L and 70.9 μg/L respectively, P < 0.001). Conclusion: Although large-scale salt iodination began long time ago, iodine deficiency is still a serious health problem among pregnant women. According to this study, use of rock salt is associated with low urinary iodine concentration in pregnant women and TSH values within the reference limits are not a good indicator for determining the iodine level.Key words: Iodine, table salt, rock salt, pregnancy, TSH

PDF

___

1. Pearce EN, Lazarus JH, Moreno-Reyes R, Zimmermann MB. Consequences of iodine deficiency and excess in pregnant women: an overview of current knowns and unknowns. American Journal of Clinical Nutrition 2016; 104 (3): 918-923. doi: 10.3945/ajcn.115.110429
2. Walker SP, Wachs TD, Gardner JM, Lozoff B, Wasserman GA et al. Child development: risk factors for adverse outcomes in developing countries. Lancet 2007; 369 (9556): 145-157. doi: 10.1016/S0140-6736(07)60076-2
3. Glinoer D, De Nayer P, Delange F, Lemone M, Toppet V et al. A randomized trial for the treatment of mild iodine deficiency during pregnancy: maternal and neonatal effects. Journal of Clinical Endocrinology and Metabolism 1995; 80 (1): 258-269.
4. Vejbjerg P, Knudsen N, Perrild H, Laurberg P, Carle A et al. Thyroglobulin as a marker of iodine nutrition status in the general population. European Journal of Endocrinology 2009; 161 (3): 475-481. doi: 10.1530/EJE-09-0262
5. Delange F. Neonatal screening for congenital hypothyroidism: results and perspectives. Hormone Research in Paediatrics 1997; 48 (2): 51-61.
6. Delange F. Iodine requirements during pregnancy, lactation and the neonatal period and indicators of optimal iodine nutrition. Public Health Nutrition 2007; 10 (12A): 1571-1580. doi: 10.1017/S1368980007360941
7. Secretariat WHO, Andersson M, De Benoist B, Delange F, Zupan J. Prevention and control of iodine deficiency in pregnant and lactating women and in children less than 2-years-old: conclusions and recommendations of the Technical Consultation. Public Health Nutrition 2007; 10 (12A):1606-1611. doi: 10.1017/ S1368980007361004
8. Glinoer D. The regulation of thyroid function in pregnancy: pathways of endocrine adaptation from physiology to pathology. Endocrine Reviews 1997; 18 (3): 404-433.
9. Zimmermann MB. Iodine deficiency. Endocrine Reviews 2009; 30 (4): 376-408.
10. Anaforoğlu İ, Algün E, İnceçayır Ö, Topbaş M, Erdoğan MF. Iodine status among pregnant women after mandatory salt iodisation. British Journal of Nutrition 2016; 115 (3): 405-410. doi: 10.1017/S0007114515004559
11. Alexander EK, Pearce EN, Brent GA, Brown RS, Chen H et al. 2017 Guidelines of the American Thyroid Association for the diagnosis and management of thyroid disease during pregnancy and the postpartum. Thyroid 2017; 27 (3): 315-389. doi: 10.1089/thy.2017.0155
12. Velasco I, Bath SC, Rayman MP. Iodine as essential nutrient during the first 1000 days of life. Nutrients 2018; 10 (3): 290. doi: 10.3390/nu10030290
13. Vermiglio F, Lo Presti VP, Moleti M, Sidoti M, Tortorella G et al. Attention deficit and hyperactivity disorders in the offspring of mothers exposed to mild-moderate iodine deficiency: a possible novel iodine deficiency disorder in developed countries. Journal of Clinical Endocrinology and Metabolism 2004; 89 (12): 6054-6060. doi: 10.1210/jc.2004-0571
14. DeLong GR, Leslie PW, Wang SH, Jiang XM, Zhang ML et al. Effect on infant mortality of iodination of irrigation water in a severely iodine-deficient area of China. Lancet 1997; 350 (9080): 771-773.
15. Yordam N, Özön A, Alikaşifoğlu A, Özgen A, Ceren N et al. Iodine deficiency in Turkey. European Journal of Pediatrics 1999; 158 (6): 501-505.
16. Manousou S, Andersson M, Eggertsen R, Hunziker S, Hulthen L et al. Iodine deficiency in pregnant women in Sweden: a national cross-sectional study. European Journal of Nutrition 2019; 59: 2535-2545. doi: 10.1007/s00394-019-02102-5
17. Koyuncu K, Turgay B, Söylemez F. Iodine deficiency in pregnant women at first trimester in Ankara. Journal of the Turkish-German Gynecological Association 2019; 20 (1): 37-40. doi: 10.4274/jtgga.galenos.2018.2017.0150
18. Erdoğan G, Erdoğan MF, Emral R, Baştemir M, Sav H et al. Iodine status and goiter prevalence in Turkey before mandatory iodization. Journal of Endocrinological Investigation 2002; 25 (3): 224-228. doi: 10.1007/BF03343994
19. Erdoğan MF, Ağbaht K, Altunsu T, Özbaş S, Yücesan F et al. Current iodine status in Turkey. Journal of Endocrinological Investigation 2009; 32 (7): 617-622. doi: 10.1007/BF03346519
20. Erdoğan MF, Demir Ö, Emral R, Kamel AN, Erdoğan G. More than a decade of iodine prophylaxis is needed to eradicate goiter among school age children in a moderately iodine-deficient region. Thyroid 2009; 19 (3): 265-268. doi: 10.1089/ thy.2008.0253
21. Mousa U, Sav H, Köseoğluları O, Erdoğan MF. Iodine status of pregnant women in Northern Cyprus. Balkan Medical Journal 2018; 35 (6): 449-450. doi: 10.4274/balkanmedj.2018.0679
22. Hollowell JG, Haddow JE. The prevalence of iodine deficiency in women of reproductive age in the United States of America. Public Health Nutrition 2007; 10 (12A): 1532-1539. doi: 10.1017/S1368980007360862
23. De Groot L, Abalovich M, Alexander EK, Amino N, Barbour L et al. Management of thyroid dysfunction during pregnancy and postpartum: an Endocrine Society clinical practice guideline. The Journal of Clinical Endocrinology and Metabolism 2012; 97 (8): 2543-2565. doi: 10.1210/jc.2011-2803
24. Caldwell KL, Pan Y, Mortensen ME, Makhmudov A, Merrill L et al. Iodine status in pregnant women in the National Children’s Study and in U.S. women (15-44 years), National Health and Nutrition Examination Survey 2005-2010. Thyroid 2013; 23 (8): 927-937. doi: 10.1089/thy.2013.0012
25. Abel MH, Korevaar TIM, Erlund I, Villanger GD, Caspersen IH et al. Iodine ıntake is associated with thyroid function in mild to moderately ıodine deficient pregnant women. Thyroid 2018; 28 (10): 1359-1371. doi: 10.1089/thy.2018.0305
26. Moleti M, Di Bella B, Giorgianni G, Mancuso A, De Vivo A et al. Maternal thyroid function in different conditions of iodine nutrition in pregnant women exposed to mild-moderate iodine deficiency: an observational study. Clinical Endocrinology 2011; 74 (6): 762-768. doi: 10.1111/j.1365-2265.2011.04007.x