Iodine Intake and Thyroid Function in Pregnant Women in a Private Clinical Practice in Northwestern Sydney before Mandatory Fortification of Bread with Iodised Salt

Abstract

Aim. The primary objective of the study was to assess the iodine nutritional status, and its effect on thyroid function, of pregnant women in a private obstetrical practice in Sydney. Methods. It was a cross-sectional study undertaken between November 2007 and March 2009. Blood samples were taken from 367 women at their first antenatal visit between 7 and 11 weeks gestation for measurement of thyroid stimulating hormone (TSH) and free thyroxine (FT4) levels and spot urine samples for urinary iodine excretion were taken at the same time as blood collection. Results. The median urinary iodine concentration (UIC) for all women was 81 μg/l (interquartile range 41–169 μg/l). 71.9% of the women exhibited a UIC of <150 μg/l. 26% of the women had a UIC <50 μg/l, and 12% had a UIC <20 μg/l. The only detectable influences on UIC were daily milk intake and pregnancy supplements. There was no statistically significant association between UIC and thyroid function and no evidence for an effect of iodine intake on thyroid function. Conclusions. There is a high prevalence of mild to moderate iodine deficiency in women in Western Sydney but no evidence for a significant adverse effect on thyroid function. The 6.5% prevalence of subclinical hypothyroidism is unlikely to be due to iodine deficiency.

Iodine Deficiency in Pregnant Women Pre- and Post-Mandatory Iodine Fortification in Australia - An Epidemiological Review

“…There was a significant increase in MUIC in women who were taking a pregnancy supplement. At 115 μg/L, however, it remained well below the recommended level of 150 μg/L [30].…”

“…72% of a sample of pregnant women in Western Sydney were iodine deficient, with 32% suffering from moderate deficiency [30]. The MUIC of 81 μg/L was similar to the level found in a pregnant population in Sydney approximately 10 years prior indicating that the situation had not improved despite publicity in the medical and lay press about iodine deficiency [27].…”

Prevalence of thyroid dysfunction and thyroid antibodies in a private obstetrical practice in Sydney

“…Women with multiple pregnancies were excluded from the study. This group is a socio‐economically middle‐class population group, who have been previously shown to be mildly iodine deficient, but no relationship was found between mild iodine deficiency and TSH level . Women included in this study were routinely prescribed iodine supplementation from the time of first presentation.…”

“…The American Endocrine Society (AES), the American Thyroid Association (ATA) and the European Thyroid Association (ETA) have all recently agreed that the clinical cut‐off point for subclinical hypothyroidism (SCH) in the first trimester should be a serum TSH >2.5mIU/l. Using this definition, we recently reported a prevalence of SCH, of 6.5% in pregnant women attending a private obstetric practice in Sydney, Australia . Reports emanating from the international clinics have reported SCH prevalence rates of between 2.0 and 12.1% …”

Asupan Yodium, Ekskresi Yodium Urine, dan Goiter pada Wanita Usia Subur di Daerah Endemis Defisiensi Yodium

“…Nilai median tersebut memberikan petunjuk bahwa, status yodium subjek di wilayah endemis telah mengalami pergeseran, melebihi ambang batas median EYU untuk menentukan endemisitas defisiensi yodium, sebesar 50 µg/l. [16][17][18] Ditemukannya angka ekses yodium pada penelitian ini merupakan fenomena keberhasilan program eliminasi defisiensi yodium. Dari lima miliar penduduk, lebih dari dua pertiga penduduk yang tinggal di negara yang terdampak kekurangan yodium, sekarang telah dapat mengakses asupan yodium melalui garam beryodium.…”