Iodine Status among Somali Immigrants in Norway

Iodine Intake in Norwegian Women and Men: The Population-Based Tromsø Study 2015-2016

Ensuring sufficient iodine intake is a public health priority, but we lack knowledge about the status of iodine in a nationally representative population in Norway. We aimed to assess the current iodine status and intake in a Norwegian adult population. In the population-based Tromsø Study 2015-2016, 493 women and men aged 40-69 years collected 24-h urine samples and 450 participants also completed a food frequency questionnaire (FFQ). The 24-h urinary iodine concentration (UIC) was analyzed using the Sandell-Kolthoff reaction on microplates followed by colorimetric measurement. Iodine intake was estimated from the FFQ using a food and nutrient calculation system at the University of Oslo. The mean urine volume in 24 h was 1.74 L. The median daily iodine intake estimated (UIE) from 24-h UIC was 159 µg/day (133 and 174 µg/day in women and men). The median daily iodine intake estimated from FFQ was 281 µg/day (263 and 318 µg/day in women and men, respectively). Iodine intake estimated from 24-h UIC and FFQ were moderately correlated (Spearman rank correlation coefficient r = 0.39, p < 0.01). The consumption of milk and milk products, fish and fish products, and eggs were positively associated with estimated iodine intake from FFQ. In conclusion, this shows that iodine intake estimated from 24-h UIC describes a mildly iodine deficient female population, while the male population is iodine sufficient. Concurrent use of an extensive FFQ describes both sexes as iodine sufficient. Further studies, applying a dietary assessment method validated for estimating iodine intake and repeated individual urine collections, are required to determine the habitual iodine intake in this population.

Poverty and immigration as a barrier to iodine intake and maternal adherence to iodine supplementation

PURPOSE

Iodine deficiency still remains a significant health issue worldwide. Pregnant and lactating women are at risk for iodine deficiency when living in mild iodine-deficient areas such as Italy. This study aims at evaluating the consumption of iodized salt, iodine-rich-foods and maternal micronutrient supplements in a group of women with limited access to the Italian National Health System.

METHODS

A cross-sectional survey was conducted among immigrant and Italian women living in poverty and referring to 40 Non-Governmental Organization throughout Italy for their health needs. 3483 women answered the ad hoc questionnaire between January 2017 and February 2018.

RESULTS

The consumption of iodized salt was very low, and even lower among immigrant women. Determinants of iodized salt consumption were the period spent in Italy for immigrant women and living in a family-type setting, parity and, particularly, the degree of education for Italian ones. 17.5% of immigrant women and 8.6% of the Italian ones reported a diagnosis of thyroid disease. 521 women, 75.4% of whom were immigrants, were pregnant or breast-feeding. The majority (57.3%) had no specific maternal supplementation.

CONCLUSIONS

Both Italian and immigrating women with a low income or without access to the public health system have a poor adherence both to the salt iodization policy and to folic acid and iodine supplements in preconception and pregnancy. They also referred a low-frequency intake of iodine-rich-foods. The identification of barriers to health care access could be useful to promote specific health interventions in this target population.

Iodine intake and chronic autoimmune thyroiditis: a comparative study between coastal and mainland regions in Greece

INTRODUCTION

The purpose of this study was to evaluate the relationship between iodine intake and autoimmune thyroiditis in Chios, an island located in the North East Aegean Sea, in comparison to mainland regions in South Western Greece (SWG).

MATERIALS AND METHODS

Urine iodine concentration (UIC), thyroid function (serum TSH, thyroid autoantibodies: anti-TPO and anti-Tg), and thyroid U/S were assessed in 200 subjects (150 females and 50 males) from Chios and 322 subjects (255 females and 67 males) from several mainland regions in SWG. All participants were recruited from outpatient clinics and were diagnosed as euthyroid.

RESULTS

Median UIC in Chios was significantly higher compared to SWG (136.1 vs. 104.5 μg/L, p < 0.001), indicating that both regions are iodine sufficient according to World Health Organization (WHO) criteria. The prevalence of thyroid autoimmunity was 66.5% in Chios and 27% in SWG, significantly higher in females (46.7%) than in males (26.5%). Furthermore, individuals with increased levels of thyroid autoantibodies either anti-TPO or anti-Tg (TAbs) showed increased median UIC levels compared to those / subjects / patients with normal levels (126.7 vs. 108.95 μg/L, p < 0.001). Serum TSH mean values (mIU/L) were greater in females (mean = 2.1 ± 1.41) compared to males (mean = 1.82 ± 1.26) (p = 0.04) and decreased with age.

CONCLUSIONS

In conclusion, in the present study, we clearly indicate that increased thyroid autoimmunity is positively associated with increased iodine intake, as well as with the female gender. Moreover, iodine intake and thyroid autoimmunity appear to be significantly higher in a coastal region (Chios) than in mainland Greece (SWG). Additional environmental factors, apart from iodine, should be investigated in future studies. Mean TSH values were increased in females and decreased with age. The latter is probably due to the presence of autonomous goiter in older Greek populations, as a result of long-term status of iodine deficiency in the past.

Suboptimal Iodine Status and Low Iodine Knowledge in Young Norwegian Women

Previous studies have documented mild to moderate iodine deficiency in pregnant and lactating women in Norway. This study focused on non-pregnant young women because their future children may be susceptible to the adverse effects of iodine deficiency. We assessed urinary iodine concentration (UIC), iodine intake from food and supplements, and iodine knowledge in 403 non-pregnant women, mainly students, aged 18–30 years. Iodine concentration was measured in spot urine samples analyzed by inductively coupled plasma mass spectrometry and iodine intake was calculated from a self-reported food frequency questionnaire. Knowledge about iodine was collected through the self-administered, paper-based questionnaire. Median (p25–p75) UIC was 75 (42–130) µg/L and 31% had UIC < 50 µg/L. Habitual iodine intake was 100 (69–136) µg/day. In multiple regression models, supplemental iodine, use of thyroid medication, and iodine intake from food were positively associated with UIC, while vegetarian practice was negatively associated, explaining 16% of the variance. Approximately 40% of the young women had low iodine knowledge score and no differences were found between women in different study programs. Young women in Norway are mild to moderately iodine-deficient, and public health strategies are needed to improve and secure adequate iodine status.