Iodine Nutritional Status in girls aged 14-19 years in the Shahriar region in 2015-2016

Abstract

Background: Iodine deficiency is one of the most important nutritional problems in the world that could be prevented. Mild pre-pregnancy iodine deficiency reduces the production of thyroid hormones during pregnancy and reduces the child's intelligence coefficient. Iran has long been suffering from endemic areas of iodine deficiency and salt iodization program has been implemented. The vulnerability of girls (aged 14 to 19) as future mothers in a region with a high prevalence of iodine deficiency disorders, namely, Shahriyar, and also due to studies and limited domestic studies in this demographic group, the present study aimed to determine the nutritional status of iodine in girls aged 14-19 years in Shahriar region in 1394-95. Methods: In this descriptive cross-sectional study, 223 students aged 14 to 19 years out of 26897 students were selected randomly by multi-stage cluster sampling. Three questionnaires including personal information, food frequency questionnaire containing iodine and food products, and questionnaire on how to use and store iodized salt for each student were completed. From each student, 15 g of salt and 10 ml of non-fasting urine samples were collected and transferred to the laboratory for analysis. The nutritional status of iodine was determined by the median urinary iodine in 5 groups <20 µg/L as “Severe deficiency”, 20-49 µg/L as “Moderate deficiency”, 50-99 µg/L as “Mild deficiency”, 100-199 µg/L as “Adequate”, and ≥200 µg/L as “Above requirements” were classified. The height and weight of the students with the lightest clothing and without shoes were measured and weight indices for age, height for age and body mass index for age were calculated in comparison with WHO standards and using Z score by Epi Info software. Result: Median urinary iodine and urinary iodine to creatinine were 129 and 70.4 µg/g, respectively. The frequency of mild, moderate and severe iodine deficiency was 22.4%, 14.3% and 0%, respectively. There was no significant difference between median urinary iodine, urinary iodine to creatinine ratio and salt iodine in age groups among urban and rural areas respectively. However the average iodine salt was 24.30 ppm, and 36% of the collected salt samples had unacceptable iodine concentration. There was a significant relationship between salt iodine status and urinary iodine status. Among all foods and iodine–rich food sources, fish and tuna fish consumption correlated with urinary level of iodine (p=0.047, r=0.16) and soya bean intake (among goitrogens) was reversely associated with urinary iodine to creatinine level (p=0.014, r=-0.189). The results indicate an inadequate consumption and maintenance of iodized salt. Conclusions: The results of this study showed that more than one third of subjects had iodine deficiency. More than one third of salt samples also contain unacceptable iodine and the teenage girls in the Shahriyar province had poor performance and information on how to properly use and store iodized salt.