Israel Medical Association Journal

Background: Congenital hypothyroidism (CH) is the most common preventable cause of mental retardation and delayed growth in children. Several prenatal and environmental factors might be associated with the disease.

Objectives: To determine the prevalence and risk factors of permanent CH and transient congenital hypothyroidism (TCH) in Israel.

Methods: We conducted a retrospective analysis of the Israeli national newborn screening program database from 2011 to 2015. Chi-square and logistic regression were used to assess the association of the demographic and gestational factors with the CH and TCH.

Results: Of the 889,033 live births screened between 2011 and 2015, 860 were diagnosed with CH (9.76 per 10,000 live births) and 298 with TCH (3.35 per 10,000 live births). In multivariate analyses, CH was positively associated with female sex, gestational ages < 38 or > 39 weeks, birth weight < 3000 grams, and winter birth. A decreased risk of TCH was detected in Arabs and neonates from high socioeconomic areas. An increased risk was independently associated with gestational ages < 38 weeks, low birth weight, and winter birth.

Conclusions: Several demographic, gestational, and geographical factors are associated with the development of CH and TCH. Future studies are needed to further investigate the pathogenesis in Israel.

Background: Data suggest that subclinical hypothyroidism (SCH) is associated with progression of chronic renal disease; however, no study to date has assessed the possible relation between SCH and acute deterioration of renal function.

Objectives: To investigate the possible relation between SCH and acute kidney injury (AKI) in a large cohort of patients with ST-elevation myocardial infarction (STEMI) treated with primary coronary intervention (PCI).

Methods: We evaluated thyroid stimulating hormone (TSH) and free T4 levels of 1591 STEMI patients with no known history of hypothyroidism or thyroid replacement treatment who were admitted to the coronary care unit (October 2007–August 2017). The presence of SCH was defined as TSH levels ≥ 5 mU/ml in the presence of normal free T4 levels. Patients were assessed for development of AKI ( 0.3 mg/dl increase in serum creatinine, according to the KDIGO criteria).

Results: The presence of SCH was demonstrated in 68/1593 (4.2%) STEMI patients. Patients presenting with SCH had more AKI complications during the course of STEMI (20.6% vs. 9.6 %; P = 0.003) and had significantly higher serum creatinine change throughout hospitalization (0.19 mg/dl vs. 0.08 mg/dl, P = 0.04). No significant difference was present in groups regarding baseline renal function and the amount of contrast volume delivered during coronary angiography. In multivariate logistic regression model, SCH was independently associated with AKI (odds ratio = 2.19, 95% confidence interval 1.05–4.54, P =0.04).

Conclusions: Among STEMI patients treated with PCI, the presence of SCH is common and may serve as a significant marker for AKI.

Background: Previous surveys demonstrated variations in the clinical practices relating to the treatment and screening of maternal thyroid dysfunction.

Objectives: To study the current practices in the management of subclinical hypothyroidism (SCH) and thyroid nodules during pregnancy of obstetricians/gynecologists (OB/GYNs) and endocrinologists in Israel.

Methods: An electronic questionnaire was sent by email to all members of the Israeli Endocrine Society and the Israel Society of Obstetrics and Gynecology. Questionnaires included demographic data and clinical scenarios with questions regarding the screening and management of pregnant women with SCH, hypothyroxinemia, and a palpable thyroid nodule. The questionnaire for OB/GYNs was slightly modified.

Results: We received 90 responses from endocrinologists and 42 responses from OB/GYNs. Among endocrinologists, 39% would repeat a thyroid-stimulating hormone (TSH) test of 2.9 mU/L with normal free thyroxine and treat with thyroxine if the second result was above 2.5 mU/L. Among OB/GYNs, 73% would manage a woman with SCH at the beginning of her pregnancy by themselves and only 22% would start thyroxine after a first TSH result above 2.5 mU/L. Concerning screening, 57% endocrinologists and 71% OB/GYNs recommended screening for thyroid dysfunction in every woman at the beginning of her pregnancy. Among endocrinologists, 54% would order an ultrasound for a palpable thyroid nodule and perform a fine needle aspiration only for suspicious lesions.

Conclusions: The medical approach to thyroid disease in pregnant women remains a matter of controversy. Our results support the need for larger and prospective clinical studies.

Background: The prevalence of thyroid dysfunction in early pregnancy in Israel is not known.

Objectives: To assess the rate of abnormal thyroid-stimulating hormone (TSH) tests in low risk pregnant women attending a community clinic in Israel.

Methods: We conducted a retrospective analysis of the charts of low risk pregnant women (n=303) who had undergone a TSH screening during the first trimester of pregnancy at Clalit Health Services Women's Health Centers in Ashkelon and Tel Aviv. The TSH normal range during first trimester was considered to be 0.1–2.5 mIU/L.

Results: The TSH levels ranged from 0.04 to 13.3 mIU/L (median 1.73 mIU/L, mean 1.88 mIU/L). The rate of abnormal TSH was 25.6%, with low TSH 2.3% and high TSH 23.4%. The prevalence of abnormal TSH was not influenced by gravidity (primigravidas versus multigravidas) or place of residence (Ashkelon or Tel Aviv).

Conclusions: In view of the high prevalence of abnormal TSH (25.6%) in pregnant women in Israel during the first trimester, a universal country-wide screening should be considered.

Background: Iodine intake is necessary to maintain normal thyroid function and prevent iodine deficiency disorders. In 1990, a resolution calling for universal salt iodination to eliminate iodine deficiency worldwide was taken by the World Health Organization and endorsed by some 130 countries. As of today, very little is known about iodine intake and the prevalence of iodine deficiency disorders in Israel, and iodine enrichment of regular salt has not been authorized.

Objectives: To assess the current level of iodine intake in an unselected group of residents from the Israeli costal area.

Methods: Spot urine samples were collected from three groups: Group A comprising 51 pregnant women attending the Women s Health Clinic at our institution, with a mean age of 32 years and at gestational week 28; group B consisting of 35 healthy subjects, mean age 38; and group C consisting of 16 euthyroid subjects harboring nodular goiters. Tap drinking and mineral water were also analyzed for iodine content. Iodine concentration was measured using the catalytic reduction of ceric ammonium sulfate method.

Results: When considering all groups together the median urinary iodine concentration was 143 µg/L, with 27% of the study population having concentrations under 100 µg/L and 7.8% under 50 µg/L. Values were distributed similarly between sites of residency, and no significant differences were seen between groups. The mean iodine concentration for tap drinking water was 22.8 µg/L (range 0.5–53.5 µg/L) and for mineral water 7 µg/L (range 0–15 µg/L).

Conclusions: Overall, iodine intake appeared to be satisfactory in our study population, however mild deficiency may exist in up to 26% of this group. A nationwide survey is needed to better determine the status of iodine intake in Israel, allowing for recommendations on salt-iodine enrichment in the future.