Sun Y Lee

• MD MSc
• Professor (Assistant) at Boston University

Context: The effects of maternal subclinical hypothyroidism on pregnancy outcomes are not clear. Objective: We aimed to assess potential associations between maternal thyrotropin (TSH) levels in pregnancy and obstetric and perinatal outcomes. Design: Retrospective cohort study. Setting: Tertiary academic medical center. Patients: Women age...

Both hyperthyroidism and hypothyroidism can have adverse effects in pregnancy. The most common causes of thyrotoxicosis in pregnancy are gestational transient thyrotoxicosis and Graves’ disease. It is important to distinguish between these entities as treatment options differ. Women of reproductive age diagnosed with Graves’ disease should be couns...

Thyroid disorders are prevalent in pregnant women. Furthermore, thyroid hormone has a critical role in fetal development and thyroid dysfunction can adversely affect obstetric outcomes. Thus, the appropriate management of hyperthyroidism, most commonly caused by Graves disease, and hypothyroidism, which in iodine sufficient regions is most commonly...

Importance: Thyroid storm is the most severe form of thyrotoxicosis, with high mortality, and is treated with propylthiouracil and methimazole. Some guidelines recommend propylthiouracil over methimazole, although the difference in outcomes associated with each treatment is unclear. Objective: To compare outcomes associated with use of propylthi...

Importance Overt hyperthyroidism, defined as suppressed thyrotropin (previously thyroid-stimulating hormone) and high concentration of triiodothyronine (T 3 ) and/or free thyroxine (FT 4 ), affects approximately 0.2% to 1.4% of people worldwide. Subclinical hyperthyroidism, defined as low concentrations of thyrotropin and normal concentrations of T...

Disclosure: C. Han: None. S. Lee: None. E.N. Pearce: None. Background: Widespread exposure to endocrine disrupting chemicals (EDCs) poses a risk to public health and environmental safety. Women of reproductive age and pregnant women may be uniquely vulnerable to adverse thyroidal effects of EDCs. A better understanding of thyroidal EDCs exposure is...

https://authors.elsevier.com/a/1j-vc,YplMsl-q Free access until 12/17/24 at above link.

Background: International guidelines recommend targeted screening to identify gestational thyroid dysfunction. However, currently used risk factors have questionable discriminative ability. We quantified the risk for thyroid function test abnormalities for a subset of risk factors currently used in international guidelines. Methods: We included pro...

Importance Excessive thyroid hormones from hyperthyroidism increase cardiovascular risks. Among 3 available treatments for hyperthyroidism, comparisons of long-term outcomes associated with antithyroid drugs (ATDs), radioactive iodine (RAI), and surgery to treat newly diagnosed hyperthyroidism are lacking. Objective To compare risks of major adver...

Background: Autism spectrum disorder (ASD) is a neurodevelopmental condition with unknown etiology. Both genetic and environmental factors have been associated with ASD. Environmental exposures during the prenatal period may play an important role in ASD development. This narrative review critically examines the evidence for a relationship between...

Disclosure: C. Han: None. S. Lee: None. E.N. Pearce: None. Background: Previous studies of the relationship between dioxin exposure and thyroid function have usually been based on multi-chemical linear models and results have been inconsistent. However, complex nonlinear relationships and interactions between mixed dioxin exposures and thyroid func...

Objective: Obesity has become an epidemic in the United States. Although bariatric surgery can effectively achieve weight loss by altering the gastrointestinal tract, it commonly results in micronutrient deficiency, requiring supplementation. Iodine is an essential micronutrient for the synthesis of thyroid hormones. We aimed to investigate change...

The prevalence of thyroid cancer has been increasing worldwide. The evaluation and management of thyroid nodules and thyroid cancers in pregnancy pose a special challenge given concerns for potential adverse effects of any procedures or treatment on the developing fetus. Nodule characteristics, serum TSH levels, and patient preferences should be co...

Background Iodine is essential for thyroid hormone production. The Recommended Dietary Allowance (RDA) for iodine in non-pregnant adults is 150μg/day. However, most product labels do not list iodine content. Meal replacements, which are meant to provide nutrients equivalent to a meal, are not required to contain specific vitamins and minerals. Neve...

Objective Iodine deficiency (ID) is a worldwide public health problem and a preventable cause of neurodevelopmental delay in children. There are no data regarding iodine sufficiency and knowledge on iodine nutrition in pregnant women in Puerto Rico. The objective of this study was to assess the iodine status, potential factors influencing iodine st...

(Abstracted from J Clin Endocrinol Metab 2020;105(5):e2015–e2023) The fetus depends on maternal thyroid hormone crossing via a placental route in a critical period of development during the first trimester. Untreated maternal hypothyroidism increases risk of adverse pregnancy outcomes including fetal loss, preeclampsia, abruption placenta, and post...

Background: Iodine is essential for thyroid hormone production and fetal development. Even mild maternal iodine deficiency in gestation may be associated with impaired child neurodevelopment. Iodine requirements increase during pregnancy and lactation. Supplements containing 150 µg/day are recommended by the American Thyroid Association for all Un...

Background: Iodine is an essential micronutrient for thyroid hormone production. Adequate iodine intake and normal thyroid function are important during early development, and breastfed infants rely on maternal iodine excreted in breast milk for their iodine nutrition. The proportion of U.S. women of childbearing age with urinary iodine concentrat...

Objective: Hypoglycemia remains one of the main challenges of insulin therapy. To reduce insulin-related hypoglycemia at our institution, we restricted inpatient ordering of high glargine doses (≥0.5 U/kg/day) to endocrine staff in May 2013. This retrospective cohort study assesses its effect on hypoglycemia and glycemic control within 48 hours of...

Background Development of goiter and hypothyroidism has been reported in patients with cystic fibrosis (CF) since the 1970s, especially when treated with iodine-based expectorants. With iodine-containing expectorants no longer in routine use, the prevalence of thyroid dysfunction in CF patients is unknown. In this cross-sectional study, we assessed...

Hyperthyroidism is characterised by increased thyroid hormone synthesis and secretion from the thyroid gland, whereas thyrotoxicosis refers to the clinical syndrome of excess circulating thyroid hormones, irrespective of the source. The most common cause of hyperthyroidism is Graves' disease, followed by toxic nodular goitre. Other important causes...

In this review, we discuss the characteristics, pathophysiology, and therapeutic implications of the euthyroid sick syndrome. Multiple mechanisms have been identified to contribute to the development of euthyroid sick syndrome, including alterations in the iodothyronine deiodinases, thyroid-stimulating hormone secretion, thyroid hormone binding to...

Metabolic syndrome (MetS) is associated with increased risks of developing cardiovascular disease and type 2 diabetes. Thyroid dysfunction is also a known cardiovascular risk factor. In obese patients, serum thyroid stimulating hormone (TSH) levels tend to be higher than in lean controls. The objective of this study was to assess potential associat...

Background: Iodinated contrast media (ICM) is a source of excess iodine that may induce thyroid dysfunction. A prospective cohort study was conducted to assess the effects of ICM on urinary iodine clearance and serum thyroid function tests (TFTs) in adults. Methods: In this prospective cohort study of 54 adults undergoing elective computed tomog...

Several studies have linked maternal iodine deficiency during pregnancy with adverse neurodevelopmental outcomes in offspring. A new study warns that excessive iodine exposure might also be detrimental to maternal thyroid health and recommends a lower limit for maternal iodine intake during pregnancy than that currently advised by the WHO.

Context: Thyroid hormone production is dependent on adequate iodine intake. Excess iodine is generally well-tolerated, but thyroid dysfunction can occur in susceptible individuals after excess iodine exposure. Radiological iodinated contrast media represent an increasingly common source of excess iodine. Objective: This review will discuss the t...

Objective: Surprisingly few studies have examined weight change in hypothyroid patients after initiation of levothyroxine (LT4) therapy. Our study aimed to investigate weight change after initiation of LT4 treatment for primary hypothyroidism. Methods: Using electronic medical records from Boston Medical Center, Boston, Massachusetts, we perform...