IODINE DEFICIENCY
Iodine content is low or absent in some US multivitamin and prenatal vitamin brands
CTFP Volume 12 Issue 5
BACKGROUND
Iodine is essential for the production of thyroid hormone and for normal development of the baby during pregnancy. During pregnancy and breastfeeding there is an increased requirement for iodine both because of a need for higher thyroid hormone production and for secretion of iodine into breast milk. Many studies have shown that iodine deficiency has been associated with adverse effects in babies and infants that range from severe mental retardation to mild brain deficits. Therefore, organizations such as the American Thyroid Association and the American Academy of Pediatrics have recommended that women who are planning a pregnancy, are pregnant or are breastfeeding should ingest a daily supplement that contains 150 mcgs of iodine.
In the US, it has been challenging to identify the sources of dietary iodine, because most food packaging does not detail their contents for this element. Dairy products and seafood are two important sources, but the consumption of these two types of foods is highly variable across the US population. Although in many regions of the world, universal salt iodization has been successful in preventing iodine deficiency, iodization of salt has never been mandated in the US. Currently, only 53% of salt sold for use in homes contains iodine and salt used in processed foods typically is not iodized.
Due to the variable intake of iodine content in food sources and different types of diets followed by the US population, there is concern that some groups of people are at risk for iodine deficiency. Specifically, mild iodine deficiency has been recently documented to be present among pregnant US women. The importance of multivitamin supplements as a source of iodine for pregnant and non-pregnant US adults is not well understood. A study reviewing the use of multivitamin supplements in the US and Canada reported that supplement use ranged from 7% to 85%, showing how difficult it is to accurately determine the extent of multivitamin use. In addition, it has been reported that only 60% of the different types of prenatal multivitamin supplements marketed in the US list iodine among the ingredients. It also has been shown that iodine content is the most variable and least accurately labeled nutrient contained in US adult multivitamins.
This study aimed to assess whether multivitamins are a significant source of iodine in nonpregnant and pregnant adults by looking at the iodine content reported in the most frequently purchased US adult and prenatal multivitamin preparations, knowing how many purchases for these supplements were made over the course of one year.
THYROID AND PREGNANCY
Pregnancy and perinatal outcome among hypothyroid mothers
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BACKGROUND
Hypothyroidism is common in women of reproductive age. About 1% of women will have known hypothyroidism before getting pregnant and another 0.5% of women will be diagnosed with hypothyroidism during pregnancy. Overt hypothyroidism (low T4 and high TSH) has known adverse effects on pregnancy outcome including a higher risk of miscarriage and lower IQ in offspring. The effect of less severe hypothyroidism (high TSH but normal T4, subclinical hypothyroidism) varies with some studies, but not all, showing increased rates of caesarean section, labor induction and ICU admission of the babies. This study took advantage of national registries in Finland where nearly all women receive free maternity care and deliver at national hospitals and data is collected. The goal of the study was to look at pregnancy complications in a large group of patients and evaluate whether consistent use of thyroid hormone in hypothyroid mothers effected the outcomes.
THE FULL ARTICLE TITLE:
Turunen S et al Pregnancy and perinatal outcome among hypothyroid mothers: a population-based cohort study. Thyroid 2019 29:135–141
SUMMARY OF THE STUDY
The investigators studied all pregnancies with a single baby in Finland from 2004-2013. There were 16,364 mothers with a diagnosis of hypothyroidism and 550,860 mothers who were not hypothyroid. They used the extensive Finnish Medical Birth Registry that collects data on mothers and newborns within 7 days of delivery, the Finnish Malformation Registry to identify congenital malformations and the Prescription Register to track thyroid hormone use. Women were considered to be hypothyroid if they had a diagnosis of hypothyroidism or if they purchased thyroid medication within 3 mo prior to pregnancy or during pregnancy.
HYPERTHYROIDISM
Treatment of hyperthyroidism resulting in hypothyroidism decreases the risk of heart disease related hospitalization and death risk
BACKGROUND
Hyperthyroidism is a state when the thyroid is overactive and there is too much thyroid hormone in the body. The main cause of hyperthyroidism in the United States is Graves' disease. This is an autoimmune disease where the body makes an antibody that attacks and turns on the thyroid. There are 3 major options for treatment of hyperthyroidism: 1) antithyroid drugs, such as methimazole or PTU, that decrease the thyroid hormone production; 2) surgery to remove the overactive thyroid and 3) radioactive iodine that is taken up by the thyroid and destroys the gland. The most common result of surgery and radioactive iodine therapy is hypothyroidism. Hypothyroidism can also develop if the dose of antithyroid drug is too high.
Thyroid hormone has major effects on the heart. Hyperthyroidism can cause major problems and symptoms such as irregular heart rhythms and palpitations. Rarely, these problems can lead to death. Despite treatment, the negative effects related to hyperthyroidism may persist. This study examined the effect of radioactive iodine therapy and surgery on heart disease related problems, hospitalizations and mortality.
THE FULL ARTICLE TITLE:
Essi et al 2018 Cardiovascular morbidity and mortality after treatment of hyperthyroidism with either radioactive iodine or thyroidectomy. Thyroid 28:1111–1120. Epub 2018 Jul 23.
SUMMARY OF THE STUDY
Two groups of patients who had been treated for hyperthyroidism in Finland from 1986 to 2007 were identified from a registry. Patients were treated either with surgery or with radioactive iodine therapy. A control group of Finnish residents was formed by randomly selecting 3 age and sex-matched subjects for each patient from a national population registry. A nationwide database system was used to identify causes of all heart related hospitalizations and death.
HYPOTHYROIDISM
Levothyroxine treatment increases mortality in patients with heart failure
BACKGROUND
Hypothyroidism is a common condition that can affect the entire body and is treated with levothyroxine. It is clear that patients with overt hypothyroidism (high TSH and a low T4) should be treated with levothyroxine. It is less clear if patients with mild hypothyroidism (high TSH, normal T4) benefit from treatment. Finally, patients with thyroid abnormalities due to medical illnesses and not due to problems with the thyroid itself should not be treated.
In terms of heart function, it is well known that overt hypothyroidism has negative effects on the heart function that improve with levothyroxine treatment. However, studies of treating patients with subclinical (mild) hypothyroidism with heart problems have shown controversial results, with some studies suggesting that treating does not provide any benefit to the patient. This is especially true in patients with heart failure. While levothyroxine replacement may improve heart failure, it is possible that in this group it could have harmful effects, especially if the levothyroxine dose is too high. This Danish nationwide study evaluated the long-term effects of levothyroxine therapy in patients with heart failure.
THE FULL ARTICLE TITLE:
Einfeldt MN 2018 Long-term outcome in heart failure patients treated with levothyroxine: an observational nationwide cohort study. J Clin Endocrinol Metab. Epub 2018 Dec 4. PMID: 30517746.
SUMMARY OF THE STUDY
This study used the Danish national registers to identify and collect clinical information for all Danish citizens >18 years of age who were diagnosed with heart failure during a hospital admission between 1997 and 2012. The patients who received levothyroxine treatment were identified from a nationwide database of all claimed prescriptions. The patients were divided in three groups: (1) patients already receiving levothyroxine at the time of the heart failure diagnosis, (2) patients who started levothyroxine treatment after being diagnosed with heart failure and (3) patients with heart failure not treated with levothyroxine The study compared the overall death rate, the heart-specific death rate, the number of heart attacks and the combination of major adverse cardiovascular events (including death, heart attack, and stroke) between these patient groups.
Active surveillance for low risk papillary thyroid cancer can be considered in select patients
https://www.thyroid.org/patient-thyroid-information/ct-for-patients/may-2019/vol-12-issue-5-p-11-12/
BACKGROUND
The number of new thyroid cancer cases has increased over recent years, especially the number of small, low-risk papillary thyroid cancers. It is clear now that treating these small cancers aggressively with surgery results in more potential harm to patients than if the small cancer was simply watched. Because of this, simply watching, known as active surveillance, became a promising alternative to surgery for these low-risk cancers in select patients. Active surveillance involves closely monitoring the thyroid cancer over time, instead of treating it with immediate surgery. Prior studies have shown that active surveillance is safe in papillary thyroid cancers measuring 1 cm or smaller and confined to the thyroid without any lymph node involvement or spread outside of the neck. However, little is known about outcomes of active surveillance for patients with larger cancers measuring 1-2 cm and confined to the thyroid. This study compared outcomes of active surveillance for these patients to this with cancers <1 cm. The authors also examined outcomes of patients who had surgery for these small cancers.
THE FULL ARTICLE TITLE:
Sakai T et al 2019 Active surveillance for T1bN0M0 papillary thyroid carcinoma. Thyroid 29:59–63. Epub 2019 Jan 8. PMID: 30560718.
SUMMARY OF THE STUDY
The study included patients who were followed at the Cancer Institute Hospital in Tokyo, Japan, since 1995. Among 406 patients with papillary thyroid cancer < 1 cm, 360 (89%) underwent active surveillance and 46 (11%) underwent surgery. Among 392 patients with papillary thyroid cancer 1-2 cm, 331 (84%) underwent active surveillance and 61 (16%) underwent surgery.
THYROID CANCER
The TIRADS ultrasound system can decrease unnecessary biopsies of PET-positive thyroid nodules
BACKGROUND
PET scanning is a type of imaging commonly used to locate areas of cancer in the human body. This is done in patients with a diagnosed cancer to see if it has spread to other parts if the body. This works because cancer cells are more active than normal cells and will take up more of the tracer (18F-FDG) and will light up positive on the PET scan. However, not all areas that are PET-positive are cancer. Some thyroid nodules are PET-positive and occasionally, PET scanning will identify unexpected/ previously undetected thyroid nodules. Up to 1/3 of PET-positive thyroid nodules will end up being thyroid cancer. For this reason, most experts recommend biopsy of these nodules, especially when they are >1 cm in diameter, in order to determine whether or not a thyroid cancer is present. Unfortunately, thyroid biopsy results do not always rule out cancer and, in such cases, thyroid surgery is often needed. This means that some surgically removed thyroid nodules will ultimately be found to be benign (noncancerous).
An important area of research is the development of new technologies that might allow doctors to avoid thyroid surgery (and even thyroid biopsy) for patients having PET-positive thyroid nodules, but for whom these nodules are benign. One such technology is thyroid ultrasound, which can identify thyroid nodule features that may predict the presence of thyroid cancer. Several different systems have been developed for predicting, on the basis of ultrasound findings, whether or not a thyroid cancer is present in a thyroid nodule. One of these systems is called TIRADS. The TIRADS system places thyroid nodules into one of four different categories (2 thorough 5), depending on how many ultrasound features suspicious for thyroid cancer are identified. The greater number of suspicious ultrasound features identified, the higher the probability of thyroid cancer and the higher the TIRADS category (with TIRADS category 5 having the highest risk of cancer and category 2 having the lowest risk). It is important to note that, although thyroid cancer risk does increase as the TIRADS category number increases, the TIRADS system is by no means perfect. A TIRADS 5 category, for example, does not mean a 100% probability of thyroid cancer.
ALEXANDROS SFAKIANAKIS ANAPAFSEOS 5 AGIOS NIKOLAOS CRETE 72100 GREECE +306932607174 +302841026182
https://www.thyroid.org/patient-thyroid-information/ct-for-patients/may-2019/vol-12-issue-5-p-11-12/
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