Prevalence Of Thyroid Peroxidase Antibodies Research Articles

Overall, sex-and race/ethnicity-specific prevalence of thyroid dysfunction in US adolescents aged 12-18 years.

Thyroid dysfunction significantly affects the health and development of adolescents. However, comprehensive studies on its prevalence and characteristics in US adolescents are lacking. We investigated the prevalence of thyroid dysfunction in US adolescents aged 12-18 years using data from the National Health and Nutrition Examination Survey (NHANES) 2001-2002 and 2007-2012 cycles. Thyroid dysfunction was assessed using serum thyroid-stimulating hormone (TSH) and free thyroxine (fT4) measurements. We analyzed the prevalence across demographic subgroups and identified associated risk factors. The study included 2,182 participants, representing an estimated 12.97 million adolescents. The group had a weighted mean age of 15.1 ± 0.06 years, with males constituting 51.4%. Subclinical hyperthyroidism emerged as the most prevalent thyroid dysfunction, affecting 4.4% of the population. From 2001-2002 to 2011-2012, subclinical hyperthyroidism remained consistent at 4.99% vs. 5.13% in the overall cohort. Subclinical and overt hypothyroidism was found in 0.41 and 1.03% of adolescents respectively, and overt hyperthyroidism was rare (0.04%). The prevalence of thyroid peroxidase antibody (TPOAb) and thyroglobulin antibody (TgAb) positivity in the overall population were 5.8 and 9.8%, respectively. Positivity for TgAb was risk factors for hypothyroidism, while older age, female and Black Americans were risk factors for hyperthyroidism. Female adolescents and adolescents with an older age were more likely to be positive for TPOAb and TgAb, while Black and Mexican Americans had a lower risk of TPOAb and TgAb positivity. Subclinical hyperthyroidism was the most common form of thyroid dysfunction, and its prevalence remained stable from 2001-2002 to 2011-2012. Notable disparities in the prevalence of hyperthyroidism and antibody positivity were observed among different age, sex and racial/ethnic groups.

Correlates of Positive Thyroid Peroxidase Antibodies Among Firefighters: A Cross-Sectional-Study.

ContextExposure to endocrine disrupting chemicals (EDCs) are associated with underactive thyroid glands, and possibly autoimmunity. Firefighters are exposed to EDCs from flame retardants; however, the prevalence and risk factor associations of thyroid antibodies among firefighters are unknown.ContextWe aimed to determine the prevalence of thyroid peroxidase antibodies (TPOAb) and associated sociodemographic and occupational risk factors among firefighters.MethodsFirefighters attending professional health and safety conferences between November 2018 and January 2020, and with no prior diagnosis of thyroid disease were invited (n = 278) to submit a health survey, blood samples, and complete a thyroid ultrasound. The survey assessed for sociodemographic and occupational characteristics, including a history of familial thyroid disease, smoking, firefighter tenure, and job rank, radiation exposure, and mitigation practices of occupational exposures. Serum thyroid peroxidase antibody (TPOAb) was also assessed.ResultsApproximately 39.9% of firefighters evaluated had a positive TPOAb test. The mean age for those TPOAb positive was lower than those who tested negative (41.4 ± 7.9 vs 43.1 ± 7.9 years, P = 0.07) but this difference was not significant. Firefighters with a family history of thyroid disease had a statistically significant higher prevalence of TPOAb compared with those without a family history (60.0% vs 37.5%, P = 0.02); this association remained significant after adjusting for sociodemographic and occupational factors (odds ratio 2.99; CI, 1.31-6.85).ConclusionThe prevalence of TPOAb is high among firefighters in our study, and family history is a significant determinant of testing positive for TPOAb. Firefighters may benefit from TPOAb and thyroid stimulating hormone tests, and screening for family history of thyroid disease at baseline employee medical check-ups. This finding suggests the need for further studies.

THE PREVALENCE OF SUBCLINICAL HYPOTHYROIDISM IN THE POPULATION OF ELDERLY NURSING HOME RESIDENTS IN ZAGREB.

The aim of the study was to investigate the prevalence of thyroid dysfunction, positive thyroid peroxidase antibodies (TPOAb) and hypercholesterolemia in elderly and younger subjects, and the association of subclinical hypothyroidism with hypercholesterolemia. The study included 204 elderly (136 females and 68 males, age median 71, range 60-92 years), and 83 younger control subjects (63 females and 20 males, age median 45, range 19-55 years). Subjects with prior thyroid dysfunction were excluded. Serum thyrotropin (TSH), free triiodothyronine (FT3), free thyroxine (FT4), TPOAb, total cholesterol, height and weight were measured. Mann-Whitney, χ2-test and Student's t-test were used on statistical analysis. The prevalence of subclinical hypothyroidism (TSH >5 mU/L) in elderly was 7.4% vs. 3.6% in younger subjects, with the highest prevalence of 8.8% in elderly women vs. 4.8% in younger women, and 4.4% in elderly men. The prevalence of hypothyroidism and subclinical hyperthyroidism in elderly subjects was 0.5% and 1.5%, respectively. In women with subclinical hypothyroidism, the prevalence of TPOAb was 77% in elderly women and 67% in younger women (overall 19.9% in elderly and 14.3% in younger women). The mean FT3 level was lower in elderly women as compared with elderly men (p<0.01) and younger women (p<0.05). The mean cholesterol level was higher in elderly subjects in comparison with younger ones (p<0.01), and in elderly women vs. elderly men (p<0.01), but without difference between subclinical hypothyroidism and euthyroid subjects (6.0 mmol/L). In conclusion, subclinical hypothyroidism is the most prevalent thyroid dysfunction in elderly, with the highest prevalence in elderly women, and autoimmune thyroiditis is the most common etiology. Hypercholesterolemia was more related to older age, especially elderly females, but not influenced by subclinical hypothyroidism.

Antithyroid autoantibodies in extrathyroid autoimmune diseases

This review summarizes data on the incidence of autoimmune diseases and examines the prevalence of antithyroid antibodies in extrathyroid autoimmune diseases. In the world, about 5–7% of the population suffers from one or another type of autoimmune diseases. Among the six most common autoimmune diseases, thyroid and associated diseases predominate. The high prevalence of autoimmune thyroid diseases raises questions about the potential role of antithyroid antibodies in the course of extrathyroid autoimmune diseases. It is believed that autoimmune diseases are the result of interactions between triggers, autoantigens, genetic predisposition, impaired tolerance of autoantigens and mechanisms of apoptosis. Among the currently known antithyroid autoantibodies, antibodies to thyroglobulin (TgAb), thyroid peroxidase (TPO), as well as bispecific autoantibodies to thyroglobulin and thyroid peroxidase are of particular importance. Categories of functionally significant autoantibodies that mimic hormone function and provoke the development of autoimmune pathology as a result of binding to the receptor and subsequent stimulation of thyrocytes include antibodies to thyroid-stimulating hormone receptor (rTSH-Ab). Circulating antibodies against thyroid antigens are not limited to autoimmune diseases of the thyroid gland, but are also found in other autoimmune diseases, most often in rheumatoid arthritis, type 1 diabetes mellitus and celiac disease. The association with other immune pathologies further confirms that TPO antibodies were also detected in 15% of patients with asthma, in 10–29% of those with idiopathic purpura and vitiligo. The prevalence of TPO antibodies is slightly higher than TgAb, and rTSH-Ab are rarely registered in non-thyroid immunological diseases.

Thyroid Autoimmunity and Dysfunction in Sri Lankan Children and Adolescents After 22 Years of Sustained Universal Salt Iodization.

Background: Sri Lanka introduced universal salt iodization (USI) in 1995 after which we demonstrated a high thyroglobulin antibody (TgAb) prevalence in 1998. However, it is unclear whether thyroid autoimmunity persists in the long term in populations exposed to sustained USI and whether such populations have an excess of thyroid dysfunction. We evaluated the prevalence of thyroid autoantibodies and dysfunction in Sri Lankan children and adolescents after more than two decades of sustained USI. Methods: We selected 10- to 18-year-old subjects of both sexes (randomized cluster sampling) from all 9 provinces of Sri Lanka in this cross-sectional study. Blood, urine, and anthropometric data were collected and thyroid ultrasound scans were performed. Validated statistical methods were used to derive local population-specific reference ranges for all thyroid parameters. We also measured urine iodine concentration (UIC), salt, and water iodine concentrations. Results: Blood and urine samples from 2507 and 2473 subjects respectively, and ultrasound scans from 882 subjects were analyzed. Population-derived upper limits for thyroid peroxidase antibody (TPOAb) and TgAb, and reference ranges for triiodothyronine, thyroxine, and thyrotropin (total and age-year-related groups) were significantly different from manufacturer's reference ranges. Using these derived ranges, the prevalence of TPOAb was 10.3% and TgAb was 6.4%. Of the TPOAb-positive subjects, TPOAb were of low concentration in 66.2% (1-3 times the upper limit of the reference range [ULRR]) and showed the strongest association with subclinical hypothyroidism (SCH) at the highest concentrations (>4 ULRR). The prevalence of SCH was 3%. Median UIC (interquartile range) was 138.5 μg/L (79.4-219.0) with regional variability, and median thyroglobulin was 8.3 ng/mL (4.1-13.5). Goiter prevalence was 0.6% and 1.93% (thyroid volume compared to age and body surface area, respectively). Salt and water iodine concentrations were satisfactory. Conclusions: Sri Lanka has safely and effectively implemented USI with good sources of iodine, leading to sustained iodine sufficiency over more than two decades. The early postiodization TgAb surge (42.1%) has settled (6.4%), and despite a persistently high TPOAb prevalence (10.3%), SCH prevalence remains low (3%). Further studies should be undertaken to monitor thyroid autoimmune dysfunction in Sri Lankan children, using age-specific, population-derived reference ranges.

Impact of Abdominal Obesity on Thyroid Auto-Antibody Positivity: Abdominal Obesity Can Enhance the Risk of Thyroid Autoimmunity in Men.

Background The interrelation between obesity and autoimmune thyroid diseases is complex and has not been confirmed. The aim of the present study was to observe the relationship between thyroid autoimmunity and obesity, especially abdominal obesity, in a large population. Methods A total of 2253 residents who had lived in Xinjiang for more than 3 years were enrolled. Serum thyroid hormone concentration, thyroid autoantibodies, lipid parameters, Weight, height, and waist and hip circumference were measured. Results The prevalence of thyroid peroxidase antibody (TPOAb) and/or thyroglobulin antibody (TgAb) positive was 32.1% (21.2% in men and 37% in women, P < 0.01). Compared with women, men had significantly higher TG levels, waist circumference, and hip circumference levels (P < 0.01), while women showed higher TSH, TPOAb, and TgAb levels (P < 0.01). The prevalence of overweight and obesity was 71.1% in men and 63.5% in women. Men had a higher prevalence of abdominal obesity than women (56.6% in men and 47.6% in women, P < 0.01). TPOAb correlates positively with waist circumference (r = 0.100, P < 0.05) in men. Binary logistic analysis showed that TPOAb positivity had increased risks of abdominal obesity in men, and the OR was 1.1044 (95% CI 1.035, 1.151, P < 0.05). Conclusion Our results indicate that men had higher lipid levels, thicker waist circumference, and higher prevalence of overweight, obesity, and abdominal obesity. Abdominal obesity is a risk factor for TPOAb positivity in men, suggesting that abdominal obesity can enhance the risk of thyroid autoimmunity in men.

Thyroid peroxidase (TPO) expressed in thyroid and breast tissues shows similar antigenic properties.

BackgroundThyroid peroxidase (TPO) is essential for physiological function of the thyroid gland. The high prevalence of thyroid peroxidase antibodies (TPOAbs) in patients with breast cancer and their protective role had previously been demonstrated, indicating a link between breast cancer and thyroid autoimmunity. Recently, TPO was shown to be present in breast cancer tissue samples but its antigenicity has not been analyzed.MethodsIn this study, we investigated TPO expression levels in a series of fifty-six breast cancer samples paired with normal (peri-tumoral) tissue and its antigenic activity using a panel of well-characterized murine anti-human TPOAbs.ResultsWe have shown that TPO transcripts were present in both normal and cancer tissue samples, although the amounts in the latter were reduced. Additionally, we observed that TPO levels are lower in more advanced cancers. TPO protein expression was confirmed in all tissue samples, both normal and cancerous. We also found that the antigenicity of the immunodominant regions (IDRs) in breast TPO resembles that of thyroid TPO, which is crucial for effective interactions with human TPOAbs.ConclusionsExpression of TPO in breast cancer together with its antigenic activity may have beneficial effects in TPOAb-positive breast cancer patients. However, further studies are needed to confirm the beneficial role of TPOAbs and to better understand the underlying mechanism.

Increase in thyroglobulin antibody and thyroid peroxidase antibody levels, but not preterm birth-rate, in pregnant Danish women upon iodine fortification.

The presence of thyroid antibodies in pregnancy has been associated with preterm birth. In the non-pregnant population, the implementation of the Danish iodine fortification program has increased the prevalence of thyroid antibodies. This study investigated the prevalence of thyroid peroxidase antibodies (TPOAbs) and thyroglobulin antibodies (TgAbs) in pregnant Danish women before, during and after implementation of the iodine fortification program and association with preterm birth. Comparative cohort study of 1368 pregnancies from three cohorts gathered before (1996-1998), during (2000-2003) and after (2008-2009) the iodine fortification program. In cohort 1 (n = 297), TPOAbs were measured (DYNOtest (BRAHMS)). In cohorts 2 (n = 148) and 3 (n = 923), both TPOAbs and TgAbs were measured (Kryptor immunofluorescent assay (BRAHMS)). The prevalence and effect of antibody positivity were explored using three cut-offs: TPOAbs and/or TgAbs >100 kU/L, TPOAbs and/or TgAbs >60 kU/L and TPOAbs >30 and/or TgAbs >20 kU/L. National preterm birth data were extracted from the National Birth Registry. In the three cohorts, TPOAb levels >60 kU/L were found in 5.4, 8.1 and 12.0% (χ2(2, n = 1367) = 11.7, P = 0.003) respectively, and TPOAbs and/or TgAbs >60 kU/L in 8.1 and 16.2% in cohorts 2 and 3 respectively (χ2(2, n = 1070) = 6.5, P = 0.01). TgAb levels (>20 kU/L) had increased plenty-fold from cohort 2 to 3 (χ2(1, n = 1071) = 136.5, P < 0.001). Preterm birth occurred in 4.1% of all pregnancies with no effect from antibody positivity (TPOAbs and/or TgAbs >60 kU/L, χ2(1, n = 1039) = 0.0, P = 0.98, aOR = 1.1, 95% CI (0.4-2.7)). The national preterm birth-rate showed no increase over the same period. Thyroid antibody positivity in Danish pregnant women has more than doubled upon the implementation of the iodine fortification program without an increase in preterm birth-rate.

Prevalence of Thyroid Peroxidase Antibody and Pregnancy Outcome in Euthyroid Autoimmune Positive Pregnant Women from a Tertiary Care Center in Haryana.

Objective:To study the prevalence of thyroid peroxidase autoantibody in euthyroid pregnant women and to evaluate the association between thyroid peroxidase autoantibody and pregnancy outcomes.Materials and Methods:One thousand thirty consecutive pregnant women attending the antenatal clinic over a period of 1 year and were carrying a healthy singleton uncomplicated intrauterine pregnancy and consuming iodized salt were recruited for the study. Outcomes of the pregnancy was compared between TPO antibody positive euthyroid women (group 1) and TPO antibody negative euthyroid women (group 2).Results:Out of 1030 women, 164 (18.9%) were detected TPO antibody positive with euthyroid status. The mean FT4 and TSH level were significantly different in those who were TPO Ab positive as compared TPO Ab negative euthyroid pregnant women. No correlation was observed between the maternal age, gestational age and gravidity with anti TPO antibody levels. Eighteen (12%) women in Group 1and 5 (3.3%) women in Group 2 had miscarriages and the difference was found to be statistically significant (P value of 0.004). Twenty-one (14%) women in Group 1 and 5 (3.3%) women in Group 2 had preterm deliveries, which was also found to be statistically significantly (p value of 0.001). Other pregnancy related complications like Intrauterine death, IUGR, preeclampsia and PIH though are present in comparatively higher number in TPO Ab positive euthyroid pregnant women as compared to TPO Ab negative euthyroid pregnant women but this difference was not found to be statistically significant.Conclusions:To conclude with the present study shows that a good number of pregnant women with euthyroid status have TPO Ab positivity and this is associated with some adverse pregnancy outcomes like miscarriage and preterm birth of the baby.

Population Reference Values and Prevalence Rates following Universal Screening for Subclinical Hypothyroidism during Pregnancy of an Afro-Caribbean Cohort

Background: Subclinical hypothyroidism (SCH) has been reported to be associated with adverse pregnancy outcomes, however universal screening and treatment is controversial. Objectives: Our objectives were to determine population-specific pregnancy reference values (R1) for serum thyroid-stimulating hormone (TSH) and free thyroxine (FT₄) at 14 weeks' gestation, along with the prevalence of SCH and thyroid peroxidase antibody (TPOAb). Methods: This was a prospective hospital-based cohort study. 1,402 subjects were recruited. Blood samples were obtained from 769 singleton pregnancies due to default between recruitment and scheduled blood draw. The prevalence of SCH was determined using R1, the laboratory non-pregnant reference values (R2) and previously recommended pregnancy reference values (R3). Results: R1 for TSH and FT₄ was 0.03-3.17 mU/l (mean ± SD, 1.1 ± 0.76) and 8.85-17.02 pmol/l (mean ± SD, 11.96 ± 2.06), respectively. The prevalence of SCH using reference values R1, R2 and R3 was 1.4% (11/769), 0.5% (4/769) and 1.9% (15/769). Prevalence was significantly greater using R3 when compared to R2 (p = 0.011). TPOAb prevalence was 2.6%. A significantly greater prevalence of TPOAb was found in subclinical hypothyroid subjects using all three reference values than in euthyroid subjects (∼25 vs. 2%, p < 0.05). Conclusions: These reference values are the first to be reported for an Afro-Caribbean population. Our findings support the use of pregnancy-specific reference values in our population.

Thyroid peroxidase antibody in hypothyroidism: It’s effect on pregnancy

Objective: To find out the prevalence of thyroid peroxidase antibodies (TPO) in pregnant women with hypothyroidism and to analyze its effect on pregnancy outcome. Methods: The prospective study was conducted on well-controlled hypothyroid pregnant patients attending the antenatal clinic at Sanjay Gandhi Post Graduate Institute of Medical Sciences, Lucknow, India from July 2009 to June 2011 and has delivered. The women were grouped into two groups depending on presence or absence of TPO antibody. Maternal complications during pregnancy and perinatal outcome were noted and compared between these two groups. Results: During the study period, 2479 women attended the high-risk pregnancy clinic. Among which 196 women were found to be hypothyroidism making prevalence of hypothyroidism as 7.91%. A total of 140 were found to be well controlled (5.6%) and included for study. Amongst the women with hypothyroidism, 40% were TPO positive. Complications like threatened abortion, spontaneous abortion, preterm delivery, fetal malformations, intrauterine growth restriction, and adverse fetal outcomes like poor apgar scores and prolonged nursery admissions were more in patients with positive TPO antibodies. Conclusion: TPO positivity is considered as high risk for pregnancy complications and hence those patients should be monitored more carefully.

Smoking and Early Pregnancy Thyroid Hormone and Anti-Thyroid Antibody Levels in Euthyroid Mothers of the Northern Finland Birth Cohort 1986

Smokers in the general population have lower thyrotropin (TSH) and higher free triiodothyronine (fT3) and free thyroxine (fT4) concentrations, but the results in pregnant population vary from no effect to a decrease in TSH and fT4 concentrations and an increase in fT3 levels. Our objective was to further evaluate the question of whether there is an association between smoking, before and during pregnancy, with maternal thyroid function during pregnancy and with the risk for subsequent hypothyroidism. Our study population was a prospective population-based cohort (N=9362), the Northern Finland Birth Cohort 1986, with extensive data throughout gestation. The mothers underwent serum sampling in early pregnancy. The samples were assayed for TSH, fT3, fT4, thyroid-peroxidase antibodies (TPO-Ab), and thyroglobulin antibodies (TG-Abs) (n=5805). Mothers with thyroid dysfunction diagnosed before or during pregnancy were excluded, leaving 4837 euthyroid mothers. The smoking status of mothers and fathers were requested by questionnaires during pregnancy. Subsequent maternal morbidity relating to hypothyroidism 20 years after the index pregnancy was evaluated using national registers. Euthyroid mothers who smoked before, or continued smoking during first trimester of pregnancy, had higher serum fT3 (p<0.001) and lower fT4 (p=0.023) concentrations than nonsmokers. Smoking in the second trimester was associated with higher fT3 (p<0.001) concentrations, but no difference in fT4 concentrations compared with nonsmokers. TG-Abs were less common among smoking than nonsmoking mothers (2.5% vs. 4.7%, p<0.001), but the prevalence of TPO-Ab was similar. Paternal smoking had no independent effect on maternal early pregnancy thyroid hormone or antibody concentrations. The risk of subsequent maternal hypothyroidism after follow-up of 20 years was similar among prepregnancy smokers and nonsmokers. In euthyroid women, smoking during pregnancy was associated with higher fT3 levels and lower fT4 levels; possibly reflecting smoking-induced changes in peripheral metabolism of thyroid hormones. No differences were found in TSH concentrations between smokers and nonsmokers. Our results differ from those of the general population, which usually have shown smoking-induced thyroidal stimulation. This is possibly due to pregnancy-induced changes in thyroid function. Decreases in fT4 levels among smokers might predispose to hypothyroidism or hypothyroxinemia during pregnancy. Despite these changes in thyroid function, smoking did not increase the woman's risk of subsequent hypothyroidism.

Thyroid peroxidase antibody in women with unexplained recurrent miscarriage: prevalence, prognostic value, and response to empirical thyroxine therapy

To determine the prevalence, prognostic value, and response to thyroxine therapy of thyroid peroxidase antibody (TPOAb) in women with unexplained recurrent miscarriage (RM). Observational, cohort study. The index cases included women with unexplained RM who tested positive for thyroid peroxidase antibody, and control cases included women with unexplained RM who tested negative for the antibodies; a second age-matched control group included women with RM who had a known cause for the repeated pregnancy loss. Tertiary referral center for RM. A total of 496 women with unexplained RM and 220 women with known diagnoses of RM who had a TPOAb test. Thyroxine replacement (50 μg daily during pregnancy) was begun in some patients who tested positive for thyroid peroxidase antibody, irrespective of TSH level. Miscarriage and live birth rates of a subsequent pregnancy. A total of 496 women with unexplained RM who had a TPOAb test were included in the study. Of these, 10.7% of subjects tested positive for TPOAb. The prevalence of TPOAb in control subjects who had a known cause for RM was 11.8%. The live birth rate of the first pregnancies after referral was 64%, 53%, and 58% in TPOAb-negative, TPOAb-positive with thyroxine treatment, and TPOAb-positive without treatment subjects; there was no significant difference in the outcome between any two or three groups, or between those who tested positive or negative for TPOAb. Among women who tested positive for TPOAb, there was no difference in the antibody titer between women with unexplained RM and those with a known cause for the pregnancy loss. Women who tested positive for TPOAb were significantly more likely to have TSH levels above the normal range (≥4.2 mIU/L). The prevalence of TPOAb-positive results in women with unexplained RM is not higher than in the general population, TPOAb-positive status does not have a prognostic value regarding the outcome of a subsequent pregnancy, and empirical thyroxine therapy in those who tested positive did not seem to improve outcome.

High prevalence of thyroid peroxidase antibodies in patients with alopecia areata

Journal of the European Academy of Dermatology and VenereologyVolume 27, Issue 1 p. e137-e139 LETTER TO THE EDITOR High prevalence of thyroid peroxidase antibodies in patients with alopecia areata M.P. Baars, M.P. Baars Department of Dermatology, Jeroen Bosch Hospital, andSearch for more papers by this authorR.J. Greebe, Corresponding Author R.J. Greebe Department of Dermatology, Jeroen Bosch Hospital, and R.J. Greebe. E-mail:[email protected]Search for more papers by this authorV.J.M. Pop, V.J.M. Pop Department of Clinical Health Psychology, Tilburg University, The NetherlandsSearch for more papers by this author M.P. Baars, M.P. Baars Department of Dermatology, Jeroen Bosch Hospital, andSearch for more papers by this authorR.J. Greebe, Corresponding Author R.J. Greebe Department of Dermatology, Jeroen Bosch Hospital, and R.J. Greebe. E-mail:[email protected]Search for more papers by this authorV.J.M. Pop, V.J.M. Pop Department of Clinical Health Psychology, Tilburg University, The NetherlandsSearch for more papers by this author First published: 06 January 2012 https://doi.org/10.1111/j.1468-3083.2011.04420.xCitations: 6Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat Citing Literature Volume27, Issue1January 2013Pages e137-e139 RelatedInformation

Effect of thyroid peroxidase antibodies on thyroid-stimulating hormone reference limits in a primarily Latina population.

The aim of the paper is to determine the prevalence of thyroid peroxidase antibodies (TPOAb) and assess its effect on the thyroid-stimulating hormone (TSH) reference range during pregnancy in a primarily Latina population. Serum samples were collected from healthy pregnant women and non-pregnant controls. TSH reference ranges were calculated when TPOAb-positive patients were either included or excluded. A total of 134 pregnant women and 107 non-pregnant controls were recruited. Positive TPOAb titres were found in 23 (17.2%) of the 134 pregnant women, and in 14 (13.1%) of the 107 non-pregnant controls. When the TPOAb-positive women were included in the TSH analysis, the upper reference limit using two different methods was consistently higher: 0-2.2 fold in the non-pregnant women, 2.01-2.78 fold in the first trimester, 3.18-4.7 fold in the second and 1.05-1.42 fold in the third. The lower TSH reference limit was not affected by the inclusion of TPOAb-positive subjects. In conclusion, inclusion of TPOAb-positive patients results in higher upper reference limits during pregnancy.

Zinc Transporter 8 Antibodies Complement GAD and IA-2 Antibodies in the Identification and Characterization of Adult-Onset Autoimmune Diabetes

OBJECTIVEZinc transporter 8 (ZnT8) is an islet β-cell secretory granule membrane protein recently identified as an autoantibody antigen in type 1 diabetes. The aim of this study was to determine the prevalence and role of antibodies to ZnT8 (ZnT8As) in adult-onset diabetes.RESEARCH DESIGN AND METHODSZnT8As were measured by a radioimmunoprecipitation assay using recombinant ZnT8 COOH-terminal or NH2-terminal proteins in 193 patients with adult-onset autoimmune diabetes having antibodies to either GAD (GADAs) or IA-2 (IA-2As) and in 1,056 antibody-negative patients with type 2 diabetes from the Non Insulin Requiring Autoimmune Diabetes (NIRAD) study.RESULTSZnT8As-COOH were detected in 18.6% patients with autoimmune diabetes and 1.4% with type 2 diabetes. ZnT8As-NH2 were rare. ZnT8As were associated with younger age and a high GADA titer. The use of GADAs, IA-2As, and ZnT8As in combination allowed a stratification of clinical phenotype, with younger age of onset of diabetes and characteristics of more severe insulin deficiency (higher fasting glucose and A1C, lower BMI, total cholesterol, and triglycerides) in patients with all three markers, with progressive attenuation in patients with two, one, and no antibodies (all Ptrend < 0.001). Autoantibody titers, association with high-risk HLA genotypes, and prevalence of thyroid peroxidase antibodies followed the same trend (all P < 0.001).CONCLUSIONSZnT8As are detectable in a proportion of patients with adult-onset autoimmune diabetes and seem to be a valuable marker to differentiate clinical phenotypes.

Possible Effects of Environmental Nitrates and Toxic Organochlorines on Human Thyroid in Highly Polluted Areas in Slovakia

Heavy environmental pollution resulting from uncontrolled industrial and agricultural activities has occurred in several areas of Slovakia. So far, field surveys focused mainly on the thyroid have been conducted in one area polluted by nitrates and in a large area polluted mainly by organochlorinated toxicants. In children from the high nitrate area (HNA, n = 324) significantly higher thyroid volume (ThV) by ultrasound was found compared with age-matched children from surrounding areas with low nitrate (LNA, n = 764). In blood samples of 324 children from the HNA and of 100 children from the LNA no difference between areas was found in the level of total thyroxine (T4) and free triiodothyronine (T3). However, positive thyroid peroxidase antibodies (TPOAb) were found in 7/324 (2.2%) and thyrotropin (TSH) levels > 4.0 mIU/L in 13/324 (4.0%) of children from the HNA area, while no positive values were obtained in the LNA. In the area heavily polluted by an organochlorine (OC) cocktail consisting of polychlorinated biphenyls (PCBs), 2,2'-bis(4-chlorophenyl)-1,1-dichloroethylene (p,p'-DDE), hexachlorobenzene (HCB), and dioxins and furans (polluted area) and in the background pollution area (background area) a total of 2046 adults were examined. In polluted area very high blood levels of OCs were found as well as increased ThV and prevalence of thyroid hypoechogenicity by ultrasound. For the evaluation of data the level of PCBs was used as a marker of all OCs. Increasing PCB levels were significantly associated with the increase of free T4 (p < 0.001) and total T3 (p < 0.05) in blood, while slight but not significant negative association of PCBs was observed with the level of TSH. In both women and men the prevalence of TPOAb was significantly higher in polluted area. Although the absolute TPOAb prevalence in both areas was higher in women than that in men, the increase in polluted vs. background area was more striking in men. From these data it appears that the effects of environmental pollution on the thyroid cannot be neglected.

Serological Evidence of Thyroid Autoimmunity among Schoolchildren in Two Different Socioeconomic Environments

The mechanisms leading to thyroid autoimmunity are largely unknown. Our objective was to assess the role of environment in the development of thyroid autoimmunity. Prevalence of thyroid autoantibodies in two neighboring populations living in completely different socioeconomic circumstances (Russian Karelia and Finland) was studied. We studied two population-based cohorts partly sharing the same ancestry. A total of 532 schoolchildren from Russian Karelia and 532 schoolchildren in Finland matched for age, gender, and season of the blood sampling were included. There were no interventions. The prevalence of thyroid peroxidase antibodies (TPOAb), thyroglobulin antibodies (TGAb) and HLA-DQ alleles was measured. The prevalence of TPOAb was significantly lower in Russian Karelian than in Finnish children (0.4 vs. 2.6%, P=0.006). A similar difference was observed for TGAb (0.6 vs. 3.4%, P=0.002). Finnish girls tested positive for both TPOAb (4.3 vs. 0.4%, P=0.01) and TGAb (5.3 vs. 0.9%, P=0.01) more frequently than Finnish boys. Seven of the 23 tested subjects with signs of thyroid autoimmunity (30%) had increased serum TSH concentrations as a sign of subclinical hypothyroidism. The frequency of HLA genotypes did not differ between the two countries or between autoantibody-positive and -negative subjects. The prevalence of thyroid autoimmunity is lower in Russian Karelia than in Finland. This difference was not related to ethnic background or HLA-DQ alleles. The results support the idea that the Russian Karelian environment, which is characterized by inferior prosperity and standard of hygiene, may provide protection against thyroid autoimmunity.

National Health and Nutrition Examination Survey III Thyroid-Stimulating Hormone (TSH)-Thyroperoxidase Antibody Relationships Demonstrate That TSH Upper Reference Limits May Be Skewed by Occult Thyroid Dysfunction

The setting of the TSH upper reference limit impacts the diagnosis of mild hypothyroidism and is currently controversial. Our objective was to evaluate factors influencing the TSH reference range. Nonpregnant subjects aged 12 yr and older from National Health and Nutrition Examination Survey III were used to study the relationships between TSH, thyroid peroxidase antibodies (TPOAb), and thyroglobulin antibodies in different ethnic groups. TPOAb prevalence was lowest (<3%) when TSH was between 0.1 and 1.5 mIU/liter in women and between 0.1 and 2.0 mIU/liter in men and progressively increased to above 50% when TSH exceeded 20 mIU/liter. TSH reference range parameters (2.5th, 50th, and 97.5th percentiles) were analyzed according to thyroid antibody status, race/ethnicity, and age for the 14,202 subjects made up of non-Hispanic Blacks (B), non-Hispanic whites (W), and Mexican-Americans (M) who did not report thyroid disease or taking thyroid-altering medications and whose total T(4) was within the reference range. For each age group of each ethnicity, the inclusion of antibody-positive subjects increased TSH medians and upper limits (97.5th percentiles). The TSH upper limit was lower for the entire B cohort vs. W or M. However, this difference was lost when age cohorts with a similar prevalence of TPOAb (B age 40-49 yr vs. W and M age 20-29 yr) were compared. Ethnic differences in TSH were not present when populations with the same relative frequency of thyroid antibodies were compared. TSH upper reference limits may be skewed by TPOAb-negative individuals with occult autoimmune thyroid dysfunction.

Perinatal Significance of Isolated Maternal Hypothyroxinemia Identified in the First Half of Pregnancy

To establish pregnancy-specific free thyroxine thresholds and to assess perinatal effects associated with isolated maternal hypothyroxinemia identified in the first half of pregnancy. Stored serum samples from 17,298 women who previously underwent thyroid-stimulating hormone (TSH) screening in the first half of pregnancy were analyzed for free thyroxine (T(4)) concentrations and thyroid peroxidase antibodies. Women with a free T(4) below 0.86 ng/dL but a normal-range TSH were identified to have isolated maternal hypothyroxinemia. Pregnancy outcomes in these women were compared to those with a normal TSH and free T(4). Thyroid peroxidase antibody status and the relationship between TSH and free T(4) were analyzed for these women and women with subclinical hypothyroidism. Isolated maternal hypothyroxinemia was identified in 233 women (1.3%). There were not any excessive adverse pregnancy outcomes in these women. Positive thyroid peroxidase antibody assays (greater than 50 international units/mL) were similar in normal women (4%) and those with isolated hypothyroxinemia (5%) but were greater in women with subclinical hypothyroidism (31%, P<.001). There was a negative correlation between TSH and free T(4) in normal women (r(s)=-0.19, P<.001) and those with subclinical hypothyroidism (r(s)=-0.11, P=.007). The correlation in women with isolated hypothyroxinemia was not significant. Isolated maternal hypothyroxinemia has no adverse effects on perinatal outcome. Moreover, unlike subclinical hypothyroidism, there was a low prevalence of thyroid peroxidase antibodies and no correlation between TSH and free T(4) levels in women with hypothyroxinemia, leading us to question its biological significance.