Iodized Salt Intake and Its Association with Urinary Iodine, Thyroid Peroxidase Antibodies, and Thyroglobulin Antibodies Among Urban Chinese

Relationship Between Urinary Iodine Concentration and the Prevalence of Thyroid Nodules and Subclinical Hypothyroidism

The aim of the study was to investigate the iodine intake in the resident population in Xi'an and analyze the relationship between iodine nutritional status and the prevalence of subclinical hypothyroidism and thyroid nodules (TNs). A total of 2507 people were enrolled in Xi'an. Venous serum thyroid stimulating hormone (TSH), thyroid peroxidase antibody (TPOAb) and thyroglobulin antibody (TgAb), urinary iodine concentration (UIC), and thyroid ultrasonography were collected. Patients with abnormal TSH were checked for free thyroxine (FT4) and triiodothyronine (FT3). Adults in Xi'an had median UICs of 220.80 μg/L and 178.56 μg/l, respectively. A sum of 16.78% of people had subclinical hypothyroidism. Both iodine excess and iodine deficit increased the frequency of subclinical hypothyroidism. The lowest was around 15.09% in females with urine iodine levels between 200 and 299 μg/l. With a rate of 10.69%, the lowest prevalence range for males was 100-199 μg/l. In Xi'an, 11.37% of people have TNs. In comparison to other UIC categories, TN occurrences were higher in females (18.5%) and males (12%) when UIC were below 100 μg/l. In conclusion, iodine intake was sufficient in the Xi'an area, while the adults' UIC remains slightly higher than the criteria. Iodine excess or deficiency can lead to an increase in the prevalence of subclinical hypothyroidism. Patients with iodine deficiency are more likely to develop TNs.

Urinary iodine concentration and its associations with thyroid function in pregnant women of Shanghai

Objective

To assess the iodine status and its associations with thyroid function in pregnant women of Shanghai.

Methods

In this cross-sectional study, a total of 562 pregnant women were enrolled from January to December 2021. Both serum thyroid-stimulating hormone (TSH), free triiodothyronine (FT3), free thyroxine (FT4), thyroid peroxidase antibody (TPOAB), thyroglobulin antibody (TGAB), and urinary iodine concentration (UIC) were detected. Participants were divided into four groups based on their UIC values. Correlation analysis was used to investigate the association between UIC and thyroid function-associated parameters.

Results

The median UIC of the pregnant women studied was 158.25µg/L (interquartile range [IQR] 90.15, 245.65µg/L). Among all the subjects, 45.55% had iodine deficiency according to the World Health Organization (WHO) criteria, and 15.65% had thyroid autoimmunity. FT3, FT4, TSH, TPOAB and TGAB levels were not different among different UIC groups (P > 0.05). UIC and TSH were negatively correlated (r=-0.127, p=0.043) in UIC<150 µg/L group. In the group with UIC 250- 499 µg/L, UIC was positively correlated with total T4 (TT4), total T3 (TT3) and TPOAB (r= 0.228, p=0.022, r=0.208, p= 0.039, r=0.190, p=0.042, respectively). A negative correlation between UIC and TPOAB values was observed in TPOAB-positive (+) pregnant women (r=-0.384, p=0.012). The prevalence of isolated hypothyroxinemia in UIC<150 µg/L group was significantly higher than that of other groups(p=0.033). The relationship between the prevalence of thyroid diseases and UIC embodied a U-shaped curve.

Conclusion

Pregnant women on Chongming Island of Shanghai were iodine sufficient during the second trimester, but iodine deficiency was still prevalent. Both low and high gestational iodine status was related to thyroid function and autoimmunity. Optimal iodine nutrition status during gestation was important.

Blood Lead Level Is Associated with Visceral Adipose Dysfunction in Patients with Type 2 Diabetes

We aimed to explore whether an elevated blood lead level (BLL) is associated with visceral adipose dysfunction in patients with type 2 diabetes mellitus (T2DM). Four thousand one hundred and fourteen diabetic participants were enrolled from seven communities in Shanghai in 2018 in the cross-sectional METAL study. BLL was measured by graphite furnace atomic absorption spectrometry. Visceral adiposity index (VAI) and lipid accumulation product (LAP)were calculated by simple anthropometric and biochemical parameters. We found that medians (IQR) of BLL were 26.0 μg/L (18.0-37.0) for men and 25.0 μg/L (18.0-35.0) for women, respectively. In men, each doubling of BLL was associated with a 2.0% higher VAI (95% CI, 0.6 to 3.5%) and 1.8% higher LAP (95% CI, 0.2 to 3.3%) after full adjustment. Using the lowest BLL quartile as the referent group, significant positive trends were observed for BLL with VAI and LAP. In women, each doubling of BLL was associated with a 1.9% higher LAP (95% CI, 0.6 to 3.1%). Additionally, there was a marginally significant positive association between BLL and VAI, either using log2-transformed concentrations as continuous variables or categorized in quartiles. In conclusion, lead exposure is associated with visceral adipose dysfunction in patients with T2DM. Further prospective studies are warranted to confirm our findings.

High prevalence of metabolic diseases, liver steatosis and fibrosis among Chinese psychiatric patients

BACKGROUND

We aimed to investigate the differences of metabolic disorders between the general population and psychiatric patients, with an emphasis on the prevalence and influencing factors of liver fibrosis in psychiatric patients.

METHODS

A total of 734 psychiatric patients and 734 general population matched for age, sex, and BMI were enrolled from Shanghai, China. All participants underwent blood pressure, glucose, lipid profile measurements, and anthropometric parameters including body weight, height and waist circumference. FibroScan examinations were also performed on psychiatric patients. Liver steatosis and fibrosis were diagnosed by controlled attenuation parameter (CAP) and liver stiffness measurement (LSM) by professional staff.

RESULTS

Compared with the general population, psychiatric patients revealed significantly higher burden of metabolic disorders. The overall prevalence of liver steatosis (CAP ≥ 233 dB/m) and fibrosis (LSM ≥ 7.0 kPa) was 48.7% and 15.5% in psychiatric patients. Psychiatric patients with liver steatosis or fibrosis showed worse metabolic profile. Meanwhile, the prevalence of liver fibrosis was also significantly higher in patients with overweight, central obesity, diabetes, hypertension, metabolic syndrome, and liver steatosis. In logistic regression analyses, age, BMI and visceral adiposity index were independent risk factors for liver fibrosis in psychiatric patients. Additionally, antipsychotic medication was suggested to be associated with an increased risk of liver fibrosis in psychiatric patients with liver steatosis.

CONCLUSIONS

Prevalence of liver steatosis and fibrosis is high in Chinese psychiatric patients. Those with antipsychotic polypharmacy and obesity are at high risk, and may benefit from early liver assessment in preventing fibrosis progression.

Prevalence and risk factors of hypothyroidism after universal salt iodisation: a large cross-sectional study from 31 provinces of China

OBJECTIVES

To investigate the prevalence and risk factors of hypothyroidism after universal salt iodisation for 20 years in mainland China.

DESIGN

Nationwide, cross-sectional survey.

SETTING AND PARTICIPANTS

The Thyroid Disorders, Iodine Status and Diabetes epidemiological study included adults from 31 provinces of China. Data included demographic, physical characteristics, urine, serum thyroid-stimulating hormone (TSH), thyroid-peroxidase antibody (TPOAb), thyroglobulin antibody (TgAb) and thyroid ultrasonography. Subclinical hypothyroidism (SCH) was classified into severe SCH (TSH >10 mU/L) and mild SCH (TSH 4.2-9.9 mU/L). A total of 78 470 (38 182 men and 40 288 women) participants were included in the final analysis.

RESULTS

The prevalence of hypothyroidism was 13.95%. The prevalence rates of overt hypothyroidism (OH) and SCH were 1.02% and 13.93%, which mild SCH was significantly higher than severe SCH (12.18% vs 0.75%). Prevalence was higher in women than in men, and this gender difference was noted among all age groups. The prevalence of mild SCH, severe SCH and OH increases by 1.16%, 1.40% and 1.29% for every 10 years older. TPOAb or/and TgAb positive were significantly associated with OH and severe SCH (OR 15.9, p<0.001). However, SCH was positively correlated with increased urine iodine concentration, but this correlation was only in antibody-negative female patients. In non-autoimmune and male populations, there was a U-shaped relationship between severe SCH and OH and urine iodine concentration.

CONCLUSIONS

Mild SCH is the most common form of hypothyroidism, which is related to iodine intake. Severe SCH is more similar to OH which autoimmune is the main cause. The various effects of iodine on hypothyroidism depend on thyroid autoimmune and gender.

Association between Iodized Salt Intake and Cognitive Function in Older Adults in China

OBJECTIVES

To investigate the association between iodized salt intake and cognitive function in older adults.

DESIGN

A cross-sectional study.

SETTINGS

Individuals from the Zhejiang Major Public Health Surveillance Program (ZPHS).

PARTICIPANTS

Data of 10,217 participants (including 4,680 coastal residents and 5,537 inland residents) aged ≥ 60 years were analyzed.

MEASUREMENTS

Salt intake was evaluated using a questionnaire, and participants were stratified into the following three groups: iodized salt, non-iodized salt, and mixed salt. Cognitive function was assessed through the Mini-Mental State Examination and defined using education-specific cut-off points. Logistic regression models controlling for an extensive range of potential confounders were generated to examine the association between salt intake and cognitive function among all participants.

RESULTS

Data from 10,217 participants with a 16.1% prevalence of cognitive impairment were analyzed. Compared with non-iodized salt intake, consumption of iodized salt was inversely associated with cognitive impairment (odds ratio [OR], 0.410; 95% confidence interval [CI], 0.351-0.480; P < 0.001) in all participants after multivariable adjustment. An association between iodized salt intake and cognitive impairment was observed in coastal (OR, 0.441; 95% CI, 0.340-0.572; P < 0.001) and inland residents (OR, 0.569; 95% CI, 0.439-0.738; P < 0.001). Despite the insufficient sample size, the results for individuals consuming mixed salt suggested an inverse association between mixed salt intake and cognitive impairment among coastal residents (OR, 0.598; 95% CI, 0.405-0.885; P = 0.010) after multivariable adjustment.

CONCLUSION

Our results indicate that iodized salt intake may reduce the risk of cognitive impairment in older adults living in coastal or inland areas, and the protective effect of iodized salt intake is greater in coastal areas than in inland areas.

Outcomes With Levothyroxine Treatment in Early Pregnancy With Subclinical Hypothyroidism

Introduction

Adverse pregnancy outcomes in women with subclinical hypothyroidism (SCH) are well documented, whereas data regarding the risk and benefit of levothyroxine treatment in such cases are insufficient and inconsistent. Our study aimed to evaluate the effects of levothyroxine treatment on pregnancy outcomes in these women.

Materials and methods

Healthy women with a singleton pregnancy were screened before 12 weeks of gestation for subclinical hypothyroidism using 2017 American Thyroid Association guidelines. They were treated with an initial dose of 50 mcg of levothyroxine and the dose was adjusted at six-week intervals to achieve a normal thyrotropin level. All the participants were followed up with thyroid function tests and ultrasonography till delivery. Pregnancy outcomes were compared with those of healthy pregnant women with normal thyroid function.

Results 

A total of 1058 women were screened and 5.1% (n=54) were found to have subclinical hypothyroidism, out of which 57.4% (n=31) were thyroid peroxidase antibody positive. The median gestational age at the initiation of levothyroxine treatment was nine weeks. The risks for miscarriage (odds ratio (OR): 1.284, p=0.811), gestational hypertension (OR: 1.993, p=0.365), intra-uterine growth restriction (OR: 1.688, p=0.488), low birth weight (OR: 1.591, p=0.392), and preterm birth (OR: 1.606, p=0.529) were not significantly higher in women with subclinical hypothyroidism as compared to euthyroid women. However, the risk of gestational diabetes mellitus was significantly higher in women with SCH (OR: 3.432, 95% confidence interval (95% CI): 1.115-10.562).

Conclusion

Levothyroxine therapy initiated in the first trimester of pregnancy has possible beneficial effects in subclinical hypothyroidism but with a higher risk for gestational diabetes.

Epidemiological survey of the status of iodine nutrition and thyroid diseases in Guangxi, China

OBJECTIVE

To survey the status of iodine nutrition and the prevalence of thyroid diseases in Guangxi, China, and to explore the risk factors for positive thyroid antibody.

METHODS

We used the multistage stratified cluster random sampling method to select a total of 2488 subjects from an urban and a rural location. All the subjects completed a questionnaire survey, blood and urine samples were also collected, and B-mode thyroid ultrasound was used to determine thyroid function and detect thyroid antibodies.

RESULTS

1) The median level of urinary iodine was 148.53 μg/L in school-age children in Guangxi, China. 2) The prevalence rates for thyroid diseases were as follows: hyperthyroidism, 0.89 %; subclinical hyperthyroidism, 1.05 %; hypothyroidism, 0.69 %; and subclinical hypothyroidism, 8.87 %. The rates of thyroid antibody positivity were as follows: thyroid peroxidase antibody (TPOAb), 13.60 %; thyroglobulin antibody (TGAb), 13.60 %; thyroid antibodies, 18.2 %; and thyroid nodules, 16.94 %. 3) The rate of TPOAb positivity was significantly higher in women aged 18-29, 30-39, 40-49, or 60-69 years than in men in the same age groups (P < 0.05), and the TGAb positivity rate was significantly higher in women than in men of the same age group (P < 0.05). 4) The rate of thyroid antibody positivity was significantly higher in individuals with iodine deficiency than in individuals with adequate iodine (21.6 % vs 18.4 %) or excess iodine (21.6 % vs 15.5 %) (both P < 0.05). 5) The female sex and a family history of thyroid diseases were the major risk factors for thyroid antibody positivity (odds ratio [OR] 3.010, P <0.05; OR 2.486, P <0.05).

CONCLUSION

The overall level of iodine is adequate in Guangxi, China; this level should be maintained to prevent the thyroid diseases related with iodine deficiency or excess of iodine. Female sex and a family history of thyroid diseases are independent risk factors for thyroid antibody positivity.

Are ethnic differences, urinary iodine status, lead and cadmium exposure associated with thyroid autoimmunity and hypothyroid status? A cross-sectional study

OBJECTIVE

We aimed to evaluate the effects of different ethnicities and potential environmental exposure on the prevalence of thyroid autoimmune status and hypothyroid status.

DESIGN

The data were obtained from two cross-sectional studies.

PARTICIPANTS

2105 participants in Shanghai (Han) and 772 participants in Yunnan Honghe Prefecture (Han, Yi, Miao and Hani), aged 18-75 were enrolled.

METHODS

Participants underwent several checkups, including urinary iodine concentration, blood lead (BPb) and blood cadmium (BCd), thyroid peroxidase antibody (TPOAb), thyroglobulin antibody (TgAb), thyroid stimulating hormone (TSH) as well as thyroid ultrasonography (US). Thyroid autoimmune status was defined as: antithyroid antibody positive (ATA+): TPOAb + or TgAb+; and ATA + and US+: TPOAb + or TgAb + together with characteristic US features.

RESULTS

The standardised prevalence of thyroid autoimmune positivity in Yunnan were higher than those in Shanghai (TPOAb+: 13.56% vs 8.27%, p<0.001; TgAb+: 9.28% vs 7.09%, p=0.045; ATA+: 16.96% vs 11.10%, p<0.001; ATA + and US+: 8.96% vs 6.64%, p=0.036). For urinary iodine-to-creatinine ratio (UI/Cr), compared with the level of 100.00-199.99 µg/g, the level of ≥300.00 µg/g had a 1.5-fold risk for ATA + and US+ (OR 1.455, p=0.041). The levels of 200.00-299.99 µg/g and ≥300.00 µg/g were positively associated with hypothyroid status (OR 1.509, p=0.002 and OR 1.338, p=0.043). Compared with the first quartiles, the fourth quartiles of BPb were positively associated with TPOAb+: (OR 1.637, p=0.006), ATA+ (OR 1.435, p=0.025), ATA + and US+ (OR 1.641, p=0.013), hypothyroid status (OR 1.467, p=0.013) and TSH levels (B 0.092, p=0.021). The fourth quartile of BCd was positively associated with the prevalence of ATA+ (OR 1.427, p=0.036).

CONCLUSIONS

Higher levels of UI/Cr, BPb and BCd may be associated with thyroid autoimmunity and hypothyroid status.

Iodine nutrition status and thyroid autoimmunity during pregnancy: a cross-sectional study of 4635 pregnant women

Background

Pregnant women in Shanghai have long been at risk for mild iodine deficiency. Because thyroid autoimmunity in pregnant women can lead to premature birth and miscarriage as well as neurodevelopmental deficits in the fetus, the aim of this study was to explore the association of iodine nutrition status with thyroid antibodies during pregnancy.

Methods

A pregnancy-birth cohort was conducted including 4635 pregnant women in Shanghai, China. The eligible participants underwent a face-to-face interview and completed questionnaire surveys to collect baseline information and diet intake. Spot urine samples were collected to test urine iodine. Thyroid antibodies including thyroid peroxidase antibodies (TPOAb), thyroglobulin antibodies (TgAb) and thyrotrophic antibodies (TRAb) were tested. Single-factor analysis and logistic regression were used to evaluate the association between iodine status and thyroid autoimmunity during pregnancy.

Results

The median urinary iodine excretion level in the sample was 138.14 μg/L (interquartile range [IQR] 80.90–219.00 μg/L). Among all the subjects, 25.9% consumed non-iodized salt, 54.5% had iodine deficiency, and 31.0% had thyroid autoimmunity. The proportion of patients with iodine deficiency was significantly higher among those who consumed non-iodized salt (36.9% vs. 33.1%; p = 0.04). After adjusting for age, educational status, former smoker status, former drinker status, first pregnancy, and previous thyroid disease, non-iodized salt (odds ratio [OR] = 1.394 [confidence interval, CI, 1.165–1.562]; p = 0.003), iodine-rich food (OR = 0.681 [CI 0.585–0.793]; p = 0.003), iodized nutritional supplements (OR = 0.427 [CI 0.347–0.526]; p = 0.003), were found to be individually associated with thyroid autoimmunity in all participants. The results of the multivariable restricted cubic spline regression analysis showed a non-linear relationship between the continuous change in iodine intake and thyroid autoimmunity (p = 0.019). Participants with iodine deficiency (urinary iodine concentration, UIC,< 100 μg/L) had an increased risk of testing positive for thyroid antibodies (TPOAb/TgAb/TRAb[+]; OR = 1.324 [CI 1.125–1.559]; p < 0.001). Moreover, this associated existed even after removing participants with previous thyroid disease.

Conclusion

Inadequate iodine nutrition in pregnant women is an independent risk factor for thyroid autoimmunity in Shanghai. It’s important to maintain the adequate iodine status in pregnant women.

Exploration of the optimal range of urinary iodine concentration in Chinese pregnant women in mildly iodine-deficient and -sufficient areas

PURPOSE

There is some uncertainty about the optimal ranges for urinary iodine concentration (UIC) during pregnancy. This study aimed to explore associations between maternal UIC and thyroid function in iodine sufficient and mildly iodine deficient areas.

METHODS

It was a cross-sectional study in which 1461 healthy pregnant women were enrolled to collect their blood and urine samples during their routine antenatal care in Tianjin and Wuqiang, China. Wuqiang was a mildly iodine-deficient region, while Tianjin was iodine sufficient. UIC, free triiodothyronine (FT3), free thyroid hormone (FT4), thyroid stimulating hormone (TSH), thyroid peroxidase antibody (TPOAb), thyroglobulin antibody (TgAb), serum iodine concentration (SIC) including total serum iodine concentration (tSIC) and non-protein bound serum iodine concentration (nbSIC) were assessed during the routine antenatal care visits.

RESULTS

The median UIC in pregnant women was 174 (113, 249) μg/L in Tianjin and 111 (63, 167) μg/L in Wuqiang, respectively. Compared with Tianjin, UIC, FT3 and TSH were lower, and FT4, tSIC, nbSIC, rates of TPOAb and TgAb positivity and the thyroid dysfunction rate (TDR) were higher in Wuqiang (P < 0.001). FT3, FT4, tSIC and nbSIC increased during pregnancy in Tianjin with increasing UIC, while only FT3 and nbSIC increased in Wuqiang (P < 0.05). In Tianjin, the TDR increased with UIC and peaked at UIC ≥ 500 μg/L (P = 0.002), while in Wuqiang, the TDR showed a weak "U-shaped" relationship with UIC and the rate was lowest with UIC 100-149 μg/L.

CONCLUSIONS

In iodine-deficient areas, there was a lower TDR in pregnant women with UIC 100-149 μg/L. We suspected that the optimal UIC criteria recommended by WHO may be a little high for pregnant women in mild-to-moderate iodine-deficient countries.

Elevated Serum Levels of Carbohydrate Antigen 72-4 in Diabetic Kidney Disease

The aim of this study was to determine whether carbohydrate antigen 72-4 (CA72-4) is elevated in diabetic kidney disease (DKD), and examine the association between urinary albumin-to-creatinine ratio (UACR) and CA72-4 in patients with type 2 diabetes mellitus (T2DM). Non-dialysis patients with T2DM (n=296) and 90 healthy controls were recruited in this study. CA72-4 level was measured by electrochemiluminescence immunoassay. DKD was defined as UACR≥ 30 mg/g in the absence of a urinary infection or other renal diseases. We found that patients with DKD had significantly higher serum CA72-4 levels compared to those with normoalbuminuria and healthy controls. Positive rates of CA72-4 increased gradually and markedly from normoalbuminuria to microalbuminuria and to macroalbuminuria in diabetic patients (7.5, 11.2, and 17.4%, respectively; P for trend< 0.05). CA72-4 also showed a positive correlation with UACR (r=0.288, P< 0.01). Logistic regression analysis revealed the association of increased UACR with an increased odds ratio of elevation of CA72-4 levels (P for trend< 0.05) after multivariable adjustment. In conclusion, serum levels of CA72-4 increase abnormally with the increase in urinary albumin excretion, which affects the specificity of diagnosis of malignancies. An appropriate interpretation of CA72-4 is essential to prevent unnecessary and even hazardous diagnostic procedures in patients with T2DM.

Iodine nutrition optimization: are there risks for thyroid autoimmunity?

Iodine deficiency is still the main cause of preventable thyroid disorders, worldwide. To optimize iodine intake, programs of voluntary or mandatory iodization of salt have been implemented in several iodine-deficient countries and iodine sufficiency has been achieved in many. Despite the clear beneficial effects on thyroid health, some concerns have been raised on the presumed detriment of iodine prophylaxis on thyroid autoimmunity. Very recent studies aimed at evaluating the long-term consequences of iodine supplementation on thyroid autoimmunity and related dysfunction, have clearly demonstrated that the early post-iodization increase in thyroid antibody positivity is largely transient and not clinically relevant, since the prevalence of overt thyroid dysfunction has remained reassuring low over two decades. The recommended iodine intake is therefore safe with regard to thyroid autoimmunity, the benefits largely outweighing the risks in a population with a stable median iodine concentration not exceeding 300 μg/L. Thus, a possible increase in thyroid autoimmunity should not represent a limitation to promoting iodine supplementation in the general population, also taking into account the steady rise in prevalence of autoimmune disorders which has occurred in the last few decades because of environmental factors other than iodine.

Relationship between Gene Polymorphisms and Urine Iodine Levels on Susceptibility to Thyroid Peroxidase Antibody Positivity in the Chinese Population

BACKGROUND/AIMS

Hashimoto thyroiditis, characterized by positive thyroid peroxidase antibodies (TPOAbs), is caused by the interaction of genetic and environment factors. The aim of this study was to clarify the interaction of gene polymorphisms and iodine intake in the incidence of TPOAb positivity.

METHODS

1,733 subjects were included in this study. Genomic DNA was extracted from peripheral blood white cells. Four SNPs (rs11675434 [TPO], rs3094228 [HCP5], rs9277555 [HLA-DPB1], and rs301799 [RERE]) were selected for genotyping. Weighted TPOAb genetic risk score (GRS) was calculated based on these 4 SNPs. Thyroid hormones and autoimmune antibodies (TPOAb and thyroglobulin antibody) were determined using the electrochemiluminescence immunoassay method.

RESULTS

The mean serum thyrotropin level in TPOAb-positive subjects was higher than in TPOAb-negative subjects (p < 0.01). Genotype GG of rs9277555 was associated with an increased risk of TPOAb positivity (OR = 1.64, 5-95% CI 1.09, 2.47, p = 0.02). Genotype TT of rs11675434 showed marginal increased risk of TPOAb positivity (OR = 1.57, 5-95% CI 1.01, 2.43, p = 0.048). Logistic regression analysis showed TPOAb-GRS and rs9277555 were associated with TPOAb positivity (OR = 5.09, 5-95% CI 1.30, 19.91, p = 0.02 and OR = 1.30, 5-95% CI 1.05, 1.61, p = 0.02). Subjects with a high TPOAb-GRS had a 52% increased risk of TPOAb positivity compared to subjects with a low TPOAb-GRS (OR 1.52, 5-95% CI 1.05, 2.21, p = 0.03).

CONCLUSION

TPOAb-GRS was associated with an increased risk of TPOAb positivity in a Chinese Han population. This effect might be attribute to rs9277555.

Influence of Rapid Urbanization on Thyroid Autoimmune Disease in China

BACKGROUND

The prevalence of autoimmune thyroid diseases (AITDs), especially Hashimoto's thyroiditis (HT), has increased dramatically in China. Moreover, China is experiencing the largest scale of urbanization in the world. We intended to explore the relationship between rapid urbanization and HT.

METHODS

A total of 2946 subjects in Zhejiang Shangyu (SY) (n = 1546) and Jiangsu Nanjing (NJ) (n = 1400) were enrolled in this study. Serum TPOAb, TGAb, and thyrotropin (TSH) were measured, and ultrasonography of the thyroid was performed in all subjects. DNA was extracted from all subjects, and four SNPs were selected for genotyping. Generalized multifactor dimensionality reduction (GMDR) was used to screen the best interaction between genetic factors and environment factors.

RESULTS

TPOAb and TGAb concentrations were higher in NJ than in SY (34.60 vs. 14.00 IU/ml and 21.05 vs. 7.50 IU/ml). People in NJ also had higher TPOAb and TGAb positivity rates than those in SY (7.8% vs. 12.7% and 8.7% vs. 16.3%). Logistic regression analysis indicated that rapid urbanization was an independent risk factor for TPOAb (OR = 1.473) and TGAb (OR = 1.689). Genotype TT in rs11675434 was associated with an increased risk of TPOAb positivity both in SY (OR = 2.955) and in NJ (OR = 1.819). GMDR analysis showed a two-locus model (SNP2 × urbanization) and a three-locus model (SNP2 × SNP3 × urbanization), which had testing accuracies of 56.88% and 57.25%, respectively (P values were 0.001 and 0.001).

CONCLUSION

Rapid urbanization influences the incidence of TPOAb and TGAb positivity. We should pay more attention to thyroid autoimmune disease in areas of China experiencing rapid urbanization.

Measuring attack on self: The need for field-friendly methods development and research on autoimmunity in human biology

BACKGROUND

Autoimmune and inflammatory disorder (AIID) prevalence appears to be increasing in all but the world's poorest regions and countries. Autoimmune diseases occur when there is a breakdown in processes that regulate inflammation and self-recognition by immune cells. Very few field-based studies have been conducted among Indigenous populations and underserved communities with limited access to medical care. This is due, in part, to the fact that autoimmune diseases are difficult to diagnose, even in clinical settings. In remote field settings these difficulties are compounded by the absence of infrastructure necessary for sample storage and analysis, and the lack of hospital/clinic access for more invasive diagnostic procedures. Because of these limitations, little is known about the prevalence of autoimmunity outside wealthy regions and clinical settings.

AIMS

The present paper discusses why AIID are of critical importance in human biology research and why more work needs to be devoted to validating, testing, and utilizing methods for detecting autoantibodies and other biomarkers related to autoimmunity in field-friendly, minimally invasively-collected samples. This paper reviews some of the methods used to diagnose AIIDs in clinical settings, and highlights methods that have been used in studies within human biology and related fields, emphasizing the invasiveness of specific methods and their feasibility in remote field settings.

DISCUSSION AND CONCLUSIONS

Risk for AIID is affected by several reproductive, dietary, environmental, and genetic factors. Human biologists have unique perspectives that they can bring to autoimmunity research, and more population-based studies on autoimmunity are needed within these and related fields.

Urinary Iodine and Genetic Predisposition to Hashimoto's Thyroiditis in a Chinese Han Population: A Case-Control Study

Background: We aimed to examine the association of urinary iodine concentration with Hashimoto's thyroiditis (HT) risk, and particularly, to investigate whether the HT-related genetic variations might modify the effects of urinary iodine on HT in the Chinese Han population. Methods: We conducted a case-control study with 1723 Chinese (731 cases, 992 controls). The associations between urinary iodine concentration and HT risk were analyzed using logistic regression models. The effects of interactions between the genetic risk scores (GRSs) and urinary iodine on HT risk were assessed by including the respective interaction terms in the models. We also applied restricted cubic spline regression to estimate the possible nonlinear relationship. The multinomial logistic regression models were performed to determine the associations of urinary iodine with euthyroid-HT and hypothyroidism-HT. Results: After controlling for potential confounders, the odds of HT increased with increasing quartiles of urinary iodine concentration: adjusted odds ratios (ORs) and 95% confidence intervals [CIs] were 1.45 [1.06-1.99], 1.66 [1.17-2.34], and 2.07 [1.38-3.10] for the quartiles 2, 3, and 4, respectively, compared with the first quartile (p for trend <0.001). Multivariable restricted cubic spline regression analysis further demonstrated that there was a near-linear association between urinary iodine concentration and HT risk (p-overall <0.001; p-nonlinear = 0.074). However, we did not find significant interactions between urinary iodine and GRSs on the risk of HT (all p for interaction >0.05). Interestingly, we found that each increment of urinary iodine was associated with a more than twofold increase in the odds of hypothyroidism-HT (adjusted OR = 2.64 [CI = 1.73-4.05]), but not with euthyroid-HT (p > 0.05). Conclusions: Higher urinary iodine concentration was associated with increased risk of HT, and this association was near linear, indicating that increased urinary iodine has a continuous and graded impact on HT risk. Moreover, the iodine-HT association was not modified by genetic predisposition to HT. Interestingly, urinary iodine concentration was significantly associated with increased risk of hypothyroidism.

Relationship between anti-thyroid peroxidase antibody positivity and pregnancy-related and fetal outcomes in Euthyroid women: a single-center cohort study

Background

Thyroid autoimmunity (TAI) and subclinical hypothyroidism (SCH) have been associated with poor pregnancy and fetal outcomes. However, whether euthyroid women with anti-thyroid peroxidase antibody (TPOAb) positivity have a higher risk of poor pregnancy and fetal outcomes is debatable. Therefore, this study aimed to investigate the association between TPOAb positivity and pregnancy-related and fetal outcomes in euthyroid women.

Methods

In total, 938 pregnant women participated in this prospective cohort study. The euthyroid group included 837 pregnant women and the TPOAb-positive group included 101 euthyroid pregnant women. Serum TPOAb, thyroglobulin antibody (TGAb), thyroid-stimulating hormone (TSH), and free thyroxine (FT4) levels were assessed. Pregnancy and fetal outcomes included gestational diabetes mellitus, spontaneous abortion, premature rupture of membranes, hypertensive disorders of pregnancy, preterm birth, fetal distress, low birth weight, fetal macrosomia, and small for gestational age infant.

Results

Logistic regression analysis showed TPOAb positivity was not associated with an increased risk of poor pregnancy or fetal outcomes in euthyroid women. However, TPOAb-positive euthyroid women pregnant with a female fetus were independently associated with preterm births (OR: 4.511, 95% CI: 1.075–18.926) after adjustment for potential confounding factors.

Conclusions

TPOAb positivity was not found to be associated with poor pregnancy-related or fetal outcomes in euthyroid women. However, in euthyroid women with a female fetus, TPOAb positivity was strongly associated with preterm births. The risk of preterm birth in the euthyroid women with TPOAb positivity should be emphasized in clinical practice.

Trial registration

ClinicalTrials.gov Identifier: NCT02966405. Registered on October 24th 2016 - Retrospectively registered.

Iodine nutrition status and its association with microvascular complications in urban dwellers with type 2 diabetes

Background

The principal function of iodine acts on thyroid function, but in recent years, the role of iodine deficiency in metabolism has also been gradually revealed. We aimed to investigate the current status of iodized salt consumption and urinary iodine concentration (UIC) in an urban Chinese population with type 2 diabetes, and to further explore whether UIC was associated with diabetic microvascular complications.

Methods

Four thousand five hundred fifty-nine subjects with diabetes from 7 communities in downtown Shanghai were enrolled in the cross-sectional Metal Study in 2018. UIC was detected using an inductively coupled plasma-mass spectrometer. Diabetic kidney disease (DKD) was defined as urinary albumin-to-creatinine ratio (UACR) > 30 mg/g or estimated glomerular filtration rate < 60 mL/min/1.73 m². Diabetic retinopathy (DR) was evaluated by high-quality fundus photographs and was remotely read by ophthalmologist.

Results

The median UIC of subjects with diabetes was 115.4 μg/L (78.9–170.8) in downtown Shanghai. Among all the subjects, 52.7% consumed non-iodized salt and 40.4% were iodine deficient. Iodine deficiency (UIC < 100 μg/L) was associated with an increased odds of DKD (OR 1.17; 95%CI 1.01–1.37) after adjustment for age, sex, education, current smokers, BMI, HbA1c, duration of diabetes, dyslipidemia, thyroid-stimulating hormone and free thyroxine. No association was observed between UIC and DR after multivariable adjustment.

Conclusions

A concerning number of subjects with diabetes consumed non-iodized salt and suffered from iodine deficiency in coastal regions of China. Low UIC might be a risk factor for DKD, which should be further confirmed by longitudinal prospective studies.

Impaired Gene Expression Due to Iodine Excess in the Development and Differentiation of Endoderm and Thyroid Is Associated with Epigenetic Changes

Background: Thyroid hormone (TH) synthesis is essential for the control of development, growth, and metabolism in vertebrates and depends on a sufficient dietary iodine intake. Importantly, both iodine deficiency and iodine excess (IE) impair TH synthesis, causing serious health problems especially during fetal/neonatal development. While it is known that IE disrupts thyroid function by inhibiting thyroid gene expression, its effects on thyroid development are less clear. Accordingly, this study sought to investigate the effects of IE during the embryonic development/differentiation of endoderm and the thyroid gland. Methods: We used the murine embryonic stem (ES) cell model of in vitro directed differentiation to assess the impact of IE on the generation of endoderm and thyroid cells. Additionally, we subjected endoderm and thyroid explants obtained during early gestation to IE and evaluated gene and protein expression of endodermal markers in both models. Results: ES cells were successfully differentiated into endoderm cells and, subsequently, into thyrocytes expressing the specific thyroid markers Tshr, Slc5a5, Tpo, and Tg. IE exposure decreased the messenger RNA (mRNA) levels of the main endoderm markers Afp, Crcx4, Foxa1, Foxa2, and Sox17 in both ES cell-derived endoderm cells and embryonic explants. Interestingly, IE also decreased the expression of the main thyroid markers in ES cell-derived thyrocytes and thyroid explants. Finally, we demonstrate that DNA methyltransferase expression was increased by exposure to IE, and this was accompanied by hypermethylation and hypoacetylation of histone H3, pointing to an association between the gene repression triggered by IE and the observed epigenetic changes. Conclusions: These data establish that IE treatment is deleterious for embryonic endoderm and thyroid gene expression.

The Role of Thyroid Hormones and Autoantibodies in Metabolic Dysfunction Associated Fatty Liver Disease: TgAb May Be a Potential Protective Factor

BACKGROUND

Previous studies have shown that metabolic dysfunction associated fatty liver disease (MAFLD) is associated with thyroid hormones (THs), immunity, and inflammation status, but few studies involved thyroid autoimmunity. This study aimed to evaluate the role of THs, thyroid autoantibodies, inflammatory biomarkers in MAFLD, its cofactors, and other possible determinants.

MATERIALS AND METHODS

In the study, a total of 424 Chinese patients were selected and categorized as non-MAFLD and MAFLD. Serum thyroid hormone, thyroid autoantibody and high-sensitive C-reactive protein (hsCRP) levels were measured. The data of blood pressure, the serum lipid profile, glucose and liver enzymes were collected. The differences and association between research findings were examined and analyzed by Wilcoxon Signed Rank Test, One-Way ANOVA test and Multiple Logistic Regression models.

RESULTS

The study showed significant increase in the prevalence of MAFLD with high thyroid stimulating hormone (TSH) levels (P < 0.01) and abnormal high-sensitive C-reactive protein (hsCRP) levels (P < 0.01). The proportion of MAFLD patients decreased significantly with the rise of free thyroxine (FT4) (P = 0.04), thyrotropin receptor antibodies (TRAb) (P < 0.01), anti-thyroglobulin antibodies (TgAb) (P < 0.01), and thyroid peroxidase antibodies (TPOAb) levels (P < 0.01). Based on logistic regression analysis, MAFLD was significantly associated with lower levels of TgAb (P < 0.01), TPOAb (P < 0.01), and higher levels of hsCRP (P < 0.01) in male. In female, elevated TgAb (P < 0.01) may be a protective factor, while higher levels of hsCRP (P < 0.01) showed increased risk of MAFLD. Logistic models were adjusted for age, BMI, SBP, DBP, FBG, ALT, AST, TC, TG, LDL, HDL.

CONCLUSIONS

Taken together, TgAb may be a potential protective factor for MAFLD and elevated hsCRP level should be considered as an independent risk factor for MAFLD in both genders. TPOAb also demonstrated protective effect, but only in male. The prevalence of MAFLD increased with higher TSH levels and lower FT4, TRAb levels, but no significant association were found. However, Our findings provide a new insight into the pathogenesis of MAFLD by further investigating the impact of THs, thyroid autoimmunity, and inflammation on MAFLD patients.

The Presence of Serum TgAb Suggests Lower Risks for Glucose and Lipid Metabolic Disorders in Euthyroid General Population From a National Survey

Purpose: The expressions of antibodies against thyroid peroxidase (TPOAb) and thyroglobulin (TgAb) are very common in the sera of patients with autoimmune thyroid diseases (AITD). The relationship between thyroid autoantibodies and the occurrence of glucose and lipid metabolic disorders remains unclear. This study was performed to investigate the correlation between the presence of serum TPOAb/TgAb and those metabolic disorders in euthyroid general population. Methods: The data of this study were derived from the Thyroid Disease, Iodine status, and Diabetes National epidemiological (TIDE) survey from all 31 provinces of mainland China. A total of 17,964 euthyroid subjects including 5,802 males (4,000 with TPOAb^-TgAb^- and 1,802 with TPOAb⁺/TgAb⁺) and 12,162 females (8,000 with TPOAb^-TgAb^- and 4,162 with TPOAb⁺/TgAb⁺) were enrolled in this study. The blood glucose and lipid levels were compared between individuals with TPOAb^-TgAb^- and those with TPOAb⁺TgAb^-, TPOAb^-TgAb⁺, TPOAb⁺TgAb⁺. Results: Both fasting blood glucose (FBG) concentration and the proportion of individuals with impaired FBG (IFG) showed the decreased trends in TPOAb^-TgAb⁺ males as compared with TPOAb^-TgAb^- men. There were significantly lower FBG and higher HDL-C levels as well as tendencies toward decreased incidences of IGT and hypertriglyceridemia in TPOAb^-TgAb⁺ females when compared with TPOAb^-TgAb^- women. Binary logistic regression analysis further showed that serum TgAb single positivity in males was an independent protective factor for IFG with an OR of 0.691 (95% CI, 0.503-0.949). For females, serum TgAb single positivity was an independent protective factor for hypertriglyceridemia with an OR of 0.859 (95% CI, 0.748-0.987). Trend test showed that with the increase of serum TgAb level, there were significant decreases in the prevalence of IFG among the men with TSH ≤ 2.5 mIU/L and that of hypertriglyceridemia in the women, especially among non-obese females. Conclusion: Serum TgAb single positivity may imply a reduced risk of IFG in euthyroid men and that of hypertriglyceridemia in euthyroid women. The mechanisms for the independent protective roles of TgAb await further investigation.

Association between iodine intake and thyroid autoantibodies: a cross-sectional study of 7073 early pregnant women in an iodine-adequate region

PURPOSE

The association between iodine intake and thyroid autoimmunity has been debated, especially in pregnant women. This study aimed to investigate thyroid autoantibodies and their association with iodine intake and hypothyroidism in early pregnancy.

METHODS

7073 early pregnant women from an iodine-sufficient region participated in this study. Urinary iodine concentrations (UICs) were measured using an ammonium persulfate method. Serum thyroid peroxidase antibody (TPOAb), thyroglobulin antibody (TgAb), thyroid-stimulating hormone (TSH), free thyroxine (FT4), and Tg were determined using an electrochemiluminescence immunoassay.

RESULTS

Iodine deficiency (UIC < 100 μg/L) was associated with higher risks of TPOAb positivity [adjusted odds ratio (aOR) = 1.64, 95% confidence interval [CI] (1.29-2.08)] and TgAb positivity [aOR = 1.44, 95% CI (1.16-1.80)]. Women with isolated TPOAb positivity, isolated TgAb positivity, or both TPOAb and TgAb positivity had a 14.64-fold, 7.83-fold, and 44.69-fold increased risk of overt hypothyroidism, and a 4.36-fold, 2.86-fold, and 6.26-fold increased risk of subclinical hypothyroidism, respectively. Moreover, the risks of overt and subclinical hypothyroidism in women with a high TPOAb titer were 16.99 and 4.80 times that in TPOAb-negative women, respectively. The risk of overt hypothyroidism in women with a high TgAb titer was 6.97 times that in TgAb-negative women.

CONCLUSIONS

Our work demonstrates that iodine deficiency during early pregnancy is an independent risk factor for both TPOAb positivity and TgAb positivity. Furthermore, positivity for both autoantibodies and a high thyroid autoantibody titer are associated with significantly higher risks of overt and subclinical hypothyroidism.

Association of 25-hydroxyvitamin D with cardiometabolic risk factors and metabolic syndrome: a mendelian randomization study

Background

Low circulating vitamin D levels have been associated with increased risk of metabolic syndrome (MS) and cardiometabolic risk factors in multiple epidemiology studies. However, whether this association is causal is still unclear. We aimed to test whether genetically lowered vitamin D levels were associated with MS and its metabolic traits, using mendelian randomization (MR) methodology.

Methods

Ten thousand six hundred fifty-five participants were enrolled from the SPECT-China study, which was performed in 23 sites in East China during 2014 to 2016. Using four single-nucleotide polymorphisms (SNPs) in the DHCR7, CYP2R1, GC and CYP24A1 genes with known effects on 25(OH) D concentrations, we created a genetic risk score (GRS) as instrumental variable (IV) to estimate the effect of genetically lowered 25(OH) D on MS and cardiometabolic risk factors. MS was defined according to the International Diabetes Federation criteria.

Results

Lower measured 25(OH)D levels were associated with MS (OR 0.921, 95% CI 0.888, 0.954) after multivariable adjustment. However, the MR-derived odds ratio of genetically determined 25(OH) D for risk of MS was 0.977 (95% CI 0.966, 1.030). The MR-derived estimates for raised fasting plasma glucose was 0.578 (95% CI 0.321, 0.980) per 10 nmol/L GRS_synthesis determined increase of 25(OH) D levels.

Conclusions

We found no evidence that genetically determined reduction in 25(OH)D conferred an increased risk of MS and its metabolic traits. However, we created our GRS only on the basis of common variants, which represent limited amount of variance in 25(OH)D. MR studies using rare variants, and large-scale well-designed RCTs about the effect of vitamin D supplementation on MS are warranted to further validate the findings.

Association of antithyroglobulin antibody with iodine nutrition and thyroid dysfunction in Nepalese children

Background

Aberrant iodine intake and thyroid autoimmunity affect thyroid function. Deficiencies of iodine including thyroid disorders have serious impact on child physical and mental development. This study was conducted to investigate iodine nutrition, thyroid function and thyroid autoimmunity in the Nepalese children, and explore the association of thyroidal autoimmunity with iodine nutrition and thyroid dysfunction.

Methods

Five schools from Udayapur district of eastern Nepal were selected for the study. A total of 213 school children aged 6–12 years were enrolled, and anthropometric data, urine samples and blood samples were collected. Urinary iodine concentration (UIC), free triiodothyronine (fT3), free thyroxine (fT4), thyroid stimulating hormone (TSH), and antithyroglobulin antibody (TgAb) was measured. Independent T test, Man-Whitney test, Chi-square test and Fisher’s Exact test were used for testing statistical significance. Spearman’s correlation analysis was done to find association between variables.

Results

The median UIC with IQR, mean ± SD fT3, mean ± SD fT4, median TSH and TgAb with IQR was 150.0 μg/L (102.8; 204.0), 2.49 ± 0.83 pg/ml, 1.33 ± 0.42 ng/dl, 2.49 mIU/L (1.58; 4.29), and 21.40 IU/ml (15.54; 31.20) respectively. Elvated TgAb (≥30 IU/ml, thyroid autoimmune condition) was seen in 25.8% (n = 55) children. UIC was less than 100 μg/L in 17.4% (n = 37) of the children. Subclinical hypothyroidism, overt hypothyroidism and sublinical hyperthyroidism was seen in 1.4% (n = 3), 3.3% (n = 7) and 3.8% (n = 8) children respectively. A strong association of TgAb with UIC (r = − 0.210, p = 0.002) and thyroid hormones; fT3 (r = − 0.160, p = 0.019), fT4 (r = − 0.275, p < 0.001), and TSH (r = 0.296, p < 0.001) was seen. The relative risk for thyroid autoimmunity in children with UIC less than 100 μg/L was 1.784 (95% CI: 1.108–2.871, p = 0.024). Similarly, children with thyroid autoimmunity had higher relative risk [7.469 (95% CI: 2.790–19.995, p < 0.001)] for thyroid dysfunction.

Conclusions

School children of eastern Nepal have adequate iodine nutrition. Thyroid autoimmunity is very common, while thyroid dysfunction is sparse in children. An association of thyroid autoimmunity with iodine nutrition and thyroid dysfunction was seen in children.

Association of single-nucleotide polymorphisms in the IL27 gene with autoimmune thyroid diseases

Background Accumulating data have shown that interleukin-27 (IL27) polymorphisms are linked to the susceptibility of some autoimmune diseases. We assessed whether there was an association between three single-nucleotide polymorphisms (SNPs) of IL27 gene and autoimmune thyroid diseases (AITDs). Methods Three SNPs (rs153109, rs17855750 and rs181206) of IL27 gene were genotyped by Hi-SNP high-throughput genotyping in 843 patients with AITDs (516 Graves' disease (GD) and 327 Hashimoto's thyroiditis (HT)) and 677 healthy controls in Chinese Han population. Results Compared with controls, rs153109 displayed significant associations with GD in allele and genotype frequencies (P = 0.002 and P = 0.008, respectively) and rs17855750 displayed significant associations with HT in allele frequencies (P = 0.02), whereas no differences in genotype or allele frequencies were found between AITD patients and controls at rs181206. Conclusion Our study, for the first time, showed the significant association of the IL27 gene SNPs with AITD.

High Thyroid Stimulating Hormone Level Is Associated With Hyperandrogenism in Euthyroid Polycystic Ovary Syndrome (PCOS) Women, Independent of Age, BMI, and Thyroid Autoimmunity: A Cross-Sectional Analysis

Background: Infertility and dyslipidemia are frequently present in both women with polycystic ovary syndrome (PCOS) and subjects with thyroid dysfunction. Limited study regarding the association between thyroid stimulating hormone (TSH) level and phenotypes in euthyroid PCOS women. We aimed to determine whether the variation of TSH level associates with phenotypes in euthyroid PCOS patients. Methods: Cross-sectional study including 600 PCOS and 200 age, body mass index (BMI), and thyroid autoimmunity-matched Chinese women from Renji hospital, Shanghai Jiaotong university during January 2010 and August 2018. The anthropometric and serum biochemical parameters related to TSH, thyroid autoimmunity, lipid profiles, and sex steroids were detected. Results: The TSH level is higher in (2.29 ± 1.24 vs. 1.86 ± 0.90 mu/L, p < 0.001) in PCOS than controls. In euthyroid PCOS patients, TSH, TG, TC, LDL-c, and apoB level increased from non-hyperandrogenism (nonHA) to HA group (all p < 0.05). TSH level is positively associated with TG, apoB, free T, FAI, and negatively associated with apoA (all p < 0.05). The percentage of HA increased from TSH level (57.93% in TSH < = 2.5 group vs. 69.46% in TSH > 2.5 mU/L group, p = 0.006). HA phenotype is increased with TSH level independently of age, BMI, WC, LDL-C. Besides, in multivariate logistic regression analysis TSH and TG significantly associated with HA phenotype. Conclusions: Higher TSH level is associated with increased prevalence of HA phenotype independent of age, BMI and thyroid autoimmunity in euthyroid PCOS.