Obesity, Thyroid Nodularity, and Thyroid Cancer: Epiphenomenon or Cause?

Associations Between Obesity and Risk of Thyroid Cancer: A Meta-Analysis of Cohort Studies

Previous cohort studies have shown conflicting findings on the associations between obesity and the risk of thyroid cancer. This meta-analysis aimed to investigate the associations between them by using a meta-analysis of cohort studies. PubMed and EMBASE were searched using keywords from inception until November 2023 to identify relevant studies on this topic. Two authors independently reviewed and selected relevant studies according to the predefined criteria. Out of 475 studies searched from the databases, a total of 22 cohort studies were included in the final analysis. In a random-effects meta-analysis, obesity was significantly associated with an increased risk of thyroid cancer [odds ratio (OR), relative risk (RR), or hazard ratio (HR) = 1.33; 95% confidence interval (CI) 1.24 - 1.43]. Obesity was consistently associated with the increased risk of thyroid cancer in the subgroup meta-analyses by various factors such as study type (prospective or retrospective cohort study), gender (male or female), continent (America, Europe, or Asia), and study quality (high or low). This meta-analysis of cohort studies suggests that obesity increases the risk of thyroid cancer.

Analysis of Body Mass Index and Clinicopathological Factors in Patients with Papillary Thyroid Carcinoma

Objective

To analyze the correlation between body mass index (BMI) and clinicopathological factors of papillary thyroid cancer (PTC).

Methods

The clinical data of patients with PCT who were hospitalized in the Department of Thyroid Surgery of the Affiliated Hospital of Guizhou Medical University from March 2023 to September 2023 were retrospectively collected, including age, gender, height, weight, BMI, v-raf murine sarcoma viral oncogene homolog B (BRAF) gene mutation, tumor size, multifocus, Hashimoto's thyroiditis, lymph node metastasis and other clinicopathological factors. According to the World Health Organization (WHO) definition for Asian population, BMI≥25kg/m2 was obese group, 23≤BMI≤24.9kg/m2 was overweight group, 18.5≤BMI≤22.9kg/m2 was normal weight group, and BMI≤18.5kg/m2 was low weight group. The clinicopathological factors of overweight and obese patients with PTC were analyzed.

Results

A total of 164 PTC patients were included, with an average BMI of (24.44±3.57) kg/m2. Age of overweight and obese PTC patients (Z=1.978, p=0.083); Gender of overweight and obese PTC patients (χ2 value: 11.570, p=0.004); Tumor size in overweight and obese PTC patients (Z=0.894, p=0.411); BRAF gene mutation in overweight and obese PTC patients (χ2 value: 1.452, p =0.623); Multifocal lesions were found in overweight and obese patients (χ2 value: 1.653, p =0.201). Hashimoto's thyroiditis was found in overweight and obese PTC patients (χ2 value: 1.147, p=0.298). Overweight and obese patients with PTC had lymph node metastasis (χ2 value: 1.690, p =0.251).

Conclusion

Overweight and obesity in PTC patients are correlated with male, but not with age, tumor size, BRAF mutation, multifocality, Hashimoto's thyroiditis and lymph node metastasis.

Establishment and validation of a multivariate logistic model for risk factors of thyroid nodules using lasso regression screening

Objective

This study aims to analyze the association between the occurrence of thyroid nodules and various factors and to establish a risk factor model for thyroid nodules.

Methods

The study population was divided into two groups: a group with thyroid nodules and a group without thyroid nodules. Regression with the least absolute shrinkage and selection operator (Lasso) was applied to the complete dataset for variable selection. Binary logistic regression was used to analyze the relationship between various influencing factors and the prevalence of thyroid nodules.

Results

Based on the screening results of Lasso regression and the subsequent establishment of the Binary Logistic Regression Model on the training dataset, it was found that advanced age (OR=1.046, 95% CI: 1.033-1.060), females (OR = 1.709, 95% CI: 1.342-2.181), overweight individuals (OR = 1.546, 95% CI: 1.165-2.058), individuals with impaired fasting glucose (OR = 1.590, 95% CI: 1.193-2.122), and those with dyslipidemia (OR = 1.588, 95% CI: 1.197-2.112) were potential risk factors for thyroid nodule disease (p<0.05). The area under the curve (AUC) of the receiver operating characteristic (ROC) curve for the Binary Logistic Regression Model is 0.68 (95% CI: 0.64-0.72).

Conclusions

advanced age, females, overweight individuals, those with impaired fasting glucose, and individuals with dyslipidemia are potential risk factors for thyroid nodule disease.

Weighty Matters: The Obesity-Thyroid Nodule Connection Unveiling the Impact of Obesity on Thyroid Cancer Risk

Background and Objectives: The effect of obesity on the development/progression of thyroid nodules with uncertain cytology is unknown. Therefore, our objective was to assess the role of body mass index (BMI) in predicting malignancy in patients with atypia of undetermined significance/follicular lesion of undetermined significance (AUS/FLUS) nodules. Materials and Methods: We retrospectively analyzed 113 patients with available BMI data and final histopathology of benign or differentiated thyroid cancer. Patients were classified into four groups based on BMI: <18.5 (underweight), 18.5-24.9 (normal weight), 25-29.9 (overweight), and ≥30 (obesity) kg/m2. The association between risk of malignancy and BMI was examined for all data and subgroups based on nodule size, sex, and age. Results: Overall, 44.2% were obese, 36.3% were ≥45 years, and 75.4% were women. Final pathological results showed malignant nodules in 52 patients (46%) and benign nodules in 61 patients (54%) (mean age: 41 ± 11.6 vs. 39.9 ± 11.7 years; p = 0.62). Men had more malignant nodules than benign nodules (32.7% vs. 16.4%, p < 0.05). Overall, no significant correlation was identified between the risk of thyroid cancer and BMI, and the risk of malignancy was not significantly different between obese men and women (p = 0.4). However, in individuals with BMI < 30 kg/m2 (non-obese group), malignant nodules were more frequent in men than in women (71% vs. 41%, p = 0.04). No significant difference was observed in mean nodule size between the benign and malignant groups. Furthermore, BMI was not related to increased risk of malignancy in multiple logistic regression models using all data, even after controlling for confounding variables (odds ratio, 0.99, 95% confidence interval: 0.93-1.06, p = 0.87) or when stratifying by sex. Conclusions: Our study showed no correlation between obesity and thyroid cancer in patients with AUS/FLUS. Moreover, men had more malignant nodules than benign nodules. Further well-designed prospective studies are required to confirm our findings.

[Sociodemographic, clinical and ultrasound characterization of thyroid nodule pathology and its association with malignancy in a Colombian high-complexity center]

BACKGROUND AND OBJECTIVE

Thyroid nodules are among the most frequent conditions, with a 10% risk of malignancy. The objective is to describe the frequency of demographic, clinical, and ultrasonographic characteristics of thyroid nodule pathology in adults and to explore the relationship with tumor malignancy.

METHODS

An analytical, retrospective cross-sectional study in adults with thyroid nodules and nodular fine-needle aspiration performed in adult patients from a Colombian reference center between 2009-2019. Data were obtained from the clinical history, descriptive measures of the patient's demographic, clinical, and ultrasound variables were estimated, and their relationship with the malignancy of the tumor was explored.

RESULTS

A total of 445 patients and 515 nodules were included. The median age was 55 years (IQR 44-64), 86.8% of women, and 54.8% had a single lesion. Percentages of 80.2 and 19.8 were benign and malignant nodules, with a median of 15.7mm (IQR 11-25) and 12.7mm (IQR 8.5-18.3), respectively (p<0.001). Hypothyroidism and levothyroxine consumption were higher in those with malignant nodules (p<0.001). The echographic characteristics were statistically different between the nodules. In the malignant ones, there was a higher frequency of solid composition, hypoechogenicity, and irregular margins. In contrast, in the benign ones, the absence of echogenic focus stood out (p<0.001).

CONCLUSION

The ultrasound characteristics are essential to define the risk of malignancy of a thyroid nodule. Therefore, considering the most frequent ones can help in the most appropriate approach to primary care.

Association of Ozone Exposures with the risk of thyroid nodules in Hunan Province: a population-based cohort study

BACKGROUND

Increasing evidence associates air pollution with thyroid dysfunction, whereas the potential relationship between exposure to ozone (O₃) and Thyroid Nodules (TNs) is unclear.

METHODS

This retrospective cohort study investigated the association between O₃ exposure and TNs in Hunan province, enrolling 191,357 Chinese adults who lived in Hunan province from January 2009 to December 2019 and received voluntary medical examinations. Individual exposure levels to O₃ from 2010 to 2019 were measured on account of participants' residential addresses at the district level. Associations of O₃ exposure with the risk of incidental TNs were assessed by restricted cubic splines and surveyed as odds ratios after adjusting for demographic factors.

RESULTS

In total, 81,900 adults were newly diagnosed with TNs during the study period. Age-standardized TNs detection rate in Hunan province increased from 25.9 to 46.3% between 2010 and 2019, with the greatest annual percent change being 8.1 [95% CI, 7.3-8.8]. A similar trend has been found in all tumor sizes, ages, and both sexes. O₃ exposure presented a statistically significant dose-dependent positive correlation (greater than 0.036 ppm) with TNs. Similarly, long-term exposure to high levels of O₃ (1-year average O₃ concentrations exceeding 0.0417 ppm) was found positively associated with increased TSH levels.

CONCLUSIONS

High-level O₃ exposure in the long term was associated with an increase in TSH. Consequently, increased TSH was related to the increased risk of TNs. Being exposed to high-level O₃ in the long term was related to the increased detection rates of TNs in Hunan province, which could be mediated by TSH.

Is There a Relationship Between Vascularity and Echogenicity of Thyroid Lobes in Ultrasonography With BMI? A Large Retrospective Cohort Study

Objective:

The aim of this study was to investigate the relationship between sonographic vascularity and echogenicity of the thyroid lobes, compared with a participant’s body mass index (BMI).

Materials and Methods:

A total of 3722 participations, with varied BMI, were included in the study. For all the participants, the thyroid-stimulating hormone (TSH) was measured, as well as thyroid volume, sonographic echogenicity, and vascularity were recorded. A multiple regression analysis was performed to assess the relationship between the sonographic vascularity and echogenicity, of thyroid lobes, compared with the participants’ BMI.

Results:

The serum TSH values were significantly higher in patients with a BMI > 25 kg/m². The sonographic vascularity and volume of thyroid lobes were positively correlated the participants’ BMI ( P < .005). Sonographic heterogenicity of the left thyroid lobe, right thyroid lobe, and the isthmus were positively associated with BMI ( P < .005). However, the hyper/hypoechogenicity did not demonstrate any significant correlation with BMI ( P > .005).

Conclusion:

Based on the findings of this study, it was concluded that thyroid volumes may have a significant positive relationship with BMI. In overweight participants (i.e., BMI more than 25), thyroid echogenicity was more heterogeneous and their thyroid lobes were more hypovascular.

Systematic review of Mendelian randomization studies on risk of cancer

BACKGROUND

We aimed to map and describe the current state of Mendelian randomization (MR) literature on cancer risk and to identify associations supported by robust evidence.

METHODS

We searched PubMed and Scopus up to 06/10/2020 for MR studies investigating the association of any genetically predicted risk factor with cancer risk. We categorized the reported associations based on a priori designed levels of evidence supporting a causal association into four categories, namely robust, probable, suggestive, and insufficient, based on the significance and concordance of the main MR analysis results and at least one of the MR-Egger, weighed median, MRPRESSO, and multivariable MR analyses. Associations not presenting any of the aforementioned sensitivity analyses were not graded.

RESULTS

We included 190 publications reporting on 4667 MR analyses. Most analyses (3200; 68.6%) were not accompanied by any of the assessed sensitivity analyses. Of the 1467 evaluable analyses, 87 (5.9%) were supported by robust, 275 (18.7%) by probable, and 89 (6.1%) by suggestive evidence. The most prominent robust associations were observed for anthropometric indices with risk of breast, kidney, and endometrial cancers; circulating telomere length with risk of kidney, lung, osteosarcoma, skin, thyroid, and hematological cancers; sex steroid hormones and risk of breast and endometrial cancer; and lipids with risk of breast, endometrial, and ovarian cancer.

CONCLUSIONS

Despite the large amount of research on genetically predicted risk factors for cancer risk, limited associations are supported by robust evidence for causality. Most associations did not present a MR sensitivity analysis and were thus non-evaluable. Future research should focus on more thorough assessment of sensitivity MR analyses and on more transparent reporting.

Obesity and Thyroid Cancer Risk: An Update

Thyroid cancer (TC) is the most common endocrine malignancy worldwide and its incidence has increased dramatically in recent years. In parallel, the prevalence of overweight and obesity has also increased, suggesting a possible link between these two diseases. Indeed, low-grade chronic inflammation, altered cytokine levels, insulin resistance, oxidative stress, and hormonal changes that occur in obese patients are all factors that contribute to the occurrence and growth of TC. In this review, the most recent evidence supporting the potential role of the mechanisms linking obesity to TC will be discussed.

Proteomic profiling of thyroid tissue in patients with obesity and benign diffuse goiter

Goiter is a term to describe the enlargement of the thyroid gland. The pathophysiology and molecular changes behind development of diffuse benign goiter remains unclear. The present study targeted to identify and describe the alterations in the thyroid tissue proteome from patients (obese euthyroid) with benign diffuse goiter (BDG) using proteomics approach. Thyroid tissue samples, from 7 age and sex matched, patients with BDG and 7 controls were obtained at the time of surgery. An untargeted proteomic analysis of the thyroid tissue was performed out utilizing two-dimensional difference (2D-DIGE) in gel electrophoresis followed by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) for identification of the proteins. Progenesis software was used to identify changes in expression of tissue proteins and found statistically significant differences in abundance in a total of 90 proteins, 46 up and 44 down (1.5-fold change, ANOVA, p ≤ 0.05) in BDG compared to the control group. Bioinformatic analysis using Ingenuity Pathway Analysis (IPA) identified dysregulation of signalling pathways linked to ERK1/2, Glutathione peroxidase and NADPH oxidase associated to organismal injury and abnormalities, endocrine system disorders and cancer. The thyroid tissue proteome in patients with BDG revealed a significant decrease in thyroglobulin along with dysregulation of glycolysis and an increase in prooxidant peroxidase enzymes. Dysregulation of metabolic pathways related to glycolysis, redox proteins, and the proteins associated with maintaining the cytoskeletal structure of the thyrocytes was also identified.

Obesity and Overweight Are Associated with Minimal Extrathyroidal Extension, Multifocality and Bilaterality of Papillary Thyroid Cancer

Epidemiological studies have shown a strong association between high body mass index (BMI) and papillary thyroid cancer (PTC). We assessed the clinical and histopathological features of PTC in patients with a higher BMI and compared them to analogous parameters in PTC patients with a normal BMI. We retrospectively analyzed 5021 medical records of patients admitted and surgically treated for thyroid tumors in one center between 2008 and 2018. Finally, we extracted data from 523 adult patients with PTC and stratified patients into two groups according to BMI: Group 1 with BMI < 25 kg/m² and Group 2 with BMI ≥ 25 kg/m². Data stratification was performed to estimate the association of overweight and obesity with clinical and histopathological features of PTC in both univariable and multivariable binary logistic regression analyses. Overall, compared to patients with a normal BMI, overweight and obese patients had a greater risk of minimal extrathyroidal extension (minimal ETE), multifocality and bilaterality of PTC (p < 0.001 for all). Analysis did not show that BMI was significantly associated with the more advanced tumor-node-metastasis (TNM) stage (p = 0.894). Obesity and overweight were significantly associated with higher aggressiveness of PTC. When considering various management options for PTC patients, these findings regarding overweight and obesity should be taken into consideration during the decision-making process.

Association among Body Mass Index, Genetic Variants of FTO, and Thyroid Cancer Risk: A Hospital-Based Case-Control Study of the Cancer Screenee Cohort in Korea

Purpose

Obesity has been determined to be associated with fat mass and obesity-associated (FTO) gene and thyroid cancer risk. However, the effect of combined interactions between obesity and the FTO gene on thyroid cancer needs further investigation. This study aimed to examine whether interactions between body mass index (BMI) and the FTO gene are associated with an increased risk of thyroid cancer.

Materials and Methods

A total of 705 thyroid cancer cases and 705 sex- and age-matched normal controls were selected from the Cancer Screenee Cohort in National Cancer Center, Korea. A conditional logistic regression model was used to calculate the odds ratios (ORs) and 95% confidence intervals (CIs) for the measure of associations and the combined effect of BMI and FTO gene on thyroid cancer.

Results

BMI was associated with an increased risk of thyroid cancer in subclasses of overweight (23–24.9 kg/m²; adjusted OR, 1.50; 95% CI, 1.12 to 2.00) and obese (≥ 25 kg/m²) (adjusted OR, 1.62; 95% CI, 1.23 to 2.14). There were positive associations between the FTO genetic variants rs8047395 and rs8044769 and an increased risk of thyroid cancer. Additionally, the combination of BMI subclasses and FTO gene variants was significantly associated with thyroid cancer risk in the codominant (rs17817288), dominant (rs9937053, rs12149832, rs1861867, and rs7195539), and recessive (rs17817288 and rs8044769) models.

Conclusion

Findings from this study identified the effects of BMI on thyroid cancer risk among individuals carrying rs17817288, rs9937053, rs12149832, rs1861867, rs7195539, and rs8044769, whereas the effects of BMI may be modified according to individual characteristics of other FTO variants.

Thyroid and Pseudothyroid Dysfunction as a Cause That is Promoting the Relapse of Benign Focal Thyroid Pathology

Several studies deal with learning causes stipulating nodular formations in the thyroid tissue, including those occurring against the ground of metabolic disorders of thyroid hormones. Our study’s objective was to determine the peculiarities of thyroid homeostasis disorders in patients suffering from benign nodular thyroid pathology with relapses of the disease and its relapse-free course. For this purpose, 96 female patients suffering from nodular thyroid pathology and 20 without thyroid pathology were examined. In the course of the study, the following were found in patients with benign focal thyroid pathology: disorders of the peripheral conversion of the thyroid hormones, compensatory activation of the hypothalamic-pituitary system evident in increased levels of the thyroid-stimulating hormone, ТSH/fT3 and ТSH/fT4 ratios, increasing titers of the anti-thyroid antibodies which can be hazardous for the risk of development of nodules or reflects the process of thyroid tissue damage; high level of thyroglobulin caused by an increased probability of relapse and rate of nodule growth, an increase of the thyroid gland volume associated with activation of the hypothalamic-pituitary system, increased antibodies titer and thyroid gland damage. Thus, changes of the examined indices in the blood can be used as prognostic markers concerning the relapse of nodule formation in the thyroid tissue.