Physical activity, diabetes, and risk of thyroid cancer: a systematic review and meta-analysis

The role of exercise in obesity-related cancers: Current evidence and biological mechanisms

Cancer ranks among the five leading causes of death in almost all countries and has important repercussions for individual and public health, the healthcare system, and society in general. Obesity increases the incidence of many types of cancer, but growing evidence suggests that physical activity may decrease risk for developing a variety of obesity-related cancer types, and, in some cases, may improve cancer prognosis and mortality rates. This review summarizes recent evidence on the effect of physical activity on obesity-related cancer prevention and survival. For some cancers, including breast, colorectal, and endometrial cancer, there is strong evidence for a preventative effect of exercise, but for many others, including gallbladder and kidney cancer, and multiple myeloma, evidence is inconsistent or largely lacking. Though many potential mechanisms have been proposed to explain the onco-protective effect of exercise, including improved insulin sensitivity, alterations in sex hormone availability, improved immune function and inflammation, myokine secretion, and modulation of intracellular signaling at the level of AMP kinase, the exact mechanism(s) of action within each cancer subtype remains poorly defined. Overall, a deeper understanding of how exercise can help against cancer and of the exercise parameters that can be altered to optimize exercise prescription is necessary and should be the subject of future investigation.

Fibrinogen-to-Neutrophil Ratio as a New Predictor of Central Lymph Node Metastasis in Patients with Papillary Thyroid Cancer and Type 2 Diabetes Mellitus

Background

Many patients have a higher risk of thyroid cancer if they have both papillary thyroid carcinoma (PTC) and Type 2 diabetes mellitus (T2DM). Meanwhile, the primary reason for local PTC recurrence is cervical lymph node metastasis. Therefore, the prognosis of patients affects how cervical lymph nodes are managed during surgery. Due to surgical complications such as laryngeal nerve palsy and hypocalcemia, it is still debatable whether to prevent central lymph node dissection (CLND). Predicting central lymph node metastasis (CLNM) is crucial to direct CLND. It is unclear how important the fibrinogen-to-neutrophil ratio (FNR) is in thyroid cancer, so we looked into how it might help patients with PTC and T2DM predict CLNM.

Patients and methods

Wenzhou Medical University's First Affiliated Hospital provided us with 413 patients with PTC and T2DM, randomly divided into a training set (N = 292) and a validation set (N = 121). Univariate and multivariate logistic regression analyses were used to identify independent risk factors. After constructing a nomogram, the validity of the model was evaluated.

Results

The maximum tumor diameter, high-density lipoprotein, thyroxine, triglyceride, lymphocyte, and FNR were all identified as independent risk factors by multivariate logistic regression analysis. The C index of the training set was 0.775, and the validation set was 0.654.

Conclusion

In patients with PTC and T2DM, preoperative FNR was an independent risk factor for CLNM.

Association Between Genetic Risk, Adherence to Healthy Lifestyle Behavior, and Thyroid Cancer Risk

Importance

Genetic and lifestyle factors are related to thyroid cancer (TC). Whether a healthy lifestyle is associated with TC and could attenuate the influence of genetic variants in TC remains equivocal.

Objectives

To examine the associations between genetics and healthy lifestyle with incident TC and whether adherence to a healthy lifestyle modifies the association between genetic variants and TC.

Design, Setting, and Participants

A prospective cohort study using UK Biobank data recruited 502 505 participants aged 40 to 69 years between March 13, 2006, and October 1, 2010. A total of 307 803 participants of European descent were recruited at baseline, and 264 956 participants were available for the present study. Data analysis was conducted from November 1, 2021, to April 22, 2022.

Exposures

Lifestyle behaviors were determined by diet index, physical activity, weight, smoking, and alcohol consumption. Lifestyle was categorized as unfavorable (scores 0-1), intermediate (score 2), and favorable (scores 3-5). The polygenic risk score (PRS) was derived from a meta-genome-wide association study using 3 cohorts and categorized as low, intermediate, and high.

Main Outcomes and Measures

Thyroid cancer was defined using the International Classification of Diseases, Ninth Revision (code 193), International Statistical Classification of Diseases and Related Health Problems, Tenth Revision (code C73), and self-report (code 1065).

Results

Of 264 956 participants, 137 665 were women (52%). The median age was 57 (IQR, 49-62) years. During a median follow-up of 11.1 (IQR, 10.33-11.75) years (2 885 046 person-years), 423 incident TCs were ascertained (14.66 per 100 000 person-years). Higher PRSs were associated with TC (hazard ratio [HR], 2.25; 95% CI, 1.91-2.64; P = 8.65 × 10-23). An unfavorable lifestyle was also associated with a higher risk of TC (HR, 1.93; 95% CI, 1.50-2.49; P < .001). When stratified by PRS, unfavorable lifestyle was associated with TC in the higher PRS group (favorable vs unfavorable HR, 0.52; 95% CI, 0.37-0.73; P < .001). Furthermore, participants with both a high PRS and unfavorable lifestyle had the highest risk of TC (HR, 4.89; 95% CI, 3.03-7.91; P < .001).

Conclusions and Relevance

In this prospective cohort study, genetic and lifestyle factors were independently associated with incident TC, which suggests that a healthier lifestyle may attenuate the deleterious influence of genetics on the risk of TC in individuals of European descent.

Glucose-to-Lymphocyte Ratio (GLR) as a Predictor of Preoperative Central Lymph Node Metastasis in Papillary Thyroid Cancer Patients With Type 2 Diabetes Mellitus and Construction of the Nomogram

Background

Detection of metastasis of central lymph nodes in papillary thyroid cancer is difficult before surgery. The role of routine or preventive central lymph node dissection in the management of papillary thyroid cancer remains inconclusive. Moreover, glucose metabolism and systemic inflammation are related to the aggressiveness of several malignant tumors and the prognoses of these patients. This study aimed to construct a nomogram based on the readily available preoperative clinical features for predicting the occurrence of preoperative central lymph node metastasis in patients with papillary thyroid cancer and type 2 diabetes mellitus. The findings may underlie clinical implications for determining the appropriate treatment strategies for these patients.

Methods

A total of 419 patients were enrolled. We used the receiver operating characteristic curves to determine the best cut-off value and converted the continuous into categorical variables. Next, a single-factor logistic analysis for the independent variables was performed, following which a multivariate regression analysis was conducted for the selected significant risk factors. Finally, the nomogram was constructed and verified using external data; the existing data were compared with the original model.

Results

According to the receiver operating characteristic curves, the best cut-off values ​​for glucose-to-lymphocyte ratio and tumor size were 4.23 cm and 0.95 cm, respectively. Findings from the multivariate logistic regression analysis suggested that age, bilateral tumors, maximum tumor size, and the ratio of glucose-to-lymphocytes were independent risk factors for preoperative central lymph node metastasis. The C-indexes in the training and the external validation data sets were 0.733 and 0.664, respectively. Both calibration curves and the Hosmer-Lemeshow tests indicated that the model was well-calibrated. Through decision curve analysis, the predictive model was estimated to have strong clinical applicability and greater benefits. To compare the performance of the new with that of the original model, we performed a net reclassification index and the integrated discrimination improvement analyses, both of which indicated that the new model had a better predictive ability.

Conclusion

In patients with type 2 diabetes mellitus and papillary thyroid cancer, a high preoperative glucose-to-lymphocyte ratio was an independent predictor of the preoperative central lymph node metastasis. The nomogram so constructed could better predict the preoperative central lymph node metastasis in these patients.

The influence of incidental detection of thyroid nodule on thyroid cancer risk and prognosis-A systematic review

BACKGROUND

Clinically inapparent thyroid nodules discovered serendipitously on imaging for nonthyroid indications are termed as thyroid incidentalomas. It is unclear whether these incidentalomas have a lower prevalence of malignancy or slower tumour progression compared to symptomatic nodules. The aims of this systematic review were to determine the impact of incidental detection of thyroid nodules on both the risk of malignancy and on prognosis in patients with thyroid cancer.

METHOD

PubMed and MEDLINE® on Web of Science databases were searched from inception to March 2020 for English language articles reporting on human studies of thyroid cancer risk and/or prognosis in incidental and nonincidental nodules.

RESULTS

Eighteen observational studies published between 1998 and 2020 were eligible for analysis; four studies reported on risk, nine on prognosis and five studies reported on both risk and prognosis. When comparing the incidental and nonincidental groups in the risk study, the odds of incidental detection in the cancer and benign groups ranged from 0.16 to 0.5 and 0.06 to 0.38, respectively (odds ratio [OR] = 0.64-2.86) in case-control studies (n = 6); the risk of malignancy for thyroid nodules ranged from 4% to 23.5% in the incidental and 3.8% to 28.7% in the nonincidental groups (relative risk = 0.13-6.27) in the cohort studies (n = 3). A meta-analysis of the eligible case-control studies (n = 3) showed a nonsignificant summated OR of 1.04 (95% confidence interval = 0.63-1.70; p = .88). In the prognosis study, five direct and thirteen indirect markers of prognosis were compared between the incidental and nonincidental groups. A meta-analysis was not possible but incidentally detected thyroid cancer had better progression-free and overall survival.

CONCLUSION

Current evidence suggests that investigation and management of thyroid nodules should not be influenced by the mode of detection.

The effect of VAV3 polymorphisms on thyroid cancer

BACKGROUND

The incidence of thyroid cancer is rising rapidly in China, but there are few studies on the risk factors of thyroid cancer in the Chinese Han population.

METHODS

We performed this case-control study of 510 patients and 509 controls to for determine the linkage of VAV3 variants (rs17019602, rs7521681, rs4915076, and rs1777451) with thyroid cancer susceptibility by computing the odds ratio (OR) and 95% confidence intervals (CI). Multi-factor dimension reduction (MDR) analysis was conducted to assess interaction of VAV3 genetic variants.

RESULTS

We found that rs7521681 was remarkably related to a higher risk of thyroid cancer (OR = 1.74, p = 0.012), whereas rs4915076 (OR = 0.66, p = 0.001) significantly decreased thyroid cancer susceptibility. Stratified analyses showed that rs4915076 had a protective role in thyroid cancer in both ages >45 years (OR = 0.70, p = 0.017) and age ≤45 years (OR = 0.63, p = 0.007). Rs17019602 could increase the susceptibility of thyroid cancer in men (OR = 4.76, p = 0.049). Rs7521681 was related to an increased risk of thyroid cancer in women (OR = 1.97, p = 0.012). Rs4915076 could protect individuals from thyroid cancer both in men (OR = 0.60, p = 0.031) and women (OR = 0.68, p = 0.010). Moreover, rs4915076 was the best single-locus model to predict thyroid cancer. Interestingly, the interaction model of rs17019602, rs7521681, rs4915076, rs1777451, and age was a candidate gene-environment model.

CONCLUSION

Our results indicated VAV3 variants were associated with thyroid cancer, which provides a new sight into etiology of thyroid cancer.

Genetic polymorphisms in the PCNXL2 gene are risk factors for thyroid cancer in the Chinese population

Background: Thyroid cancer is the most common endocrine malignancy and the fastest growing cancer worldwide. Thyroid cancer has the largest genetic component of all cancers. Previous genome-wide association studies indicated that genetic polymorphism in PCNXL2 is related to thyroid cancer susceptibility in European populations. This study aims to determine the influence of PCNXL2 polymorphisms on thyroid cancer risk in Chinese individuals. Methods: This case-control study identified four polymorphisms in PCNXL2 among 510 thyroid cancer cases and 509 healthy controls. The associations of PCNXL2 polymorphisms with thyroid cancer susceptibility were detected by calculating odds ratios. Multifactor dimensionality reduction was performed to detect the impact of SNP (single nucleotide polymorphism)-SNP interactions on the risk of thyroid cancer. Results: The study showed that rs10910660 in PCNXL2 was related to thyroid cancer susceptibility. Rs12129938 played a protective role in thyroid cancer susceptibility. Stratification analysis indicated that rs10910660 increased thyroid cancer risk at age >45 years. Rs12129938 enhanced susceptibility to thyroid cancer at age >45 years, while this SNP decreased thyroid cancer risk at age ≤45 years. Rs4649295 was associated with lower susceptibility to thyroid cancer at age ≤45 years. An association was observed between rs6424270 and rs12129938 with decreased susceptibility to thyroid cancer in women. Rs10910660 was related to thyroid cancer risk in men. The combination of rs6424270, rs10910660, rs12129938 and rs4649295 was the best model to predict thyroid cancer. Conclusion: This study suggests that PCNXL2 polymorphisms are risk factors for thyroid cancer in the Chinese population.

Insulin Resistance and Cancer: In Search for a Causal Link

Insulin resistance (IR) is a condition which refers to individuals whose cells and tissues become insensitive to the peptide hormone, insulin. Over the recent years, a wealth of data has made it clear that a synergistic relationship exists between IR, type 2 diabetes mellitus, and cancer. Although the underlying mechanism(s) for this association remain unclear, it is well established that hyperinsulinemia, a hallmark of IR, may play a role in tumorigenesis. On the other hand, IR is strongly associated with visceral adiposity dysfunction and systemic inflammation, two conditions which favor the establishment of a pro-tumorigenic environment. Similarly, epigenetic modifications, such as DNA methylation, histone modifications, and non-coding RNA, in IR states, have been often associated with tumorigenesis in numerous types of human cancer. In addition to these observations, it is also broadly accepted that gut microbiota may play an intriguing role in the development of IR-related diseases, including type 2 diabetes and cancer, whereas potential chemopreventive properties have been attributed to some of the most commonly used antidiabetic medications. Herein we provide a concise overview of the most recent literature in this field and discuss how different but interrelated molecular pathways may impact on tumor development.

Type 2 Diabetes and Cancer: An Umbrella Review of Observational and Mendelian Randomization Studies

BACKGROUND

Type 2 diabetes mellitus (T2DM) has been associated with an increased risk of developing several common cancers, but it is unclear whether this association is causal. We aimed to summarize the evidence on T2DM and cancer and evaluate the validity of associations from both observational and Mendelian randomization (MR) studies.

METHODS

We performed an umbrella review of the evidence across meta-analyses of observational studies that examined associations of T2DM with risk of developing or dying from site-specific cancers, and MR studies that explored the potential causal association of T2DM and associated biomarkers with cancer risk.

RESULTS

We identified eligible observational meta-analyses that assessed associations between T2DM and cancer incidence for 18 cancer sites, cancer mortality for seven sites, and cancer incidence or mortality for four sites. Positive associations between T2DM and six cancers reached strong or highly suggestive evidence. We found eight MR studies assessing the association of genetically predicted T2DM and seven and eight studies assessing the association of genetically predicted fasting insulin or fasting glucose concentrations, respectively, upon site-specific cancers. Positive associations were found between genetically predicted T2DM and fasting insulin and risk of six cancers. There was no association between genetically predicted fasting plasma glucose and cancer except for squamous cell lung carcinoma.

CONCLUSIONS

We found robust observational evidence for the association between T2DM and colorectal, hepatocellular, gallbladder, breast, endometrial, and pancreatic cancers.

IMPACT

Potential causal associations were identified for genetically predicted T2DM and fasting insulin concentrations and risk of endometrial, pancreas, kidney, breast, lung, and cervical cancers.

Environmental exposure to cadmium and risk of thyroid cancer from national industrial complex areas: A population-based cohort study

BACKGROUND

Cadmium is known to act as a thyroid disruptor and carcinogen in humans. Recent evidence suggests that cadmium may play a role as a thyroid carcinogen due to its endocrine-disrupting activity, but this characterization remains unclear.

OBJECTIVE

We investigated the association between urinary cadmium and primary thyroid cancer, and the modifying effect of diabetes on this association.

METHODS

We included 5406 participants over 19 years old with measured urinary cadmium from samples collected at eight National Industrial Complex areas from 2003 to 2011. Among 5406 participants, 68 cases were diagnosed with thyroid cancer between enrollment and the end of follow-up (December 31, 2016). Incidence rate ratios for thyroid cancer were estimated using random-effects Cox proportional hazards models with follow-up time as the time scale. In addition, we conducted a stratified analysis by diabetes status.

RESULTS

Compared with the lowest tertile, the middle and highest tertiles had higher risks of thyroid cancer, respectively (HR_{middle vs. lowest} = 1.90, 95% CI = 0.93 to 3.91; HR_{highest vs. lowest} = 2.28, 95% CI = 1.09 to 4.78), with a significant dose-response relationship (P for trend = 0.03). There was no linear association between cadmium level and risk of thyroid cancer. Higher cadmium levels increased thyroid cancer risk in participants without diabetes (HR_{middle vs. lowest} = 2.35, 95% CI = 1.05 to 5.24; HR_{highest vs. lowest} = 2.70, 95% CI = 1.18 to 6.19); although, an association between cadmium levels and thyroid cancer risk in participants with diabetes was not found.

CONCLUSION

Low-level exposure to cadmium is associated with thyroid cancer risk. Our results provide the evidence to limit exposure to cadmium for cancer prevention in the general population. Further studies are needed to investigate the consequence of diabetes and antidiabetic drugs between cadmium and thyroid cancer.

Hypercholesterolemia Is an Associated Factor for Risk of Differentiated Thyroid Cancer in Chinese Population

Background

Hyperlipidemia has been hypothesized as a risk factor for thyroid cancer. However, the association between hypercholesterolemia and thyroid cancer is unclear, especially in Chinese population without available published data. We conducted this study to investigate the relationship between hypercholesterolemia and differentiated thyroid cancer (DTC) in Chinese population.

Methods

Three thousand seven hundred forty-eight patients were enrolled in the study, including 2,021 DTC patients and 1,727 benign subjects with benign thyroid nodules. Demographic characteristics, medical history, and clinical hematological examination were collected. Stratified analyses of association between hypercholesterolemia and risk of DTC were done. Multivariable logistic regression models were used to estimate the association between hypercholesterolemia and the risk of thyroid nodules being malignant. This study protocol was approved by the ethics committee of Shandong Provincial Qianfoshan Hospital and assigned in ClinicalTrials.gov protocol registration and results system (NCT03006289, https://clinicaltrials.gov/ct2/show/NCT03006289).

Results

The level of serum total cholesterol in patients with DTC is higher than that in benign subjects (P < 0.001). After adjusting hypercholesterolemia, age (P < 0.001), triglyceride (P = 0.003), and thyroid stimulating hormone (TSH) (P < 0.001) are found to be confounding factors. The risk of DTC in patients younger than 45 years old is 2.08 times than that of patients older than 45 years old (odds ratio = 0.48, 95% CI (0.38, 0.61), P < 0.001). A high TSH level is highly associated with the increased risk of DTC (P < 0.001). The multivariable logistic regression analysis revealed that the absence of hypercholesterolemia could reduce the risk of thyroid nodules being malignant (odds ratio = −0.75, 95% CI (−1.39, −0.12), P = 0.02). Comparing to the higher level of serum total cholesterol (>5.7 mmol/L), the closer the serum total cholesterol level is to normal (3.17–5.7 mmol/L), the less the risk of thyroid nodules being malignant is, and this difference is statistically significant (odds ratio = −0.67, 95% CI (−1.31, −0.03), P = 0.040). However, this difference is not found in the group of patients with lower level of total cholesterol (<3.17 mmol/L, odds ratio = 0.43, 95% CI (−1.22, 2.09), P = 0.068), suggesting that hypocholesterolemia is not a protective factor in the risk of thyroid nodules being malignant.

Conclusions

Hypercholesterolemia is an associated factor for risk of DTC in Chinese population.

Glycemic control and the incidence of neoplasm in patients with type 2 diabetes: a meta-analysis of randomized controlled trials

PURPOSE

Previous epidemiologic studies indicate an increased risk of cancer and cancer mortality in patients with type 2 diabetes (T2D). Whether the resolution of hyperglycemia will lead to reduced risk of neoplasm in T2D remains uncertain. Therefore, we performed a meta-analysis to assess the association between glycemic control and incidence of neoplasm in T2D patients.

METHODS

Randomized controlled trials (RCTs) in T2D with significant HbA1c reduction difference between intensive/active and standard/control groups plus follow-up ≥48 weeks were included and analyzed by fixed-effect models, random-effect model, and meta-regression analysis accordingly.

RESULTS

Overall, 52 studies were included. Compared with standard/control treatment, intensive/active treatment led to significantly greater HbA1c reduction from baseline (WMD = -0.51%, 95% CI, -0.55 to -0.46%, P < 0.001), but was not associated with a decreased incidence of neoplasm (OR = 0.99, 95% CI, 0.94-1.03, I² = 2%) in T2D. Meta-regression analysis indicated that HbA1c reduction difference between intensive/active treatment and standard/control treatment was not associated with the incidence of neoplasm in T2D patients (β = -0.0011, 95% CI, -0.0058 to 0.0035, P = 0.625). In neoplasm-site subgroup analysis, a decreased incidence of breast neoplasm was observed in T2D patients using dipeptidyl-peptidase-4 inhibitor (OR = 0.56, 95% CI, 0.35-0.89, I² = 0%) and incidence of prostate neoplasm was reduced in T2D patients with glucagon-like peptide-1 receptor agonist treatment (OR = 0.66, 95% CI, 0.47-0.91, I² = 0%).

CONCLUSION

Improved glycemic control in short and medium periods achieved by existing glucose-lowering drugs or strategies may not confer reduced risk of neoplasm in patients with T2D. Studies with longer follow-up duration are needed to better elucidate the long-period effects.

Risk Factors for Thyroid Cancer: What Do We Know So Far?

Thyroid cancer (TC) is the most common endocrine cancer today. The rising incidence of the differentiated papillary type cannot be entirely explained by early and meticulous diagnosis, since a proportion of large tumors has also been reported. In this review, we present the results of numerous investigations focused on possible factors causing increased TC incidence, such as chromosomal and genetic alterations, iodine intake, TSH level, autoimmune thyroid disease, gender, estrogen, obesity, lifestyle changes, and environmental pollutants. Up to now, only childhood exposure to ionizing radiation has been fully recognized as a risk factor. There is also a possibility that yet undiscovered carcinogens, especially during intrauterine life or early childhood, might be responsible for increased TC incidence as well as epigenetic changes. Therefore, more studies are necessary in order to further investigate the potential risk factors for TC and their mechanisms of action.

American College of Sports Medicine Roundtable Report on Physical Activity, Sedentary Behavior, and Cancer Prevention and Control

INTRODUCTION

The American College of Sports Medicine convened an International Multidisciplinary Roundtable on Exercise and Cancer in March 2018 to evaluate and translate the evidence linking physical activity and cancer prevention, treatment, and control. This article discusses findings from the Roundtable in relation to the biologic and epidemiologic evidence for the role of physical activity in cancer prevention and survival.

RESULTS

The evidence supports that there are a number of biologically plausible mechanisms, whereby physical activity can influence cancer risk, and that physical activity is beneficial for the prevention of several types of cancer including breast, colon, endometrial, kidney, bladder, esophageal, and stomach. Minimizing time spent in sedentary behavior may also lower risk of endometrial, colon and lung cancers. Conversely, physical activity is associated with higher risk of melanoma, a serious form of skin cancer. Further, physical activity before and after a cancer diagnosis is also likely to be relevant for improved survival for those diagnosed with breast and colon cancer; with data suggesting that postdiagnosis physical activity provides greater mortality benefits than prediagnosis physical activity.

CONCLUSIONS

Collectively, there is consistent, compelling evidence that physical activity plays a role in preventing many types of cancer and for improving longevity among cancer survivors, although the evidence related to higher risk of melanoma demonstrates the importance of sun safe practices while being physically active. Together, these findings underscore the importance of physical activity in cancer prevention and control. Fitness and public health professionals and health care providers worldwide are encouraged to spread the message to the general population and cancer survivors to be physically active as their age, abilities, and cancer status will allow.

Physical Activity and Thyroid Cancer Risk: A Case-Control Study in Catania (South Italy)

Background: The health benefits of physical activity are well established, but the association between physical activity and thyroid cancer remains poorly understood. The aim of the study was to investigate the relationship between physical activity and thyroid cancer in order to determine type, frequency, and duration of exercise needed to maximize prevention. Method: Cases, diagnosed from January 2009 to July 2018, and controls were enrolled at the University Hospital “Policlinico-Vittorio Emanuele” of Catania (South Italy). Logistic regression models were used to estimate the crude and adjusted odds ratios (ORs) and their 95% confidence intervals. Results: A total of 106 cases (91.2% papillary type) and 217 controls were enrolled. Physical activity was rare in Catania (32.8%) and was not correlated to risk of total thyroid cancer (OR: 0.997; 95% CI: 0.515–1.929). Conversely, walking every day for at least 60 minutes reduced the risk of thyroid cancer (OR: 0.357; 95% CI: 0.157–0.673). Conclusions: Our study showed that daily walking duration was associated with lower risk of thyroid cancer using a case-control study. Unfortunately, the frequency of physical activity often declines with age, particularly among the elderly, thus more research on physical activity adherence is needed to determine which approaches are most effective in promoting sustained physical activity participation.

Aggressive papillary thyroid carcinoma in a child with type 2 congenital generalized lipodystrophy

Thyroid carcinoma (TC) is rare in children, particularly in those aged < 10 years. Several studies have demonstrated a correlation between neoplasms and hyperinsulinemia and insulin resistance, which are often associated with a higher risk for and/or aggressiveness of the neoplasm. Congenital generalized lipodystrophy (CGL) with autosomal recessive inheritance is a rare disease and is characterized by the lack of adipose tissue, severe insulin resistance, and early metabolic disturbances. Here, we reported a rare case of a type 2 CGL in a girl who presented with a papillary TC (PTC) at the age of 7 years. She had no family history of TC or previous exposure to ionizing radiation. She had a generalized lack of subcutaneous fat, including the palmar and plantar regions, muscle hypertrophy, intense acanthosis nigricans, hepatomegaly, hypertriglyceridemia, severe insulin resistance, and hypoleptinemia. A genetic analysis revealed a mutation in the BSCL2 gene (p.Thr109Asnfs* 5). Ultrasound revealed a hypoechoic solid nodule measuring 1.8 × 1.0 × 1.0 cm, and fine needle aspiration biopsy suggested malignancy. Total thyroidectomy was performed, and a histopathological examination confirmed PTC with vascular invasion and parathyroid lymph node metastasis (pT3N1Mx stage). This is the first report to describe a case of differentiated TC in a child with CGL. Severe insulin resistance that is generally observed in patients with CGL early in life, especially in those with type 2 CGL, may be associated with this uncommon presentation of aggressive PTC during childhood.

Effect of insulin on thyroid cell proliferation, tumor cell migration, and potentially related mechanisms

BACKGROUND

Diabetes has recently been identified as a risk factor for a variety of cancers, possibly due to hyperinsulinemia or exogenous insulin use. Thyroid cancer is the most common endocrine malignancy, and its incidence has been exponentially increasing worldwide at an alarming rate. The aim of this study was to establish whether insulin use affects thyroid cancer development and progression, specifically cell proliferation and migration in vitro.

METHODS

In this study, we investigated the effects of the insulin agents most commonly used in the clinic, regular human insulin (HI) and insulin glargine (IG), on the proliferation and migration of thyroid cells.

RESULTS

Both HI and IG affected the thyroid cells in a dose-dependent manner and at high concentrations significantly promoted thyroid cell proliferation and tumor cell migration. The promoting effect might be elicited by activation of the insulin receptor and insulin-like growth factor-1 receptor and through the downstream Akt-signaling pathway, which inhibits the activity of the tumor-suppressor FoxO3a. In particular, MAPK-signaling cascades were activated in papillary thyroid carcinoma cell-1 cells but not in follicular rat thyroid-5 cells.

CONCLUSION

The in vitro evidence demonstrated that HI and IG can promote thyroid cell proliferation and tumor cell migration at supraphysiological concentrations, but the effect was not significant at low concentrations. Whether high-dose insulins could affect diabetic patients with thyroid cancer or undetected (pre)cancerous lesions needs further in vivo study.

ABBREVIATIONS

HI: human regular insulin; IG: insulin glargine; IR: insulin receptor; IGF-1R: insulin-like growth factor-1 receptor; Akt: protein kinase B (PKB); MAPK: mitogen-activated protein kinase; FoxO3a: the forkhead box-containing protein: class O 3a.

Leukocyte Mitochondrial DNA Copy Number and Risk of Thyroid Cancer: A Two-Stage Case-Control Study

Background: Mitochondrial DNA copy number (mtDNA-CN) may contribute to the development of various cancer types in a tumor-specific manner. However, little is known about whether leukocyte mtDNA content confers susceptibility to thyroid cancer (TC). This study aimed to investigate the associations of leukocyte mtDNA-CN with the risk and clinicopathological features of TC in a Chinese population. Methods: In this two-stage case-control study with a total of 402 TC patients and 406 controls, leukocyte mtDNA-CN content was measured with a quantitative PCR method. In a subset of 100 cases and 100 controls, levels of leukocyte 8-hydroxy-2'-deoxyguanosine (8-OHdG) and plasma malondialdehyde, as two biomarkers for oxidative stress, were determined by ELISA and colorimetric kits, respectively. Results: In a combined analysis of discovery and validation sets, high mtDNA-CN content was positively associated with increased TC risk, after adjusting for confounders (OR for per SD increment: 1.43; 95%CI, 1.23-1.66; P < 0.001; OR for tertile 3 vs. tertile 1: 2.10; 95%CI, 1.48-3.00; P _trend < 0.001). This linear dose-response relationship was more pronounced in subtype analyses for papillary and follicular thyroid carcinoma (P < 0.001 for all), as well as in subgroup analyses for subjects with overweight and obesity (P _interaction = 0.015). In TC patient, we observed the positive correlations of mtDNA-CN with advanced TNM stage (P = 0.006) and the presence of lymph node metastasis (P = 0.012). Leukocyte mtDNA-CN content was also identified to increase with the levels of leukocyte 8-OHdG (P < 0.001), a biomarker for oxidative DNA damage. Conclusion: Our data suggest that the increase in leukocyte mtDNA-CN content may correlate with oxidative DNA damage, and serve as an independent risk factor for TC.

A Linkage Between Thyroid and Breast Cancer: A Common Etiology?

Breast and thyroid cancers are two malignancies with highest incidence in women. These cancers often occur metachronously. Women with thyroid cancer are at increased risk for subsequent breast cancer; women with breast cancer have an increased incidence of later development of thyroid cancer, suggesting a common etiology. This bidirectional relationship is reported worldwide; however, the underlying reasons for this co-occurrence are unknown. In this review, we summarize the current epidemiologic evidence and putative mechanisms of these metachronous or synchronous cancers. Key potential causative factors are chemotherapy and radiotherapy of the primary tumor, genetic variants linking the two diseases, hormonal signaling both from the thyroid gland and from estrogens, and lifestyle and environmental factors. There is a critical need for additional epidemiologic studies focused on gender and regional incidence together with molecular investigations on common tumorigenic pathways in these endocrine cancers. Understanding the putative mechanisms will aid in the diagnosis and clinical management of both diseases.

The Relationship Between Human Development Index and Its Components with Thyroid Cancer Incidence and Mortality: Using the Decomposition Approach

BACKGROUND

The link between age specific-rates of thyroid cancer (TC) and human development index (HDI) and also its components can be a new direction for planning by policy makers.

OBJECTIVES

This study aimed at identifying the relationship between TC rates by gender, and HDI and its components in different regions of the world.

METHODS

An ecological study was conducted; the data was obtained from the GLOBOCAN project in 2012. Inequality in TC estimates (age-specific incidence and mortality rates), according to the HDI and its components was calculated. Concentration index (CI) was used to estimate inequality and CI was decomposed to determine contribution of HDI and its components in inequality.

RESULTS

The inequality index (CI) was 0.29 (95% CI: 0.21 - 0.38) and -0.15 (95% CI: -0.23 - 0.06) for incidence and mortality of TC by HDI, respectively. The important contributors in inequality for incidence rates of TC were life expectancy at birth (0.30), mean years of schooling (0.26), and expected years of schooling (0.18). The important contributors in inequality of mortality rates were mean years of schooling (0.19), expected years of schooling (0.17), and urbanization (0.17).

CONCLUSIONS

According to the findings of this study, global inequalities exist in the TC incidence and mortality rates; incidence rates of TC are more concentrated in countries with high HDI, yet inequality index showed that deaths occurred more in disadvantaged countries.

Sex differences in the association between diabetes and cancer: a systematic review and meta-analysis of 121 cohorts including 20 million individuals and one million events

AIMS/HYPOTHESIS

Diabetes has been shown to be a risk factor for some cancers. Whether diabetes confers the same excess risk of cancer, overall and by site, in women and men is unknown.

METHODS

A systematic search was performed in PubMed for cohort studies published up to December 2016. Selected studies reported sex-specific relative risk (RR) estimates for the association between diabetes and cancer adjusted at least for age in both sexes. Random-effects meta-analyses with inverse-variance weighting were used to obtain pooled sex-specific RRs and women-to-men ratios of RRs (RRRs) for all-site and site-specific cancers.

RESULTS

Data on all-site cancer events (incident or fatal only) were available from 121 cohorts (19,239,302 individuals; 1,082,592 events). The pooled adjusted RR for all-site cancer associated with diabetes was 1.27 (95% CI 1.21, 1.32) in women and 1.19 (1.13, 1.25) in men. Women with diabetes had ~6% greater risk compared with men with diabetes (the pooled RRR was 1.06, 95% CI 1.03, 1.09). Corresponding pooled RRRs were 1.10 (1.07, 1.13) for all-site cancer incidence and 1.03 (0.99, 1.06) for all-site cancer mortality. Diabetes also conferred a significantly greater RR in women than men for oral, stomach and kidney cancer, and for leukaemia, but a lower RR for liver cancer.

CONCLUSIONS/INTERPRETATION

Diabetes is a risk factor for all-site cancer for both women and men, but the excess risk of cancer associated with diabetes is slightly greater for women than men. The direction and magnitude of sex differences varies by location of the cancer.

Low Vitamin D Deficiency Associated With Thyroid Disease Among Type 2 Diabetic Mellitus Patients

BACKGROUND

The aim of this study was to investigate the relationship between vitamin D deficiency and thyroid diseases among type 2 diabetes mellitus (T2DM) patients.

METHODS

This was a cohort case and control study, 546 T2DM patients and 546 control study participants were enrolled, aged between 25 and 65 years. The subjects were also investigated for fasting blood glucose levels (FBG), post prandial glucose (PPG,) glycosylated hemoglobin (HbA1c), thyroid stimulating hormone (TSH), T3, T4, and presence of other comorbid conditions. Thyroid fine needle aspiration biopsy was suggested to patients whose thyroid nodules were greater than 1.00 cm.

RESULTS

There were significant differences between T2DM patients and control subjects regarding BMI (kg/m2), physical activity, cigarette smoking, sheesha smoking, family history of diabetes, hypertension and family history of thyroid nodules. The clinical biochemistry values among T2DM for vitamin D, calcium, magnesium, potassium, phosphorous, fasting blood glucose, cholesterol, HbA1c, HLDL, LDL, triglyceride, systolic blood pressure (SBP) and diastolic blood pressure (DBP) were lower than control subjects, but higher in creatinine, albumin, TSH, T3, and T4 which appeared statistically significant differences (P < 0.001). Also, the study revealed statistically significant differences between subjects vitamin D deficiency and with thyroid nodules for calcium, magnesium, phosphorous, HbA1c, high density lipoprotein (HDL), SBP and DBP, TSH, T3, and T4 among T2DM patients and control subjects (P < 0.001). Multivariable stepwise logistic regression analysis showed that TSH, HbA1c, vitamin D deficiency, SBP (mm Hg), BMI, family history of DM, serum calcium level and family history of thyroid were considered at higher risk as predictors of thyroid among T2DM patients.

CONCLUSIONS

This study suggests that obesity, HbA1c, the environment, and genetic susceptibility among T2DM, may increase the risk of thyroid disease and cancer. Although evidence has shown that thyroid cancer incidence has been rising more rapidly over time than the occurrence of cancers of other sites, due to an increase of obesity, diabetes and lack of physical activity, this study lacks of direct evidence supporting this conclusion.

An 18-year study of thyroid carcinoma in the western region of Saudi Arabia: a retrospective single-center study in a community hospital

BACKGROUND

Thyroid carcinoma (TC) is the ninth most common site of all cancers in women in the world and the second most common malignancy in Saudi Arabia. This reports updates data on the epidemiology of the disease in Saudi Arabia.

OBJECTIVE

Describe and interpret changes in the frequency of TC to compare with other populations and determine proportions of certain histological types of TC.

DESIGN

Medical record review.

SETTING

Military hospital in Jeddah, Saudi Arabia.

PATIENTS AND METHODS

We reviewed the pathological and clinical records from January 2000 to December 2017 of patients with TC.

MAIN OUTCOME MEASURES

Frequency and types of TC.

SAMPLE SIZE

347 patients.

RESULTS

Over the 18-year period, out of 456 patients with TC, 347 patients had sufficiently complete records: 275 (79.3%) were female and 72 (20.7%) were male for a female to male ratio of 3.8:1. The mean (SD) age at surgery of all patients was 45.2 (16.0) years. There were 287 (82.7%) cases of papillary TC. The next common malignancy was follicular TC with 32 (9.2%) cases followed by Hurthle cell cancer with 11 (3.2%) cases. Lymphoma was found in only 7 (2%) cases. All TC types occurred at a younger age in females than males except for lymphoma. All TC types occurred with the greatest frequency in the fourth and fifth decades. There was a 2.3-fold increase in the number of TCs from 8 (2.3%) in 2000 to 26 (7.5%) in 2017. The rate per 100000 residents of Jeddah increased for the period from 2000 to 2002 from 1.6 to 3.4 for 2015-2017. Papillary TC cases in females accounted for most of the increase.

CONCLUSION

Our findings are consistent with similar studies worldwide. Etiological factors promoting the rise in TC must be investigated and may provide insight in developing suitable management strategies for the Saudi population.

LIMITATION

Small sample size and retrospective over a long period.

CONFLICT OF INTEREST

None.

A Comparison Study: The Risk Factors in the Lifestyles of Thyroid Cancer Patients and Healthy Adults of South Korea

BACKGROUND

In South Korea, there has been a rapid increase in thyroid cancer diagnoses, and the thyroid cancer incidence rate is the highest in the world. This study explored possible risk factors that may influence the development of thyroid cancer by comparing life habits of thyroid cancer patients and healthy adults.

OBJECTIVE

The aims of this study were to identify lifestyle and habit differences in thyroid cancer patients and healthy adults and to investigate risk factors that influence the development of thyroid cancer.

METHODS

The study was designed as a retrospective comparison survey study of thyroid cancer patient group and healthy adult group. One hundred two thyroid cancer patients in a university hospital and 115 healthy adults were recruited for this study. Data were analyzed using descriptive statistics, χ test/t test, and logistic regression with SPSS program.

RESULTS

Previous smoking history, lower physical activity level, higher stress, and unhealthy eating habits (consumption of instant food products) were shown to be risk factors in the development of thyroid cancer.

CONCLUSION

Based on the results of this study comparing thyroid cancer patients and healthy adults, it is recommended to encourage an increase in physical activity, minimize both direct and indirect exposure to smoking, develop healthy eating habits of consuming more vegetables, and effectively manage stress levels.

IMPLICATIONS FOR PRACTICE

Lifestyle preferences and habits may influence the development of thyroid cancer. It is imperative to identify and modify the risk factors in order to prevent thyroid cancer development.

A meta-analysis of alcohol consumption and thyroid cancer risk

Background

It is still inconclusive whether alcohol consumption affects the risk of thyroid cancer. We conducted a meta-analysis of available epidemiological data to address this issue.

Results

Compared with nondrinkers, the pooled relative risks (RRs) and corresponding 95% confidential intervals (CIs) of thyroid cancer were 0.80 (95% CI 0.71-0.90) for any drinkers, 0.81 (95% CI 0.70-0.93) for light and 0.71 (95% CI 0.63-0.79) for moderate drinkers. The dose–response analysis suggested that there is no evidence of a dose-risk relationship between alcohol intaking and thyroid cancer risk (P = 0.112).

Methods

Eligible studies were identified by searching PubMed and EMbase databases. A total of 24 studies, included 9,990 cases with thyroid cancer, were included in this meta-analysis. We defined light alcohol intake as ≤ one drink/day and moderate as >one drink/day. The summary risk estimates were calculated by the random effects model. A dose-response analysis was also conducted for modeling the dose-risk relation.

Conclusion

This meta-analysis confirmed an inverse association between alcohol consumption and thyroid cancer risk. Further studies are needed to better understand the potential mechanisms underlying this association.

Heart Rate Recovery and Cancer Risk: Prospective Cohort Study

This study aims to determine the association between 2-minute heart rate recovery (HRR) and cancer risk. Each participant (5379 women; 8485 men) provided HRR obtained from treadmill tests. The outcome was site-specific cancer. Over 9 years of follow-up, 630 cancer events (258 women) were accrued. Slower HRR was associated with increased thyroid cancer risk in women ( P for trend = .0121) and colorectal cancer risk in men ( P for trend = .0034). The lowest HRR (<13 bpm) had higher hazards of thyroid cancer (hazard ratio [HR] = 2.20; 95% CI = 1.28-3.77) in women and colorectal cancer (HR = 3.08; 95% CI = 1.32-7.15) in men. In women, slower HRR and lower proportions of heart rate recovery (PHRR) were associated with higher hazards of thyroid cancer in women and metabolically related cancers (liver and colorectal) in men. Slower HRR and lower PHRR were independent risk factors for thyroid cancer in women and metabolically related cancers in men.

Association between type 2 diabetes and risk of cancer mortality: a pooled analysis of over 771,000 individuals in the Asia Cohort Consortium

AIMS/HYPOTHESIS

The aims of the study were to evaluate the association between type 2 diabetes and the risk of death from any cancer and specific cancers in East and South Asians.

METHODS

Pooled analyses were conducted of 19 prospective population-based cohorts included in the Asia Cohort Consortium, comprising data from 658,611 East Asians and 112,686 South Asians. HRs were used to compare individuals with diabetes at baseline with those without diabetes for the risk of death from any cancer and from site-specific cancers, including cancers of the oesophagus, stomach, colorectum, colon, rectum, liver, bile duct, pancreas, lung, breast, endometrium, cervix, ovary, prostate, bladder, kidney and thyroid, as well as lymphoma and leukaemia.

RESULTS

During a mean follow-up of 12.7 years, 37,343 cancer deaths (36,667 in East Asians and 676 in South Asians) were identified. Baseline diabetes status was statistically significantly associated with an increased risk of death from any cancer (HR 1.26; 95% CI 1.21, 1.31). Significant positive associations with diabetes were observed for cancers of the colorectum (HR 1.41; 95% CI 1.26, 1.57), liver (HR 2.05; 95% CI 1.77, 2.38), bile duct (HR 1.41; 95% CI 1.04, 1.92), gallbladder (HR 1.33; 95% CI 1.10, 1.61), pancreas (HR 1.53; 95% CI 1.32, 1.77), breast (HR 1.72; 95% CI 1.34, 2.19), endometrium (HR 2.73; 95% CI 1.53, 4.85), ovary (HR 1.60; 95% CI 1.06, 2.42), prostate (HR 1.41; 95% CI 1.09, 1.82), kidney (HR 1.84; 95% CI 1.28, 2.64) and thyroid (HR 1.99; 95% CI 1.03, 3.86), as well as lymphoma (HR 1.39; 95% CI 1.04, 1.86). Diabetes was not statistically significantly associated with the risk of death from leukaemia and cancers of the bladder, cervix, oesophagus, stomach and lung.

CONCLUSIONS/INTERPRETATION

Diabetes was associated with a 26% increased risk of death from any cancer in Asians. The pattern of associations with specific cancers suggests the need for better control (prevention, detection, management) of the growing epidemic of diabetes (as well as obesity), in order to reduce cancer mortality.

Review of Factors Related to the Thyroid Cancer Epidemic

Thyroid cancer is the most common endocrine cancer, of which the incidence has dramatically increased worldwide in the past few decades. The reasons for the observed rapid increase still are not fully understood, but evidence suggests that overdiagnosis, with the advancement in detection methods and screening policies, is not the sole driver of the substantial increase of the incidence. However, the effect of environmental/lifestyle factors remains speculative other than that of radiation exposure at a young age. This review tries to give a balanced view of debated factors leading to the thyroid cancer epidemic, to offer some alternatives in understanding the controversies, and to suggest potential directions in the search of modifiable risk factors to help reduce thyroid cancer.

The changing incidence of thyroid cancer

During the past few decades, the incidence of thyroid cancer has increased substantially in many countries, including the USA. The rise in incidence seems to be attributable both to the growing use of diagnostic imaging and fine-needle aspiration biopsy, which has led to enhanced detection and diagnosis of subclinical thyroid cancers, and environmental factors. The latest American Thyroid Association (ATA) practice guidelines for the management of adult patients with thyroid nodules and differentiated thyroid cancer differ substantially from the previous ATA guidelines published in 2009. Specifically, the problems of overdiagnosis and overtreatment of a disease that is typically indolent, where treatment-related morbidity might not be justified by a survival benefit, now seem to be acknowledged. As few modifiable risk factors for thyroid cancer have been established, the specific environmental factors that have contributed to the rising incidence of thyroid cancer remain speculative. However, the findings of several large, well-designed epidemiological studies have provided new information about exposures (such as obesity) that might influence the development of thyroid cancer. In this Review, we describe the changing incidence of thyroid cancer, suggest potential explanations for these trends, emphasize the implications for patients and highlight ongoing and potential strategies to combat this growing clinical and public health issue.

Burden Assessment of Thyroid cancer in Iran from 1990 to 2010: Lessons Obtained from Global Burden of Disease Report 2010

BACKGROUND

Thyroid tumors are generally regarded as rare malignancies. Nowadays, however, their global incidence is growing continuously partially due to western life style and utilization of more sensitive methods of early detection. It is approximately three times more prevalent in females than in males. Most cases of thyroid cancer are asymptomatic nodules or just have local cervical symptoms or adenopathy in early stages.

MATERIALS AND METHODS

The Global Burden of Diseases report 2010 study (released 3/2013) profited from 100 collaborators worldwide and used a vast network of data on health outcomes, vital registries, and population surveys. It shared many of the Global Burden of Diseases 1990 principal databases such as all available data on injuries, diseases, risk factors, as well as comparable metrics, and used different scientific approved methods to estimate important health status data like: death rate, life expectancy, healthy adjusted life expectancy, disability-adjusted life years (DALY), years of living lost due to premature death and years of life with disabilities.

RESULTS

DALY as thyroid cancer burden per 100,000 Iranian populations had increased by about 14% during 1990 to 2010 in all ages; from 6.1 (95% UI 4.2-9.74) years in 1990 to 6.95 (95% UI 5.06-9.18) years in 2010 in both sex. The 2010 peak age-group was estimated at 45-49 years in males and 40-45 years in females.

AMERICAN ASSOCIATION OF CLINICAL ENDOCRINOLOGISTS AND AMERICAN COLLEGE OF ENDOCRINOLOGY DISEASE STATE CLINICAL REVIEW: THE INCREASING INCIDENCE OF THYROID CANCER

OBJECTIVE

(1) Describe current epidemiology of thyroid cancer in the United States; (2) evaluate hypothesized causes of the increased incidence of thyroid cancer; and (3) suggest next steps in research and clinical action.

METHODS

Analysis of data from Surveillance, Epidemiology and End Results System and the National Center for Vital Statistics. Literature review of published English-language articles through December 31, 2013.

RESULTS

The incidence of thyroid cancer has tripled over the past 30 years, whereas mortality is stable. The increase is mainly comprised of smaller tumors. These facts together suggest the major reason for the increased incidence is detection of subclinical, nonlethal disease. This has likely occurred through: health care system access, incidental detection on imaging, more frequent biopsy, greater volumes of and extent of surgery, and changes in pathology practices. Because larger-size tumors have increased in incidence also, it is possible that there is a concomitant true rise in thyroid cancer incidence. The only clearly identifiable contributor is radiation exposure, which has likely resulted in a few additional cases annually. The contribution of the following causes to the increasing incidence is unclear: iodine excess or insufficiency, diabetes and obesity, and molecular disruptions. The following mechanisms do not currently have strong evidence to support a link with the development of thyroid cancer: estrogen, dietary nitrate, and autoimmune thyroid disease.

CONCLUSION

Research should focus on illuminating which thyroid cancers need treatment. Patients should be advised of the benefits as well as harms that can occur with treatment of incidentally identified, small, asymptomatic thyroid cancers.

Iodine deficiency and thyroid cancer trends in three regions of Thailand, 1990-2009

BACKGROUND

Iodine deficiency may play a role in thyroid cancer carcinogenesis. Because Thailand has region-specific historical iodine deficiency, it is ideal to evaluate the potential impact of recent national iodine supplementation policies on thyroid cancer incidence trends.

METHODS

We examined thyroid cancer trends in Thailand from 1990 to 2009 in three geographically separated populations (Songkhla Province [south], Chiang Mai Province [north], and Khon Kaen Province [northeast]), each with a different historical prevalence of iodine deficiency. We used Joinpoint analysis and age-period-cohort (APC) models to investigate trends in thyroid cancer incidence.

RESULTS

Pooled incidence of papillary cancers significantly increased (Males APC: 2.0, p<0.05; Females APC: 7.3 [1990-2001, p<0.05], -2.1 [2001-2009]) and incidence of follicular cancers significantly decreased (Males APC: -5.2, p<0.05; Females APC: -4.3 [1990-1998, p<0.05], 12.3 [1998-2001], -17.0 [2001-2005, p<0.05], 8.2 [2005-2009]) in both males and females between 1990 and 2009. The largest increases in papillary cancer incidence, and the largest decreases in follicular cancer incidence, occurred in historically iodine-deficient regions. Interestingly, the significant histological changes coincided with Thailand's most recent national iodination policy. The thyroid cancer trends in females were better explained by period effects than cohort effects.

CONCLUSIONS

This study adds to the research indicating that papillary carcinoma incidence increases, and follicular carcinoma incidence decreases, as population-level iodine deficiency declines, and suggests that iodine exposure may affect late stages of thyroid carcinogenesis. However, our findings are limited by the ecological study design and lack of data prior to iodine supplementation.

Recreational Physical Activity and Differentiated Thyroid Cancer Risk: A Pooled Analysis of Two Case-Control Studies

PURPOSE

Physical activity has been hypothesized to influence cancer occurrence through several mechanisms. To date, its relation with thyroid cancer risk has been examined in relatively few studies. We pooled 2 case-control studies conducted in Cuba and Eastern France to assess the relationship between self-reported practice of recreational physical activity since childhood and thyroid cancer risk.

METHODS

This pooled study included 1,008 cases of differentiated thyroid cancer (DTC) matched with 1,088 controls (age range 9-35 and 17-60 years in the French and Cuban studies, respectively). Risk factors associated with the practice of recreational physical activity were estimated using OR and 95% CI. Logistic regressions were stratified by age class, country, and gender and were adjusted for ethnic group, level of education, number of pregnancies for women, height, BMI, and smoking status.

RESULTS

Overall, the risk of thyroid cancer was slightly reduced among subjects who reported recreational physical activity (OR = 0.8; 95% CI 0.5-1.0). The weekly frequency (i.e. h/week) seems to be more relevant than the duration (years).

CONCLUSION

Long-term recreational physical activity, practiced since childhood, may reduce the DTC risk. However, the mechanisms whereby the DTC risk decreases are not yet entirely clear.

Risk Factors for Thyroid Cancer: A Hospital-Based Case-Control Study in Korean Adults

PURPOSE

Although the incidence of thyroid cancer in Korea has rapidly increased over the past decade, few studies have investigated its risk factors. This study examined the risk factors for thyroid cancer in Korean adults.

MATERIALS AND METHODS

The study design was a hospital-based case-control study. Between August 2002 and December 2011, a total of 802 thyroid cancer cases out of 34,211 patients screened from the Cancer Screenee. Cohort of the National Cancer Center in South Korea were included in the analysis. A total of 802 control cases were selected from the same cohort, and matched individually (1:1) by age (±2 years) and area of residence for control group 1 and additionally by sex for control group 2.

RESULTS

Multivariate conditional logistic regression analysis using the control group 1 showed that females and those with a family history of thyroid cancer had an increased risk of thyroid cancer, whereas ever-smokers and those with a higher monthly household income had a decreased risk of thyroid cancer. On the other hand, the analysis using control group 2 showed that a family history of cancer and alcohol consumption were associated with a decreased risk of thyroid cancer, whereas higher body mass index (BMI) and family history of thyroid cancer were associated with an increased risk of thyroid cancer.

CONCLUSION

These findings suggest that females, those with a family history of thyroid cancer, those with a higher BMI, non-smokers, non-drinkers, and those with a lower monthly household income have an increased risk of developing thyroid cancer.

Diabetes, Diabetes Treatment, and Risk of Thyroid Cancer

OBJECTIVE

The objective of this study was to assess the relationships among diabetes, diabetes treatment and thyroid cancer risk using a large prospective cohort, the Women's Health Initiative.

METHODS

A total of 147 934 women who were free of known cancer at baseline were followed prospectively. Diabetes status and diabetes treatment at baseline and during follow-up were ascertained. Incident cases of thyroid cancers were confirmed by physician review of central medical records and pathology reports. Time-dependent Cox proportional hazards regressions were used to estimate hazard ratios and 95% confidence intervals for thyroid cancer risk associated with diabetes status, diabetes treatment, and duration of diabetes.

RESULTS

With a median follow-up time of 15.9 years, 391 incident thyroid cancers were identified. We found no significant associations between thyroid cancer and diabetes (hazard ratio = 1.09; 95% confidence interval, 0.79-1.52), diabetes treatment, or duration of diabetes.

CONCLUSION

Our findings do not support the hypothesis that diabetes, or treatment of diabetes is associated with risk of thyroid cancer among postmenopausal women. Studies to investigate the specific effects of hyperinsulinemia and insulin resistance on thyroid cancer risk may provide additional information.

Human contamination by persistent toxic substances: the rationale to improve exposure assessment

We know quite a lot about the generalized human contamination by environmental chemical agents; this statement is fully compatible with the view that most countries lack the necessary monitoring systems. We also know quite a lot about the toxic effects of environmental pollutants; this statement is fully compatible with the proposal that we need both more research and more energetic policies to decrease human contamination by such pollutants. Unsurprisingly, we know too little about the (environmental and social) causes and the etiopathogenesis (mechanisms) of the most prevalent diseases, and we will continue to miss relevant causes and mechanisms if we neglect the toxic chemicals that commonly contaminate humans, worldwide. Basic, clinical end environmental-epidemiological research on human health should more often consider integrating biomarkers of internal dose of environmental chemical pollutants. When we act in more responsible, rational, and scientific ways; when we become less dismissive towards environmental hazards; and when we thus neglect less the generalized human contamination by environmental chemical agents and their toxic effects, we will expand mechanistic biologic knowledge, and we shall as well increase the effectiveness of interventions and policies that enable the primary prevention of human diseases which cause huge amounts of economic burden and human suffering.

Increasing Incidence of Thyroid Nodules and Thyroid Cancer: Does Increased Detection of a Subclinical Reservoir Justify the Associated Anxiety and Treatment?

The incidence of thyroid cancer has been increasing over the last few decades, and it is subject to debate regarding whether the incidence is reflective of better diagnostic techniques and therefore better detection or if it is a reflection of a true increase in incidence. This increase in incidence has been most clearly manifested by an exponential increase in the diagnosis of micropapillary thyroid carcinomas. This article reviews the diagnosis of thyroid cancers, the dilemmas facing clinicians in the management of these micropapillary thyroid carcinomas, and the advances in molecular diagnostics that are being used to assist in the decision-making process. We consider the possibility of overtreatment of a relatively indolent disease and propose a less aggressive management plan in the appropriate clinical scenario.

The Rotterdam Study: 2016 objectives and design update

The Rotterdam Study is a prospective cohort study ongoing since 1990 in the city of Rotterdam in The Netherlands. The study targets cardiovascular, endocrine, hepatic, neurological, ophthalmic, psychiatric, dermatological, otolaryngological, locomotor, and respiratory diseases. As of 2008, 14,926 subjects aged 45 years or over comprise the Rotterdam Study cohort. The findings of the Rotterdam Study have been presented in over 1200 research articles and reports (see www.erasmus-epidemiology.nl/rotterdamstudy ). This article gives the rationale of the study and its design. It also presents a summary of the major findings and an update of the objectives and methods.

Antihyperglycaemic therapies and cancer risk

AIMS

This review is aimed at highlighting the potential mitogenic/tumour growth-promoting or antimitogenic/tumour growth-inhibiting effects of the main antihyperglycaemic drug classes.

METHODS

We review and discuss the most current studies evaluating the association between antidiabetic medications used in clinical practice and malignancies as described so far.

RESULTS

Metformin seems to be the only antidiabetic drug to exert protective effects both on monotherapy and also when combined with other oral antidiabetic drugs or insulins in several site-specific cancers. In contrast, several other drug classes may increase cancer risk. Some reason for concern remains regarding sulphonylureas and also the incretin-based therapies regarding pancreas and thyroid cancers and the sodium glucose cotransporter-2 inhibitors as well as pioglitazone regarding bladder cancer. The majority of meta-analyses suggest that there is no evidence for a causal relationship between insulin glargine and elevated cancer risk, although the studies have been controversially discussed. For α-glucosidase inhibitors and glinides, neutral or only few data upon cancer risk exist.

CONCLUSION

Although the molecular mechanisms are not fully understood, a potential risk of mitogenicity and tumour growth promotion cannot be excluded in case of several antidiabetic drug classes. However, more large-scale, randomized, well-designed clinical studies with especially long follow-up time periods are needed to get reliable answers to these safety issues.

Thyroid volume in patients with glucose metabolism disorders

OBJECTIVE

Thyroid volume and the prevalence of thyroid nodules are higher in patients with insulin resistance. A relationship between thyroid volume and glucose metabolism disorders (GMD) has not as yet been clarified. The present retrospective study aimed to investigate the association between GMD and thyroid volume.

SUBJECTS AND METHODS

We investigated the data of 2,630 patients who were evaluated for thyroid biopsy in our hospital. The study population included 602 patients with GMD, 554 patients with diabetes mellitus (DM) and 1,474 patients with normal glucose metabolism as a control group. We obtained the levels of serum thyroid stimulating hormone (TSH) and the thyroid volumes of those patients retrospectively.

RESULTS

The median ages for the control group, GMD group and DM group were 55 (15-91) years, 60 (27-97) years, and 65 (27-91) years respectively and there was a statistically significant difference between the groups with regard to age and gender (p<0.001). Levels of TSH were similar in all groups. The median total thyroid volumes for patients with DM and GMD were significantly higher than that of the control group [22.5 (3-202) mL, 20.2 (4-190) mL, and 19.2 (3-168) mL respectively, p≤0.001 for all parameters]. Also the median total thyroid volume for patients with DM was significantly higher than that of the GMD group (p<0.001). According to the correlation analysis, thyroid volume was significantly correlated with age (r=0.92, p<0.001) and TSH (r=0.435, p<0.001). Age, gender, TSH levels, GMD and DM diagnosis were independently correlated with thyroid volume.

CONCLUSION

The thyroid gland is one of the target tissues of metabolic disorders. We reported a positive correlation between GMD/type 2 DM and thyroid volume. Further controlled, prospective, randomized studies on this subject are required to gain more information.

Diabetes, prediabetes and the survival of nasopharyngeal carcinoma: a study of 5,860 patients

BACKGROUND

The incidence of diabetes is increasing. But the impact of diabetes and prediabetes on survival of patients with nasopharyngeal carcinoma (NPC) has received little evaluation.

METHODS

In a cohort of 5,860 patients, we compared the disease specific survival (DSS), locoregional relapse-free survival (LRFS) and distant metastasis-free survival (DMFS) of patients with diabetes, prediabetes and normoglycemia defined by pretreatment fasting plasma glucose (FPG) using Kaplan-Meier method, log-rank test and Cox proportional hazards model.

RESULTS

Comparing to normoglycemic patients, the diabetic and the prediabetic were generally older, fatter, had hypertension, heart diseases and hyperlipaemia and usually received radiotherapy alone. But both the diabetic and the prediabetic had similar DSS, LRFS and DMFS to normoglycemic patients, even adjusting for such important factors as age, gender, smoking, drinking, hypertension, heart diseases, body mass index, hyperlipaemia, titer of VCA-IgA and EA-IgA, pathology, T-stage, N-stage, chemotherapy and radiotherapy (P>0.05 for all). Additionally, the findings remained unchanged in sensitivity analysis by excluding patients with known diabetes history and in subgroups of the various factors.

CONCLUSIONS

The diabetic and prediabetic NPC patients had similar survival to normoglycemic NPC patients. These data, in the largest reported cohort, are the first to evaluate the association between diabetes, prediabetes and the survival in NPC. The findings are relevant to patient management and provided evidence of the effect on this disease exerted by comorbidities.