Diabetes and risk of incident cancer: a large population-based cohort study in Israel

Associations between Diabetes Mellitus and Selected Cancers

Cancer is one of the major causes of mortality and is the second leading cause of death. Diabetes mellitus is a serious and growing problem worldwide, and its prevalence continues to grow; it is the 12th leading cause of death. An association between diabetes mellitus and cancer has been suggested for more than 100 years. Diabetes is a common disease diagnosed among patients with cancer, and evidence indicates that approximately 8-18% of patients with cancer have diabetes, with investigations suggesting an association between diabetes and some particular cancers, increasing the risk for developing cancers such as pancreatic, liver, colon, breast, stomach, and a few others. Breast and colorectal cancers have increased from 20% to 30% and there is a 97% increased risk of intrahepatic cholangiocarcinoma or endometrial cancer. On the other hand, a number of cancers and cancer therapies increase the risk of diabetes mellitus. Complications due to diabetes in patients with cancer may influence the choice of cancer therapy. Unfortunately, the mechanisms of the associations between diabetes mellitus and cancer are still unknown. The aim of this review is to summarize the association of diabetes mellitus with selected cancers and update the evidence on the underlying mechanisms of this association.

Association between insulin resistance, metabolic syndrome and its components and lung cancer: a systematic review and meta-analysis

BACKGROUND

A growing body of evidence points to the association between insulin resistance (IR), metabolic syndrome (MetS) and its components and lung cancer incidence, but remains controversial and unknown.

METHODS

A systematic search was conducted through PubMed, Embase, Cochrane Library, the China National Knowledge Infrastructure (CNKI) and Wanfang databases for the corresponding studies. Each study reported the risk estimate and 95% confidence intervals (CI) for lung cancer, and a fixed effects model or random effects model was used for outcome.

RESULTS

We included 31 publications involving 6,589,383 people with 62,246 cases of lung cancer. Diabetes mellitus (DM) (RR = 1.11, 95% CI  1.06-1.16, P = 0.000) and IR (RR = 2.35, 95% CI  1.55-3.58, P = 0.000) showed a positive association with lung cancer risk. BMI (RR = 0.66, 95% CI  0.54-0.81, P = 0.000) and HDL-C (RR = 0.88, 95% CI  0.79-0.97, P = 0.010) were negatively correlated with lung cancer. MetS(RR = 0.99, 95% CI  0.90-1.09, P = 0.801), TC (RR = 0.93, 95% CI  0.81-1.06, P = 0.274), TG (RR = 0.99, 95% CI  0.88-1.12,P = 0.884), LDL-C (RR = 1.01, 95% CI  0.87-1.16, P = 0.928), hypertension (RR = 1.01, 95% CI  0.88-1.15, P = 0.928), FBG (RR = 1.02, 95% CI  0.92-1.13, P = 0.677) and obesity (RR = 1.11, 95% CI  0.92-1.35, P = 0.280) were not associated with lung cancer.

CONCLUSION

Our study showed that the risk of lung cancer is correlated with DM, IR, BMI, and HDL-C. Timely control of these metabolic disorders may have a positive effect on preventing lung cancer. Trial registration Our study has been registered in the Prospective Register of Systematic Reviews (PROSPERO), ID: CRD42023390710.

The effects of pathophysiological changes in Type-2 diabetic patients on thyroid dysfunction and nodular goiter development in Turkey

Objective: The prevalence of thyroid dysfunction is higher in patients with diabetes, and its diagnosis could cause better diabetes management. The purpose of the present study is to examine the impact of pathophysiological changes in patients with Type-2 diabetes on the frequency of thyroid dysfunction, thyroid autoimmunity, thyroid nodule, and thyroid cancer in Turkey. Methods: The study was conducted on a total of 3.276 patients with Type-2 diabetes who underwent thyroid tests and thyroid ultrasonography (US). The demographic characteristics, biochemical and hormonal values, thyroid US reports, and histopathology reports were collected from the patient's electronic records. Results: Thyroid autoimmunity positive TPOab 15.9% (n = 524) and/or positive TGab 9.9% (n = 327), the rate of positivity of both antibodies (TPOab + TGab) in the same patient, and total thyroid autoimmunity was found to be 32.57% (n=1067) in Type-2 diabetic patients. Thyroid dysfunction was detected in 18.3% (n = 602) of these patients. The distribution of thyroid dysfunction was 9.09% (n = 298) subclinical hypothyroidism, 4.1% (n = 135) clinical hypothyroidism, 3.1% (n = 102) subclinical hyperthyroidism, 2.0% (n = 67) clinical hyperthyroidism. Also, 67.9% (n = 2225) thyroid nodules, and 5% (n = 164) thyroid cancer were detected. Conclusion: Thyroid dysfunction was found to have increased in patients with Type-2 diabetes at significant levels.

Different types of diabetes mellitus and risk of thyroid cancer: A meta-analysis of cohort studies

Objective

Sex-specific thyroid cancer risk exists in patients diagnosed with diabetes mellitus (DM). However, thyroid cancer risk in different types of DM is still unclear. This meta-analysis aims to identify the real correlation between different types of DM and thyroid cancer risk in both sexes.

Methods

Studies were identified by an electronic search of PubMed, EMBASE, and Cochrane Library on 16 January 2022. A random-effects model was used to estimate the relative risks (RRs). The Cochran's Q and I2 statistics were computed to detect heterogeneity between studies.

Results

In comparison with non-DM counterparts, patients with DM had a 1.32-fold higher risk of thyroid cancer (95% CI, 1.22-1.44) with 1.26-fold (95% CI, 1.12-1.41) in men and 1.36-fold (95% CI, 1.22-1.52) in women, respectively. Subgroup analysis by the type of DM showed that the RR of thyroid cancer in patients with type 2 diabetes was 1.34 (95% CI, 1.17-1.53) in the study population with 1.32 (95% CI, 1.12-1.54) in men and 1.37 (95% CI, 1.12-1.68) in women, respectively; the RR of thyroid cancer was 1.30 (95% CI, 1.17-1.43) in patients with gestational diabetes; the risk of thyroid cancer in patients with type 1 diabetes was 1.51-fold in women but not in men. Although there were some heterogeneities, it did not affect the above results of this study.

Conclusion

This study indicates that, compared with non-DM individuals, patients with any type of DM have an elevated thyroid cancer risk. This positive correlation between type 2 diabetes and thyroid cancer risk exists in both men and women.

Systematic Review Registration

https://www.crd.york.ac.uk/prospero/, CRD42022304028.

Relationship between diabetes and risk of gastric cancer: A systematic review and meta-analysis of cohort studies

Patients with diabetes mellitus (DM) are at increased risk of developing several cancers; however, there is a lack of consensus on the relationship between gastric cancer (GC) and DM. This study aimed to explore the association between GC and DM based on the type and duration of DM. We searched nine databases from inception to December 1, 2021, and 40 cohort studies that evaluated the relationship between DM and the incidence of GC were included in this review. The summary relative ratios for the relationship of GC incidence with type 1 DM (T1DM) and type 2 DM (T2DM) were estimated using the fixed-effect and random-effect models, respectively. The risk of GC was 46% and 14% higher in individuals with T1DM and T2DM, respectively, than in those without diabetes. The risk of GC development in patients with diabetes showed a U-shape curve of change with DM duration. Our meta-analysis suggested that both T1DM and T2DM present a higher risk of GC development. The risk of GC may be influenced by the different time windows following the onset of diabetes. Future studies are required to explore the mechanism by which the duration of DM, antidiabetic medication use, and sex affect this association.

Impaired Glucose Metabolism, Anti-Diabetes Medications, and Risk of Thyroid Cancer

Simple Summary

An epidemiologic link exists between obesity, insulin resistance, diabetes, and some cancers, such as breast cancer and colon cancer. The prevalence of obesity and diabetes is increasing, and additional epidemiologic data suggest that there may be a link between obesity and risk of thyroid abnormalities. Factors that may link obesity and diabetes with thyroid proliferative disorders include elevated circulating levels of insulin, increased body fat, high blood sugars, and exogenous insulin use. However, mechanisms underlying associations of obesity, diabetes, and thyroid proliferative disorders are not yet fully understood. The present manuscript reviews and summarizes current evidence of mechanisms and epidemiologic associations of obesity, insulin resistance, and use of anti-diabetes medications with benign and malignant proliferative disorders of the thyroid.

Abstract

The prevalence of obesity is progressively increasing along with the potential high risk for insulin resistance and development of type 2 diabetes mellitus. Obesity is associated with increased risk of many malignancies, and hyperinsulinemia has been proposed to be a link between obesity and cancer development. The incidence of thyroid cancer is also increasing, making this cancer the most common endocrine malignancy. There is some evidence of associations between obesity, insulin resistance and/or diabetes with thyroid proliferative disorders, including thyroid cancer. However, the etiology of such an association has not been fully elucidated. The goal of the present work is to review the current knowledge on crosstalk between thyroid and glucose metabolic pathways and the effects of obesity, insulin resistance, diabetes, and anti-hyperglycemic medications on the risk of thyroid cancer development.

Effects of concomitant obesity and diabetes on the aggressiveness and outcomes of differentiated thyroid cancer patients

OBJECTIVE

Obesity and diabetes are the risk factors for cancer development including differentiated thyroid cancer (DTC). Contradictory accumulated data indicates the possible negative effects of obesity and hyperglyceamia as a factor for aggressiveness of DTC. The aim of the present study is to investigate the association of high body mass index (BMI) and presence of type 2 diabetes mellitus (T2DM) on the histological aggressiveness and clinical outcomes in DTC patients followed for over 4 years in a single center.

METHODS

Consequative 526 DTC patients who had undergone total thyroidectomy and/or radioactive iodine (RAI) ablation were reviewed retrospectively. Patients were divided into groups based on their BMI: normal weight, overweight, obese and also were evalauted in 3 groups presence of diabetes, prediabetes and nomoglyceamia. Histological aggressiveness of DTC at the time of diagnosis and clinical response at the time of last clinical visit were reassessed according to the criteria suggested by ATA 2015 guideline.

RESULTS

No differences in histopathologic features, risk of recurrence, cumulative dose of RAI ablation and prevalence of 131I avid metastatic disease were demonstrated among the groups both classified according to BMI and hyperglycemia. Mean of 3.4 year follow-up also showed no differences in the clinial repsonse to therapy and percentage of nonthyroid primary cancer in DTC patients.

CONCLUSION

In this retrospective study we demonstrated that obesity and T2DM have no additive effect on DTC aggressiveness and response to therapy. DTC patients with obesity and diabetes can be treated according to present guidelines without requirement for spesific attention.

[Diabetes mellitus and cancer: a system of insulin-like growth factors]

Diabetes mellitus and malignant tumors are among the most common and complex diseases. Epidemiological studies have shown a strong relationship between these pathologies. The causality of this relationship has not yet been unambiguously established, but a number of probable biological mechanisms have been proposed to explain it through the effects of hyperglycemia, hyperinsulinemia on the process of oncogenesis. An important role in this is played by the axis of insulin-like growth factors, their receptors and binding proteins (IGF / IGFR / IGFBP). The review provides data on the structural elements of the insulin / IGF / IGFR / IGFBP signaling axis and their internal relationships in diabetes mellitus and in the development of malignant tumors. Significant changes in the axis that occur during the formation of the diabetic environment prepare the background, which, under certain conditions, can lead to the stimulation or inhibition of tumor development. The considered signaling system, playing a significant role in the physiology of normal cells, often functions as a decisive factor in the survival of tumor cells, providing fine context-dependent regulation of many cellular processes associated with oncogenesis. However, despite many years of in-depth studies of the pathogenesis of diabetes mellitus and malignant tumors, the molecular mechanisms of the relationship between these pathologies are still largely unclear, and the internal heterogeneity of pathologies complicates research and interpretation of the results, leaving many questions.

The Relationship between Diabetes Mellitus and Gastric Cancer and the Potential Benefits of Metformin: An Extensive Review of the Literature

The objective of this review is to summarize the findings of published research that investigated the relationship between diabetes mellitus and gastric cancer (GCa) and the potential benefits of metformin on GCa. Related literature has been extensively reviewed, and findings from studies investigating the relationship between diabetes mellitus and GCa suggest that hyperglycemia, hyperinsulinemia and insulin resistance are closely related to the development of GCa. Although not supported by all, most observational studies suggest an increased risk of GCa in patients with type 2 diabetes mellitus, especially in women and in Asian populations. Incidence of second primary malignancy diagnosed after GCa is significantly higher in diabetes patients. Diabetes patients with GCa may have more complications after gastrectomy or chemotherapy and they may have a poorer prognosis than patients with GCa but without diabetes mellitus. However, glycemic control may improve in the diabetes patients with GCa after receiving gastrectomy, especially after procedures that bypass the duodenum and proximal jejunum, such as Roux-en-Y gastric bypass or Billroth II reconstruction. The potential links between diabetes mellitus and GCa may involve the interactions with shared risk factors (e.g., obesity, hyperglycemia, hyperinsulinemia, insulin resistance, high salt intake, smoking, etc.), Helicobacter pylori (HP) infection, medications (e.g., insulin, metformin, statins, aspirin, proton pump inhibitors, antibiotics, etc.) and comorbidities (e.g., hypertension, dyslipidemia, vascular complications, heart failure, renal failure, etc.). With regards to the potential benefits of metformin on GCa, results of most observational studies suggest a reduced risk of GCa associated with metformin use in patients with T2DM, which can be supported by evidence derived from many in vitro and animal studies. Metformin use may also reduce the risk of HP infection, an important risk factor of GCa. In patients with GCa, metformin users may have improved survival and reduced recurrence. More studies are required to clarify the pathological subtypes/anatomical sites of GCa associated with type 2 diabetes mellitus or prevented by metformin, to confirm whether GCa risk can also be increased in patients with type 1 diabetes mellitus and to explore the possible role of gastric microbiota in the development of GCa.

Genome-wide scanning for CHD1L gene in papillary thyroid carcinoma complicated with type 2 diabetes mellitus

PURPOSE

Papillary thyroid carcinoma (PTC) represents the most common subtype of thyroid cancer (TC). This study was set out to explore the potential effect of CHD1L on PTC and type 2 diabetes mellitus (T2DM).

METHODS

We searched for T2DM susceptibility genes through the GWAS database and obtained T2DM-related differentially expressed gene from the GEO database. The expression and clinical data of TC and normal samples were collated from the TCGA database. Receiver operating characteristic (ROC) curve analysis was subsequently applied to assess the sensitivity and specificity of the CHD1L for the diagnosis of PTC. The MCP-counter package in R language was then utilized to generate immune cell score to evaluate the relationship between CHD1L expression and immune cells. Then, we performed functional enrichment analysis of co-expressed genes and DEGs to determine significantly enriched GO terms and KEGG to predict the potential functions of CHD1L in PTC samples and T2DM adipose tissue.

RESULTS

From two genes (ABCB9, CHD1L) were identified to be DEGs (p < 1 * 10^-5) that exerted effects on survival (HR > 1, p < 0.05) in PTC and served as T2DM susceptibility genes. The gene expression matrix-based scoring of immunocytes suggested that PTC samples with high and low CHD1L expression presented with significant differences in the tumor microenvironment (TME). The enrichment analysis of CHD1L co-expressed genes and DEGs suggested that CHD1L was involved in multiple pathways to regulate the development of PTC. Among them, Kaposi sarcoma-associated herpesvirus infection, salmonella infection and TNF signaling pathways were highlighted as the three most relevant pathways. GSEA analysis, employed to analyze the genome dataset of PTC samples and T2DM adipose tissue presenting with high and low expression groups of CHD1L, suggests that these differential genes are related to chemokine signaling pathway, leukocyte transendothelial migration and TCELL receptor signaling pathway.

CONCLUSION

CHD1L may potentially serve as an early diagnostic biomarker for PTC, and a target of immunotherapy for PTC and T2DM.

Increased Risk of Hospitalization for Pancreatic Cancer in the First 8 Years after a Gestational Diabetes Mellitus regardless of Subsequent Type 2 Diabetes: A Nationwide Population-Based Study

Simple Summary

Pancreatic cancer is one of the cancers with the highest mortality rate which is most often attributed to late diagnosis. The identification of risk factors is therefore important. While gestational diabetes also shares mechanisms of action with diabetes mellitus, several studies have provided hypotheses that could explain the pathophysiology of the link between diabetes mellitus and risk of pancreatic cancer. Accordingly, the aim of our study was to determine the risk of developing pancreatic cancer in women with a history of gestational diabetes from a quasi-exhaustive national medico-administrative database for deliveries in France. We included 1,368,755 women in our study. We showed that gestational diabetes was significantly associated with a greater risk of pancreatic cancer, regardless of subsequent type 2 diabetes. Our results suggest a better follow-up of patients after a gestational diabetes in order to identify high-risk profiles of developing more serious conditions, such as pancreatic cancer.

Abstract

The aim of this large retrospective cohort study was to use a quasi-exhaustive national medico-administrative database of deliveries in France to determine the risk of developing pancreatic cancer (PC) in women with a history of gestational diabetes mellitus (GDM). This nationwide population-based study included women aged 14–55 who gave birth between 1st January 2008 and 31 December 2009. The women were followed-up epidemiologically for eight years. Survival analyses using Cox regression models, adjusted for age, subsequent type 2 diabetes, and tobacco consumption, were performed on the time to occurrence of hospitalization for PC. The onset of GDM, tobacco consumption and subsequent type 2 diabetes were considered as time-dependent variables. Among 1,352,560 women included, 95,314 had a history of GDM (7.05%) and 126 women were hospitalized for PC (0.01%). Over the eight years of follow-up, GDM was significantly associated with a higher risk of hospitalization with PC in the first Cox regression model adjusted for age and subsequent type 2 diabetes (HR = 1.81 95% CI [1.06–3.10]). The second Cox regression model adjusted for the same covariates, plus tobacco consumption, showed that GDM was still significantly associated with a higher risk of hospitalization for PC with nearly the same estimated risk (HR = 1.77 95% CI [1.03–3.03]). Gestational diabetes was significantly associated with a greater risk of hospital admission for pancreatic cancer within eight years, regardless of subsequent type 2 diabetes.

Diabetes mellitus and the risk of ovarian cancer: a systematic review and meta-analysis of cohort and case-control studies

OBJECTIVE

Emerging evidence from observational studies (cohort and case-control studies) suggests that a history of diabetes mellitus (DM) has been linked to increased risk of ovarian cancer (OC), but the association between them remains inconclusive. The aim of this systematic review and meta-analysis of observational studies was to clarify this association.

DESIGN

Systematic review and meta-analysis.

METHODS

We searched PubMed, Embase and the Cochrane library databases published from the inception through 9 April 2020 without language restriction. Observational studies that evaluated the correlation between DM and the incidence of OC were included in our study. Relative risk (RR) with 95% CI was pooled by use of a random-effects model.

RESULTS

A total of 36 epidemiological articles, including 9 case-control and 27 cohort studies, were finally enrolled, consisting of 14 496 incident cases of OC. Synthesised RRs of developing OC by history of DM were 1.20 (95% CI=1.10 to 1.31) for all eligible studies, 1.08 (95% CI=0.77 to 1.53) for case-control studies and 1.22 (95% CI=1.11 to 1.33) for cohort studies. The above-mentioned positive association persisted across most of subgroup analyses, whereas it was not significant among studies from North American and European countries, level of unadjusted, and patients with low-quality and gestational DM group. The cumulative meta-analysis and sensitivity analysis showed pooled effect was stable and reliable, and no apparent publication bias was identified in this study.

CONCLUSIONS

Our study found weaker but still association between DM and OC risk. However, further well-designed prospective studies that control for potential confounders are warranted.

Distinct trajectories in HbA1c are associated with different all-cause mortality and morbidity in newly diagnosed patients with type 2 diabetes

AIMS

To identify trajectories of long-term HbA1c levels and examine associations with subsequent risk for morbidity and mortality.

METHODS

We conducted a longitudinal follow-up among 27,724 patients, newly diagnosed with type 2 diabetes, in a large healthcare organization. We identified trajectories of long-term HbA1c levels during the first 5 years post diabetes onset to examine associations with subsequent risk for morbidity and all-cause mortality.

RESULTS

We identified two HbA1c trajectories; the "Steady-plateau HbA1c trajectory" in 93% of patients and a "Sharp-incline HbA1c trajectory" in 7% of patients. When compared to the steady-plateau group, patients in the sharp-incline group were younger, male, from a lower socio-economic background, and higher levels of HbA1c at baseline. Patients in the sharp-incline trajectory had a HR = 1.83 (95%CI: 1.58-2.12) for all-cause mortality, HR = 1.99 (95%CI: 1.74-2.27) for cardiovascular disease, and HR = 1.68 (95%CI: 1.51-1.86) for renal disease, compared to patients in the steady-plateau trajectory.

CONCLUSIONS

Patients in the sharp-incline trajectory had a higher risk for all-cause mortality, cardiovascular disease, and renal disease, compared to patients in the steady-plateau trajectory. Estimation of HbA1c variability in the first years of diagnosis may be a useful indicator of those patients at high risk for diabetes related complications.

Association between diabetes mellitus and lung cancer: Meta-analysis

BACKGROUND

This study aimed to summarize the association between diabetes mellitus (DM) and the incidence of lung cancer using a meta-analysis of cohort studies.

MATERIALS AND METHODS

We systematically searched PubMed, Embase and the Cochrane Library to identify potential cohort studies. Relative risk (RR) was used to calculate the association between DM and the risk of lung cancer. Subgroup analysis, sensitivity analysis and test for publication bias were performed. Twenty cohort studies were selected.

RESULTS

The participants with DM showed little or no significant effect on the risk of lung cancer (RR: 1.10; 95% CI: 0.99-1.23; P = .087). DM was not associated with the risk of lung cancer in men (RR: 1.11; 95%CI: 0.92-1.35; P = .270), but a significant association was observed in women (RR: 1.18; 95%CI: 1.10-1.28; P < .001). Subgroup analysis suggested that smoker status was confounding variables that could bias the relationship between DM and the incidence of lung cancer.

CONCLUSIONS

This meta-analysis suggests that DM has no significant impact on the incidence of lung cancer in men but has a harmful effect on women.

Relations of prediabetes and type 2 diabetes to the thyroid cancer

OBJECTIVE

Patients with type 2 diabetes (T2DM) generally experience a higher incidence of cancer. However, the association between T2DM and thyroid cancer is inconclusive.

METHODS

Case-control prospective study, 722 patients were screened for T2DM and prediabetes (PDM) and underwent thyroid ultrasound and biochemical tests. The patients were assigned to groups of PDM (n=55), T2DM (n=79) or a non-diabetes group (NDM) (n=588). Fine needle aspiration biopsy was carried out in 263 patients. Histological examinations were done for 109 patients after surgery, with findings of 52 benign (BS) and 57 malignant tumors (MS).

RESULTS

33 % of patients with T2DM and especially PDM were newly diagnosed by our screening: 6.5 % with T2DM and 72 % with PDM, respectively. The percentage of thyroid cancers did not significantly differ between the groups (χ2 test=0.461; p=0.794). Relevant positive thyroid predictors for T2DM (t-statistic=25.87; p<0.01) and PDM (21.69; p<0.01) contrary to NDM (-26.9; p<0.01) were thyroid volume (4.79; p<0.01), thyroid nodule volume (3.25; p<0.01) and multinodular thyroid gland (4.83; p<0.01), while negative relevant predictors included the occurrence of autoimmune thyroid disease (AITD) (-2.01; p<0.05).

CONCLUSION

In general, we did not observe an increased risk for thyroid cancer in the diabetic and prediabetic groups in comparison to controls, in spite of well-established increased risk for other malignancies. Structural and benign changes such as larger and multinodular thyroid glands, in comparison to autoimmune thyroid disease, are present more often in diabetics.

Diabetes and cancer: A comprehensive review

Diabetes mellitus (DM) is a common worldwide endocrine disorder characterized by hyperglycemia resulting from defects in insulin secretion and insulin action or both. A number of clinical studies have investigated diabetes and its causal relation with neoplasm. Several epidemiological studies have found that diabetic patients have an increased risk of different types of cancers, for example liver, pancreas, gastric (stomach), colorectum, kidney, and breast, and it is predicted that hyperglycemic state observed in diabetic milieu enhances the cancer risk in prediabetic and diabetic individuals. To explore the strength of evidence and biases in the claimed associations between type 2 DM (T2DM) and risk of developing cancer, an umbrella review of the evidence across published meta-analyses or systematic reviews is performed. The concurrence of T2DM with the growing burden of cancer globally has generated interest in defining the epidemiological and biological relationships between these medical conditions. Through this review, it was found that diabetes could be related to cancer. Yet, the results from most of the studies are obscure and conflicting and need a robust research so that the link between diabetes and cancer could be firmly and impeccably documented.

Diabetes Increases Risk of Gastric Cancer After Helicobacter pylori Eradication: A Territory-Wide Study With Propensity Score Analysis

OBJECTIVE

Whether diabetes mellitus (DM) increases risk of gastric cancer (GC) remains controversial because of inadequate adjustments for important risk factors, including Helicobacter pylori (HP) infection status, concomitant medication use, and cancer site. We investigated whether type 2 DM increased risk of GC in patients after they received treatment for HP infection.

RESEARCH DESIGN AND METHODS

This was a territory-wide cohort study of patients aged ≥45 years who had received clarithromycin-based triple therapy for HP infection between 2003 and 2012 in Hong Kong. Data were retrieved from a public electronic health database. Observation started from receipt of therapy for HP infection to GC diagnosis, death, or the end of the study (December 2015). Exclusion criteria included type 1 DM, GC diagnosed within the 1st year of HP therapy, prior GC or gastrectomy, and retreatment for HP infection. The adjusted hazard ratio (aHR) of GC with type 2 DM was calculated by using a Cox model that adjusted for 20 covariates (age, sex, comorbidities, and medications) through propensity score regression.

RESULTS

During a median follow-up of 7.1 years (interquartile range 4.8-9.3 years), 153 of 46,460 patients (0.33%) developed GC at a median age of 72.4 years. Type 2 DM was associated with an increased risk of GC (aHR 1.73 [95% CI 1.08-2.79]). Stratified analysis showed an increase in risk for cardia cancer only (aHR 3.40 [95% CI 1.45-7.97]) and in those with suboptimal DM control (time-weighted mean HbA_1c ≥6.0% [42 mmol/mol]; aHR 1.68 [95% CI 1.07-2.63]).

CONCLUSIONS

Type 2 DM is associated with an increased risk of GC among patients in whom HP was eradicated, in particular gastric cardia cancer and in those with suboptimal DM control.

Prediabetes and diabetes in relation to risk of gastric adenocarcinoma

BACKGROUND

Whether prediabetes or diabetes increases the risk of gastric adenocarcinoma is not clear.

METHODS

This cohort study included 111,198 participants in the Northern Swedish Health and Disease Study. The participants were followed up from November 1985 to April 2017. The exposure to prediabetes or diabetes was assessed by oral glucose tolerance tests and self-reports. The incidence of the outcome gastric adenocarcinoma was identified from the Swedish Cancer Registry. Multivariable Cox regressions were used to analyse the associations between prediabetes or diabetes and the risk of gastric adenocarcinoma, providing hazard ratios (HR) with 95% confidence intervals (CI), with adjustment for sex, age, calendar year, body mass index, tobacco smoking and education level.

RESULTS

Compared with normoglycaemic participants, the risk of gastric adenocarcinoma was not increased among participants with prediabetes (HR 1.07, 95% CI 0.79-1.44), diabetes (HR 0.77, 95% CI 0.46-1.29) or any of these exposures (HR 0.96, 95% CI 0.73-1.27). No associations were identified between prediabetes or diabetes and the risk of gastric adenocarcinoma in stratified analyses or in analyses separating cardia and non-cardia gastric adenocarcinoma.

CONCLUSIONS

This study does not support the hypothesis that prediabetes or diabetes increases the risk of gastric adenocarcinoma.

Adherence to quality of care measurements among 58,182 patients with new onset diabetes and its association with mortality

OBJECTIVES

Disease registry for diabetes care encourages transparency and benchmarking of quality of care (QoC) measurements for all service providers and seems to improve diabetes care. This study evaluate changes over time in QoC measurement performance in a large diabetes registry among newly diagnosed diabetics and it association with mortality.

METHODS

Retrospective cohort study of patients in a large health maintenance organization diabetes registry from years 2000 to 2013. We identified 58,182 patients diagnosed with diabetes from 2000-2008 and examined the level of performance for seven QoC measurements (HbA1c, LDL, albumin-creatinine-ratio, fundus/foot examinations, BMI and Blood-pressure) at diagnosis year. We also searched data regarding visits to dietitians or endocrinologists, and purchase of diabetes and statin medications. We used Mantel-Haenszel's χ2 test to assess QoC performance and mortality rate by calendar year of entry into the registry, and Cox regression to calculate hazard ratios (HRs) and 95% confidence intervals (CIs) for all-cause mortality up to 5 years from diagnosis adjusted for age, gender, socio-economic status and comorbidities.

RESULTS

The total QoC measurements improved from a mean of 2.71 tests performed in 2000 to 5.69 in 2008 (p<0.001). The mortality rate dropped from 7.7% in 2000 to 5.7% in 2008 (p<0.001). Patients with more QoC measurements performance who visited a dietitian and purchased statin medications had a lower mortality risk (HRs (95% CIs) 0.89 (0.87-0.92), 0.83 (0.76-0.91) and 0.70(0.65-0.75) respectively). Visits to endocrinologists and purchases of oral diabetes medication and insulin were associated with a higher risk of mortality (HRs (95% CIs) 1.20(1.07-1.35), 1.35(1.26-1.46) and 3.36(2.92-3.87) respectively).

CONCLUSION

Performance of QoC measurements including visiting a dietitian and purchase of statin medications were associated with lower mortality in patients with diabetes. It may be that the early active involvement of the patients in their care plays a protective role in long term mortality.

Evaluation of the Association between Gestational Diabetes Mellitus at First Pregnancy and Cancer within 10 Years Postpartum Using National Health Insurance Data in South Korea

This study aims to evaluate the association between gestational diabetes mellitus (GDM) at first pregnancy and the incidence of cancer within 10 years postpartum. We used customized health information data from the National Health Insurance Corporation (NHIC). This retrospective cohort study included data from women who were not previously diagnosed with diabetes or any kind of malignancy in the National Health Screening Examination through the NHIC during 2002–2003, and only women who had their first delivery between 2004 and 2005 was included. Follow-up cancer diagnosis was carried out up until 2015. Among the 102,900 primiparous women, 4970 (4.83%) were diagnosed with GDM. During 10 year total follow-up period, 6569 (6.38%) cases of primary cancer were identified. The incidence of cancer was higher in women with GDM and the most common type of cancer was thyroid cancer, followed by breast cancer. On the basis of survival analysis, we adopted the Cox proportional hazards model and found that GDM was positively associated with cancer, particularly in thyroid cancer (HR: 1.27, 95% CI: 1.054–1.532, p = 0.012). However, the incidence of other malignancies (including ovarian and breast cancers) were not significantly associated with GDM, though they did show positive trends. Our findings suggest that GDM is associated with the incidence of cancer, particular thyroid cancer.

Adiposity, history of diabetes, and risk of pancreatic cancer in postmenopausal women

PURPOSE

The purpose of this study was to examine the association of type II diabetes and anthropometric variables with risk of pancreatic cancer among postmenopausal women.

METHODS

Weight, height, waist circumference, and hip circumference were measured by trained personnel, whereas history of diabetes and weight earlier in life were self-reported. Pancreatic cancer was ascertained via central review of medical records by physician adjudicators. After exclusions, 1045 cases of pancreatic cancer were diagnosed among 156,218 women over a median follow-up of approximately 18 years. Cox proportional hazards models were used to estimate the associations of study factors with pancreatic cancer risk.

RESULTS

Diabetes (hazards ratio (HR): 1.30; 95% confidence intervals (95% CI): 1.01-1.66), and in particular, waist circumference, waist-to-hip ratio, and waist-to-height ratio showed positive associations with pancreatic cancer risk (HRs for highest vs. lowest level 1.38; 95% CI: 1.14-1.66, 1.40; 1.17-1.68; and 1.36; 1.13-1.64, respectively). Body mass index at the baseline showed only a borderline positive association with risk (HR: 1.21; 95% CI: 0.97-1.51). Body mass index at age 50 years, but not at ages 18 and 35 years, was also associated with increased pancreatic cancer risk.

CONCLUSIONS

In this study of postmenopausal women, central adiposity and, to a lesser extent, general adiposity and a history of diabetes, were associated with increased pancreatic cancer risk.

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.

The association between thyroid cancer and insulin resistance, metabolic syndrome and its components: A systematic review and meta-analysis

BACKGROUND

Thyroid cancer is rapidly increasing in incidence worldwide in the past several decades, same as the incidence of metabolic syndrome. We performed a system review and meta-analysis of the association between metabolic syndrome, its components and insulin resistance and thyroid cancer incidence.

METHODS

We searched several computer-assisted databases PUBMED, EMBASE and ISI Web of Science to identify studies published before 31st January 2018. Every study must report either risk estimates of thyroid cancer incidence with 95% confidence interval (CI) or related data can speculate. Two investigators independently identified eligible studies and extracted data. Evaluating the summaries of relative risk estimates use both fixed and random effects methods.

RESULTS

We found 42 articles met the inclusion criteria of this review. There is an increased risk for thyroid cancer for patients with insulin resistance (relative risk [RR] = 1.59, 95%confidence interval [CI] = 1.12-2.27, P = 0.01), dysglycemia (RR = 1.40, 95%CI = 1.15-1.70,P < 0.001), high BMI (RR = 1.35,95%CI = 1.23-1.48,P < 0.001) and hypertension(RR = 1.34,95%CI = 1.22-1.47, p < 0.001). However, patients with dyslipidemia, both total cholesterol (RR = 1.09, 95%CI = 0.98-1.21, P = 0.13) and triglyceride (RR = 1.01, 95%CI = 0.91-1.12, P = 0.82) was not associated with thyroid cancer.

CONCLUSIONS

Our meta-analysis showed Insulin Resistance, dysglycemia, high BMI and hypertension significantly increased the thyroid cancer risk. These results may help identify people with high risk of thyroid cancer and change to healthy life style.

Difference in prostate cancer incidence around sixty years: effects of age and metabolic diseases

We examined the risk of prostate cancer in the Korean population stratified on the basis of age group and risk based on metabolic diseases, using National Health Insurance System (NHIS) data. Of the 51,827,813 people from the NHIS data in 2015, 10,879,591 men without prostate cancer who underwent a health examination were analyzed. The risk of prostate cancer was analyzed with stratification by age. Multivariate-adjusted Cox regression analysis was conducted to examine the association between prostate cancer and metabolic diseases by age groups. The risk of prostate cancer increased continuously with age and 59 years may be a point of inflection. The hazard ratio (HR) of prostate cancer development rose sharply as that age point passed. The population with metabolic diseases was more likely to develop prostate cancer than the population without any of these components. In addition, the incidence rate ratio (IRR) decreased from the youngest age group to the age group comprising 55-59 year olds. Beyond this age group, there was a plateau. The relative risk for prostate cancer associated with metabolic diseases also showed divergent associations with age. The risk of prostate cancer increased continuously with age and the peak Youden index was at 59 years. The relative risk for prostate cancer according to metabolic diseases also showed divergent associations beyond 59 years of age. Therefore, setting the age threshold at 59 years would improve the present clinical risk stratification for prostate cancer in Korea.

Diabetes mellitus and the risk of gastrointestinal cancer in women compared with men: a meta-analysis of cohort studies

Background

The increasing epidemic proportions of diabetes mellitus (DM) are a major cause of premature illness and death. However, whether DM confers the same excess risk of gastrointestinal cancer for women as it does for men remains controversial. The purpose of this study was to estimate the relation between DM and gastrointestinal cancer in women compared with men after accounting for other major risk factors based on cohort studies.

Methods

We performed a meta-analysis of cohort studies published through May 2017 from PubMed, Embase, and the Cochrane Library. Studies with cohort designs were stratified by sex and reported the relation between DM and esophageal cancer (EC), gastric cancer (GC), colorectal cancer (CRC), colon cancer (CC), rectal cancer (RC), hepatocellular carcinoma (HCC), or pancreatic cancer (PC) risk. The ratio of relative risk (RRR) between men and women was employed to measure the sex differences in the relation between DM and gastrointestinal cancer with a random effects model with inverse variance weighting.

Results

We included 38 cohort studies reporting data on 18,060,698 individuals. The pooled RRR indicated DM women was associated with an increased risk of GC (RRR: 1.14; 95%CI: 1.06–1.22; p < 0.001), while the risk of HCC was lower (RRR: 0.88; 95%CI: 0.79–0.99; p = 0.031) as compared with DM men. Further, there was no evidence of sex differences in the RRR between participants who had DM compared with those without DM for EC (p = 0.068), CRC (p = 0.618), and PC (p = 0.976). In addition, the pooled RRR showed a statistically significant association between DM and the risk of CC in women compared with men (RRR: 0.93; 95%CI: 0.86–1.00; p = 0.050), and there was no evidence of sex differences for RC among participants with DM compared to those without DM (p = 0.648). Finally, the sex differences of the comparison between DM and non-DM for gastrointestinal cancer risk at different sites were variable after stratification for different effect estimates.

Conclusions

The findings of this study suggested female-to-male RRR of DM was increased for GC, while reduced for HCC and CC. However, there were no sex differences for the relation between DM and the risk of EC, CRC, PC, and RC.

Electronic supplementary material

The online version of this article (10.1186/s12885-018-4351-4) contains supplementary material, which is available to authorized users.

Diabetes mellitus and the risk of gastric cancer: a meta-analysis of cohort studies

Studies examining the relationship between diabetes mellitus (DM) and the risk of gastric cancer incidence or gastric cancer mortality have produced inconsistent results. The purpose of this study was to evaluate the evidence regarding the relationship between DM and subsequent gastric cancer incidence or gastric cancer mortality risk on the basis of cohort studies. A systematic search of articles in PubMed, EmBase, the Cochrane Library, and reference lists was conducted to identify relevant literature. Twenty-two cohort studies reporting data on 8,559,861 participants were included in the study. Overall, participants with DM had little or no change in the risk of gastric cancer, or gastric cancer mortality. There was no evidence of difference in the RR for gastric cancer between men and women. Participants with DM had a non-significant trend towards an increased risk of gastric cancer mortality in men. There was no significant difference between men and women for this relationship. Finally, although subgroup analysis suggested DM was associated with a significant impact on gastric cancer incidence and gastric cancer mortality risk in several specific populations, a significance based on gender difference was not observed. In conclusion, DM might increase the risk of gastric cancer in men when the study used standard incidence/mortality ratio as effect estimate. Further, DM were associated with higher risk of gastric cancer mortality in men if the mean age at baseline less than 55.0 years, used RR or HR as effect estimate, the study adjusted smoking or not, and the study not adjusted alcohol drinking.

Association of diabetes mellitus with thyroid cancer risk: A meta-analysis of cohort studies

BACKGROUND

Diabetes mellitus (DM) is inconsistently associated with thyroid cancer risk. The purpose of this study was to summarize findings from cohort studies regarding the strength of the association of DM with subsequent thyroid cancer risk.

METHODS

Electronic searches were performed in PubMed, EmBase, and the Cochrane Library to identify studies from inception to July 2016. Cohort studies reporting risk estimates with 95% confidence intervals (CIs) of thyroid cancer in DM and non-DM patients were included. A random-effects meta-analysis was performed to the risk of thyroid cancer in DM compared with non-DM participants.

RESULTS

Sixteen cohort studies were included, with a total of 10,725,884 individuals. These studies reported a total of 8032 cases of thyroid cancer. Overall, DM was associated with an increased risk of thyroid cancer (relative risk [RR], 1.20; 95% CI, 1.09-1.33; P < .001). Further, there was no significant difference was found between DM and non-DM for the risk of thyroid cancer in men (RR, 1.14; 95% CI, 1.00-1.30; P = .057), while a significant correlation was found in a pooled analysis in women (RR, 1.11; 95% CI, 1.06-1.17; P < .001). Finally, subgroup analyses suggested that country and mean age might correlate with the relationship between DM and the risk of thyroid cancer.

CONCLUSION

This study suggested that patients with DM have significantly increased risk of thyroid cancer compared nondiabetics. This positive association was prominent in women, and not significant in men. Further large-scale studies are required to verify the nature of the association, which should be evaluated in specific subpopulations.

Diabetes mellitus and risk of ovarian cancer. A systematic review and meta-analysis of 15 cohort studies

AIM

Diabetes mellitus (DM) is hypothesized to be associated with an increased risk of ovarian cancer (OC), but current evidences are inconsistent. We aimed to further study this association.

METHODS

PubMed, EMBASE, Web of Science, and Scopus were searched for eligible articles. After descriptive summary of the data, a random-effects model was applied in quantitative synthesis. Subgroup analysis was performed by study locales and settings, and sensitivity analysis was conducted based on restrictive selection criteria. Funnel plots and the Egger's test were used to assess publication bias. Statistical heterogeneity in meta-analysis was assessed by the P value derived from the Cochrane Q statistic and I-squared value.

RESULTS

Fourteen articles involving data of 15 cohort studies were included for our research. Overall, 17 risk ratios (RRs) were synthesized and yielded a pooled RR of 1.32 (95%CI: 1.14-1.52, P_Cochrane<0.001, I²=79.8%). Thirteen RRs were synthesized for type 2DM, and the pooled RR was 1.24 (95%CI: 1.06-1.44, P_Cochrane<0.001, I²=81.8%). Four RRs were synthesized for type 1DM, and the result was significant (RR: 1.83, 95%CI: 1.21-2.78, P_Cochrane=0.080, I²=55.7%). Results of sensitivity analysis suggested the robustness of a positive association between DM and OC risk, and subgroup analysis demonstrated that the association between DM and OC was much more substantial among Asia population. No publication bias was identified in meta-analysis.

CONCLUSION

Our study suggests there is a moderate relative increase in the risk of OC among DM patients. Future studies should investigate the effect of duration of DM and anti-diabetes intervention to OC risk.

Association between diabetes mellitus and subsequent ovarian cancer in women: A systematic review and meta-analysis of cohort studies

Epidemiologic studies have suggested that diabetes mellitus (DM) might be associated with risk of ovarian cancer; however, the results have been inconsistent. The aim of this study was to determine the relationship between DM and the incidence of ovarian cancer on the basis of cohort studies.Relevant studies from PubMed, Embase, and the Cochrane Library until September 2016 were collected. The summary risk ratio (RR) was used as the effect measure in a random effects model. Sensitivity analysis, subgroup analysis, and calculation of publication bias were conducted.Thirteen articles including 14 cohorts comprising a total of 3708, 313 women and reporting 5534 cases of ovarian cancer were included. The summary RR suggested that patients with DM had a higher risk of ovarian cancer than patients without DM (RR: 1.19; 95% confidence interval: 1.06-1.34; P = .004), and no evidence of publication bias was found. The subgroup analysis indicated a higher incidence of ovarian cancer in patients with DM in studies published after 2010, studies not conducted in Europe or the United States, studies that did not adjust for body mass index or smoking status, and studies with lower Newcastle-Ottawa Scale scores.The present findings indicated that DM is a risk factor for ovarian cancer, and future large-scale epidemiologic studies should be performed to evaluate this relation in specific populations.

Expression characteristics of proteins of IGF-1R, p-Akt, and survivin in papillary thyroid carcinoma patients with type 2 diabetes mellitus

Type 2 diabetes mellitus (T2DM) is related to increased risk of papillary thyroid carcinoma (PTC). Insulin-like growth factor-1 receptor (IGF-1R) is increased in patients with T2DM. The increased IGF-1R may be responsible for the development of PTC. In this study, we investigated the expression of phosphorylation of Akt (p-Akt)/survivin pathway activated by IGF-1R in PTC subjects with and without diabetes.Clinicopathological data of 20 PTC patients with T2DM were retrospectively analyzed and compared with those of 21 PTC subjects without diabetes. Meanwhile, IGF-1R, p-Akt, and survivin expressions of PTC tissues were detected by immunohistochemical staining.The immunohistochemical results found that the expression level of IGF-1R was significantly higher in diabetic PTC patients than that in nondiabetic PTC patients (P < 0.05). However, no significant differences of p-Akt and survivin expression were found between PTC patients with T2DM and PTC patients without T2DM. In addition, among 20 PTC patients with T2DM, subgroup analysis showed that the ratio of tumor size >10 mm was significantly higher in IGF-1R moderate to strong expression group than that in IGF-1R negative to weak expression group (P < 0.05).IGF-1R expression level was higher in PTC patients with T2DM, and the increased IGF-1R expression was associated with lager tumor size. IGF-1R may play an important role in carcinogenesis and tumor growth in PTC patients with T2DM.

Insulin Resistance: Any Role in the Changing Epidemiology of Thyroid Cancer?

In the past few decades, the incidence of thyroid cancer (TC), namely of its papillary hystotype (PTC), has shown a steady increase worldwide, which has been attributed at least in part to the increasing diagnosis of early stage tumors. However, some evidence suggests that environmental and lifestyle factors can also play a role. Among the potential risk factors involved in the changing epidemiology of TC, particular attention has been drawn to insulin-resistance and related metabolic disorders, such as obesity, type 2 diabetes, and metabolic syndrome, which have been also rapidly increasing worldwide due to widespread dietary and lifestyle changes. In accordance with this possibility, various epidemiological studies have indeed gathered substantial evidence that insulin resistance-related metabolic disorders might be associated with an increased TC risk either through hyperinsulinemia or by affecting other TC risk factors including iodine deficiency, elevated thyroid stimulating hormone, estrogen-dependent signaling, chronic autoimmune thyroiditis, and others. This review summarizes the current literature evaluating the relationship between metabolic disorders characterized by insulin resistance and the risk for TC as well as the possible underlying mechanisms. The potential implications of such association in TC prevention and therapy are discussed.

Type 2 diabetes and gender differences in liver cancer by considering different confounding factors: a meta-analysis of cohort studies

PURPOSE

Questions remain uncertainty regarding the gender differences in the relationship between type 2 diabetes (T2DM) and liver cancer risk. By considering several confounding factors, we aimed to identify this issue according to a meta-analysis of cohort studies.

METHODS

We searched EMBASE and MEDLINE for studies on the association between T2DM and risk of liver cancer up to November 30, 2014. A random-effects model was performed to calculate summary relative risks (SRRs) with corresponding 95% confidence intervals (CIs).

RESULTS

A total of 24 cohort studies (including more than 20,000 liver cancer cases) were recruited. T2DM was associated with an elevated liver cancer incidence in both men (SRR = 2.16; 95% CI, 1.74-2.69) and women (SRR = 1.85; 95% CI, 1.40-2.44). Stratified analyses showed that the risk associations were significantly stronger in non-Asian than those in Asian for both men and women. Both tobacco smoking and body mass index were significant confounding factors for the T2DM-liver cancer association in men, whereas alcohol use was not the case. The SRR estimates of liver cancer mortality with T2DM were statistically significant in both men and women (men: SRR = 2.26; 95% CI, 1.60-3.19 and women: SRR = 2.01; 95% CI, 1.45-2.74).

CONCLUSIONS

Results of this meta-analysis indicate that the T2DM-liver cancer correlation is confounded by smoking and body mass index in both men and women. Results also suggest a significantly stronger T2DM-liver cancer correlation in non-Asian than that in Asian for both men and women.

Metformin use and its effect on survival in diabetic patients with advanced non-small cell lung cancer

Background

Previous population-based studies have demonstrated an association between metformin use and improved survival among diabetic patients with cancer. We sought to analyze the effects of diabetes and its treatment in terms of the survival of patients with lung cancer.

Methods

Overall, 1106 patients with non-small cell lung cancer (94.3 % with stage IV disease) were included. The outcomes were compared between the patients with (n = 186) and without diabetes (n = 920). The characteristics associated with antidiabetic treatment and proper glycemic control (defined as a mean plasma glucose <130 mg/dL) were examined at diagnosis. The overall survivals (OSs) of the different patient populations were analyzed using Kaplan-Meier curves, and a multivariate Cox proportional hazard model was used to determine the influences of the patient and tumor characteristics on survival.

Results

The OS for the entire population was 18.3 months (95 % CI 16.1-20.4). There was no difference in the OSs of the diabetic and non-diabetic patients (18.5 vs 16.4 months, p = 0.62). The diabetic patients taking metformin exhibited a superior OS than did those on other antidiabetic treatments (25.6 vs 13.2 months, p = 0.017). Those with proper glycemic control had a better OS than did those without proper glycemic control and the non-diabetics (40.5 vs 13.2 and 18.5 months, respectively, p < 0.001). Both the use of metformin (HR 0.53, p < 0.0001 and HR 0.57, p = 0.017, respectively) and proper glycemic control (HR 0.49, p < 0.0001 and HR 0.40, p = 0.002, respectively) were significant protective factors in all and only diabetic patients, respectively.

Conclusions

The diabetic patients with proper glycemic control exhibited a better OS than did those without proper glycemic control and even exhibited a better OS than did the patients without diabetes mellitus. Metformin use was independently associated with a better OS.

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-016-2658-6) contains supplementary material, which is available to authorized users.

Diabetes, prostate cancer screening and risk of low- and high-grade prostate cancer: an 11 year historical population follow-up study of more than 1 million men

AIMS/HYPOTHESIS

An inverse association has consistently been shown between diabetes and prostate cancer incidence. We investigated whether lower prostate cancer incidence among men with diabetes is attributable to lower detection due to prostate cancer screening patterns.

METHODS

We studied a population-based historical cohort of 1,034,074 Israeli men aged 21-90 years, without a previous history of cancer. The cohort was followed-up from 2002 to 2012, according to diabetes morbidity, for frequency of prostate-specific antigen (PSA) testing, mean PSA values and detection of prostate cancer, after adjustment for age, ethnic origin, socioeconomic status and PSA testing.

RESULTS

In January 2002, 74,756 men had prevalent diabetes. During the 11 year follow-up, 765,483 (74%) remained diabetes-free and 193,835 developed diabetes. Approximately 10% more PSA screening was performed in men with than without diabetes, but the rate of PSA positivity (>4 μg/l) was 20% lower in men with diabetes. PSA values were already significantly lower in men who developed diabetes than in those who did not, 3 years before diabetes diagnosis. Reduced prostate cancer risk was observed among men with incident diabetes only for low-moderate grade tumours (Gleason score 2-6: adjusted HR 0.83; 95% CI 0.77, 0.89). No association was observed for high-grade tumours (Gleason score 7-10: HR 0.99; 95% CI 0.88, 1.11).

CONCLUSIONS/INTERPRETATION

Our findings suggest that diabetes comorbidity is a factor to be considered in prostate cancer screening strategies, and specifically in the interpretation of PSA levels. Furthermore, our demonstration of reduced incidence of low-moderate grade but not high-grade prostate cancer tumours among men with diabetes supports the possibility that low PSA levels, rather than lower tumour risk, explains the observed reduced incidence of prostate cancer in men with diabetes.

TRIAL REGISTRATION

ClinicalTrials.gov NCT02072902.

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.

Type 2 diabetes mellitus and risk of gallbladder cancer: a systematic review and meta-analysis of observational studies

AIMS

Increasing evidence suggests that a history of type 2 diabetes mellitus (type 2 DM) may be involved in the development of various sites of cancer. However, the association with risk of gallbladder cancer remains unclear.

METHODS

We identified studies by a literature search of MEDLINE and EMBASE through 31 August 2014 and by searching the reference lists of pertinent articles. All data were independently extracted by two investigators using a standardized data abstraction tool. Summary relative risks (SRRs) with 95% confidence intervals (CIs) were calculated with a random effects model.

RESULTS

A total of 20 studies (eight case-control studies and 12 cohort studies) were included in this meta-analysis. Analysis of these 20 studies found that compared with non-diabetic individuals, diabetic individuals had an increased risk of gallbladder cancer (SRR = 1.56, 95% CI: 1.36-1.79). There was evidence of moderate heterogeneity among these studies (p = 0.010 and I(2)  = 43.5%). This increased risk relationship is independent of smoking, body mass index and a history of gallstones. However, whether or not controlled for, alcohol use may be one of the potential confounders that significantly affect the association between type 2 DM and the risk of gallbladder cancer. Diabetic women and men had a similarly increased risk of gallbladder cancer associated with type 2 DM.

CONCLUSIONS

These findings of this systematic review indicate that compared with non-diabetic individuals, both men and women with type 2 DM had an increased risk of gallbladder cancer. Copyright © 2015 John Wiley & Sons, Ltd.

Long-Term Diabetes Mellitus Is Associated with an Increased Risk of Pancreatic Cancer: A Meta-Analysis

Purpose

Previous studies have shown a bidirectional relationship between diabetes and pancreatic cancer (PC). In particular, new-onset diabetes might be induced by PC, and people with long-term diabetes might be at increased risk for the development of PC. The purpose of our study was to examine whether long-term diabetes represented an independent risk factor for PC development.

Methodology

A literature search was performed by searching electronic databases for studies published before July 1, 2014, and relative risks (RRs) and corresponding 95% confidence intervals (CIs) were calculated. Data pertaining to diabetes were recorded at both individual and study levels, with RRs calculated separately to analyze the relationship between the duration of diabetes and the development of PC.

Results

Forty-four studies were included in this meta-analysis, including 18 studies with a case-control design, 5 with a nested case-control design and 21 with a cohort design. The overall summary estimate for the relationship between the population with a duration of diabetes ≥2 years and PC was 1.64 (1.52-1.78). The pooled RR (95% CI) of PC for the population with a duration of diabetes ≥5 years was 1.58 (1.42-1.75). For the population with a duration of diabetes ≥10 years, the RR (95% CI) of PC was 1.50 (1.28-1.75).

Conclusions

Our study suggests that long-term diabetes mellitus is associated with an increased risk of PC. However, the level of risk is negatively correlated with increasing diabetes mellitus duration.

Clinical benefits of metformin in gynecologic oncology

Evidence has suggested that diabetes may contribute to the initiation and progression of specific types of cancer. Metformin, a biguanide, has become the preferred first-line therapy for the treatment of type 2 diabetes. Metformin is inexpensive, has a proven safety profile and is able to be safely combined with additional antidiabetic agents. In addition to the well-established antidiabetic effects of metformin, there has also been notable interest in its antitumor properties. The present review discusses the emerging role of metformin as an example of an existing drug, used worldwide in the treatment of diabetes, which has been demonstrated to exert significant in vitro and in vivo anticancer activities and has thus been investigated in clinical trials. In gynecologic oncology, metformin has been suggested to exhibit significant treatment efficacy against endometrial cancer. Three studies have demonstrated the potential therapeutic effects of metformin on the survival outcome of patients with ovarian cancer and in ovarian cancer prevention. However, this evidence was based on observational studies. Metformin has been shown to exert no statistically significant beneficial effect on cervical cancer incidence or mortality. By cancer site, the current limited insights highlight the need for clinical investigations and better-designed studies, along with evaluation of the effects of metformin on cancer at other sites.

The association between type 2 diabetes mellitus and women cancer: the epidemiological evidences and putative mechanisms

Type 2 diabetes mellitus (T2DM), a chronic disease increasing rapidly worldwide, is well established as an important risk factor for various types of cancer. Although many factors impact the development of T2DM and cancer including sex, age, ethnicity, obesity, diet, physical activity levels, and environmental exposure, many epidemiological and experimental studies are gradually contributing to knowledge regarding the interrelationship between DM and cancer. The insulin resistance, hyperinsulinemia, and chronic inflammation associated with diabetes mellitus are all associated strongly with cancer. The changes in bioavailable ovarian steroid hormone that occur in diabetes mellitus (the increasing levels of estrogen and androgen and the decreasing level of progesterone) are also considered potentially carcinogenic conditions for the breast, endometrium, and ovaries in women. In addition, the interaction among insulin, insulin-like growth factors (IGFs), and ovarian steroid hormones, such as estrogen and progesterone, could act synergistically during cancer development. Here, we review the cancer-related mechanisms in T2DM, the epidemiological evidence linking T2DM and cancers in women, and the role of antidiabetic medication in these cancers.

Population-based cohort studies of type 2 diabetes and stomach cancer risk in Chinese men and women

Although positive associations have been found for diabetes and a number of cancer sites, investigations of stomach cancer are limited and the results lack consistency. In this prospective study we investigated the relationship between type 2 diabetes mellitus (T2DM) and stomach cancer risk in mainland China. We assessed the associations among T2DM, T2DM duration, and stomach cancer risk in two prospective population-based cohorts, the Shanghai Women's Health Study and the Shanghai Men's Health Study. Included in the study were 61 480 men and 74 941 women. Stomach cancer cases were identified through annual record linkage to the Shanghai Cancer Registry, and verified through home visits and review of medical charts. After a median follow-up of 7.5 years for the Shanghai Men's Health Study and 13.2 years for the Shanghai Women's Health Study, a total of 755 incident cases of stomach cancer (376 men and 379 women) were identified through to September 2013. Overall, we did not find any evidence that T2DM was associated with an increased risk of stomach cancer either in men (multi-adjusted hazard ratio = 0.83, 95% confidence interval, 0.59–1.16) or in women (multi-adjusted hazard ratio = 0.92, 95% confidence interval, 0.68–1.25). Our findings from two large prospective population-based cohorts suggest that T2DM was not associated with stomach cancer risk.

Incretin-mimetic therapies and pancreatic disease: a review of observational data

BACKGROUND/OBJECTIVE

Signals from the FDA Adverse Event Reporting System (AERS) and pre-clinical and human pancreata obtained from organ donors have suggested that incretin-based therapies used to treat type 2 diabetes mellitus, such as glucagon-like peptide 1 (GLP-1) receptor agonists and dipeptidyl peptidase-4 (DPP-4) inhibitors, may increase the risk of acute pancreatitis (AP) and pancreatic cancer (PC). However, data from observational studies and randomized trials have been conflicting. We conducted a literature review to identify and summarize all observational data published assessing the pancreatic safety of incretins.

METHODS

Searches were conducted in MEDLINE via PubMed and Embase using the key terms for the time period of 1 January 2005, to 12 February 2014. A total of 180 articles were screened in abstract form and 49 were subsequently reviewed in full text for inclusion. Data from 12 articles are included in this report.

FINDINGS

Data from the FDA AERS database suggest increased risk of AP and PC with GLP-1 receptor agonist and DPP-4 inhibitor use. These findings are not supported by population-based observational studies for either AP or PC; however, studies assessing the relationship between PC and incretin-based therapies are limited.

CONCLUSIONS

Current evidence is conflicting and inadequate to conclude whether use of incretin-based therapies increases the risk of AP and PC. Further studies, with the ability to provide long term follow-up, are needed.

Metformin may function as anti-cancer agent via targeting cancer stem cells: the potential biological significance of tumor-associated miRNAs in breast and pancreatic cancers

Metformin is one of the most used diabetic drugs for the management of type II diabetes mellitus (DM) in the world. Increased numbers of epidemiological and clinical studies have provided convincing evidence supporting the role of metformin in the development and progression of a variety of human tumors including breast and pancreatic cancer. Substantial pre-clinical evidence from in vitro and in vivo experimental studies strongly suggests that metformin has an anti-cancer activity mediated through the regulation of several cell signaling pathways including activation of AMP kinase (AMPK), and other direct and indirect mechanisms; however, the detailed mechanism(s) has not yet been fully understood. The concept of cancer stem cells (CSCs) has gained significant attention in recent years due its identification and defining its clinical implications in many different tumors including breast cancer and pancreatic cancer. In this review, we will discuss the protective role of metformin in the development of breast and pancreatic cancers. We will further discuss the role of metformin as an anti-cancer agent, which is in part mediated through targeting CSCs. Finally, we will discuss the potential role of metformin in the modulation of tumor-associated or CSC-associated microRNAs (miRNAs) as part of the novel mechanism of action of metformin in the development and progression of breast and pancreatic cancers.

Independent and joint effect of type 2 diabetes and gastric and hepatobiliary diseases on risk of pancreatic cancer risk: 10-year follow-up of population-based cohort

Background:

Type 2 diabetes mellitus, gastric and hepatobiliary comorbidities, and cancer share common risk factors: for example, tobacco, obesity, physical inactivity, high calorie intake, and metabolic disorders. Prior studies find type 2 diabetes and gastric and hepatobiliary comorbidities heightening risk of pancreatic cancer. Yet joint association of type 2 diabetes mellitus and gastric and hepatobiliary comorbidities on pancreatic cancer risk has not been assessed.

Methods:

This study rates independent/joint effects of type 2 diabetes as well as gastric and hepatobiliary comorbidity on pancreatic cancer risk for a retrospective population-based cohort of 166 850 type 2 diabetics identified in 1997–1998 and followed for 10–11 years, comparing their cancer incidence with that of 166 850 non-diabetics matched for age, gender, and locale. Time-dependent Cox's proportional hazards model evaluted joint association of type 2 diabetes and chronic conditions on pancreatic cancer risk.

Results:

A total of 1178 subjects were newly diagnosed with pancreatic cancer during follow-up, with incidence rates of 0.49 per 1000 person-years in type 2 diabetes and 0.26 per 1000 person-years in the non-diabetics. We observed greater magnitude of hazard ratios (HRs) of pancreatic cancer for patients with type 2 diabetes along with acute alcoholic hepatitis, acute pancreatitis, cholecystitis, and gastric ulcer compared with patients without type 2 diabetes or counterpart comorbidity (HR: 1.36, 95% confidence interval (CI): 1.19–1.56; 1.74, 1.23–2.45; 9.18, 7.44–11.33; and 2.31, 1.98–2.70, respectively). Main effects of type 2 diabetes were all statistically with narrow 95% CI and remained similar across risk stratification with various comorbidities: range 1.59–1.80.

Conclusions:

Our study demonstrates that pre-existing type 2 diabetes, acute alcoholic hepatitis, acute pancreatitis, cholecystitis, and gastric ulcer independently or jointly predict subsequent pancreatic cancer risk. Clinicians must recognise burden of these gastric and hepatobiliary comorbidities and keep clinically vigilant for their diagnosis.

CARING (CAncer Risk and INsulin analoGues): the association of diabetes mellitus and cancer risk with focus on possible determinants - a systematic review and a meta-analysis

Background:

Patients suffering from diabetes mellitus (DM) may experience an increased risk of cancer; however, it is not certain whether this effect is due to diabetes per se.

Objective:

To examine the association between DM and cancers by a systematic review and meta-analysis according to the PRISMA guidelines.

Data Sources:

The systematic literature search includes Medline at PubMed, Embase, Cinahl, Bibliotek.dk, Cochrane library, Web of Science and SveMed+ with the search terms: “Diabetes mellitus”, “Neoplasms”, and “Risk of cancer”.

Study Eligibility Criteria:

The included studies compared the risk of cancer in diabetic patients versus non-diabetic patients. All types of observational study designs were included.

Results:

Diabetes patients were at a substantially increased risk of liver (RR=2.1), and pancreas (RR=2.2) cancer. Modestly elevated significant risks were also found for ovary (RR=1.2), breast (RR=1.1), cervix (RR=1.3), endometrial (RR=1.4), several digestive tract (RR=1.1-1.5), kidney (RR=1.4), and bladder cancer (RR=1.1). The findings were similar for men and women, and unrelated to study design. Meta-regression analyses showed limited effect modification of body mass index, and possible effect modification of age, gender, with some influence of study characteristics (population source, cancer- and diabetes ascertainment).

Limitations:

Publication bias seemed to be present. Only published data were used in the analyses.

Conclusions:

The systematic review and meta-analysis confirm the previous results of increased cancer risk in diabetes and extend this to additional cancer sites. Physicians in contact with patients with diabetes should be aware that diabetes patients are at an increased risk of cancer.

Plasma insulin, C-peptide and blood glucose and the risk of gastric cancer: the Japan Public Health Center-based prospective study

To date, the association between diabetes mellitus (DM) and gastric cancer has been controversial, including the underlying mechanism. We investigated the association between plasma diabetic biomarkers (insulin, C-peptide, and blood glucose) and gastric cancer risk. In addition, homeostasis model assessment of insulin resistance (HOMA-IR) and homeostasis model assessment of β-cell function (HOMA-β) were calculated. A total of 36,745 subjects aged 40-69 years in the Japan Public Health Center-based prospective study (JPHC) who returned the baseline questionnaire and provided blood samples were followed from 1990 to 2004. In the present analysis, 477 cases and 477 matched controls were used. The odds ratios (ORs) and their corresponding 95% confidence intervals (CIs) for developing gastric cancer were calculated using conditional logistic regression models. Plasma insulin was positively associated with increased risk of gastric cancer; compared to tertile 1, ORs were 1.69 (95% CI = 1.11-2.59) and 2.01 (1.19-3.38) for tertiles 2 and 3, respectively (p for trend = 0.009). In men, C-peptide was also positively associated with a significant risk; corresponding ORs were 1.42 (0.85-2.38) and 1.91 (1.03-3.54), respectively (p for trend = 0.04). These findings were confirmed for blood samples from the fasting group (≥8 hr after a meal). Higher HOMA-IR was also associated with increased risk, whereas no association was observed for blood glucose. Our findings suggest that Japanese population with higher insulin and C-peptide levels derived from insulin resistance have an elevated risk of gastric cancer.

Pre-existing type 2 diabetes and risk of lung cancer: a report from two prospective cohort studies of 133 024 Chinese adults in urban Shanghai

OBJECTIVES

Observational studies of type 2 diabetes (T2D) and lung cancer risk are limited and controversial. We thus examined the association between T2D and risk of incident lung cancer using a cohort design.

SETTING

Data from two ongoing population-based cohorts (the Shanghai Men's Health Study, SMHS, 2002-2006 and the Shanghai Women's Health Study, SWHS, 1996-2000) were used. Cox proportional-hazards regression models with T2D as a time-varying exposure were modelled to estimate HRs and 95% CIs.

PARTICIPANTS

The study population included 61 491 male participants aged 40-74 years from SMHS and 74 941 female participants aged 40-70 years from SWHS.

OUTCOME MEASURE

Lung cancer cases were identified through annual record linkage to the Shanghai Cancer Registry and Shanghai Municipal Registry of Vital Statistics, and were further verified through home visits and a review of medical charts by clinical and/or pathological experts. Outcome data until 31 December 2010 for men and women were used for the present analysis.

RESULTS

After a median follow-up of 6.3 years for SMHS and 12.2 years for SWHS, incident lung cancer cases were detected in 492 men and 525 women. A null association between T2D and lung cancer risk was observed in men (HR=0.87, 95% CI 0.62 to 1.21) and women (HR=0.92, 95% CI 0.69 to 1.24) after adjustments for potential confounders. Similar results were observed among never smokers.

CONCLUSIONS

There is little evidence that pre-existing T2D may influence the incidence of lung cancer.