Risk of bladder cancer in patients with diabetes: a retrospective cohort study

Casual effects of type 1 diabetes mellitus on site-specific digestive cancers: a Mendelian randomisation analysis

Objective

Despite several observational studies attempting to investigate the potential association between type 1 diabetes mellitus (T1DM) and the risk of digestive cancers, the results remain controversial. The purpose of this study is to examine whether there is a causal relationship between T1DM and the risk of digestive cancers.

Methods

We conducted a Mendelian randomisation (MR) study to systematically investigate the effect of T1DM on six most prevalent types of digestive cancers (oesophageal cancer, stomach cancer, hepatocellular carcinoma, biliary tract cancer, pancreatic cancer, and colorectal cancer). A total of 1,588,872 individuals were enrolled in this analysis, with 372,756 being the highest number for oesophageal cancer and 3,835 being the lowest for pancreatic cancer. Multiple MR methods were performed to evaluate the causal association of T1DM with the risk of six site-specific cancers using genome-wide association study summary data. Sensitivity analyses were also conducted to assess the robustness of the observed associations.

Results

We selected 35 single nucleotide polymorphisms associated with T1DM as instrumental variables. Our findings indicate no significant effect of T1DM on the overall risk of oesophageal cancer (OR= 0.99992, 95% CI: 0.99979-1.00006, P= 0.2866), stomach cancer (OR=0.9298,95% CI: 0.92065-1.09466, P= 0.9298), hepatocellular carcinoma (OR= 0.99994,95% CI: 0.99987-1.00001, P= 0.1125), biliary tract cancer (OR=0.97348,95% CI: 0.8079-1.1729, P= 0.7775)), or pancreatic cancer (OR =1.01258, 95% CI: 0.96243-1.06533, P= 0.6294). However, we observed a causal association between T1DM and colorectal cancer (OR=1.000, 95% CI: 1.00045-1.0012, P<0.001), indicating that T1DM increases the risk of colorectal cancer. We also performed sensitivity analyses, which showed no heterogeneity or horizontal pleiotropy. For the reverse MR from T1DM to six digestive cancers, no significant causal relationships were identified.

Conclusions

In this MR study with a large number of digestive cancer cases, we found no evidence to support the causal role of T1DM in the risk of oesophageal cancer, stomach cancer, hepatocellular carcinoma, biliary tract cancer, or pancreatic cancer. However, we found a causal positive association between T1DM and colorectal cancer. Further large-scale prospective studies are necessary to replicate our findings.

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.

The Relationship Between Diabetes Mellitus and Cancers and Its Underlying Mechanisms

Epidemiological studies suggest associations between diabetes mellitus and some cancers. The risk of a number of cancers appears to be increased in diabetes mellitus. On the other hand, some cancer and cancer therapies could lead to diabetes mellitus. Genetic factors, obesity, inflammation, oxidative stress, hyperglycemia, hyperinsulinemia, cancer therapies, insulin and some oral hypoglycemic drugs appear to play a role in the crosstalk between diabetes mellitus and cancers. This review summarized the associations between various types of diabetes and cancers and updated available evidence of underlying mechanisms between diabetes and cancers.

The association between diabetes and cancer in Mexico: Analysis using death certificate databases, 2009-2017

Context

Previous studies have shown that diabetes mellitus (DM) is a risk factor of some type-specific cancers. However, no data are available on the association between cancer and DM in Latin America.

Aims

The aim of this study is to determine which type-specific cancers are associated with DM using multiple cause of death data.

Settings and Design

Whole country of Mexico, cross-sectional design.

Materials and Methods

Analysis of all cancer deaths (2009-2017) using death certificate databases of Mexican adults aged ≥20 years.

Statistical Analysis Used

Multivariable logistic regression.

Results

There were 710,292 total cancer deaths. DM increased the risk of pancreatic (adjusted odds ratio [aOR] = 1.7), liver (aOR = 1.6), kidney (aOR = 1.4), gallbladder (aOR = 1.2) and endometrial (aOR = 1.1) cancers, all P < 0.05. Type 2 or unknown-type DM were associated with the same cancer types with little variation of estimates. Higher estimates were found in males than females (except for kidney cancer). Type 1 DM was associated with pancreatic cancer only (aOR = 1.9).

Conclusions

DM in Mexico is associated with gastrointestinal (pancreatic, liver, gallbladder), kidney and endometrial cancers. Dissemination of knowledge to both health-care workers and diabetics regarding potential cancer risks including adequate diet, regular exercise, weight reduction if obese/overweight, cessation of smoking, and good glucose control and medication compliance should be reinforced. Specific cancer preventative measures should be implemented for patients with DM.

Diabetes and cancer: Epidemiological and biological links

The incidence of diabetes and cancer has increased significantly in recent years. Furthermore, there are many common risk factors for both diabetes and cancer, such as obesity, sedentary lifestyle, smoking, and ageing. A large body of epidemiological evidence has indicated that diabetes is considered as an independent risk factor for increased rates of heterogeneous types of cancer occurrence and death. The incidence and mortality of various types of cancer, such as pancreas, liver, colorectal, breast, endometrial, and bladder cancers, have a modest growth in diabetics. However, diabetes may work as a protective factor for prostate cancer. Although the underlying biological mechanisms have not been totally understood, studies have validated that insulin/insulin-like growth factor (IGF) axis (including insulin resistance, hyperinsulinemia, and IGF), hyperglycemia, inflammatory cytokines, and sex hormones provide good circumstances for cancer cell proliferation and metastasis. Insulin/IGF axis activates several metabolic and mitogenic signaling pathways; hyperglycemia provides energy for cancer cell growth; inflammatory cytokines influence cancer cell apoptosis. Thus, these three factors affect all types of cancer, while sex hormones only play important roles in breast cancer, endometrial cancer, and prostate cancer. This minireview consolidates and discusses the epidemiological and biological links between diabetes and various types of cancer.

Risk of urothelial cancer death among people using antihypertensive drugs-a cohort study from Finland

Background: To analyse the association between antihypertensive (anti-HT) drug use and risk of urothelial cancer (UC) death. UC occurs as bladder cancer (BCa) and upper tract urothelial carcinomas (UTUCs). Hypertension is a suggested risk factor for BCa and may impair disease prognosis. However, it's unclear if use of anti-HT drugs could improve the prognosis of UC.Materials and methods: This study evaluated the association between use of anti-HT drugs and UC survival among 14,065 participants diagnosed with BCa and 1080 with UTUC during 1995-2012 in Finland. It analyzed data using the multivariable adjusted conditional Cox regression model.Results: Angiotensin-receptor (ATR) blocker use before BCa diagnosis was associated with slightly decreased risk of BCa death (HR = .81, CI = .71-0.93). The association was dose-dependent and it decreased in association with elevated intensity of ATR-blocker use. Post-diagnostic use of ATR-blockers was similarly associated with better survival compared to non-users (HR = .81, CI = .71-0.92. Interestingly, use of calcium-channel blockers also associated with better survival and the risk of BCa death decreased with increasing intensity of use (HR = .67, CI = .52-0.86 for highest intensity).Conclusions: This large population-based cohort suggests decreased risk of BCa death among ATR-blocker and calcium-channel blocker users. The risk association among ATR-blockers and calcium-channel blockers was dose-dependent suggesting a causal explanation. Similar risk associations are not observed for other anti-HT drug users, which may suggest a direct effect of ATR blocker or calcium-channel blocker use. Further studies are needed to elucidate the potential anticancer mechanism.

The association between metabolic syndrome and bladder cancer susceptibility and prognosis: an updated comprehensive evidence synthesis of 95 observational studies involving 97,795,299 subjects

Background

The association between metabolic syndrome (MS) and bladder cancer (BC) was not fully investigated, and most primary studies and pooled analyses were only focused on certain specific components.

Objective

To further investigate this issue and obtain more precise findings, we conducted this updated evidence synthesis of published studies, which involved not only MS components but also the MS in its entirety.

Materials and methods

We searched the PubMed, EMBASE, and Web of Science databases for observational studies on the association between BC susceptibility and/or mortality, and MS and its components. We extracted data from included studies, evaluated heterogeneity, and performed meta-analytic quantitative syntheses.

Results

A total of 95 studies with 97,795,299 subjects were included in the present study. According to the results, MS significantly increased the risk of BC (risk ratio [RR]=1.11, 95% CI=1.00–1.23); diabetes significantly increased the risk of BC (RR=1.29, 95% CI=1.19–1.39) and associated with poor survival (RR=1.24, 95% CI=1.08–1.43). Excessive body weight was associated with increased susceptibility (RR=1.07, 95% CI=1.02–1.12), recurrence (RR=1.46, 95% CI=1.18–1.81), and mortality (RR=1.17, 95% CI=1.00–1.37). As indicated by cumulative meta-analysis, sample size was inadequate for the association between BC susceptibility and MS, the association between BC recurrence and excessive body weight, and the association between BC survival and diabetes. The sample size of the meta-analysis was enough to reach a stable pooled effect for other associations.

Conclusion

Diabetes and excessive body weight as components of MS are associated with increased susceptibility and poor prognosis of BC. Uncertainty remains concerning the impact of overall MS, hypertension, and dyslipidemia on BC susceptibility and prognosis, for which further investigations are needed.

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.

Type 1 diabetes mellitus and risk of cancer: a meta-analysis of observational studies

Objective

Previous observational studies have focused on the link between type 2 diabetes and the risk of cancer. However, the association between type 1 diabetes and the risk of cancer has not been well addressed. This study aimed to investigate the association between type 1 diabetes and the risk of cancer by using a meta-analysis of observational studies.

Methods

We searched PubMed and EMBASE for observational studies that examined the association between type 1 diabetes and cancer in April 2017. We calculated the pooled odds ratios (ORs) or relative risks (RRs) with confidence intervals (CIs) from individual studies based on a random-effects model meta-analysis.

Results

We included a total of 15 observational studies with two case-control studies and 13 cohort studies involving 31 893 cancer patients among a total of 1 915 179 participants in the final analysis. In the random-effects meta-analysis of all studies, patients with type 1 diabetes had an increased risk of cancer (OR or RR, 1.29; 95% CI, 1.09-1.52; n = 15; I2 = 95.2%). In the subgroup meta-analysis by type of cancer, type 1 diabetes significantly increased the risk of cancers of stomach, lung, pancreas, liver, ovary and kidney, whereas it significantly decreased the risk of breast cancer (OR or RR, 0.91; 95% CI, 0.86-0.95; n = 9; I2 = 0%).

Conclusion

This meta-analysis suggests that type 1 diabetes is associated with the increased risk of several types of cancer and the decreased risk of breast cancer. However, the plausible mechanisms for the decreased risk of breast cancer remain unclear. Further prospective studies with proper adjustment for possible confounding factors are warranted.

Computational identification of microRNAs associated to both epithelial to mesenchymal transition and NGAL/MMP-9 pathways in bladder cancer

Bladder cancer is one of the leading cancer of the urinary tract. It is often diagnosed at advanced stage of the disease. To date, no specific and effective early detection biomarkers are available. Cancer development and progression are associated with the involvement of both epithelial-mesenchymal transition (EMT) and tumor microenvironment of which NGAL/MMP-9 complex represents the main player in bladder cancer. It is known that change in microRNAs (miRNAs) expression may result in gene modulation. Therefore, the identification of specific miRNAs associated with EMT pathway and NGAL/MMP-9 complex may be useful to detect the development of bladder cancer at early stages.

On this ground, the expression levels of miRNAs in public available datasets of bladder cancer containing data of non-coding RNA profiling was evaluated. This analysis revealed a group of 16 miRNAs differentially expressed between bladder cancer patients and related healthy controls. By miRNA prediction tool (mirDIP), the relationship between the identified miRNAs and the EMT genes was established. Using the DIANA-mirPath (v.2) software, miRNAs, able to modulate the expression of NGAL and MMP-9 genes, were recognized.

The results of this study provide evidence that the downregulated hsa-miR-145-5p and hsa-miR-214-3p may modulate the expression of both EMT and NGAL/MMP-9 pathways. Therefore, further validation analyses may confirm the usefulness of these selected miRNAs for predicting the development of bladder cancer at the early stage of the disease.

Diabetes mellitus and the risk of bladder cancer: A PRISMA-compliant meta-analysis of cohort studies

BACKGROUND

Epidemiologic studies have reported inconsistent results regarding the relationship between diabetes mellitus (DM) and the incidence of bladder cancer. This comprehensive systematic review and meta-analysis explored and evaluated this relationship in participants with different characteristics.

METHODS

Studies indexed in the PubMed, Embase, and the Cochrane Library databases that compared bladder cancer incidence mortality between DM and non-DM participants were included in the present study. The relative risks (RRs) of a random-effects model were used to assess these associations.

RESULTS

The final analysis included 21 cohort studies, involving a total of 13,505,643 participants. Overall, DM was associated with an increased risk of bladder cancer or cancer mortality when compared with non-DM participants (RR: 1.23; 95% confidence interval [CI]: 1.12-1.35; P < .001). Furthermore, DM had a harmful impact on subsequent bladder cancer risk in men compared with those without DM (RR: 1.23; 95% CI: 1.06-1.42; P = .005), whereas no significant relationship was observed between DM and bladder cancer in women (RR: 1.24; 95% CI: 0.95-1.61; P = .119). There was no significant gender difference for this relationship (ratio of RR: 0.99; 95% CI: 0.73-1.34; P = .958). In addition, cancer incidence (RR: 1.21; 95% CI: 1.09-1.35; P < .001) and cancer mortality (RR: 1.25; 1.17-1.35; P < .001) both increased in DM patients. Finally, smoking status and follow-up duration might also affect this relationship in men and women.

CONCLUSIONS

The findings of this study indicated that DM was associated with elevated bladder cancer or cancer mortality risk, especially in men. This relationship in women requires further exploration.

Deciphering the Roles of Thiazolidinediones and PPAR in Bladder Cancer

The use of thiazolidinedione (TZD) therapy in type II diabetic patients has proven useful in the lowering of blood glucose levels. However, recent investigations have shown that there may be potential health concerns associated, including the risk of developing bladder cancer as well as complications in the cardiovasculature. TZDs are ligands for the nuclear receptor PPARγ, and activation causes lipid uptake and insulin sensitization, both of which are critical processes for diabetic patients whose bodies are unable to utilize insulin effectively. Several studies have shown that PPARγ/TZDs decrease IGF-1 levels and, thus, reduce cancer growth in carcinomas such as the pancreas, colon, liver, and prostate. However, other studies have shed light on the potential of the receptor as a biomarker for uroepithelial carcinomas, particularly due to its stimulatory effect on migration of bladder cancer cells. Furthermore, PPARγ may provide the tumor-promoting microenvironment by de novo synthesis of nutrients that are needed for bladder cancer development. In this review, we closely examine the TZD class of drugs and their effects on PPARγ in patient studies along with additional molecular factors that are positive modulators, such as protein phosphatase 5 (PP5), which may have considerable implications for bladder cancer therapy.

Trends in incidence, prevalence and prescribing in type 2 diabetes mellitus between 2000 and 2013 in primary care: a retrospective cohort study

OBJECTIVE

To investigate trends in incident and prevalent diagnoses of type 2 diabetes mellitus (T2DM) and its pharmacological treatment between 2000 and 2013.

DESIGN

Analysis of longitudinal electronic health records in The Health Improvement Network (THIN) primary care database.

SETTING

UK primary care.

PARTICIPANTS

In total, we examined 8,838,031 individuals aged 0-99 years.

OUTCOME MEASURES

The incidence and prevalence of T2DM between 2000 and 2013, and the effect of age, sex and social deprivation on these measures were examined. Changes in prescribing patterns of antidiabetic therapy between 2000 and 2013 were also investigated.

RESULTS

Overall, 406,344 individuals had a diagnosis of T2DM, of which 203,639 were newly diagnosed between 2000 and 2013. The incidence of T2DM rose from 3.69 per 1000 person-years at risk (PYAR) (95% CI 3.58 to 3.81) in 2000 to 3.99 per 1000 PYAR (95% CI 3.90 to 4.08) in 2013 among men; and from 3.06 per 1000 PYAR (95% CI 2.95 to 3.17) to 3.73 per 1000 PYAR (95% CI 3.65 to 3.82) among women. Prevalence of T2DM more than doubled from 2.39% (95% CI 2.37 to 2.41) in 2000 to 5.32% (95% CI 5.30 to 5.34) in 2013. Being male, older, and from a more socially deprived area was strongly associated with having T2DM, (p<0.001). Prescribing changes over time reflected emerging clinical guidance and novel treatments. In 2013, metformin prescribing peaked at 83.6% (95% CI 83.4% to 83.8%), while sulfonylureas prescribing reached a low of 41.4% (95% CI 41.1% to 41.7%). Both remained, however, the most commonly used pharmacological treatments as first-line agents and add-on therapy. Thiazolidinediones and incretin based therapies (gliptins and GLP-1 analogues) were also prescribed as alternate add-on therapy options, however were rarely used for first-line treatment in T2DM.

CONCLUSIONS

Prevalent cases of T2DM more than doubled between 2000 and 2013, while the number of incident cases increased more steadily. Changes in prescribing patterns observed may reflect the impact of national policies and prescribing guidelines on UK primary care.

Influence of metformin intake on the risk of bladder cancer in type 2 diabetes patients

AIM

The aim of this study was to look at the influence of metformin intake and duration, on urinary bladder cancer (UBC) risk, with sulfonylurea (SU) only users as control using a new user design (inception cohort).

METHODS

We conducted a retrospective cohort study using data from the UK Clinical Practice Research Datalink (CPRD) including all patients with at least one prescription of oral anti-diabetic drugs (ADD) and/or insulin. The risk of UBC in different groups of ADD users (metformin alone (one), metformin in combination (two) with other ADD medication (glinides, glitazones, DPP-4-inhibitors, SUs, insulin or more than one combination), all metformin users (1 + 2) was compared with SU only users using Cox proportional hazards models. The estimates were adjusted for age, gender, smoking status, BMI and diabetes duration.

RESULTS

The inception cohort included 165,398 participants of whom 132,960 were metformin users and 32,438 were SU only users. During a mean follow-up time of more than 5 years 693 patients developed UBC, 124 of the control group and 461 of the all metformin users. There was no association between metformin use and UBC risk (HR = 1.12, 95% CI 0.90, 1.40) compared with SU only users, even after adjustment for diabetes duration (HR = 1.13, 95% CI 0.90, 1.40). We found a pattern of decreasing risk of UBC with increasing duration of metformin intake, which was statistically not significant.

CONCLUSION

Metformin has no influence on the risk of UBC compared with SU in type 2 diabetes patients using a new user design.