Time-Dependent Risk of Cancer After a Diabetes Diagnosis in a Cohort of 2.3 Million Adults

Diabetes Mellitus and Colon Carcinogenesis: Expectation for Inhibition of Colon Carcinogenesis by Oral Hypoglycemic Drugs

The global deaths due to colorectal cancer and diabetes mellitus have increased by 57% and 90%, respectively. The relationship between various cancers and diabetes mellitus has been shown in multiple epidemiological studies. Hence, better management of diabetes mellitus is expected to reduce the risk of various cancers. This review focuses on colorectal cancer and aims to summarize recent findings on the antitumor effects of various oral hypoglycemic drugs on colorectal cancer and their estimated mechanisms. Of the seven classes of oral hypoglycemic agents, only metformin was found to have suppressive effects on colorectal cancer in both clinical and basic research. Clinical and basic researches on suppressing effects of glinides, dipeptidyl peptidase-4 inhibitors, thiazolidinedione, α-glucosidase inhibitors, and sodium glucose cotransporter-2 inhibitors against colon carcinogenesis have been insufficient and have not arrived at any conclusion. Therefore, further research regarding these agents is warranted. In addition, the suppressive effects of these agents in healthy subjects without diabetes should also be investigated.

Metformin is associated with a lower risk of non-Hodgkin lymphoma in patients with type 2 diabetes

BACKGROUND

Whether metformin use might affect the risk of non-Hodgkin lymphoma (NHL) remained to be answered.

METHODS

A total of 610,089 newly diagnosed type 2 diabetes patients with 2 or more times of prescription of antidiabetic drugs during 1999-2009 were enrolled from Taiwan's National Health Insurance database. They were followed up for NHL incidence until December 31, 2011. Both intention-to-treat and per-protocol analyses were conducted. Cox regression incorporated with the inverse probability of treatment-weighting using propensity scores was used to estimate hazard ratios.

RESULTS

There were 414,783 metformin initiators and 195,306 non-metformin initiators within the initial 12-month of prescriptions of antidiabetic drugs. After a median follow-up of 5.07 years in metformin initiators and 6.78 years in non-metformin initiators, 1076 and 755 patients were diagnosed of new-onset NHL, respectively. The respective incidence was 47.74 and 57.68 per 100,000 person-years and the hazard ratio for metformin initiators versus non-metformin initiators was 0.849 (95% confidence interval 0.773-0.932) in the intention-to-treat analysis. In the per-protocol analysis, the hazard ratio was 0.706 (95% confidence interval 0.616-0.808). Sensitivity analyses after excluding patients with irregular follow-up, with an extension of minimal observation periods of 24 or 36 months, with incretin-based therapies, or in patients enrolled during 2 different periods (i.e., 1999-2003 and 2004-2009) consistently showed a lower risk among metformin initiators in both the intention-to-treat and the per-protocol analyses.

CONCLUSIONS

Metformin use is associated with a lower risk of NHL compared with non-metformin antidiabetics.

Association between type 1 and type 2 diabetes and risk of non-Hodgkin's lymphoma: A meta-analysis of cohort studies

AIM

Diabetes mellitus (DM) is thought to be associated with an increased risk of non-Hodgkin's lymphoma (NHL), although the evidence so far remains inconsistent. Thus, our study aimed to further assess this association.

METHODS

Electronic searches were performed of the PubMed, Web of Science and Embase databases up to 11 March 2019. A random-effects model was used to calculate summary relative risks (RRs) with corresponding 95% confidence intervals (CIs).

RESULTS

A total of 20 articles including data from 35 cohort studies matched our inclusion criteria, and 31 RRs were calculated for type 2 DM; the summary RR was 1.20 (95% CI: 1.12-1.30, I² = 84.7%). Also, four RRs were calculated for type 1 DM, and the result was significant (RR: 1.55, 95% CI: 1.15-2.08, I² = 0.0%). The results of subgroup analyses demonstrated that the association between DM and NHL was much more substantial in an Asian population, while sensitivity analyses suggested the robustness of a positive association between DM and NHL risk. In addition, the RR of NHL correlated negatively with duration of DM, with the highest risk found in patients within 1-2 years of DM diagnosis.

CONCLUSION

Our study findings suggest a moderate increase in risk of NHL in type 1 and 2 DM patients. Future studies should investigate the effects of duration of DM and antidiabetes interventions on NHL risk.

Pancreatic Cancer Following Incident Diabetes in African Americans and Latinos: The Multiethnic Cohort

Background

Diabetes has been proposed to be a risk factor for and a consequence of pancreatic cancer (PC). The relationship between recent-onset diabetes and PC is not well understood, and data in minorities are sparse. We examined the relationships between recent-onset diabetes and PC incidence in African Americans and Latinos in the Multiethnic Cohort.

Methods

A total of 48 995 African Americans and Latinos without prior diabetes and cancer at baseline (1993-1996) were included in the study. Questionnaires, Medicare data, and California hospital discharge files were used to identify new diabetes diagnoses. Cox regressions were used to calculate hazard ratios (HRs) and 95% confidence intervals (CIs) for cancer associated with diabetes and with diabetes duration.

Results

A total of 15 833 (32.3%) participants developed diabetes between baseline and 2013. A total of 408 incident PC cases were identified during follow-up. Diabetes was associated with PC (HRage75 = 2.39, 95% CI = 1.91 to 2.98). Individuals with recent-onset diabetes (within three or fewer years of PC diagnosis) had a greater risk compared with those with long-term diabetes across all ages. The HRage75 for recent-onset diabetes was 4.08 (95% CI = 2.76 to 6.03) in Latinos and 3.38 (95% CI = 2.30 to 4.98) in African Americans.

Conclusions

Diabetes was associated with a more than twofold higher risk of PC in African Americans and Latinos, but recent-onset diabetes was associated with a 2.3-fold greater increase in risk of PC than long-standing diabetes. Our findings support the hypothesis that recent-onset diabetes is a manifestation of PC and that long-standing diabetes is a risk factor for this malignancy.

Cancer and comorbidity: The role of leptin in breast cancer and associated pathologies

Obesity is an important risk factor for postmenopausal breast cancer and also a poor prognostic factor among cancer patients. Moreover, obesity is associated with a number of health disorders such as insulin resistance/type-2 diabetes mellitus, hypertension, and other cardiovascular diseases. Frequently, these health disorders exhibit as components/complications of the metabolic syndrome. Nevertheless, obesity-related diseases may coexist with postmenopausal breast cancer; and these comorbid conditions could be substantial. Therefore, it may be assumed that different diseases including breast cancer could originate from a common pathological background in excessive adipose tissue. Adipocyte-released hormone-like cytokine (or adipokine) leptin behaves differently in a normal healthy state and obesity. A growing body of evidence suggests an important role of leptin in our major obesity-related health issues such as insulin resistance, hypertension, and neoplasia. In this context, this review describes the relationships of the abovementioned pathologies with leptin.

Maternal breast cancer risk in relation to birthweight and gestation of her offspring

BACKGROUND

Parity and age at first pregnancy are well-established risk factors for breast cancer, but the effects of other characteristics of pregnancies are uncertain and the literature is inconsistent.

METHODS

In a cohort of 83,451 parous women from the general population of the UK, which collected detailed information on each pregnancy and a wide range of potential confounders, we investigated the associations of length of gestation and birthweight of offspring in a woman's pregnancies with her breast cancer risk, adjusting for a full range of non-reproductive as well as reproductive risk factors unlike in previous large studies.

RESULTS

Gestation of the first-born offspring was significantly inversely related to the risk of pre-menopausal breast cancer (p trend = 0.03; hazard ratio (HR) for 26-31 compared with 40-41 weeks, the baseline group, = 2.38, 95% confidence interval (CI) 1.26-4.49), and was borderline significantly related to risk of breast cancer overall (p trend = 0.05). Risk was significantly raised in mothers of high birthweight first-born (HR for breast cancer overall = 1.53, 95% CI 1.06-2.21 for ≥ 4500 g compared with 3000-3499 g, the baseline group). For gestation and birthweight of most recent birth, there were no clear effects. Analyses without adjustment for confounders (other than age) gave similar results.

CONCLUSIONS

Our data add to evidence that short gestation pregnancies may increase the risk of breast cancer, at least pre-menopausally, perhaps by hormonal stimulation and breast proliferation early in pregnancy without the opportunity for the differentiation that occurs in late pregnancy. High birthweight first pregnancies may increase breast cancer risk, possibly through the association of birthweight with oestrogen and insulin-like growth factor 1 levels.

Diabetes, Plasma Glucose, and Incidence of Fatty Liver, Cirrhosis, and Liver Cancer: A Prospective Study of 0.5 Million People

The prevalence of diabetes is increasing rapidly in China. However, evidence is limited about its effects on chronic liver diseases and liver cancer. We examined the associations of diabetes with chronic liver diseases and liver cancer and of random plasma glucose (RPG) with these liver diseases among participants without diabetes in Chinese adults and the possible interaction by hepatitis B virus (HBV) infection. The prospective China Kadoorie Biobank recruited 512,891 adults. During 10 years of follow-up, 2,568 liver cancer, 2,082 cirrhosis, 1,298 hospitalized nonalcoholic fatty liver disease (NAFLD), and 244 hospitalized alcoholic liver disease (ALD) cases were recorded among 503,993 participants without prior history of cancer or chronic liver diseases at baseline. Cox regression was used to estimate hazard ratios (HRs) for each disease by diabetes status (previously diagnosed or screen-detected) and, among those without previously diagnosed diabetes, by levels of RPG. Overall 5.8% of participants had diabetes at baseline. Compared to those without diabetes, individuals with diabetes had adjusted HRs of 1.49 (95% confidence interval 1.30-1.70) for liver cancer, 1.81 (1.57-2.09) for cirrhosis, 1.76 (1.47-2.16) for NAFLD, and 2.24 (1.42-3.54) for ALD. The excess risks decreased but remained elevated in those with longer duration. Among those without previously diagnosed diabetes, RPG was positively associated with liver diseases, with adjusted HRs per 1 mmol/L higher RPG of 1.04 (1.03-1.06) for liver cancer, 1.07 (1.05-1.09) for cirrhosis, 1.07 (1.05-1.10) for NAFLD, and 1.10 (1.05-1.15) for ALD. These associations did not differ by HBV infection.

CONCLUSION

In Chinese adults, diabetes and higher blood glucose levels among those without known diabetes are associated with higher risks of liver cancer and major chronic liver diseases.

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 Relationship Between Vitamin B6, Diabetes and Cancer

Pyridoxal 5′-phosphate (PLP), the active form of vitamin B6, works as cofactor in numerous enzymatic reactions and it behaves as antioxidant molecule. PLP deficiency has been associated to many human pathologies including cancer and diabetes and the mechanism behind this connection is now becoming clearer. Inadequate intake of this vitamin increases the risk of many cancers; furthermore, PLP deprivation impairs insulin secretion in rats, whereas PLP supplementation prevents diabetic complications and improves gestational diabetes. Growing evidence shows that diabetes and cancer are correlated not only because they share same risk factors but also because diabetic patients have a higher risk of developing tumors, although the underlying mechanisms remain elusive. In this review, we will explore data obtained in Drosophila revealing the existence of a connection between vitamin B6, DNA damage and diabetes, as flies in the past decade turned out to be a promising model also for metabolic diseases including diabetes. We will focus on recent studies that revealed a specific role for PLP in maintaining chromosome integrity and glucose homeostasis, and we will show that these aspects are correlated. In addition, we will discuss recent data identifying PLP as a putative linking factor between diabetes and cancer.

Newly diagnosed type 2 diabetes may serve as a potential marker for pancreatic cancer

Pancreatic cancer has an extremely highly case fatality. Diabetes is a well-established strong risk factor for pancreatic cancer. Compared with a nondiabetic population, we previously reported a 15- and 14-fold greater risk for detecting pancreatic cancer during the first year after diagnosing diabetes in adult women and men, respectively, which dropped during the second year to 5.4-fold and 3.5-fold, respectively, and stabilized around 3-fold for the rest of the 11-year follow-up in our historical cohort. The population attributable risk during the 11-year period was 13.3% and 14.1% in prevalent diabetic women and men, respectively. This means that one out of about every 8 patients diagnosed with pancreatic cancer has been previously diagnosed with diabetes. The globally high prevalence of diabetes and the aggravating implications of a delayed pancreatic cancer diagnosis call for newly-onset diabetes to be considered a potential marker for an underlying pancreatic cancer and addressed accordingly.

Diabetes and cancer: Pathophysiological fundamentals of a 'dangerous affair'

Diabetes and cancer are worldwide chronic diseases with a major impact on the quality and expectancy of life. Metabolic abnormalities observed during the onset and progression of diabetes may have a critical role on the initiation and progression of carcinogenesis. To date, there are no conclusive data on the mechanisms underlying the relationship between diabetes and any type of human cancer. However, recent evidence suggests that both hyperglycemia and hyperinsulinemia in diabetes could elicit cell damage responses, such as glucotoxicity, lipotoxicity and oxidative stress, which participate in the cell transformation process raising the risk of cancer development. In addition, clinical trials have revealed that several anti-diabetes therapies may potentially affect the risk of cancer though largely undefined mechanisms. In this review, we highlight epidemiological and pathophysiological aspects of diabetes, which may influence cancer initiation and progression.

Epidemiological dimensions of the association between type 2 diabetes and cancer: A review of observational studies

Type 2 diabetes (T2D) is a major cause of complications and death in many countries. The possible causal relation between T2D and cancer has been the aim of many research investigations. In view of the importance of the topic we carried out a narrative review of observational studies to summarize the available evidence of the association between T2D and cancer. To deal with the problem of abundance of published studies, we reviewed up to December 2017, the literature of meta-analyses of observational studies first, then we reviewed cohort studies not reported in meta-analyses because of more recent publication. We found that the association of T2D with risk of colorectal cancer was robust, whereas the evidence of the associations with other cancer sites was lower. Some of the observed associations could be overestimated, due to publication bias, unmeasured confounders (such as obesity) and surveillance bias. In conclusion a probable causal association of T2D with risk of colorectal cancer was confirmed. A possible causal association with pancreatic, endometrial, hepatocellular and gallbladder carcinoma was also found. Substantial uncertainty exists for other cancer sites.

Neoplasms Reported With Liraglutide or Placebo in People With Type 2 Diabetes: Results From the LEADER Randomized Trial

OBJECTIVE

This study explored neoplasm risk with liraglutide versus placebo in the LEADER (Liraglutide Effect and Action in Diabetes: Evaluation of Cardiovascular Outcome Results) cohort.

RESEARCH DESIGN AND METHODS

LEADER (NCT01179048) was an international, phase 3b, randomized, double-blind, controlled trial. Participants aged ≥50 years with type 2 diabetes and high cardiovascular risk were assigned 1:1 to receive liraglutide (≤1.8 mg daily; n = 4,668) or placebo (n = 4,672) in addition to standard care and monitored for 3.5-5 years (median follow-up 3.8 years). The occurrence of neoplasms was a prespecified, exploratory secondary end point. Post hoc analyses of the time to the first confirmed neoplasms were conducted using a Cox regression model.

RESULTS

Neoplasm was confirmed in 10.1% of patients with liraglutide versus 9.0% with placebo (hazard ratio [HR] 1.12 [95% CI 0.99; 1.28]). The HR (95% CI) for liraglutide versus placebo was 1.06 (0.90; 1.25) for malignant neoplasms and 1.16 (0.93; 1.44) for benign neoplasms. Sensitivity analyses excluding neoplasms occurring <1 year or <2 years after randomization and analyses by sex provided similar results. In our main analyses, the 95% CI for the HR included one for all malignant neoplasms evaluated (including pancreatic and thyroid neoplasms) except for prostate neoplasms, which occurred in fewer liraglutide-treated patients.

CONCLUSIONS

LEADER was not primarily designed to assess neoplasm risk. Firm conclusions cannot be made regarding numeric imbalances observed for individual neoplasm types (e.g., pancreatic cancer) that occurred infrequently. LEADER data do, however, exclude a major increase in the risk of total malignant neoplasms with liraglutide versus placebo. Additional studies are needed to assess longer-term exposure.

Diabetes, plasma glucose and incidence of colorectal cancer in Chinese adults: a prospective study of 0.5 million people

Background

Diabetes is associated with higher risk of colorectal cancer (CRC). Uncertainty remains about the relevance of duration of diabetes and about the association of blood glucose with CRC risk among individuals without diabetes.

Methods

The prospective China Kadoorie Biobank recruited 512 713 participants in 2004–2008 from 10 diverse areas in China. After 10 years of follow-up, 3024 incident cases of CRC (1745 colon, 1716 rectal) were recorded among 510 136 participants without prior cancer at baseline. Cox regression was used to estimate adjusted HRs for CRC associated with diabetes (previously diagnosed or screen-detected) and, among those without previously diagnosed diabetes, with levels of random plasma glucose (RPG).

Results

Overall 5.8% of participants had diabetes at baseline. Individuals with diabetes had an adjusted HR of 1.18 (95% CI 1.04 to 1.33) for CRC, with similar risk for colon and rectal cancer (1.19 [1.01 to 1.39] vs 1.14 [0.96 to 1.35]). The HRs decreased with longer duration of diabetes (p for trend 0.03). Among those without previously diagnosed diabetes, RPG was positively associated with CRC, with adjusted HRs per 1 mmol/L higher baseline RPG of 1.04 (1.02 to 1.05) for CRC, again similar for colon and rectal cancer (1.03 [1.01to 1.05] and 1.04 [1.02 to 1.06], respectively). The associations of diabetes and RPG appeared stronger in men than in women, but the differences were non-significant (p for heterogeneity 0.3 and 0.2).

Discussion

Among Chinese adults, diabetes and higher blood glucose levels among those without known diabetes are associated with higher risk of CRC.

Type 2 Diabetes in Relation to the Risk of Renal Cell Carcinoma Among Men and Women in Two Large Prospective Cohort Studies

OBJECTIVE

We assessed whether type 2 diabetes is associated with renal cell carcinoma (RCC), independent of key potential confounders, in two large prospective cohorts with biennially updated covariate data.

RESEARCH DESIGN AND METHODS

A total of 117,570 women from the Nurses' Health Study (NHS) and 48,866 men from the Health Professionals Follow-Up Study (HPFS) were followed from 1976 and 1986, respectively, through 2014. Multivariable Cox proportional hazards models were used to calculate hazard ratios (HRs) and 95% CIs for associations between type 2 diabetes and pathology-confirmed RCC, overall and by stage, grade, and histologic subtype.

RESULTS

During 38 years of follow-up in the NHS, we confirmed 418 RCC case subjects, including 120 fatal cases. Over 28 years in the HPFS, we confirmed 302 RCC case subjects, including 87 fatal cases. Women with type 2 diabetes had a significantly increased risk of RCC compared with women without type 2 diabetes (multivariable HR 1.53; 95% CI 1.14-2.04), with some evidence that the association was stronger for ≤5 (HR 2.15; 95% CI 1.44-3.23) than >5 (HR 1.22; 95% CI 0.84-1.78) years' duration of type 2 diabetes (P_difference 0.03). Among men, type 2 diabetes was not associated with total RCC (HR 0.89; 95% CI 0.56-1.41) or with RCC defined by stage, grade, or subtype. Sample sizes for analyses by stage, grade, and subtype were limited.

CONCLUSIONS

We found that type 2 diabetes was independently associated with a greater risk of RCC in women but not in men.

Differences in cancer survival among white and black cancer patients by presence of diabetes mellitus: Estimations based on SEER-Medicare-linked data resource

Diabetes prevalence and racial health disparities in the diabetic population are increasing in the US. Population‐based cancer‐specific survival estimates for cancer patients with diabetes have not been assessed. The Surveillance, Epidemiology, and End Results (SEER)‐Medicare linkage provided data on cancer‐specific deaths and diabetes prevalence among 14 separate cohorts representing 1 068 098 cancer patients ages 66 +  years diagnosed between 2000 and 2011 in 17 SEER areas. Cancer‐specific survival estimates were calculated by diabetes status adjusted by age, stage, comorbidities, and cancer treatment, and stratified by cancer site and sex with whites without diabetes as the reference group. Black patients had the highest diabetes prevalence particularly among women. Risks of cancer deaths were increased across most cancer sites for patients with diabetes regardless of race. Among men the largest effect of having diabetes on cancer‐specific deaths were observed for black men diagnosed with Non‐Hodgkin lymphoma (NHL) (HR = 1.53, 95%CI = 1.33‐1.76) and prostate cancer (HR = 1.37, 95%CI = 1.32‐1.42). Diabetes prevalence was higher for black females compared to white females across all 14 cancer sites and higher for most sites when compared to white and black males. Among women the largest effect of having diabetes on cancer‐specific deaths were observed for black women diagnosed with corpus/uterus cancer (HR = 1.66, 95%CI = 1.54‐1.79), Hodgkin lymphoma (HR = 1.62, 95%CI = 1.02‐2.56) and breast ER+ (HR = 1.39, 95%CI = 1.32‐1.47). The co‐occurrence of diabetes and cancer significantly increases the risk of cancer death. Our study suggests that these risks may vary by cancer site, and indicates the need for future research to address racial and sex disparities and enhance understanding how prevalent diabetes may affect cancer deaths.

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 in midlife and risk of cancer in late life: A nationwide Swedish twin study

The association between diabetes and cancer risk remains controversial. Hence, we examined whether midlife diabetes is related to the risk of cancer in late-life, and whether genetic and early-life environmental factors play a role in this association. This study included 25,154 twin individuals born in 1958 or earlier from the Swedish Twin Registry. Information on cancer diagnosis in late life (aged ≥ 65) during 1998-2014, was derived from the National Patient and Cancer Registries. Diabetes was ascertained based on self- or informant-reported history, patient registry and antidiabetic medication use. Midlife diabetes was defined when diabetes was diagnosed before 65 years. Data were analyzed following two strategies: (i) unmatched case-control analysis for all participants using generalized estimating equation (GEE) models, and (ii) co-twin control analysis for cancer-discordant twin pairs using conditional logistic regression. Overall, 1,766 (7.0%) had midlife diabetes and 5,293 (21.0%) had cancer in late-life. In multiadjusted GEE models, the odds ratios (95% CIs) of diabetes were 10.55 (2.95-37.67) for pharynx cancer, 5.78 (1.72-19.40) for small intestine cancer, 2.37 (1.14-4.91) for liver cancer and 0.48 (0.35-0.67) for prostate cancer. In people with diabetes, diabetes duration was dose-dependently associated with cancer risk. In conditional logistic regression analysis of 176 prostate cancer-discordant twin pairs, the association between midlife diabetes and prostate cancer in later life became stronger. Midlife diabetes increases the risk of pharynx, small intestine and liver cancers, but reduces prostate cancer risk in late life. Genetic and early-life environmental factors may partially contribute to the diabetes-prostate cancer association.

The Association of Recently Diagnosed Diabetes and Long-term Diabetes With Survival in Pancreatic Cancer Patients: A Pooled Analysis

OBJECTIVES

It is unclear whether long-standing diabetes or new-onset pancreatogenic diabetes contributes to poor prognosis in patients with pancreatic ductal adenocarcinoma (PDAC).

METHODS

We investigated the influence of diabetes diagnosed shortly before PDAC and long-term diabetes on overall survival in 2792 PDAC patients who had participated in 3 PDAC case-control studies in the Pancreatic Cancer Case-Control Consortium. There were 300 patients with long-term diabetes of more than 3 years' duration (11%) and 418 patients with recently diagnosed diabetes of 3-year duration or less (15%). We performed Cox regression to determine the association of long-term diabetes and recently diagnosed diabetes with overall survival, adjusting for study site, age, sex, race, stage of disease, surgery, chemotherapy, smoking history, and body mass index at diagnosis.

RESULTS

In the overall population, neither long-term diabetes (hazard ratio [HR], 1.10; 95% confidence interval [CI], 0.97-1.26) nor recently diagnosed diabetes (HR, 1.06; 95% CI, 0.94-1.18) was associated with shorter survival. When stratified by stage of disease, long-term diabetes was associated with 42% increase in rate of death in persons with resectable PDAC (HR, 1.42; 95% CI, 1.13-1.78), whereas it was not associated with survival in PDAC patients with more advanced disease.

CONCLUSION

Long-term diabetes was associated with increased rate of death in patients with resectable PDAC.

Linking type 2 diabetes and gynecological cancer: an introductory overview

Type 2 diabetes (T2D) is a chronic disease with a growing prevalence and a leading cause of death in many countries. Several epidemiological studies observed an association between T2D and increased risk of many types of cancer, such as gynecologic neoplasms (endometrial, cervical, ovarian and vulvar cancer). Insulin resistance, chronic inflammation and high free ovarian steroid hormones are considered the possible mechanisms behind this complex relationship. A higher risk of endometrial cancer was observed in T2D, even though this association largely attenuated after adjusting for obesity. A clear relationship between the incidence of cervical cancer (CC) and T2D has still not be determined; however T2D might have an impact on prognosis in patients with CC. To date, studies on the association between T2D and ovarian cancer (OC) are limited. The effect of pre-existing diabetes on cancer-specific mortality has been evaluated in several studies, with less clear results. Other epidemiological and experimental studies focused on the potential role of diabetes medications, mainly metformin, in cancer development in women. The correct understanding of the link between T2D and gynecologic cancer risk and mortality is currently imperative to possibly modify screening and diagnostic-therapeutic protocols in the future.

Incretin-Based Therapies and the Short-term Risk of Pancreatic Cancer: Results From Two Retrospective Cohort Studies

OBJECTIVE

Concerns have been raised about a possible increased risk of pancreatic cancer associated with incretin-based therapies. We examined the risk of pancreatic cancer among patients with diabetes prescribed incretin drugs.

RESEARCH DESIGN AND METHODS

With the use of public health insurance databases of Belgium and the Lombardy Region, Italy, we created two retrospective cohorts that included adult patients who were first prescribed an incretin drug or another noninsulin antidiabetic drug (NIAD) from 1 July 2008 to 31 December 2013 in Belgium and from 1 January 2008 to 31 December 2012 in the Lombardy Region. The risk of pancreatic cancer was evaluated by multivariate-adjusted Cox models that included time-dependent variables. Adjusted hazard ratios (aHRs) from Belgium and Italy were pooled by using fixed-effects meta-analyses.

RESULTS

The cohorts included 525,733 patients with diabetes treated with NIADs and 33,292 with incretin drugs. Results in both cohorts were similar. Eighty-five and 1,589 subjects who developed pancreatic cancer were registered among the incretin and NIAD new users, respectively, which represented an aHR of pancreatic cancer of 2.14 (95% CI 1.71-2.67) among those prescribed an incretin compared with an NIAD. The aHR with a drug use lag exposure of 6 months was 1.69 (1.24-2.32). The aHR decreased from 3.35 (2.32-4.84) in the first 3 months after the first incretin prescription to 2.12 (1.22-3.66) in months 3-5.9, 1.95 (1.20-3.16) in months 6-11.9, and 1.69 (1.12-2.55) after 12 months. Among those prescribed an NIAD, pancreatic cancer occurred mostly within the year after the first prescription. The risk of pancreatic cancer among patients subsequently prescribed insulin was 6.89 (6.05-7.85).

CONCLUSIONS

The recent prescription of incretin therapy is associated with an increased risk of pancreatic cancer. The reason for such an increase is likely the consequence of an occult pancreatic cancer that provokes or aggravates diabetes. Studies are warranted for assessing the risk of pancreatic cancer associated with long-term use of incretin drugs.

A systematic review of the literature exploring the interplay between prostate cancer and type two diabetes mellitus

Prostate cancer (PCa) and type two diabetes mellitus (T2DM) are both increasing prevalent conditions and often occur concurrently. However, the relationship between the two is more complex than just two prevalent conditions co-existing. This review systematically explores the literature around the interplay between the two conditions. It covers the impact of pre-existing T2DM on PCa incidence, grade and stage, as well as exploring the impact of T2DM on PCa outcomes and mortality and the interaction between T2DM and PCa treatments.

Sex differences in obesity related cancer incidence in relation to type 2 diabetes diagnosis (ZODIAC-49)

Background

Diabetes and obesity seem to be partly overlapping risk factors for the development of obesity-related cancer (mainly breast, prostate and colorectal cancer) in patients with type 2 diabetes (T2DM). In the general population, women have a lower risk for obesity-related cancer compared to men. Previous studies involving cardiovascular disease have shown that T2DM eliminates a female advantage of lower CVD risk in the general population compared to men. It is unclear whether the same could be true for obesity-related cancer. This study aimed to this investigate obesity-related cancer incidence in women and men known with T2DM as compared to the Dutch general population.

Methods

This study included 69,583 patients with T2DM selected from a prospective primary care cohort, which was linked to the Dutch National Cancer Registry to obtain cancer specific data. Obesity-related cancers included liver, kidney, colorectal, gallbladder, pancreas, ovarian, endometrial, advanced prostate cancer, post-menopausal breast cancer and oesophageal adenocarcinoma. Primary outcome was sex-stratified, age and year of cancer diagnosis adjusted standardized incidence ratios (SIRs) for three time periods: 5 years before, the year after diagnosis and the next 4 years after T2DM diagnosis. The Dutch general population was used as reference group.

Results

Women with T2DM were at an increased risk for obesity-related cancer compared to women in the general population already 5 years before diabetes diagnosis (SIR 1.77; 95%CI: 1.63–1.91). In both men and women, there was a peak in obesity-related cancer incidence following diabetes diagnosis (SIR: 1.38; 95%CI 1.11–1.64 and SIR: 2.21; 95%CI 1.94–2.30, respectively). From the second to the fifth year after diabetes diagnosis the obesity-related cancer incidence was higher in women compared to women in the general population (SIR: 2.12; 95%CI 1.94–2.30).

Conclusions

Women with T2DM seem to have a substantially higher obesity-related cancer risk. As opposed to men, in women this risk was already increased years before diabetes diagnosis. These results could imply that a relative advantage of women in the general population with regard to cancer risk is lost in women with T2DM.

Type II Diabetes and Incidence of Estrogen Receptor Negative Breast Cancer in African American Women

White women with type II diabetes (T2D) have an estimated 20% increased risk of developing breast cancer. Little is known about associations by breast cancer subtype or among African American (AA) women, who are disproportionately affected by T2D and estrogen receptor negative (ER-) breast cancer. We assessed the relation of T2D to incidence of ER- and ER+ breast cancer in data from the Black Women's Health Study, a prospective cohort of AA women enrolled in 1995 and followed biennially. During 847,934 person-years of follow-up, there were 1,851 incident invasive breast cancers, including 914 ER+ and 468 ER- cases. Multivariable Cox proportional hazards models were used to compute HRs for breast cancer incidence associated with T2D relative to no T2D, controlling for body mass index (BMI) and other potential confounders. The HR for T2D relative to no T2D was 1.18 [95% confidence interval (CI) 1.00-1.40] for overall breast cancer incidence, with the increase accounted for by ER- cancer: HRs were 1.02 (95% CI, 0.80-1.31) for ER+ and 1.43 (95% CI, 1.03-2.00) for ER- cancer. The HR for T2D and ER- breast cancer was highest among nonobese women (1.92; 95% CI, 1.22-3.04). The findings suggest that AA women with T2D are at increased risk of developing ER- breast cancer and that poor metabolic health may be more important than obesity for this subtype. Given the high prevalence of T2D in AA women, the observed association could, in part, explain racial disparities in incidence of ER- breast cancer. Cancer Res; 77(22); 6462-9. ©2017 AACR.

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.

Investigating spousal concordance of diabetes through statistical analysis and data mining

OBJECTIVE

Spousal clustering of diabetes merits attention. Whether old-age vulnerability or a shared family environment determines the concordance of diabetes is also uncertain. This study investigated the spousal concordance of diabetes and compared the risk of diabetes concordance between couples and noncouples by using nationally representative data.

METHODS

A total of 22,572 individuals identified from the 2002-2013 National Health Insurance Research Database of Taiwan constituted 5,643 couples and 5,643 noncouples through 1:1 dual propensity score matching (PSM). Factors associated with concordance in both spouses with diabetes were analyzed at the individual level. The risk of diabetes concordance between couples and noncouples was compared at the couple level. Logistic regression was the main statistical method. Statistical data were analyzed using SAS 9.4. C&RT and Apriori of data mining conducted in IBM SPSS Modeler 13 served as a supplement to statistics.

RESULTS

High odds of the spousal concordance of diabetes were associated with old age, middle levels of urbanization, and high comorbidities (all P < 0.05). The dual PSM analysis revealed that the risk of diabetes concordance was significantly higher in couples (5.19%) than in noncouples (0.09%; OR = 61.743, P < 0.0001).

CONCLUSIONS

A high concordance rate of diabetes in couples may indicate the influences of assortative mating and shared environment. Diabetes in a spouse implicates its risk in the partner. Family-based diabetes care that emphasizes the screening of couples at risk of diabetes by using the identified risk factors is suggested in prospective clinical practice interventions.

Epidemiology of pancreatic cancer in France: descriptive study from the French national hospital database

INTRODUCTION

Although indirect evidence suggests that the incidence of pancreatic adenocarcinoma has increased in the last decade, few data are available in European countries. The aim of the present study was to update the epidemiology of pancreatic cancer in France in 2014 from the French national hospital database (Programme de Médicalisation des Systèmes d'Information).

PATIENTS AND METHODS

All patients hospitalized for pancreatic cancer in France in 2014 in public or private institutions were included. Patient and stays (length, type of support, institutions) characteristics were studied. The results were compared with those observed in 2010.

RESULTS

A total of 13 346 (52% men, median age 71 years) new patients were treated for pancreatic cancer in 2014, accounting for a 12.5% increase compared with 2010. Overall, 22% of patients were operated on. Liver metastases were present in 60% of cases. The disease accounted for 146 680 hospital stays (+24.8% compared with 2010), 76% of which were related to chemotherapy (+32%). The average annual number and length of stay were 7 and 2.6 days, respectively. In 2014, 11 052 deaths were reported (+15.8%).

CONCLUSION

Approximately 13 350 new cases of pancreatic cancer were observed in France in 2014. The increase in incidence was associated with a marked increase in hospital stays for chemotherapy.

Associations between prediagnostic blood glucose levels, diabetes, and glioma

Previous literature indicates that pre-diagnostic diabetes and blood glucose levels are inversely related to glioma risk. To replicate these findings and determine whether they could be attributed to excess glucose consumption by the preclinical tumour, we used data from the Apolipoprotein MOrtality RISk (AMORIS) (n = 528,580) and the Metabolic syndrome and Cancer project (Me-Can) cohorts (n = 269,365). We identified individuals who were followed for a maximum of 15 years after their first blood glucose test until glioma diagnosis, death, emigration or the end of follow-up. Hazard ratios (HRs), 95% confidence intervals (CIs) and their interactions with time were estimated using Cox time-dependent regression. As expected, pre-diagnostic blood glucose levels were inversely related to glioma risk (AMORIS, P_trend = 0.002; Me-Can, P_trend = 0.04) and pre-diagnostic diabetes (AMORIS, HR = 0.30, 95% CI 0.17 to 0.53). During the year before diagnosis, blood glucose was inversely associated with glioma in the AMORIS (HR = 0.78, 95% CI 0.66 to 0.93) but not the Me-Can cohort (HR = 0.99, 95% CI 0.63 to 1.56). This AMORIS result is consistent with our hypothesis that excess glucose consumption by the preclinical tumour accounts for the inverse association between blood glucose and glioma. We discuss additional hypothetical mechanisms that may explain our paradoxical findings.

Insights into the relationships between diabetes, prediabetes, and cancer

Diabetes mellitus and cancer are two growing health problems. They have in common many modifiable risk factors including sex, age, obesity, physical activity, diet, alcohol, and smoking, and have a long latency before overtly manifesting. Patients with diabetes experience a roughly 20-25% higher cancer incidence compared to individuals without diabetes, and it depends on cancer site. Moreover, patients with diabetes who further develop cancer have increased early and late mortality in comparison with cancer patients without diabetes. Prediabetes and metabolic syndrome are also related to an increased risk of developing and die from cancer. Possible mechanisms linking diabetes and prediabetes with cancer include hyperglycemia (endogenous or exogenous), hyperinsulinemia, and alterations of insulin-like growth factor system, chronic subclinical inflammation, abnormalities in sex hormone metabolism, and adipokines. It becomes crucial to define the right orientation of the associations between diabetes and cancer in order to identify the modifiable pathogenic mechanisms. The common soil hypothesis claims that prediabetes and diabetes, as well as metabolic syndrome, may be considered a surrogate sign for dietary risk factors of cancer. The clepsydra of foods may help choose foods associated with healthy benefit while avoiding foods associated with harm, including cancer.

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.

2017 update on the relationship between diabetes and colorectal cancer: epidemiology, potential molecular mechanisms and therapeutic implications

Worldwide deaths from diabetes mellitus (DM) and colorectal cancer increased by 90% and 57%, respectively, over the past 20 years. The risk of colorectal cancer was estimated to be 27% higher in patients with type 2 DM than in non-diabetic controls. However, there are potential confounders, information from lower income countries is scarce, across the globe there is no correlation between DM prevalence and colorectal cancer incidence and the association has evolved over time, suggesting the impact of additional environmental factors. The clinical relevance of these associations depends on understanding the mechanism involved. Although evidence is limited, insulin use has been associated with increased and metformin with decreased incidence of colorectal cancer. In addition, colorectal cancer shares some cellular and molecular pathways with diabetes target organ damage, exemplified by diabetic kidney disease. These include epithelial cell injury, activation of inflammation and Wnt/β-catenin pathways and iron homeostasis defects, among others. Indeed, some drugs have undergone clinical trials for both cancer and diabetic kidney disease. Genome-wide association studies have identified diabetes-associated genes (e.g. TCF7L2) that may also contribute to colorectal cancer. We review the epidemiological evidence, potential pathophysiological mechanisms and therapeutic implications of the association between DM and colorectal cancer. Further studies should clarify the worldwide association between DM and colorectal cancer, strengthen the biological plausibility of a cause-and-effect relationship through characterization of the molecular pathways involved, search for specific molecular signatures of colorectal cancer under diabetic conditions, and eventually explore DM-specific strategies to prevent or treat colorectal cancer.

Colon cancer modulation by a diabetic environment: A single institutional experience

Background

Multiple observational studies suggest an increased risk of colon cancer in patients with diabetes mellitus (DM). This can theoretically be the result of an influence of the diabetic environment on carcinogenesis or the tumor biologic behavior.

Aim

To gain insight into the influence of a diabetic environment on colon cancer characteristics and outcomes.

Material and methods

Retrospective analysis of clinical records in an academic tertiary care hospital with detailed analysis of 81 diabetic patients diagnosed of colon cancer matched with 79 non-diabetic colon cancer patients. The impact of streptozotocin-induced diabetes on the growth of colon cancer xenografts was studied in mice.

Results

The incidence of DM in 1,137 patients with colorectal cancer was 16%. The diabetic colon cancer cases and non-diabetic colon cancer controls were well matched for demographic and clinical variables. The ECOG Scale Performance Status was higher (worse) in diabetics (ECOG ≥1, 29.1% of controls vs 46.9% of diabetics, p = 0.02), but no significant differences were observed in tumor grade, adjuvant therapy, tumor site, lymphovascular invasion, stage, recurrence, death or cancer-related death. Moreover, no differences in tumor variables were observed between patients treated or not with metformin. In the xenograft model, tumor growth and histopathological characteristics did not differ between diabetic and nondiabetic animals.

Conclusion

Our findings point towards a mild or negligible effect of the diabetes environment on colon cancer behavior, once cancer has already developed.

[Breast cancer and diabetes mellitus: Complex interactions]

The aim of this literature review was to quantify the incidence and mortality of breast cancer for women treated for a diabetes mellitus and to analyze the complex relationship between these two common diseases.

METHODS

The articles analyzed were extracted from the PubMed database from 2000 to 2015. A total of 22 case/control studies or cohorts were retained, allowing the realization of a meta-analysis.

RESULTS

The incidence of breast cancer for women with diabetes is significantly increased for cohorts (RR=1.32; 95% CI: 1.06 to 1.65) and not significantly for case/control studies (RR=1.46; 95% CI: 0.99 to 2.26). Overall, mortality of women with breast cancer is significantly increased for diabetic patients compared with non-diabetic patients (RR=1.53; 95% CI: 1.23 to 1.90). The links between diabetes and breast cancer are explained by common risk factors (overweight/obesity, qualitative and quantitative dietary errors, physical inactivity), biological changes and the impact of some anti-diabetic treatments or hormonotherapy.

CONCLUSION

Physicians facing a diabetic patient treated for breast cancer have a role in choosing the best anti-diabetic treatment and implementing lifestyle modifications. Diabetic women without breast cancer should participate in organized breast screening programs and have an annual breast clinical examination.