Association between type 2 diabetes and cancer incidence in China: data in hospitalized patients from 2006 to 2013

A large-scale, observational study to investigate the current status of diabetes complication and their prevention in Japan: incidence/risk factors for malignancies during follow-up-JDCP study 11 (English version)

In the large-scale, prospective, observational JDCP study, a total of 5944 people with type 2 diabetes (mean age at baseline, 61.4 years old; women, 39.9%; and duration of diabetes, 10.8 years) were followed up for incidence of malignancy. During a mean 5.38 ± 2.92 years of follow-up, malignancies occurred in 322 individuals, accounting for a crude incidence of 10.35/1000 person-years. The 3 most frequently reported malignancies included colorectal cancers (20.4%), breast cancer (16.5%) and lung cancers (13.6%) in women, and gastric cancers (18.3%), colorectal cancers (15.7%) and lung/prostate cancers (12.7%) in men. During follow-up, men had a significantly higher relative risk for malignancy than women. In contrast, women had a significantly shorter time to the first diagnosis of malignancy following a diagnosis of diabetes than men (13.79 ± 7.90 and 17.11 ± 8.50 years, respectively), although there was no marked difference in the age at the diagnosis of malignancy (67.39 ± 7.27 and 68.44 ± 6.62 years, respectively). Cox proportional hazard models revealed that increasing age, a history of drinking and a history of acute myocardial infarction were significantly associated with an increased risk of malignancy. This report may be of interest in that it provides valuable insight into which malignancies Japanese people with type 2 diabetes are likely to be at risk of developing over time.

[Type-2-diabetes and gastrointestinal cancer screening]

More than 8000000 Germans suffer from diabetes. People with type-2-diabetes (T2D) are at increased risk of gastrointestinal adenocarcinomas. They often develop cancer at younger age and their tumor-specific 5-year-survival is generally shorter. Cancer has become the leading cause of death of T2D-patients. Both chronic hyperglycemia and insulin resistance can stimulate gastrointestinal (GI) tumor growth. T2D can cause colorectal, pancreatic, hepatocellular, biliary and gastric cancer as well as esophageal adenocarcinoma. Both low-risk lifestyle and gastrointestinal cancer screening are effective and reduce GI cancer risk and GI cancer mortality of T2D-patients.

Krebsrisiko bei Prädiabetes und Typ-2-Diabetes mellitus

Krebs ist nun die führende Todesursache bei Typ-2-Diabetes mellitus (T2D). Prädiabetes und T2D erhöhen das Risiko für bestimmte Tumoren. Zu den Prädiabetes- bzw. T2D-assoziierten Malignomen zählen gastrointestinale, gynäkologische, urologische und endokrine Karzinome aber auch Leukämien. Prädiabetes und T2D bedingen eine 1,2- bis 2,7-fach erhöhte Krebssterblichkeit. Zugrundeliegende Mechanismen der Assoziation zwischen T2D und Krebs beinhalten die chronische Hyperglykämie, einen chronischen systemischen Entzündungszustand, oxidativen Stress, Dyslipidämie, die Insulinresistenz sowie chronisch erhöhte Spiegel von insulin-like growth factor 1 (IGF-1) und von Insulin. Eine dauerhafte Gewichtsreduktion kann das Krebsrisiko adipöser T2D-Patienten signifikant senken. Ein gesunder Lebensstil und die regelmäßige Teilnahme an Vorsorgeuntersuchungen sind wichtig und können die Krebsmortalität von Diabetespatienten erheblich verringern.

Metformin inhibits tumor growth and affects intestinal flora in diabetic tumor-bearing mice

Many studies have found that diabetes increases the risk of some cancers such as hepatocellular carcinoma. However, there are few studies on the relationship between the two diseases and their effects on intestinal flora. Therefore, we used streptozotocin and high-fat diet to establish a mouse model of type 2 diabetes, and then inoculated the Huh-7 hepatocellular carcinoma cells to obtain mouse diabetic tumor model. Mice inoculated with Huh-7 cells alone served as control. The tumor size in the diabetic tumor group was significantly higher than that in the tumor group. Our study also showed that the expression levels of inflammation-related factors (TNFα, IL-1β, IL-6, TLR4 and MCP1) in the diabetic tumor group were significantly higher than that in the tumor group. We found that metformin alleviated blood glucose level, reduced the expressions of inflammation-related factors and retarded xenograft tumor growth in the diabetic tumor group, but it couldn't reduce the tumor growth in the tumor group. Subsequent studies found that the content of some short chain fatty acids (SCFAs) including acetic acid, propionic acid and isobutyric acid decreased significantly in diabetic tumor group. Metformin increased short chain fatty acid levels (acetic acid, butyic acid and valeric acid) and enriched the abundance of SCFA-producing bacterial genera such as Ruminococcaceae, Clostridiales, Anaerovorax, Odoribacter and Marvinbryantia. In conclusion, type 2 diabetes could promote the growth of hepatoma cells in mice. Metformin could inhibit the growth of tumor under the condition of diabetes and play a role in the intestinal homeostasis in mice.

Glucose Intolerance and Cancer Risk: A Community-Based Prospective Cohort Study in Shanghai, China

Background

Cancer becomes the leading cause of premature death in China. Primary objective of this study was to determine the major risk factors especially glucose intolerance for cancer prophylaxis.

Methods

A cluster sampling method was applied to enroll 10,657 community-based adults aged 15-92 years in Shanghai, China in 2013. A structured questionnaire and physical examination were applied in baseline survey. Prediabetes was diagnosed using 75-g oral glucose tolerance test. After excluding 1433 subjects including 224 diagnosed with cancer before and 1 year after baseline survey, the remaining 9,224 subjects were followed-up to December 31, 2020.

Results

A total of 502 new cancer cases were diagnosed. The cancer incidence was 10.29, 9.20, and 5.95/1,000 person-years in diabetes patients, those with prediabetes, and healthy participants, respectively (p<0.001). The multivariate Cox regression analysis indicated that age, prediabetes and diabetes, were associated with an increased risk of cancer in those <65 years, the hazard ratios (95% confidence interval) for prediabetes and diabetes were, 1.49(1.09-2.02) and 1.51(1.12-2.02), respectively. Glucose intolerance (prediabetes and diabetes) were associated with increased risks of stomach cancer, colorectal cancer, and kidney cancer in those <65 years. Anti-diabetic medications reduced the risk of cancer caused by diabetes. The multivariate Cox analysis showed that age, male, <9 years of education, and current smoking were associated with increased risks of cancer in those ≥65 years independently.

Conclusions

Glucose intolerance is the prominent cancer risk factor in adults <65 years. Lifestyle intervention and medications to treat glucose intolerance help prevent cancer in this population.

[Type-2-diabetes and cancer risk]

Type-2-diabetes (T2D) increases the risk for several cancers and cancer has become the major cause of death of T2D-patients. T2D is causally associated with colorectal, pancreatic, gallbladder, biliary, hepatocellular, gastric, esophageal, oral, breast, endometrial, ovary, kidney and thyroid cancers as well as leukemias. When T2D goes along with tobacco smoking, alcohol use, physical inactivity, excess body weight, poor diet, familial risk or certain chronic infections, the cumulative cancer risk rises, and T2D-patients often suffer from cancer disease at younger age. T2D-patients should be encouraged to join cancer screening programmes even at younger age than the average non-diabetic population.