Diabetes mellitus and the risk of cancer: results from a large-scale population-based cohort study in Japan

Diabetes mellitus and cancer risk: review of the epidemiological evidence

Diabetes mellitus and cancer are diseases of epidemic proportions across the globe. These diseases are influenced by many factors, both genetic and environmental. A possible association between diabetes and cancer risk has long been speculated. Increased incidence of several cancers has been observed in diabetes patients, notably pancreatic, hepatic, colorectal, breast, urinary tract, and endometrial cancers. In contrast, a decreased incidence of prostate cancer is observed in diabetes patients, implying a protective effect. Precise knowledge of the complex associations and interactions between these two conditions is of great importance for their prevention and treatment. Multiple potential mechanisms have been proposed, but they have tended to be site-specific. Possible common mechanisms for a biological link between diabetes and cancer include hyperinsulinemia, hyperglycemia, and inflammation. Today, 366 million people live with diabetes globally, and this figure is expected to increase. Thus, if diabetes is associated with even a small increase in cancer risk, this may have important consequences at the population level. The aim of this review is to summarize recent epidemiological evidence of an association between diabetes and total cancer and specific sites of cancer, and to consider causal associations between these diseases.

Diabetes increases the risk of breast cancer: a meta-analysis

The aim of this meta-analysis was to collate and analyse all primary observational studies investigating the risk of breast cancer (BC) associated with diabetes. In addition, we aimed to complete subgroup analyses by both type of diabetes and gender of study participants to further clarify the origin of any such association between the two. Studies were obtained from a database search of MEDLINE, EMBASE, PubMed, Current Contents Connect and Google Scholar with additional cross-checking of reference lists. Collated data were assessed for heterogeneity and a pooled odds ratio (OR) calculated. Forty-three studies were included in the meta-analysis with 40 studies investigating BC in women and six studies investigating BC in men. Overall, we found a significantly increased risk of BC associated with diabetes in women (OR 1.20, 95% confidence interval (CI) 1.13-1.29). After subgroup analysis by type of diabetes, the association was unchanged with type 2 diabetes (OR 1.22, 95% CI 1.07-1.40) and nullified with gestational diabetes (OR 1.06, 95% CI 0.79-1.40). There were insufficient studies to calculate a pooled OR of the risk of BC associated with type 1 diabetes. There was an increased risk of BC in males with diabetes mellitus; however, the results did not reach statistical significance (OR 1.29, 95% CI 0.99-1.67). In conclusion, diabetes increases the risk of BC in women. This association is confirmed in women with type 2 diabetes and supports the hypothesis that diabetes is an independent risk factor for BC.

Protection from non-alcoholic steatohepatitis and liver tumourigenesis in high fat-fed insulin receptor substrate-1-knockout mice despite insulin resistance

AIMS/HYPOTHESIS

Epidemiological studies have revealed that obesity and diabetes mellitus are independent risk factors for the development of non-alcoholic steatohepatitis (NASH) and hepatocellular carcinoma. However, the debate continues on whether insulin resistance as such is directly associated with NASH and liver tumourigenesis. Here, we investigated the incidence of NASH and liver tumourigenesis in Irs1 ( -/- ) mice subjected to a long-term high-fat (HF) diet. Our hypothesis was that hepatic steatosis, rather than insulin resistance may be related to the pathophysiology of these conditions.

METHODS

Mice (8 weeks old, C57Bl/6J) were given free access to standard chow (SC) or an HF diet. The development of NASH and liver tumourigenesis was evaluated after mice had been on the above-mentioned diets for 60 weeks. Similarly, Irs1 ( -/- ) mice were also subjected to an HF diet for 60 weeks.

RESULTS

Long-term HF diet loading, which causes obesity and insulin resistance, was sufficient to induce NASH and liver tumourigenesis in the C57Bl/6J mice. Obesity and insulin resistance were reduced by switching mice from the HF diet to SC, which also protected these mice against the development of NASH and liver tumourigenesis. However, compared with wild-type mice fed the HF diet, Irs1 ( -/- ) mice fed the HF diet were dramatically protected against NASH and liver tumourigenesis despite the presence of severe insulin resistance and marked postprandial hyperglycaemia.

CONCLUSIONS/INTERPRETATION

IRS-1 inhibition might protect against HF diet-induced NASH and liver tumourigenesis, despite the presence of insulin resistance.

Racial disparities in colorectal cancer incidence by type 2 diabetes mellitus status

PURPOSE

Type 2 diabetes mellitus (T2DM) prevalence has increased dramatically in the United States since the early 1970s. Though T2DM is known to be associated with colorectal cancer (CRC), information on racial differences in the relationship between T2DM and CRC is limited.

METHODS

Using a retrospective cohort design, we compared the association between T2DM and CRC, including subsites of the colon, in African Americans (AAs) and European Americans (EAs) in South Carolina, a region with large racial disparities in rates of both diseases. A total of 91,836 individuals who were ≥30 years old on 1 January 1990 and had ≥12 months of South Carolina Medicaid eligibility between 1 January 1990 and 31 December 1995 were included in the analyses. Cancer data from 1996 to 2007 included information on anatomic subsite.

RESULTS

Subjects who had T2DM (n = 6,006) were >50 % more likely to be diagnosed with colon cancer compared to those without T2DM (n = 85,681). The association between T2DM and colon cancer was higher in AAs [odds ratio (OR) = 1.72 (95 % confidence interval: 1.21, 2.46); n = 47,984] than among EAs (OR = 1.24; 0.73, 2.11; n = 43,703). Overall, individuals with T2DM were over twice as likely to be diagnosed with in situ or local colon cancer (OR = 2.12; 1.40, 3.22; n = 191) compared to those without T2DM, with a higher likelihood among AAs (OR = 2.49; 1.52, 4.09; n = 113).

CONCLUSIONS

Results from a Medicaid population in a high-risk region of the United States showed an increased likelihood of CRC with T2DM and suggest a racial disparity that disfavors AAs and provides further impetus for efforts aimed at diabetes prevention in this group.

Association between glucose tolerance level and cancer death in a general Japanese population: the Hisayama Study

The authors examined the associations of glucose tolerance status and fasting and 2-hour postload glucose levels with the risk of cancer death in a 19-year follow-up study of 2,438 Japanese subjects aged 40-79 years who underwent a 75-g oral glucose tolerance test (1988-2007). During follow-up, 229 subjects died of cancer. The risk of cancer death was significantly higher in subjects with fasting plasma glucose levels of ≥5.6 mmol/L or 2-hour postload glucose levels of ≥11.1 mmol/L than in those with the lowest fasting or 2-hour postload glucose levels, after adjustment for potentially confounding factors. According to glucose tolerance status, not only diabetes but also impaired fasting glycemia and impaired glucose tolerance were significant risk factors for cancer death (for impaired fasting glycemia, multivariable-adjusted hazard ratio (HR) = 1.49 (95% confidence interval (CI): 1.05, 2.11); for impaired glucose tolerance, HR = 1.52 (95% CI: 1.05, 2.22); and for diabetes, HR = 2.10 (95% CI: 1.41, 3.12)). With regard to site-specific cancers, elevated fasting or 2-hour postload glucose levels were associated with the risks of death from stomach, liver, and lung cancer. These findings suggest that both prediabetic hyperglycemia and diabetes are significant risk factors for cancer death in the general Japanese population.

A genetic variant in pre-miR-27a is associated with a reduced renal cell cancer risk in a Chinese population

BACKGROUND

MicroRNAs (miRNAs) are a class of small non-coding RNAs to regulate cell differentiation, proliferation, development, and apoptosis. The single nucleotide polymorphism (SNP) rs895819 is located at the terminal loop of pre-miR-27a. Here, we aimed to investigate whether SNP rs895819 was associated with the development of renal cell cancer (RCC) in a Chinese population.

METHODS

In this case-control study, we recruited 594 RCC patients and 600 cancer-free controls with frequency matched by age and sex. We genotyped this polymorphism using the TaqMan assay and assessed the effect of this polymorphism on RCC survival. Logistic regression model was used to assess the genetic effects on the development of RCC and interactions between rs895819 polymorphism and risk factors.

RESULTS

Compared with AA homozygote, individuals carrying AG/GG genotypes had a statistically significant reduced susceptibility to RCC (adjusted OR = 0.71, 95% CI = 0.56-0.90). Furthermore, AG/GG genotypes were associated with reduced RCC susceptibility in localized clinical stage (adjusted OR = 0.71, 95% CI = 0.55-0.91), and similar effects were observed in well differentiated and poorly differentiated RCC (adjusted OR = 0.71, 95% CI = 0.55-0.93 for well differentiated, adjusted OR = 0.51, 95% CI = 0.28-0.93 for poorly differentiated). We also observed that rs895819 had multiplicative interactions with age and hypertension. However, the polymorphism did not influence the survival of RCC.

CONCLUSION

Our results suggest that the pre-miR-27a rs895819 polymorphism can predict RCC risk in a Chinese population. Larger population-based prospective studies should be used to validate our findings.

Nutritional status in relation to lifestyle in patients with compensated viral cirrhosis

AIM: To assess the nourishment status and lifestyle of non-hospitalized patients with compensated cirrhosis by using noninvasive methods.

METHODS: The subjects for this study consisted of 27 healthy volunteers, 59 patients with chronic viral hepatitis, and 74 patients with viral cirrhosis, from urban areas. We assessed the biochemical blood tests, anthropometric parameters, diet, lifestyle and physical activity of the patients. A homeostasis model assessment-insulin resistance (HOMA-IR) value of ≥ 2.5 was considered to indicate insulin resistance. We measured height, weight, waist circumference, arm circumference, triceps skin-fold thickness, and handgrip strength, and calculated body mass index, arm muscle circumference (AMC), and arm muscle area (AMA). We interviewed the subjects about their dietary habits and lifestyle using health assessment computer software. We surveyed daily physical activity using a pedometer. Univariate and multivariate logistic regression modeling were used to identify the relevant factors for insulin resistance.

RESULTS: The rate of patients with HOMA-IR ≥ 2.5 (which was considered to indicate insulin resistance) was 14 (35.9%) in the chronic hepatitis and 17 (37.8%) in the cirrhotic patients. AMC (%) (control vs chronic hepatitis, 111.9% ± 10.5% vs 104.9% ± 10.7%, P = 0.021; control vs cirrhosis, 111.9% ± 10.5% vs 102.7% ± 10.8%, P = 0.001) and AMA (%) (control vs chronic hepatitis, 128.2% ± 25.1% vs 112.2% ± 22.9%, P = 0.013; control vs cirrhosis, 128.2% ± 25.1% vs 107.5% ± 22.5%, P = 0.001) in patients with chronic hepatitis and liver cirrhosis were significantly lower than in the control subjects. Handgrip strength (%) in the cirrhosis group was significantly lower than in the controls (control vs cirrhosis, 92.1% ± 16.2% vs 66.9% ± 17.6%, P < 0.001). The results might reflect a decrease in muscle mass. The total nutrition intake and amounts of carbohydrates, protein and fat were not significantly different amongst the groups. Physical activity levels (kcal/d) (control vs cirrhosis, 210 ± 113 kcal/d vs 125 ± 74 kcal/d, P = 0.001), number of steps (step/d) (control vs cirrhosis, 8070 ± 3027 step/d vs 5789 ± 3368 step/d, P = 0.011), and exercise (Ex) (Ex/wk) (control vs cirrhosis, 12.4 ± 9.3 Ex/wk vs 7.0 ± 7.7 Ex/wk, P = 0.013) in the cirrhosis group was significantly lower than the control group. The results indicate that the physical activity level of the chronic hepatitis and cirrhosis groups were low. Univariate and multivariate logistic regression modeling suggested that Ex was associated with insulin resistance (odds ratio, 6.809; 95% CI, 1.288-36.001; P = 0.024). The results seem to point towards decreased physical activity being a relevant factor for insulin resistance.

CONCLUSION: Non-hospitalized cirrhotic patients may need to maintain an adequate dietary intake and receive lifestyle guidance to increase their physical activity levels.

Type 2 diabetes mellitus, insulin-use and risk of bladder cancer in a large cohort study

Type 2 diabetes mellitus (T2DM) is associated with increased bladder cancer incidence in some, but not all, studies. Many studies had limited statistical power and few examined risk by insulin-use, duration of diabetes or cancer stage. We examined the association between T2DM and bladder cancer incidence in the Cancer Prevention Study II Nutrition Cohort, a large prospective study with information on insulin-use and duration of diabetes. Diabetes and insulin-use were ascertained from a questionnaire at study enrollment in 1992 or 1993 and updated in 1997 and every 2 years thereafter. During follow-up through 2007, 1,852 cases of incident bladder cancer were identified among 172,791 participants. Multivariable adjusted relative risks (RRs) and 95% confidence intervals (CIs) were estimated using extended Cox regression modeling. There were no associations of T2DM with the risk of bladder cancer overall (RR = 1.01, 95% CI: 0.87-1.17), noninvasive disease (RR = 0.93, 95% CI: 0.76-1.14) or invasive disease (RR = 1.13, 95% CI: 0.91-1.40). Compared to participants without T2DM, risk of invasive bladder cancer was higher among participants who had had T2DM for >15 years (RR = 1.63, 95% CI: 1.09-2.43) and among those using insulin (RR = 1.64, 95% CI: 1.18-2.27). These results do not support an association of T2DM with overall bladder cancer incidence, but do suggest positive associations of long-term T2DM and insulin-use or other factors correlated with severe diabetes, with invasive bladder cancer incidence.

Type 2 diabetes and risk of prostate cancer: a meta-analysis of observational studies

BACKGROUND

Emerging evidence suggests that diabetes may increase the risk of cancers. However, available evidence on prostate cancer is conflicting. We therefore examined the association between Type 2 diabetes and risk of prostate cancer by conducting a detailed meta-analysis of all studies published regarding this subject.

METHODS

PubMed database and bibliographies of retrieved articles were searched for epidemiological studies (published between 1970 and 2011), investigating the relationship between Type 2 diabetes and prostate cancer. Pooled risk ratio (RR) was calculated using random-effects model. Subgroup, sensitivity analysis and cumulative meta-analysis were also done.

RESULTS

Forty-five studies (29 cohort and 16 case-control studies) involving 8.1 million participants and 132 331 prostate cancer cases detected a significant inverse association between Type 2 diabetes and risk of prostate cancer (RR 0.86, 95% confidence interval (CI) 0.80-0.92). For cohort studies alone, the RR was 0.87 (95% CI 0.80-0.94), and for case-control studies alone, the RR was 0.85 (95% CI 0.74-0.96). Sensitivity analysis done by excluding one outlier further strengthened our negative association (RR 0.83, 95% CI 0.78-0.87). No evidence of publication bias was observed.

CONCLUSIONS

This meta-analysis provides strongest evidence supporting that Type 2 diabetes is significantly inversely associated with risk of developing prostate cancer.

Incidence and predictors of all-cause and site-specific cancer in type 2 diabetes: the Fremantle Diabetes Study

OBJECTIVE

To explore the relationship between diabetes and cancer.

DESIGN

The Fremantle Diabetes Study (FDS) was a community-based longitudinal observational study of 1426 subjects, 1294 of which had type 2 diabetes.

METHODS

The FDS type 2 cohort and four age-, sex- and postcode-matched controls per case were followed for cancer events from 1993 until mid-2010 and incidence rate ratios (IRRs) were calculated. Competing risks proportional hazards models generated risk factors for incident cancers in the diabetic group.

RESULTS

There were 309 first cancers over 13 051 patient-years, or 2368 (95% confidence interval (95% CI) 2111-2647)/100 000 patient-years in the diabetes patients vs 1131 over 60 324 patient-years (1875 (1769-1987)/100 000 patient-years) in the controls. For those aged ≥45 years, the risk of all-cause cancer was elevated in type 2 diabetic men (IRRs 1.23, 95% CI 1.04-1.45) and women (1.30, 1.06-1.59). The incidence of colorectal cancer was increased (1.36, 1.01-1.82), especially in diabetic men aged 75-84 years (2.14, 1.22-3.64). Age at diabetes diagnosis (sub-hazard ratio 1.05, 1.02-1.09), calcium channel blocker therapy (2.37, 1.39-4.06), recent exercise (2.11, 1.06-4.20) and serum total cholesterol (0.68, 0.52-0.88) increased colorectal cancer risk. Pancreatic cancer was also more frequent in the diabetic patients (IRR 2.26, 1.20-4.10). Diabetic men and women had similar risks of prostate and breast cancer to those of controls (0.83, 0.59-1.14 and 0.86, 0.52-1.36).

CONCLUSIONS

Type 2 diabetes is associated with a moderately increased cancer risk in well-characterised community-based patients, especially pancreatic cancer and colorectal cancer in older men. Recommended cancer screening should be considered as part of routine diabetes management.

Diabetes and breast cancer risk: a meta-analysis

Background:

The potential of an increased risk of breast cancer in women with diabetes has been the subject of a great deal of recent research.

Methods:

A meta-analysis was undertaken using a random effects model to investigate the association between diabetes and breast cancer risk.

Results:

Thirty-nine independent risk estimates were available from observational epidemiological studies. The summary relative risk (SRR) for breast cancer in women with diabetes was 1.27 (95% confidence interval (CI), 1.16–1.39) with no evidence of publication bias. Prospective studies showed a lower risk (SRR 1.23 (95% CI, 1.12–1.35)) than retrospective studies (SRR 1.36 (95% CI, 1.13–1.63)). Type 1 diabetes, or diabetes in pre-menopausal women, were not associated with risk of breast cancer (SRR 1.00 (95% CI, 0.74–1.35) and SRR 0.86 (95% CI, 0.66–1.12), respectively). Studies adjusting for body mass index (BMI) showed lower estimates (SRR 1.16 (95% CI, 1.08–1.24)) as compared with those studies that were not adjusted for BMI (SRR 1.33 (95% CI, 1.18–1.51)).

Conclusion:

The risk of breast cancer in women with type 2 diabetes is increased by 27%, a figure that decreased to 16% after adjustment for BMI. No increased risk was seen for women at pre-menopausal ages or with type 1 diabetes.

Diabetes and risk of esophageal and gastric adenocarcinomas

Diabetes has been consistently associated with an increased risk of liver, pancreas and endometrial cancer and has been implicated as a risk factor for esophageal and gastric cancers, although this association has been less well studied. We sought to determine the role of diabetes in the etiology of esophageal, gastric cardia and distal gastric adenocarcinomas (DGAs). This analysis included patients with esophageal adenocarcinoma (EA) (n = 209), gastric cardia adenocarcinoma (GCA) (n = 257) and DGA (n = 382), and 1,309 control participants from a population-based case-control study conducted in Los Angeles County. The study included non-Hispanic whites, African Americans, Hispanics and Asian Americans. The association of diabetes with the three tumor types was estimated using polytomous logistic regression. Odds ratios (ORs) and corresponding 95% confidence intervals (CIs) were estimated. Nine percent of control participants and 13% of the case patients reported a history of diabetes. After adjustment for age, gender, race, birthplace, education, cigarette smoking status and body mass index, diabetes was associated with an increased risk of EA (OR, 1.48; 95% CI, 0.94-2.32; p = 0.089) and DGA (OR, 1.47; 95% CI, 1.01-2.15; p = 0.045), but was not associated with risk of GCA (OR, 0.96; 95% CI, 0.59-1.55; p = 0.87). However, the association between diabetes and risk of DGA was statistically significant only among patients for whom we interviewed their next of kin. Our study further investigated the association between diabetes and adenocarcinomas of the esophagus and distal stomach.

Type II diabetes mellitus and the incidence of epithelial ovarian cancer in the cancer prevention study-II nutrition cohort

BACKGROUND

Despite consistent associations of type II diabetes mellitus with hormonally related cancers such as breast and endometrium, the relation between type II diabetes mellitus and ovarian cancer risk is unclear.

METHODS

Associations of type II diabetes mellitus status, duration, and insulin use with epithelial ovarian cancer overall, and with serous and nonserous histologic subtypes were examined in the Cancer Prevention Study-II Nutrition Cohort, a prospective study of U.S. men and women predominantly aged 50 years and older. Between 1992 and 2007, 524 incident epithelial ovarian cancer cases were identified among 63,440 postmenopausal women. Multivariable-adjusted relative risks (RR) and 95% confidence intervals (CI) were computed using extended Cox regression to update diabetes status and bilateral oophorectomy status during follow-up.

RESULTS

Type II diabetes mellitus status (RR = 1.05; 95% CI, 0.75-1.46) and duration were not associated with epithelial ovarian cancer risk. Although not statistically significantly different (P(difference) = 0.39), the RR was higher for type II diabetes mellitus with insulin use (RR = 1.28; 95% CI, 0.74-2.24) than for type II diabetes mellitus without insulin use (RR = 0.96; 95% CI, 0.64-1.43). Diabetes seemed to be more strongly associated with nonserous (RR = 1.41; 95% CI, 0.70-2.85) than serous (RR = 0.71; 95% CI, 0.41-1.23) histologic subtypes.

CONCLUSIONS

Type II diabetes mellitus was not associated with risk of epithelial ovarian cancer, although higher risks with nonserous subtypes and among insulin users cannot be ruled out.

IMPACT

Larger studies are needed to clarify associations of type II diabetes mellitus with or without insulin use with risk of ovarian cancer overall and by histologic subtypes.

OBAYA (obesity and adverse health outcomes in young adults): feasibility of a population-based multiethnic cohort study using electronic medical records

Background

Although obesity is a risk factor for many chronic diseases, we have only limited knowledge of the magnitude of these associations in young adults. A multiethnic cohort of young adults was established to close current knowledge gaps; cohort demographics, cohort retention, and the potential influence of migration bias were investigated.

Methods

For this population-based cross-sectional study, demographics, and measured weight and height were extracted from electronic medical records of 1,929,470 patients aged 20 to 39 years enrolled in two integrated health plans in California from 2007 to 2009.

Results

The cohort included about 84.4% of Kaiser Permanente California members in this age group who had a medical encounter during the study period and represented about 18.2% of the underlying population in the same age group in California. The age distribution of the cohort was relatively comparable to the underlying population in California Census 2010 population, but the proportion of women and ethnic/racial minorities was slightly higher. The three-year retention rate was 68.4%.

Conclusion

These data suggest the feasibility of our study for medium-term follow-up based on sufficient membership retention rates. While nationwide 6% of young adults are extremely obese, we know little to adequately quantify the health burden attributable to obesity, especially extreme obesity, in this age group. This cohort of young adults provides a unique opportunity to investigate associations of obesity-related factors and risk of cancer in a large multiethnic population.

Dietary glycemic load, glycemic index, and carbohydrates on the risk of primary liver cancer among Chinese women and men

BACKGROUND

Dietary glycemic index (GI) and glycemic load (GL) typically have a positive relationship with obesity and diabetes, which are risk factors for liver cancer. However, studies on their association with liver cancer have yielded inconsistent results. Therefore, we assessed the association of GI, GL, and carbohydrates with liver cancer risk.

PATIENTS AND METHODS

A total of 72 966 women and 60 207 men from the Shanghai Women's Health Study (SWHS) and the Shanghai Men's Health Study (SMHS) were included for analysis. Food frequency questionnaire (FFQ) data were used to calculate daily dietary GI, GL, and carbohydrate intake. These values were energy adjusted and categorized into quintiles. The hazard ratios (HRs) and 95% confidence intervals (CI) were calculated with adjustment for potential confounders.

RESULTS

After a median follow-up time of 11.2 years for the SWHS and 5.3 years for the SMHS, 139 and 208 incident liver cancer cases were identified in the SWHS and SMHS, respectively. In multivariable Cox regression models, no statistically significant trends by quintile of GI, GL, or carbohydrate intake were observed. Stratification by chronic liver disease/hepatitis, diabetes, or body mass index (BMI) did not alter the findings.

CONCLUSIONS

There is little evidence that dietary GI, GL, or carbohydrates affect the incidence of liver cancer in this Asian population.

Age- and sex-specific risks of colorectal cancers in diabetic patients

Diabetes has been reported to increase the risk of colorectal neoplasm in most but not all studies. However, the data on age- and sex-specific incidence rates and relative risks associated with diabetes are limited. We carried out this population-based cohort study to investigate the overall sex- and age-specific risks of colorectal cancer in association with diabetes. Diabetic patients (n = 615,532) and age- and sex-matched control individuals (n = 614,871), selected from the claim datasets, were followed up from 2000 to 2006. The rates of admission due to colon and rectum cancers were estimated using the person-years approach, and the age- and sex-specific hazard ratio (HR) for both the malignancies were determined using the Cox regression model. The overall incidence rate of colon cancer was 9.94 per 10,000 patient-years for the diabetic patients, as opposed to 7.84 per 10,000 patient-years for the control-group patients. The corresponding observation for rectal cancer was 7.16 and 6.28 per 10,000 patient-years. Diabetic patients aged ≥ 45 years had significantly high HRs for developing colon cancer (1.20-1.45-fold). We also noted a significantly high HR of rectal cancer in diabetic men (1.18-fold) aged ≥ 45 years, but not in diabetic women. In conclusion, diabetes may significantly increase the risk of colorectal cancer, especially in patients aged 45-64 years. Diabetologists should keep this relationship in mind while treating middle-aged diabetic men and should also advise these patients to undergo regular screening tests for colorectal cancer.

Development of a prediction model for 10-year risk of hepatocellular carcinoma in middle-aged Japanese: the Japan Public Health Center-based Prospective Study Cohort II

OBJECTIVE

The purpose of the present study was to develop a risk estimation model for the 10-year risk of hepatocellular carcinoma (HCC) that could be easily used in a general population to aid in the prevention of HCC.

METHODS

Our prediction model was derived from data obtained on 17,654 Japanese aged 40 to 69 years who participated in health checkups (follow-up: 1993-2006). Cox proportional hazards regression was applied to obtain coefficients for each predictor.

RESULTS

During follow-up, a total of 104 cases of HCC were newly diagnosed. After checking the model fit, we incorporated age, sex, alcohol consumption, body mass index, diabetes, coffee consumption, and hepatitis B and C virus infection into the prediction model. The model showed satisfactory discrimination (Harrell's c-index=0.94) and was well calibrated (the overall observed/expected ratio=1.03, 95% confidence interval=0.83-1.29). We also developed a simple risk scoring system. Those subjects with total scores of 17 or more under this system (score range: -1 to 19) had an estimated 10-year HCC risk of over 90%; those with 4 points or less had an estimated risk of less than 0.1%.

CONCLUSION

We developed a simple 10-year risk prediction model for HCC in the Japanese general population as a public education tool.

Diabetes and lung cancer among postmenopausal women

OBJECTIVE

Epidemiological evidence of diabetes as a lung cancer risk factor is limited and conflicting. Therefore, we assessed associations among diabetes, diabetes therapy, and lung cancer risk in postmenopausal women participating in the Women's Health Initiative (WHI) study.

RESEARCH DESIGN AND METHODS

Postmenopausal women (n = 145,765), ages 50-79 years, including 8,154 women with diabetes at study entry were followed for a mean of 11 years with 2,257 lung cancers diagnosed. Information on diabetes therapy was collected via two methods (self-reported information on treatment history collected on a questionnaire at baseline and a face-to-face review of current medication containers that participants brought to the baseline visit). Lung cancers were confirmed by central medical record and pathology report review. Cox proportional hazards regression models adjusted for lung cancer risk factors were used to estimate hazard ratios (HRs) (95% CI) for diagnosis of diabetes and treatment of disease as risk factors for lung cancer.

RESULTS

Compared with women without diabetes, women with self-reported treated diabetes had a significantly higher risk of lung cancer (HR 1.27 [95% CI 1.02-1.59]), with risks increasing for women with diabetes requiring insulin treatment (1.71 [1.15-2.53]). However, we did not observe a significant association between lung cancer risk and diabetes not treated with medication or with duration of diabetes.

CONCLUSIONS

Postmenopausal women with treated diabetes, especially those using insulin, have a significantly higher risk of lung cancer. The influence of diabetes severity and specific classes of therapy for diabetes on lung cancer risk require future study.

The relationship between glucose metabolism disorders and malignant thyroid disease

BACKGROUND

Previous studies have shown a positive relationship between insulin resistance and several common adult cancers. The present retrospective study aimed to investigate the association between glucose metabolism disorders (GMDs) and the prevalence of thyroid cancer.

METHODS

We investigated the data of 4272 patients who had undergone fine-needle aspiration biopsy (FNAB) of thyroid nodules. The biopsy results were evaluated as diagnostic or non-diagnostic and the diagnostic results were classified as benign, malignant, and indeterminate. In this study, we included 2234 of the above patients who had undergone FNAB at our hospital and whose biopsy results were evaluated as diagnostic and were classified as either benign or malignant. We obtained the cytologic data and the glucose metabolism status of these patients retrospectively.

RESULTS

Of the 2234 patients, 629 (28.1 %) had GMD (impaired fasting glucose, impaired glucose tolerance). Malignant cytology was determined in 106 (4.7 %) patients overall. Of the 629 patients with GMD, 582 (92.5 %) patients had benign cytology and 47 (7.5 %) patients had malignant cytology. Fifty-nine (3.7 %) of the 1605 normoglycemic patients had malignant cytology. Malignant cytology was determined more frequently ın the patients who had GMDs (p < 0.001).

CONCLUSION

The results demonstrated that thyroid cancer prevalence was higher in patients with GMD. According to our results, GMD should be considered as a risk factor for malignancy in the evaluation of thyroid nodules.

Cardiometabolic factors and breast cancer risk in U.S. black women

Previous studies have suggested that metabolic syndrome may be associated with an increased risk of breast cancer, particularly in postmenopausal women, but U.S. black women have not been assessed. We examined the associations of abdominal obesity, type 2 diabetes, hypertension, and high cholesterol individually and in combination with breast cancer incidence in the Black Women's Health Study. By means of Cox regression models, we estimated incidence rate ratios (IRR) and 95 % confidence intervals (CI) for the associations of baseline and time-dependent values of self-reported abdominal obesity, type 2 diabetes, hypertension, and high cholesterol with breast cancer incidence. During 516,452 person years of follow-up (mean years = 10.5; standard deviation = 2.9) from 1995 to 2007, 1,228 breast cancer cases were identified. After adjustment for age, education, body mass index at age 18, physical activity, and individual cardiometabolic factors, neither individual nor combinations of cardiometabolic factors were associated with breast cancer incidence overall; the multivariable IRR was 1.04 (95 % CI 0.86-1.25) for the combination of ≥3 factors relative to the absence of all factors, and 1.17 (0.85-1.60) for having all four factors. Among postmenopausal women, however, the comparable IRRs were 1.23 (0.93-1.62) and 1.63 (1.12-2.37), respectively. Our findings provide some support for an association between cardiometabolic factors and breast cancer incidence among postmenopausal U.S. black women.

Association of type 2 diabetes and colon adenomas

INTRODUCTION

Type 2 diabetes mellitus (DM) is associated with hyperinsulinemia, which may lead to increased risk of carcinogenesis by increasing insulin-like growth factor-1 level. In this study, we sought to determine the association between type 2 DM and colon adenomas.

METHODS

In this retrospective case-control study, all the colonoscopies performed in an urban medical center during a 3-year period were reviewed. Patients with adenomatous polyps were considered as cases (n = 261). Age- and sex-matched controls with a 2:1 ratio were selected (n = 522). Among diabetic subjects, the association of different anti-diabetic medications and HbA1C level with high-risk adenoma features was analyzed.

RESULTS

Type 2 DM was significantly associated with colon adenomas (odds ratio (OR) = 1.45, 95% confidence interval (CI) = 1.05-2.01, p = 0.024). Exposure to insulin (OR = 1.734, 95% CI = 1.13-2.65, p = 0.013) and thiazolidinediones (OR = 2.83, 95% CI = 1.28-6.26, p = 0.01) was associated with developing adenomas. Neither the type of antidiabetic medication nor the level of HbA1C was a predictor for high-risk adenomas. Smoking (OR = 1.47, 95% CI = 1.07-2.02, p = 0.02), use of aspirin (OR = 1.59, 95% CI = 1.15-2.20, p = 0.005), and statins (OR = 1.54, 95% CI = 1.13-2.10, p = 0.007) appeared to increase the risk of adenomas.

CONCLUSION

This study shows a significant association between type 2 DM and colon adenomas. Establishing this association may lead to inclusion of diabetic patients in the high-risk group for developing colorectal cancer.

Diabetes and thyroid cancer risk: literature review

Diabetic patients have a higher risk of various types of cancer. However, whether diabetes may increase the risk of thyroid cancer has not been extensively studied. This paper reviews and summarizes the current literature studying the relationship between diabetes mellitus and thyroid cancer, and the possible mechanisms linking such an association. Epidemiologic studies showed significant or nonsignificant increases in thyroid cancer risk in diabetic women and nonsignificant increase or no change in thyroid cancer risk in diabetic men. A recent pooled analysis, including 5 prospective studies from the USA, showed that the summary hazard ratio (95% confidence interval) for women was 1.19 (0.84-1.69) and was 0.96 (0.65-1.42) for men. Therefore, the results are controversial and the association between diabetes and thyroid cancer is probably weak. Further studies are necessary to confirm their relationship. Proposed mechanisms for such a possible link between diabetes and thyroid cancer include elevated levels of thyroid-stimulating hormone, insulin, glucose and triglycerides, insulin resistance, obesity, vitamin D deficiency, and antidiabetic medications such as insulin or sulfonylureas.

The influence of type 2 diabetes and glucose-lowering therapies on cancer risk in the Taiwanese

Objective. To investigate the association between type 2 diabetes, glucose-lowering therapies (monotherapy with either metformin, sulphonylurea or insulin) and cancer risk in Taiwan. Methods. Using Taiwan's National Health Research Institutes database of 1,000,000 random subjects from 2000–2008, we found 61777 patients with type 2 diabetes (age ≥20 years) and 677378 enrollees with no record of diabetes. Results. After adjusting for age and sex, we found patients with diabetes to have significantly higher risk of all cancers (OR: 1.176; 95% CI: 1.149–1.204, P < 0.001). Diabetic patients treated with insulin or sulfonylureas had significantly higher risk of all cancers, compared to those treated with metformin (OR: 1.583; 95% CI: 1.389–1.805, P < 0.001 and OR: 1.784; 95% CI: 1.406–2.262, P < 0.001). Metformin treatment was associated with a decreased risk of colon and liver cancer compared to sulphonylureas or insulin treatment. Sulfonylureas treatment was associated with an increased risk of breast and lung cancer compared to metformin therapy. Conclusions. Taiwanese with type 2 diabetes are at a high risk of breast, prostate, colon, lung, liver and pancreatic cancer. Those treated with insulin or sulfonylureas monotherapy are more likely to develop colon and liver cancer than those treated with metformin.

Diabetes mellitus and the incidence of colorectal cancer: an updated systematic review and meta-analysis

AIM

The purpose of this study was to determine whether diabetes mellitus is associated with an increased risk of colorectal cancer.

METHODS

Relevant studies were identified in MEDLINE and EMBASE (up until November 1st, 2011). Inclusion criteria were original, peer-reviewed publications, with case-control and cohort studies (for studies on diabetes mellitus and colorectal cancer). Summary relative risks with 95% confidence intervals were calculated with a random-effects model.

RESULTS

Twenty-four studies including eight case-control and 16 cohort studies, with a total of 3,659,341 participants, were included in this updated systematic review and meta-analysis, and all involved diabetes mellitus and colorectal cancer risk. Meta-analysis of the 24 included studies indicated that diabetes was associated with an increased risk of colorectal cancer, compared with no diabetes (summary RR of colorectal cancer incidence = 1.26, 95% CI = 1.20-1.31), without heterogeneity between studies (P(heterogeneity) = 0.296). Sub-group analyses found that these results were consistent between case-control and cohort studies and among studies conducted in different areas. The association between diabetes and colorectal cancer incidence did not differ significantly by sex and sub-sites. Insulin therapy was also positively associated with risk of colorectal cancer (summary RR = 1.61, 95% CI 1.18-1.35), with evidence of heterogeneity between studies (P(heterogeneity) = 0.014).

CONCLUSIONS

Our findings further support a relationship between diabetes and increased risk of colon and rectal cancer in both women and men, and insulin therapy for diabetes may increase this risk.

Diabetes mellitus is an independent risk factor for colorectal cancer

BACKGROUND

Epidemiological studies have suggested positive associations between diabetes and colorectal cancer. However, the findings were inconsistent, especially regarding specific sex or cancer subsite.

AIMS

To conduct a systematic review with meta-analysis to examine the association of diabetes mellitus with risk of colorectal cancer and to investigate whether the association is dependent on sex, cancer subsite, race/ethnicity, or duration of diabetes.

METHODS

Relevant studies were identified by searching Pubmed to May 12, 2011. The reference lists of identified articles were also reviewed. Two authors independently selected the studies and extracted relevant data. The study quality was assessed.

RESULTS

Thirty-nine studies (28 cohort studies and 11 case-control studies) were included in the final analysis. Compared with non-diabetic subjects, the pooled risk estimate of colorectal cancer for diabetic subjects was 1.29 (95% CI = 1.23-1.35). The subgroup analyses revealed that the risk was significantly increased for both genders, for every cancer subsite, and for both short duration and long duration of diabetes. Exposure to diabetes increased the risk of colorectal cancer for White and Asian, whereas there was no evidence of such an association either among Black or native Hawaiians.

CONCLUSIONS

Our results confirmed that subjects with diabetes are at modestly increased risk of developing colorectal cancer.

Consumption of n-3 fatty acids and fish reduces risk of hepatocellular carcinoma

BACKGROUND & AIMS

Fish is a rich source of n-3 polyunsaturated fatty acids (PUFAs), such as eicosapentaenoic acid (EPA), docosapentaenoic acid (DPA), and docosahexaenoic acid (DHA). Although consumption of fish and n-3 PUFA has been reported to protect against the development of some types of cancer, little is known about its association with hepatocellular carcinoma (HCC).

METHODS

We investigated the association between fish and n-3 PUFA consumption and HCC incidence (n = 398) in a population-based prospective cohort study of 90,296 Japanese subjects (aged, 45-74 y). Hazard ratios and 95% confidence intervals (CIs) for the highest vs the lowest quintile were estimated from multivariable adjusted Cox proportional hazards regression models. We also conducted subanalyses of subjects with known hepatitis B virus (HBV) or hepatitis C virus (HCV) status, and of subjects who were anti-HCV and/or hepatitis B surface antigen positive. All tests of statistical significance were 2-sided.

RESULTS

Among all subjects, consumption of n-3 PUFA-rich fish and individual n-3 PUFAs was associated inversely with HCC, in a dose-dependent manner. Hazard ratios for the highest vs lowest quintiles were 0.64 (95% CI, 0.42-0.96) for n-3 PUFA-rich fish, 0.56 (95% CI, 0.36-0.85) for EPA, 0.64 (95% CI, 0.41-0.98) for DPA, and 0.56 (95% CI, 0.35-0.87) for DHA. These inverse associations were similar irrespective of HCV or HBV status.

CONCLUSIONS

Consumption of n-3 PUFA-rich fish or n-3 PUFAs, particularly EPA, DPA, and DHA, appears to protect against the development of HCC, even among subjects with HBV and/or HCV infection.

Diabetes mellitus as a risk factor for gastrointestinal cancers among postmenopausal women

OBJECTIVES

While diabetes has been linked to several cancers in the gastrointestinal (GI) tract, findings have been mixed for sites other than colorectal and liver cancer. We used the Women's Health Initiative (WHI) data and conducted a comprehensive assessment of associations between diabetes and GI malignancy (esophagus, stomach, liver, biliary, pancreas, colon, and rectal).

METHODS

A total of 145,765 postmenopausal women aged 50-79 enrolled in the WHI were followed for a mean 10.3 years. Cox proportional hazard regression models were used to estimate hazard ratios (HRs) and 95 % confidence intervals (CIs) for the association between GI cancers and diagnosed diabetes, including its duration and treatment.

RESULTS

Diabetes at enrollment was associated with increased risk of liver (HR = 2.97; 95 % CI, 1.66-5.32), pancreatic (HR = 1.62; 95 % CI, 1.15-2.30), colon (HR = 1.38; 95 % CI, 1.14-1.66), and rectal (HR = 1.87, 95 % CI: 1.22-2.85) cancer. Diabetes severity, assessed by duration or need for pharmacotherapy, appeared to have stronger links to risk of liver, pancreatic, and rectal cancer, but not colon cancer. There was no statistically significant association of diabetes with biliary, esophageal, and stomach cancers.

CONCLUSION

Type 2 diabetes is associated with a significantly increased risk of cancers of the liver, pancreas, colon, and rectum in postmenopausal women. The suggestion that diabetes severity further increases these cancer risks requires future studies.

Modest increase in risk of specific types of cancer types in type 2 diabetes mellitus patients

Most studies associated diabetes mellitus (DM) with risk of cancer have focused on the Caucasian population and only a few types of cancer. Therefore, a large and comprehensive nationwide retrospective cohort study involving an Asian population was conducted to evaluate the risk of several major types of cancer among Type 2 DM patients. The study analyzed the nationwide population-based database from 1996 to 2009 released by the National Health Research Institute in Taiwan. Incidence and hazard ratios (HRs) were calculated for specific types of cancer. The overall risk of cancers was significantly greater in the DM cohort [N = 895,434; HR = 1.19, 95% confidence interval (CI) = 1.17-1.20], compared with non-DM controls (N = 895,434). Several organs in the digestive and urogenital systems showed increased risk of cancer. The three highest HRs were obtained from cancers of the liver (HR = 1.78, 95% CI = 1.73-1.84), pancreatic (HR = 1.52, 95% CI = 1.40-1.65), and uterus and corpus (HR = 1.38, 95% CI = 1.22-1.55). The risk increased with age, and men with DM aged ≥ 75 years exhibited the highest risk (HR = 7.76, 95% CI = 7.39-8.15). Subjects with DM in this population have a modest increased risk of cancer, similar to the Caucasian population for several specific types of cancer. Old men with DM have the highest risk of cancer. Careful screening for cancer in DM patients is important for early diagnosis and effective treatment.

Low glycemic load experimental diet more satiating than high glycemic load diet

Effective strategies for reducing food intake are needed to reduce risk of obesity-related cancers. We investigated the effect of low and high glycemic load (GL) diets on satiety and whether satiety varied by body mass index (BMI), gender, and serum leptin. Eighty normal weight (BMI = 18.5-24.9 kg/m²) and overweight/ obese (BMI = 28.0-40.0 kg/m²) adults participated in a randomized, crossover controlled feeding study testing low GL vs. high GL diets. The 28-day diets were isocaloric with identical macronutrient distributions, differing only in GL and fiber. Participants completed visual analog satiety surveys and fasting serum leptin after each 28-day period. T-tests compared mean within- and between-person satiety scores and leptin values. Participants reported 7% greater satiation on the low GL vs. the high GL diet (P = 0.03) and fewer food cravings on the low GL vs. the high GL diet (P < 0.001). Compared to males, females reported less hunger (P = 0.05) and more satiety on the low GL vs. the high GL diet (P < 0.01). Participants with low body fat (<25.0% for men; <32.0% for women) and BMI <25.0 kg/m² reported study food was tastier on the low GL vs. the high GL diet (P = 0.04 and P = 0.05, respectively). In summary, reducing GL, and/or increasing fiber, may be an effective way to lower calories consumed, improve energy balance, and ultimately reduce cancer risk.

Diabetes and cancer I: risk, survival, and implications for screening

Type 2 diabetes mellitus (DM) and cancer are common diseases that are frequently diagnosed in the same individual. An association between the two conditions has long been postulated. Here, we review the epidemiological evidence for increased risk of cancer, decreased cancer survival, and decreased rates of cancer screening in diabetic patients. The risk for several cancers, including cancers of the pancreas, liver, colorectum, breast, urinary tract, and endometrium, is increased in patients with DM. In a pooled risk analysis weighting published meta-analytic relative risk (RR) for individual cancer by differences in their incidence rates, we found a population RR of 0.97 (95 % CI, 0.75-1.25) in men and 1.29 (95 % CI, 1.16-1.44) in women. All meta-analyses showed an increased relative risk for cancer in diabetic men, except studies of prostate cancer, in which a protective effect was observed. The relationship between diabetes and cancer appears to be complex, and at present, a clear temporal relationship between the two conditions cannot be defined. DM also impacts negatively on cancer-related survival outcomes and cancer screening rates. The overwhelming evidence for lower cancer screening rates, increased incidence of certain cancers, and poorer prognosis after cancer diagnosis in diabetic patients dictates a need for improved cancer care in diabetic individuals through improved screening measures, development of risk assessment tools, and consideration of cancer prevention strategies in diabetic patients. Part two of this review focuses on the biological and pharmacological mechanisms that may account for the association between DM and cancer.

Evaluation of prevalent and incident ovarian cancer co-morbidity

BACKGROUND

The peak in incidence of ovarian cancer occurs around 65 years and concurrent increasing risk by age for a number of diseases strongly influence treatment and prognosis. The aim was to explore prevalence and incidence of co-morbidity in ovarian cancer patients compared with the general population.

METHODS

The study population was patients with ovarian cancer in Sweden 1993-2006 (n=11 139) and five controls per case (n=55 687). Co-morbidity from 1987 to 2006 was obtained from the Swedish Patient Register. Prevalent data were analysed with logistic regression and incident data with Cox proportional hazards models.

RESULTS

Women developing ovarian cancer did not have higher overall morbidity than other women earlier than 3 months preceding cancer diagnosis. However, at time of diagnosis 11 of 13 prevalent diagnosis groups were more common among ovarian cancer patients compared with controls. The incidence of many common diagnoses was increased several years following the ovarian cancer and the most common diagnoses during the follow-up period were thromboembolism, haematologic and gastrointestinal complications.

CONCLUSION

Women developing ovarian cancer do not have higher overall morbidity the years preceding cancer diagnosis. The incidence of many common diagnoses was increased several years following the ovarian cancer. It is crucial to consider time between co-morbidity and cancer diagnosis to understand and interpret associations.

Branched-chain amino acids prevent insulin-induced hepatic tumor cell proliferation by inducing apoptosis through mTORC1 and mTORC2-dependent mechanisms

Branched-chain amino acids (BCAA) supplementation has been reported to suppress the incidence of liver cancer in obese patients with liver cirrhosis or in obese and diabetic model animals of carcinogenesis. Whether BCAA directly suppresses cell proliferation of hepatic tumor cells under hyperinsulinemic condition remain to be defined. The aim of this study was to investigate the effects of BCAA on insulin-induced proliferation of hepatic tumor cells and determine the underlying mechanisms. BCAA suppressed insulin-induced cell proliferation of H4IIE, HepG2 cells. In H4IIE cells, BCAA did not affect cell cycle progression but increased apoptosis by suppressing expressions of anti-apoptotic genes and inducing pro-apoptotic gene via inactivation of PI3K/Akt and NF-κB signaling pathways. Further studies demonstrated that BCAA inhibited PI3K/Akt pathway not only by promoting negative feedback loop from mammalian target of rapamycin complex 1 (mTORC1)/S6K1 to PI3K/Akt pathway, but also by suppressing mTORC2 kinase activity toward Akt. Our findings suggest that BCAA supplementation may be useful to suppress liver cancer progression by inhibiting insulin-induced PI3K/Akt and subsequent anti-apoptotic pathway, indicating the importance of BCAA supplementation to the obese patients with advanced liver disease.

Prevalence of the DNA repair enzyme-NEIL1 gene mutation in patients with type 2 diabetes in the Turkish population

In spite of the fact that an indirect relationship between NEIL1 gene and Type 2 diabetes has been demonstrated in animal model studies, there have been no human studies showing this relationship. In our study, we aimed to show the relationship between NEIL1 mutation and Type 2 diabetes in humans. The study group consisted 70 patients with Type 2 diabetes and the control group consisted of 50 healthy individuals. The mean age was 53±11 yr and 49±11 yr, respectively. Two NEIL1 mutations (2.9%) were detected in the patient group. There was A→G change (133A→G) at the 133. position of the 8th exon with 257 bp length in base sequencing. There was no mutation in the control group. We searched NEIL1 gene mutation for the first time in patients with Type 2 diabetes. This mutation was "silent" as it did not cause any amino acid change. The effects of these mutations on the etiopathogenesis of disease are not known. Although the lysine encoded by AAG was identical to the lysine encoded by AAA, it is not clear if they have functional differences due to the changing environmental conditions. NEIL1 gene mutation may have causative role in the development of Type 2 diabetes.

All-cause cancer mortality over 15 years in multi-ethnic Mauritius: the impact of diabetes and intermediate forms of glucose tolerance

There are accumulating data describing the association between diabetes and cancer mortality from Westernised populations. There are no data describing the relationship between diabetes and cancer mortality in African or South Asian populations from developing countries. We explored the relationship of abnormal glucose tolerance and diabetes on cancer mortality risk in a large, multi-ethnic cohort from the developing nation of Mauritius. Population-based surveys were undertaken in 1987, 1992 and 1998. The 9559 participants comprised 66% of South Asian (Indian), 27% of African (Creole), and 7% of Chinese descent. Cox's proportional hazards model with time varying covariates was used to obtain hazard ratios (HRs) and 95% confidence intervals (95% CI) for risk of cancer mortality, after adjustment for confounding factors. In men, but not women, cancer mortality risk increased with rising 2h-PG levels with HR for the top versus bottom quintile of 2.77 (95%CI: 1.28 to 5.98). South Asian men with known diabetes had a significantly greater risk of cancer mortality than those with normal glucose tolerance (NGT) HR: 2.74 (95%CI: 1.00-7.56). Overall, impaired glucose tolerance was associated with an elevated risk of cancer mortality compared to NGT (HR: 1.47, 95% CI: 0.98-2.19), though this was not significant. We have shown that the association between abnormal glucose tolerance and cancer extends to those of African and South Asian descent. These results highlight the importance of understanding this relationship in a global context to direct future health policy given the rapid increase in type 2 diabetes, especially in developing nations.

The risk of cancer in people with diabetes and chronic kidney disease

BACKGROUND

Diabetes and chronic kidney disease (CKD) are both associated with an increased risk of cancer but it is unclear whether diabetes complicated by CKD further augments an individual's cancer risk. The aim of our study was to determine the association of CKD [defined as an estimated glomerular filtration rate (eGFR) < 60 mL/min] with the overall and site-specific risks of incident cancers among individuals with Type 2 diabetes.

METHODS

Cox proportional hazard regression models and competing risk analyses were used to examine the univariate and multivariate adjusted associations between reduced kidney function and the overall and site-specific risks of cancer in participants enrolled in the Action in Diabetes and Vascular disease: Preterax and Diamicron MR controlled evaluation (ADVANCE) trial.

RESULTS

Over a median follow-up of 5.0 years, 700 malignant neoplasms occurred in the 11 140 (6.4%) participants. There was no increase in overall cancer risk [adjusted hazard ratio: 1.07 (95% confidence interval: 0.89-1.29, P = 0.50)] or site-specific cancer risk for individuals with CKD (defined as eGFR < 60 mL/min) compared to those without CKD at baseline. These results were robust to multiple methods and thresholds used to estimate CKD.

CONCLUSIONS

Mild to moderate CKD does not increase the risk of cancer in people with Type 2 diabetes. ADVANCE is registered with ClincalTrial.gov (number NCT00145925).

ABO blood type, diabetes and risk of gastrointestinal cancer in northern China

AIM: To explore the potential risk factors related to gastrointestinal cancer in northern China.

METHODS: A total of 3314 cases of gastrointestinal cancer (esophageal, gastric, pancreatic and biliary) and 2223 controls (including healthy individuals, glioma and thyroid cancer) were analyzed by case-control study. Multivariable logistic regression analysis was applied to evaluate the association between different cancers and hepatitis B surface antigen, sex, age, blood type, diabetes, or family history of cancer.

RESULTS: Type 2 diabetes was significantly associated with gastric, biliary and pancreatic cancer with an OR of 2.0-3.0. Blood type B was significantly associated with esophageal cancer [odd ratio (OR) = 1.53, 95% confidence interval (CI) = 1.10-2.14] and biliary cancer (OR = 1.49, 95% CI = 1.09-2.05). The prevalence of type 2 diabetes was significantly higher in gastric, biliary and pancreatic cancers compared with other groups, with ORs ranging between 2.0 and 3.0. Family history of cancer was strongly associated with gastrointestinal compared with other cancers.

CONCLUSION: Blood type B individuals are susceptible to esophageal and biliary cancer. Type 2 diabetes is significantly associated with gastric, biliary and especially pancreatic cancer.

High susceptibility to zymbal gland and intestinal carcinogenesis in diabetic Otsuka long-evans Tokushima Fatty rats

Diabetes mellitus (DM) and obesity are believed to be risk factors for colorectal cancer in humans. In experiment 1, male nondiabetic Long-Evans Tokushima Otsuka (LETO) rats and Otsuka Long-Evans Tokushima Fatty (OLETF) rats, a model animal of type 2 DM, were whole-body X-irradiated (4 Gy) at 6 and 8 weeks of age and euthanized at 78 weeks of age (n=15, respectively). The incidences of small intestine adenocarcinoma in LETO and OLETF rats were 0% and 30%, respectively. In experiment 2, male LETO and OLETF rats (n=24, respectively) were given s.c. injections of 15 mg/kg azoxymethane (AOM) once weekly for 3 weeks and euthanized at 36 weeks of age. The incidences of Zymbal gland tumors in LETO and OLETF rats were 0% and 67%, respectively (P<0.001), whereas those of small intestine adenocarcinoma were 0% and 43% (P<0.001) and those of cecum/colon adenocarcinoma were 46% and 79% (P<0.05), respectively. Fatty change of hepatocytes was common in OLETF rats (63%) but not in LETO rats. Serum triglyceride and free fatty acid levels in OLETF rats were significantly higher than in LETO rats at sacrifice, whereas serum insulin levels in OLETF rats were very diverse. These data suggest that hyperlipidemia plays a significant role in high susceptibility to lower intestinal tract carcinogenesis in OLETF rats; this strain is susceptible to AOM-induced Zymbal gland carcinogenesis.

Diabetes mellitus and risk of hepatocellular carcinoma: a systematic review and meta-analysis

Studies of diabetes and hepatocellular carcinoma (HCC) yielded inconsistent findings. This meta-analysis was conducted to examine the association between diabetes and risk of HCC. Studies were identified by searching PUBMED and MEDLINE database up to February 2011. Pooled risk estimates were calculated using the random-effects model. Potential sources of heterogeneity were explored by subgroup analyses. A total of 17 case-control studies and 32 cohort studies were included in the meta-analysis. The combined risk estimate of all studies showed a statistically significant increased risk of HCC prevalence among diabetic individuals (RR = 2.31, 95% CI: 1.87-2.84). The pooled risk estimate of 17 case-control studies (OR = 2.40, 95% CI: 1.85-3.11) was slightly higher than that from 25 cohort studies (RR = 2.23, 95% CI: 1.68-2.96). Metformin treatment was potentially protective. On the contrary, long duration of diabetes and sulfonylureas or insulin treatment possibly increase HCC risk. Also meta-analysis of 7 cohort studies found a statistically significant increased risk of HCC mortality (RR = 2.43, 95% CI: 1.66-3.55) for individuals with (versus without) diabetes. This meta-analysis shows that diabetes is associated with moderately increased risk of HCC prevalence, as well as HCC mortality. Considering the rapidly increasing prevalence of diabetes mellitus, the study underlines the need for cancer prevention in diabetic individuals. Further investigation is needed to focus on the potential mechanism for the pathogenesis of HCC and the link between HCC and different types, severity, treatment and duration of diabetes.

Significantly increased risk of cancer in patients with diabetes mellitus: a systematic review and meta-analysis

OBJECTIVE

To conduct a review and meta-analysis of the effect of diabetes mellitus on the incidence of and mortality attributable to cancer at any anatomic site.

METHODS

We performed a search of MEDLINE and the Cochrane Library for pertinent articles published from the origin of these databases to July 5, 2010, and included them in a qualitative review and meta-analysis of the risk of all-cancer incidence and mortality in patients with diabetes.

RESULTS

Among patients with diabetes (n = 257,222) in 12 cohort studies, the cancer incidence was about 7%. The cancer mortality was approximately 3% among patients with diabetes (n = 152,091) in 19 cohort studies. The pooled adjusted risk ratio (RR) of all-cancer incidence was significantly elevated-RR, 1.10 (95% confidence interval [CI], 1.04 to 1.17) overall; RR, 1.14 (CI, 1.06 to 1.23) for men; and RR, 1.18 (CI, 1.08 to 1.28) for women. Diabetes was also associated with an increased RR of mortality across all cancer types-RR, 1.16 (CI, 1.03 to 1.30) overall; RR, 1.10 (CI, 0.98 to 1.23) for men; and RR, 1.24 (CI, 1.11 to 1.40) for women.

CONCLUSION

Cancer prevention and early detection by appropriate screening methods in patients with diabetes should be important components of clinical management and investigation, inasmuch as the exponentially increasing prevalence of diabetes will translate into substantial clinical and public health consequences on a global scale.

Happy experience of a medical doctor curing from pancreatic cancer: a 60-day diary

Pancreatic cancer was found by an abdominal CT scan in a medical doctor, the author of this article, before the appearance of any symptoms. After considering all the imaging findings including the CT, MRI, and PET, a diagnosis was made. He was admitted in the University of Tokyo Hospital on the 14th day after the CT finding. On the 18th day, the operation was successfully performed, and no tumor invading to adjacent tissue was seen. On the 29th day, 11th day after the operation, he left the hospital with a drain still in place to excrete abdominal exudation. The remaining drain was finally removed on the 60th day, and the treatment by the surgeon was completed. The chronological events that occurred during these 60 days are described in diary form. There is nothing superior to early detection and early treatment in the fight against cancer. He recommends everybody to receive periodical medical examinations before praying for good luck.

Hepatocellular carcinoma in non-alcoholic steatohepatitis: Growing evidence of an epidemic?

The incidence of hepatocellular carcinoma in non-viral-related chronic liver disease has gradually increased in Japan. Obesity and diabetes mellitus type 2 have been established as a significant risk factor for hepatocellular carcinoma (HCC) by epidemiologic observations and experimental studies. The risks of these factors for HCC are likely conferred by two factors: the increased risk for development of non-alcoholic steatohepatitis (NASH) and the carcinogenic potential of themselves. Hepatocellular carcinoma in NASH is difficult to evaluate because histological diagnosis is required for diagnosis of NASH, which can lead selection bias. Furthermore, end-stage NASH is in effect "burned-out" NASH, for which the diagnosis of NASH cannot be made any more. At all events, previous studies on the etiology of Japanese HCC showed that non-alcoholic fatty liver disease accounts for 1-5% of all HCC (male predominant, median age 72 years). They have high prevalences of obesity and/or diabetes mellitus type 2 and 10-75% of the HCC arose from non-cirrhotic livers. HCC in NASH may be of multicentric origin, similar to HCC based on viral hepatitis. Regular screening for HCC is extremely important especially in cirrhotic NASH patients and recurrence should be warned. In western and Asian countries, the prevalence of non-alcoholic fatty liver disease in the general population is increasing dramatically. Therefore, there is an urgent need to elucidate pathogenesis and clinical features of HCC in NASH. In this review we summarize current concepts for HCC in NASH.

The role of pre-existing diabetes mellitus on hepatocellular carcinoma occurrence and prognosis: a meta-analysis of prospective cohort studies

Background

The impact of pre-existing diabetes mellitus (DM) on hepatocellular carcinoma (HCC) occurrence and prognosis is complex and unclear. The aim of this meta-analysis is to evaluate the association between pre-existing diabetes mellitus and hepatocellular carcinoma occurrence and prognosis.

Methods

We searched PubMed, Embase and the Cochrane Library from their inception to January, 2011 for prospective epidemiological studies assessing the effect of pre-existing diabetes mellitus on hepatocellular carcinoma occurrence, mortality outcomes, cancer recurrence, and treatment-related complications. Study-specific risk estimates were combined by using fixed effect or random effect models.

Results

The database search generated a total of 28 prospective studies that met the inclusion criteria. Among these studies, 14 reported the risk of HCC incidence and 6 studies reported risk of HCC specific mortality. Six studies provided a total of 8 results for all-cause mortality in HCC patients. Four studies documented HCC recurrence risks and 2 studies reported risks for hepatic decomposition occurrence in HCC patients. Meta-analysis indicated that pre-existing diabetes mellitus (DM) was significantly associated with increased risk of HCC incidence [meta-relative risk (RR) = 1.87, 95% confidence interval (CI): 1.15–2.27] and HCC-specific mortality (meta-RR = 1.88, 95%CI: 1.39–2.55) compared with their non-DM counterparts. HCC patients with pre-existing DM had a 38% increased (95% CI: 1.13–1.48) risk of death from all-causes and 91% increased (95%CI: 1.41–2.57) risk of hepatic decomposition occurrence compared to those without DM. In DM patients, the meta-RR for HCC recurrence-free survival was 1.93(95%CI: 1.12–3.33) compared with non-diabetic patients.

Conclusion

The findings from the current meta-analysis suggest that DM may be both associated with elevated risks of both HCC incidence and mortality. Furthermore, HCC patients with pre-existing diabetes have a poorer prognosis relative to their non-diabetic counterparts.

Diabetes mellitus and gastric carcinoma: Is there an association?

Diabetes mellitus (DM) has been associated with the risk of several gastrointestinal cancers including liver, pancreas, colon and rectum. However, the evidence is inconclusive for gastric adenocarcinoma (GC). In the current review, we summarize 20 population-based cohort studies that compared GC incidence and mortality between diabetic and non-diabetic population. We discuss the shared risk factors and provide qualitative and quantitative (meta-analytic) summary of the current evidence evaluating the association by high-risk subgroups. The overall risk-estimate based on all studies did not show an increased risk of GC in diabetics. However, 2 cohort studies conducted in East Asian countries, where Helicobacter pylori infection and GC rates are higher, showed a higher risk of GC in diabetics. Additionally, high plasma glucose levels in the presence of Helicobacter pylori infection increased the risk of GC by over four times, suggesting a multiplicative effect. Results from the meta-analysis show that, the risk of GC was also higher in populations with greater prevalence of type 1 DM (relative risk = 1.60), suggesting an insulin-independent carcinogenic process in this subgroup. The risk of mortality due to GC was higher in diabetics compared to non-diabetics (relative risk = 1.62). Although the overall risk estimates do not show an association between DM and GC, complex interactions between infectious, molecular, demographic and host factors may convey a higher risk in certain subgroups. Future studies should be sufficiently powered for detailed subgroup analysis to elucidate the causative and mechanistic association between DM and GC.

Antidiabetes drugs correlate with decreased risk of lung cancer: a population-based observation in Taiwan

BACKGROUND

The risk of some forms of cancer has been found to be higher in patients with diabetes mellitus (DM) than in the general population. The aim of this study was to examine, with sufficient statistical power, the association between DM and lung cancer and the impact of antidiabetes drugs on lung cancer risk in Taiwan.

MATERIALS AND METHODS

From a randomly selected data set of 1 million National Health Insurance (NHI) claims in Taiwan from 2000-2005, 19,624 cases (patients ≥ 20 years of age) of newly diagnosed DM were identified. From the same data set, 78,496 enrollees with no record of DM were selected as controls and were matched in sex and age to the first group. The incidence of newly diagnosed lung cancer was compared between patients with DM and controls for a period of 9 years (2000-2008).

RESULTS

The multivariate Cox model analysis showed a slightly increased hazard ratio (HR) of 1.05 of lung cancer in patients with DM, but the association was not statistically significant. However the use of antidiabetes drugs, such as metformin, thiazolidinediones, or alpha-glucosidase inhibitors, correlates with a decreased lung cancer risk of 39%-45%. A significant association was found between lung cancer risk and male sex (HR, 2.23), pulmonary tuberculosis (HR, 1.60), chronic obstructive pulmonary disease (HR, 1.21), and age (HR, 1.07).

CONCLUSION

Patients with DM are not at increased risk for the development of lung cancer, but the use of antidiabetes drugs would considerably decrease the risk. In this cohort, male sex, age, pulmonary tuberculosis, and chronic obstructive pulmonary disease were all associated with an increased risk of lung cancer, consistent with findings in the literature and indicative of the validity of our study.

Risk of esophageal cancer in diabetes mellitus: a meta-analysis of observational studies

OBJECTIVE

Inconsistent findings from observational studies have prolonged the controversy over the effects of history of diabetes mellitus (DM) on the risk of esophageal cancer (EC). We conducted a meta-analysis of epidemiologic studies to evaluate the association of a history of DM with the risk of EC.

METHODS

We identified studies by a literature search of MEDLINE (from 1 January 1966) and EMBASE (from 1 January 1974), through 28 Feburary 2011, and by searching the reference lists of pertinent articles. Summary relative risks (SRRs) with 95% confidence intervals (CIs) were calculated with a random-effects model. All statistical tests were two-sided.

RESULTS

A total of 17 studies (6 case-control studies and 11 cohort studies) fulfilled the inclusion and exclusion criteria. Compared with non-diabetic individuals, diabetic individuals had a modestly increased risk of EC (SRRs 1.30, 95% CI: 1.12-1.50), with significant heterogeneity among studies (p = 0.042). In stratified analysis, the SRRs of EC were 1.28 (1.10-1.49) for diabetic men and 1.07 (95% CI, 0.71-1.62) for diabetic women, respectively. In addition, DM was associated with an increased risk of esophageal adenocarcinoma (SRR 2.12, 95% CI 1.01-4.46). There was no significant publication bias (p = 0.127 for Begg's adjusted rank correlation test and p = 0.629 for Egger's regression test).

CONCLUSION

These findings support the hypothesis that men with diabetes may have a modestly increased risk of EC, while diabetic women were not the case.