Type 2 diabetes, socioeconomic status and risk of cancer in Scotland 2001-2007

Melanoma risk, tumour stage, and melanoma-specific mortality in individuals with diabetes: a systematic review and meta-analysis

BACKGROUND

Cancer has become the leading diabetes-related cause of death in high-income countries, and more knowledge is needed to clarify the impact of diabetes on site-specific cancers. The purpose of this study is to assess the association between diabetes and malignant melanoma by conducting a comprehensive systematic review and meta-analysis.

METHODS

Using predefined eligibility criteria, PubMed, The Cochrane Library and Web of Science were systematically searched up to February 22, 2023. Exposure was defined as diabetes or type 2 diabetes and the outcomes were defined as melanoma incidence, melanoma stage or melanoma-specific mortality. The identified articles were evaluated by two independent reviewers and quality assessment was conducted using the Newcastle-Ottawa Scale for observational studies. Meta-analyses were conducted using RevMan 5.4.1 on melanoma risk using adjusted risk estimates and on melanoma stage using a dichotomous model.

RESULTS

The literature search revealed 20 studies in total eligible for inclusion, 14 for the analysis of melanoma risk, 3 for melanoma thickness and ulceration, and 4 for melanoma-specific survival. According to the meta-analyses, diabetes did not impact the risk of developing melanoma (RR:1.05, 95%CI:0.99-1.12, p = 0.10). However, type 2 diabetes was associated with more advanced melanoma stages at the time of diagnosis (Breslow-thickness > 1 mm: RR 1.35, 95%CI: 1.22-1.49, p = < 0.001) and presence of ulceration (RR 1.30, 95%CI: 1.00-1.68, p = 0.05). A meta-analysis on the association between diabetes and melanoma-specific mortality was not feasible due to diverse study designs.

CONCLUSION

Our meta-analysis found no association between diabetes and the risk of developing melanoma, but diabetes was associated with increased tumour thickness and the presence of ulceration at the time of diagnosis. Further research is warranted to explore the association between diabetes melanoma stage and prognosis.

TRIAL REGISTRATION

PROSPERO ID CRD42023394187.

The relationship between metabolic syndrome and its components with bladder cancer: a systematic review and meta-analysis of cohort studies

A previous meta-analysis, entitled "The association between metabolic syndrome and bladder cancer susceptibility and prognosis: an updated comprehensive evidence synthesis of 95 observational studies involving 97,795,299 subjects," focused on all observational studies, whereas in the present meta-analysis, we focused on cohort studies to obtain more accurate and stronger evidence to evaluate the association between metabolic syndrome and its components with bladder cancer. PubMed, Embase, Scopus, and Web of Science were searched to identify studies on the association between metabolic syndrome and its components with bladder cancer from January 1, 2000 through May 23, 2021. The pooled relative risk (RR) and 95% confidence intervals (CI) were used to measure this relationship using a random-effects meta-analytic model. Quality appraisal was undertaken using the Newcastle-Ottawa Scale. In total, 56 studies were included. A statistically significant relationship was found between metabolic syndrome and bladder cancer 1.09 (95% CI, 1.02 to 1.17), and there was evidence of moderate heterogeneity among these studies. Our findings also indicated statistically significant relationships between diabetes (RR, 1.23; 95% CI, 1.16 to 1.31) and hypertension (RR, 1.07; 95% CI, 1.01 to 1.13) with bladder cancer, but obesity and overweight did not present a statistically significant relationship with bladder cancer. We found no evidence of publication bias. Our analysis demonstrated statistically significant relationships between metabolic syndrome and the risk of bladder cancer. Furthermore, diabetes and hypertension were associated with the risk of bladder cancer.

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

AIMS

The association between type 2 diabetes mellitus (T2DM) and risk of head and neck cancer (HNC) remains unclear. This study aims to perform a system review and meta-analysis to explore this relationship.

METHODS

PubMed, Web of Science, and Embase databases were searched for studies published up to July 31, 2020, regarding the association between T2DM and HNC risk. A random-effects model was utilized to calculate summary relative risks (RRs) with corresponding 95% confidence intervals (CIs).

RESULTS

Fourteen case-control studies and thirteen cohort studies were included in our analysis. We observed a weak association between T2DM and risk of HNC overall, but there was no statistical significance (RR, 1.04; 95% CI, 0.88-1.23; I² = 83.2%). Interestingly, there was a strong association in East Asia (RR, 1.46; 95% CI, 1.21-1.77; I² = 36.6%). For HNC subtypes, T2DM conferred a significantly elevated risk in oral cancer (RR, 1.22; 95% CI, 1.01-1.47; I² = 89.0%). However, in subgroup analyses of smoking, alcohol use, and body mass index (BMI)/obesity adjustments, the association between T2DM and oral cancer risk became insignificant. In addition, T2DM was not associated with a statistically elevated risk of pharyngeal cancer (RR, 1.18; 95% CI, 0.94-1.49; I² = 72.9%) and laryngeal cancer (RR, 1.03; 95% CI, 0.88-1.22; I² = 71.2%).

CONCLUSIONS

This meta-analysis indicates that T2DM is associated with an increased risk of HNC in East Asia. As for site-specific cancer types, the risk of oral cancer was significantly increased in T2DM patients, which appear to be mediated or confounded by smoking, alcohol use, or BMI/obesity.

Heterogeneity in risk of prostate cancer: A Swedish population-based cohort study of competing risks and Type 2 diabetes mellitus

Most previous studies of prostate cancer have not taken into account that men in the studied populations are also at risk of competing event, and that these men may have different susceptibility to prostate cancer risk. The aim of our study was to investigate heterogeneity in risk of prostate cancer, using a recently developed latent class regression method for competing risks. We further aimed to elucidate the association between Type 2 diabetes mellitus (T2DM) and prostate cancer risk, and to compare the results with conventional methods for survival analysis. We analysed the risk of prostate cancer in 126,482 men from the comparison cohort of the Prostate Cancer Data base Sweden (PCBaSe) 3.0. During a mean follow-up of 6 years 6,036 men were diagnosed with prostate cancer and 22,393 men died. We detected heterogeneity in risk of prostate cancer with two distinct latent classes in the study population. The smaller class included 9% of the study population in which men had a higher risk of prostate cancer and the risk was stronger associated with class membership than any of the covariates included in the study. Moreover, we found no association between T2DM and risk of prostate cancer after removal of the effect of informative censoring due to competing risks. The recently developed latent class for competing risks method could be used to provide new insights in precision medicine with the target to classify individuals regarding different susceptibility to a particular disease, reaction to a risk factor or response to treatment.

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.

Cardiovascular Disease, Cancer, and Mortality Among People With Type 2 Diabetes and Alcoholic or Nonalcoholic Fatty Liver Disease Hospital Admission

OBJECTIVE

To describe associations between alcoholic liver disease (ALD) or nonalcoholic fatty liver disease (NAFLD) hospital admission and cardiovascular disease (CVD), cancer, and mortality in people with type 2 diabetes mellitus (T2DM).

RESEARCH DESIGN AND METHODS

We performed a retrospective cohort study by using linked population-based routine data from diabetes registry, hospital, cancer, and death records for people aged 40-89 years diagnosed with T2DM in Scotland between 2004 and 2013 who had one or more hospital admission records. Liver disease and outcomes were identified by using ICD-9 and ICD-10 codes. We estimated hazard ratios (HRs) from Cox proportional hazards regression models, adjusting for key risk factors.

RESULTS

A total of 134,368 people with T2DM (1,707 with ALD and 1,452 with NAFLD) were studied, with a mean follow-up of 4.3 years for CVD and 4.7 years for mortality. Among those with ALD, NAFLD, or without liver disease hospital records 378, 320, and 21,873 CVD events; 268, 176, and 15,101 cancers; and 724, 221, and 16,203 deaths were reported, respectively. For ALD and NAFLD, respectively, adjusted HRs (95% CIs) compared with the group with no record of liver disease were 1.59 (1.43, 1.76) and 1.70 (1.52, 1.90) for CVD, 40.3 (28.8, 56.5) and 19.12 (11.71, 31.2) for hepatocellular carcinoma (HCC), 1.28 (1.12, 1.47) and 1.10 (0.94, 1.29) for non-HCC cancer, and 4.86 (4.50, 5.24) and 1.60 (1.40, 1.83) for all-cause mortality.

CONCLUSIONS

Hospital records of ALD or NAFLD are associated to varying degrees with an increased risk of CVD, cancer, and mortality among people with T2DM.

Prospective study of Type 2 diabetes mellitus, anti-diabetic drugs and risk of prostate cancer

Type 2 diabetes mellitus (T2DM) has consistently been associated with decreased risk of prostate cancer; however, if this decrease is related to the use of anti-diabetic drugs is unknown. We prospectively studied men in the comparison cohort in the Prostate Cancer data Base Sweden 3.0, with data on T2DM, use of metformin, sulfonylurea and insulin retrieved from national health care registers and demographic databases. Cox proportional hazards regression models were used to compute hazard ratios (HR) and 95% confidence intervals (CI) of prostate cancer, adjusted for confounders. The study consisted of 612,846 men, mean age 72 years (standard deviation; SD = 9 years), out of whom 25,882 men were diagnosed with prostate cancer during follow up, mean time of 5 years (SD = 3 years). Men with more than 1 year's duration of T2DM had a decreased risk of prostate cancer compared to men without T2DM (HR = 0.85, 95% CI = 0.82-0.88) but among men with T2DM, those on metformin had no decrease (HR = 0.96, 95% CI = 0.77-1.19), whereas men on insulin (89%) or sulfonylurea (11%) had a decreased risk (HR = 0.73, 95% CI = 0.55-0.98), compared to men with T2DM not on anti-diabetic drugs. Men with less than 1 year's duration of T2DM had no decrease in prostate cancer risk (HR = 1.11, 95% CI = 0.95-1.31). Our results gave no support to the hypothesis that metformin protects against prostate cancer as recently proposed. However, our data gave some support to an inverse association between T2DM severity and prostate cancer risk.

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Using Large Diabetes Databases for Research

There are an increasing number of clinical, administrative and trial databases that can be used for research. These are particularly valuable if there are opportunities for linkage to other databases. This paper describes examples of the use of large diabetes databases for research. It reviews the advantages and disadvantages of using large diabetes databases for research and suggests solutions for some challenges. Large, high-quality databases offer potential sources of information for research at relatively low cost. Fundamental issues for using databases for research are the completeness of capture of cases within the population and time period of interest and accuracy of the diagnosis of diabetes and outcomes of interest. The extent to which people included in the database are representative should be considered if the database is not population based and there is the intention to extrapolate findings to the wider diabetes population. Information on key variables such as date of diagnosis or duration of diabetes may not be available at all, may be inaccurate or may contain a large amount of missing data. Information on key confounding factors is rarely available for the nondiabetic or general population limiting comparisons with the population of people with diabetes. However comparisons that allow for differences in distribution of important demographic factors may be feasible using data for the whole population or a matched cohort study design. In summary, diabetes databases can be used to address important research questions. Understanding the strengths and limitations of this approach is crucial to interpret the findings appropriately.

Type 2 diabetes and risk of hospital admission or death for chronic liver diseases

BACKGROUND & AIMS

The impact of type 2 diabetes (T2DM) on hospital admissions and deaths due to common chronic liver diseases (CLDs) is uncertain. Our aim was to investigate associations between T2DM and CLDs in a national retrospective cohort study and to investigate the role of sex and socio-economic status (SES).

METHODS

We used International Classification of Disease codes to identify incident alcoholic liver disease (ALD), autoimmune liver disease, haemochromatosis, hepatocellular carcinoma, non-alcoholic fatty liver disease (NAFLD) and viral liver disease from linked diabetes, hospital, cancer and death records for people of 40-89years of age in Scotland 2004-2013. We used quasi Poisson regression to estimate rate ratios (RR).

RESULTS

There were 6667 and 33624 first mentions of CLD in hospital, cancer and death records over ∼1.8 and 24million person-years in people with and without T2DM, respectively. The most common liver disease was ALD among people without diabetes and was NAFLD among people with T2DM. Age-adjusted RR for T2DM compared to the non-diabetic population (95% confidence intervals) varied between 1.27 (1.04-1.55) for autoimmune liver disease and 5.36 (4.41-6.51) for NAFLD. RRs were lower for men than women and for more compared to less deprived populations for both ALD and NAFLD.

CONCLUSIONS

T2DM is associated with increased risk of hospital admission or death for all common CLDs and the strength of the association varies by type of CLD, sex and SES. Increasing prevalence of T2DM is likely to result in increasing burden of all CLDs.

Cancer among patients with type 2 diabetes mellitus: A population-based cohort study in northeastern Italy

Diabetes mellitus (DM) is associated with an elevated risk of cancer. The aim of this study was to assess cancer risk and survival in individuals with type 2 DM (T2DM) in Friuli Venezia Giulia, Italy. A retrospective population-based cohort study of 32,247 T2DM patients aged 40-84 years was conducted through a record linkage of local healthcare databases and cancer registry for the period 2002-2009. Standardized incidence ratios (SIRs) with 95% confidence intervals (95%CIs) and 5-year survival probabilities after T2DM and cancer diagnosis were computed. The SIRs for all cancers (n=2069) was 1.28 (95%CI: 1.23-1.34). The highest SIRs were observed for cancers of the liver, female genital organs, small intestine, and pancreas. After 3 years from T2DM diagnosis, a reduced risk of prostate cancer (SIR=0.73, 95%CI: 0.54-0.96) was found in men aged 65-74 years, and a higher risk for breast cancer (SIR=1.24, 95%CI: 1.00-1.52) was found among T2DM female patients. The overall 5-year survival after T2DM was 88.7%. Furthermore, T2DM appeared to have a negative effect on survival of women with breast cancer. This population-based study confirmed that T2DM patients are at increased risk of several cancers, and of premature death in women with breast cancer.

Association of diabetes mellitus and pancreatic adenocarcinoma: a meta-analysis of 88 studies

BACKGROUND

Pancreatic ductal adenocarcinoma (PDAC) is often diagnosed at an advanced, incurable stage. Previous epidemiological data suggests that diabetes mellitus (DM) is a risk factor for PDAC, which may be important in early detection. However, the strength of this association needs to be determined, taking into account a number of recently published studies.

METHODS

A systematic review of the association between DM and PDAC was undertaken by searching electronic databases and journal references from 1973 to 2013. Summary estimates were obtained separately for case-control and cohort studies by means of a 'random effects' approach. Data pertaining to the DM was recorded and plotted at both an individual and study level, with the relative risks (RR) pooled separately to determine the relationship of DM duration and PDAC.

RESULTS

A total of 88 independent studies, including 50 cohort and 39 case-control studies were examined. The overall summary-combined RR was 1.97 (95 % CI 1.78-2.18) with marked heterogeneity that could not be clearly attributed to any subgroup analyses. The risk of PDAC was greatest early after the diagnosis of DM but remained elevated long after the diagnosis. The individual-level RR ranged from 6.69 at less than 1 year to 1.36 at 10 years.

CONCLUSION

The results demonstrate a strong association between PDAC and recently diagnosed DM, which may be attributed to a paraneoplastic effect. However, the presence of diabetes also remains a modest risk factor for the development of PDAC long-term. Selective screening of patients with new-onset DM for PDAC needs to be considered.