Insulin resistance-related biomarker clustering and subclinical inflammation as predictors of cancer mortality during 21.5 years of follow-up

The Association Between Serum Gamma-Glutamyl Transferase and Gastrointestinal Cancer Risk: A Systematic Review and Meta-Analysis

BACKGROUND

Gamma-glutamyl transferase (GGT) has been shown to have associations with several diseases including cancers. Previous studies have investigated the effect of GGT levels on the gastrointestinal (GI) cancer incidence. We aim to systematically investigate these studies to provide better insights into the interrelationship between GGT and GI cancers.

METHODS

Online databases were searched to find relevant studies investigating different GGT levels' effects on the incidence of GI cancers including colorectal, esophageal, liver, pancreas, gastric, and biliary duct cancers. Random-effect meta-analysis was conducted to pool the hazard ratios (HRs) of GGT quartiles (Qs) effect on cancer incidence.

RESULTS

A total of 26 studies were included in the final review, 12 of which underwent meta-analysis that investigated 11 million patients. Based on the meta-analysis, Q4 patients had a 69% higher hazard of GI cancer incidence (HR 1.69, 95% CI 1.41-2.02, p-value < 0.001). The hazard ratio significance was also similar for Q3 (HR 1.22, 95% CI 1.15-1.30, p-value < 0.001) and Q2 (HR 1.10, 95% CI 1.05-1.16, p-value =0.002) of GGT. Colorectal and liver cancers showed a higher hazard ratio among Q2, Q3, and Q4 of GGT compared to Q1. In pancreas and bile duct cancers, only Q4 of GGT had significantly higher HR. Q3 and Q4 of GGT levels had statistically significant associations with gastric cancer incidence.

CONCLUSION

Higher GGT levels correlate with higher rates of GI cancer incidence, especially in colorectal and hepatic cancers. Future studies should investigate this biomarker's potential role in risk assessment for digestive cancers.

METS-IR and all-cause mortality in Korean over 60 years old: Korean genome and epidemiology study-health examinees (KoGES-HEXA) cohorts

Background

The metabolic score for insulin resistance index (METS-IR) is a novel non insulin-based marker that indicates the risk for metabolic syndrome and type 2 diabetes mellitus (T2DM). However, METS-IR has not been investigated in relation to all-cause mortality. We investigated the longitudinal effect of METS-IR on all-cause mortality in a significantly large cohort of Korean adults over 60 years old.

Methods

Data were assessed from 30,164 Korean participants over 60 years of age from the Korean Genome and Epidemiology Study-Health Examinees (KoGES-HEXA) cohort data, linked with the death certificate database of the National Statistical Office. The participants were grouped into three according to METS-IR tertiles. We used multivariate Cox proportional-hazard regression models to prospectively assess hazard ratios (HRs) for all-cause mortality with 95% confidence intervals (CIs) over an 11-year postbaseline period.

Results

During the mean 11.7 years of follow-up, 2,821 individuals expired. The HRs of mortality for METS-IR tertiles were 1.16 (95% CI, 1.01-1.34) in T3 after adjustment for metabolic parameters, but the T2 did not show statistical significance towards increases for incident mortality respectively. In subgroup analysis depending on the cause of mortality, higher METS-IR was associated with cancer mortality (HR, 1.23, 95% CI, 1.01-1.51) but not with cardiovascular mortality (HR, 1.14, 95% CI, 0.83-1.57) after adjustment for the same confounding variables.

Conclusion

The METS-IR may be a useful predictive marker for all-cause mortality and cancer mortality, but not for cardiovascular mortality in subjects over 60 years of age. This implies that early detection and intervention strategies for metabolic syndrome could potentially benefit this identified group.

Association Between a Novel Metabolic Score for Insulin Resistance and Mortality in People With Diabetes

BACKGROUND

Growing studies have shown that insulin resistance (IR) is associated with poor prognoses among patients with diabetes, whereas the association between IR and mortality has not been determined. Hence we aimed to evaluate the associations between IR and all-cause, cardiovascular diseases (CVDs) and cancer-related mortality in patients with diabetes.

METHODS

We enrolled 2,542 participants with diabetes with an average age of 57.12 ± 0.39 years and 52.8% men from the 1999-2014 National Health and Nutrition Examination Survey (NHANES 1999-2014). A novel metabolic score for insulin resistance (METS-IR) was considered as alternative marker of IR. Mortality data were obtained from the National Death Index records and all participants were followed up until December 31, 2015. Cox proportional hazards regression, restricted cubic spline and Kaplan-Meier survival curves were performed to evaluate the associations between METS-IR and all-cause and cause-specific mortality in patients with diabetes.

RESULTS

During 17,750 person-years of follow-up [median (months), 95% CI: 90, 87-93], 562 deaths were documented, including 133 CVDs-related deaths and 90 cancer-related deaths. Multivariate Cox regression showed that compared with Quintile 1 (METS-IR ≤ 41), METS-IR in Quintile 2, 3, and 4 was all associated with all-cause mortality (Q2 vs. Q1: HR 0.65, 95% CI 0.49-0.87, P = 0.004; Q3 vs. Q1: HR 0.69, 95% CI 0.50-0.96, P = 0.029; Q4 vs. Q1: HR 0.57, 95% CI 0.36-0.91, P = 0.019; respectively). Restricted cubic spline indicated that METS-IR was non-linearly associated with all-cause and CVDs-related mortality. Threshold effect analyses determined that threshold values of METS-IR for all-cause and CVDs-related mortality were both 33.33. Only METS-IR below the threshold was negatively associated with all-cause and CVDs-related mortality (HR 0.785, 95% CI 0.724-0.850, P < 0.001; HR 0.722, 95% CI 0.654-0.797, P < 0.001; respectively). Sensitivity analyses showed that when excluding participants who died within 1 years of follow-up, the results of threshold effect analyses remained consistent, whereas excluding participants with CVDs, METS-IR below the threshold was only negatively correlated with all-cause mortality. Subgroup analyses indicated that for all-cause mortality, the results were still stable in all subgroups except newly diagnosed diabetes, but for CVDs-related mortality, the association persisted only in participants who were ≤ 65 years, male, White, non-White, already diagnosed diabetes, or uesd oral drugs, insulin, insulin sensitizing drugs.

CONCLUSION

METS-IR was non-linearly associated with all-cause and CVDs-related mortality in patients with diabetes, and METS-IR below the threshold was negatively associated with all-cause and CVDs-related mortality.

Triglyceride-Glucose Index Is Not Associated With Lung Cancer Risk: A Prospective Cohort Study in the UK Biobank

BACKGROUND

The triglyceride-glucose (TyG) index is a practical substitute measure for insulin resistance (IR). The relationship between IR and lung cancer has been examined in previous studies; however, the findings have been controversial. In addition, previous studies had small sample sizes. Thus, we systematically examined the association between IR and lung cancer risk based on the UK Biobank with IR measured by the TyG index and further examined the interactions and joint effects for lung cancer.

METHODS

A total of 324,334 individuals free from any type of cancer at recruitment from the UK Biobank prospective cohort were included. The participants were predominantly between 40 and 70 years old. After adjusting for relevant confounders, multivariable Cox regression models were constructed to examine the relationship between the TyG index and the risk of lung cancer. We also checked the interactions and joint effects using a polygenic risk score (PRS) for lung cancer.

RESULTS

During a median follow-up of 9 years, 1,593 individuals were diagnosed with lung cancer. No association was found between the TyG index and lung cancer risk after multivariate Cox regression analysis adjusted for risk factors (hazard ratio: 0.91; 95% confidence interval: 0.64-1.18). No interaction or joint effects for genetic risk and the TyG index were observed.

CONCLUSION

The TyG index was not associated with the risk of lung cancer. Our results provide limited evidence that IR is not correlated with the risk of lung cancer.

Insulin Resistance and Cancer-Specific and All-Cause Mortality in Postmenopausal Women: The Women's Health Initiative

BACKGROUND

Insulin resistance has been proposed as a mediator of the increased cancer incidence and mortality associated with obesity. However, prior studies included limited cancer deaths and had inconsistent findings. Therefore, we evaluated insulin resistance and cancer-specific and all-cause mortality in postmenopausal women participating in the Women's Health Initiative (WHI).

METHODS

Eligible were a subsample of 22 837 WHI participants aged 50-79 years enrolled at 40 US clinical centers from 1993 to 1998 who had baseline fasting glucose and insulin levels. Baseline insulin resistance was measured by the homeostasis model assessment of insulin resistance (HOMA-IR). Cancers were verified by central medical record review and deaths verified by medical record and death certificate review enhanced by National Death Index queries. Cox proportional hazards regression models were used to calculate adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) for cancer-specific and all-cause mortality. All statistical tests were two-sided.

RESULTS

During a median of 18.9 years of follow-up, 1820 cancer deaths and 7415 total deaths occurred. Higher HOMA-IR quartile was associated with higher cancer-specific mortality (Q4 vs Q1, HR = 1.26, 95% CI = 1.09 to 1.47; Ptrend = .003) and all-cause mortality (Q4 vs Q1, HR = 1.63, 95% CI = 1.51 to 1.76; Ptrend < .001). A sensitivity analysis for diabetes status did not change findings. Among women with body mass index less than 25 kg/m2, higher HOMA-IR quartile was associated with higher cancer mortality (Fine and Gray, P = .004).

CONCLUSIONS

High insulin resistance, as measured by HOMA-IR, identifies postmenopausal women at higher risk for cancer-specific and all-cause mortality who could potentially benefit from early intervention.

Association of fasting serum insulin and cancer mortality in a healthy population - 28-year follow-up of the French TELECOM Study

AIMS

Epidemiologic, pharmacoepidemiologic and pathophysiologic evidence points consistently to an association between type 2 diabetes and cancer. This association could be explained by hyperinsulinemia induced by insulin resistance. We studied the association between fasting serum insulin (FSI) and cancer mortality in a population of non-diabetic individuals.

METHODS

We followed 3117 healthy workers (50.2% women), included in the TELECOM cohort study, between 1985 and 1987; their median age was 38 years (Q1-Q3=30-50). Baseline FSI was measured by radioimmunoassay, the INSI-PR method. People with diabetes or cancer at baseline were excluded. Vital status and causes of death were available until December 2013. The association between FSI and cancer deaths was analysed by sex, using a Cox proportional hazards model with age as the time scale, adjusting for body mass index, smoking habits, alcohol consumption, occupational category and ethnic origin.

RESULTS

After a 28-year follow-up, 330 (10.6%) deaths were reported, among which, 150 were cancer-related (80 men, 70 women). In men, the association between FSI and death by cancer was J-shaped: compared to the average FSI of 7.1mU/L, men with 5mU/L and 12.9mU/L had respectively adjusted hazard-ratios (HR) of 1.88 (95% confidence interval, 1.00-3.56) and 2.30 (95% CI, 1.34-3.94). Among women, no significant association was found (adjusted HR, 1.03; 95% CI, 0.96-1.11) for an increase of 1mU/L in FSI.

CONCLUSION

These results strengthen the hypothesis of an independent risk of cancer death associated with extreme values of FSI, mainly the highest, among men, but not among women.

Serum glucose and risk of cancer: a meta-analysis

BACKGROUND

Raised serum glucose has been linked to increased risk of many solid cancers. We performed a meta-analysis to quantify and summarise the evidence for this link.

METHODS

Pubmed and Embase were reviewed, using search terms representing serum glucose and cancer. Inclusion and exclusion criteria focused on epidemiological studies with clear definitions of serum glucose levels, cancer type, as well as well-described statistical methods with sufficient data available. We used 6.1 mmol/L as the cut-off for high glucose, consistent with the WHO definition of metabolic syndrome. Random effects analyses were performed to estimate the pooled relative risk (RR).

RESULTS

Nineteen studies were included in the primary analysis, which showed a pooled RR of 1.32 (95% CI: 1.20 - 1.45). Including only those individuals with fasting glucose measurements did not have a large effect on the pooled RR (1.32 (95% CI: 1.11-1.57). A stratified analysis showed a pooled RR of 1.34 (95% CI: 1.02-1.77) for hormonally driven cancer and 1.21 (95% CI: 1.09-1.36) for cancers thought to be driven by Insulin Growth Factor-1.

CONCLUSION

A positive association between serum glucose and risk of cancer was found. The underlying biological mechanisms remain to be elucidated but our subgroup analyses suggest that the insulin- IGF-1 axis does not fully explain the association. These findings are of public health importance as measures to reduce serum glucose via lifestyle and dietary changes could be implemented in the context of cancer mortality.

Gamma-glutamyltransferase predicts increased risk of mortality: a systematic review and meta-analysis of prospective observational studies

The aim of this study was to evaluate the association between gamma-glutamyltransferase (GGT) and mortality through a comprehensive analysis of existing evidence. PubMed, Embase, Chinese Biomedical Literature, and Science Citation Index databases were electronically searched. Studies were included if the study design was prospective and included reference and at-risk levels of GGT at baseline and mortality as a separate outcome. The quality of the studies included was assessed on the basis of Newcastle-Ottawa scale. Data from selected qualified studies were systematically reviewed, pooled, and analyzed according to the MOOSE guidelines and PRISMA statement. The results included the following: 1. 35 studies including 571,511 participants and 72,196 cases of mortality; 2. GGT, even at physiologic levels, was associated with increased all-cause mortality and cardiovascular mortality, and might also be associated with cancer-related mortality in the general population; and 3. GGT was very likely to be associated with all-cause mortality and cardiovascular mortality in patients with coronary artery disease and type 2 diabetes mellitus. Many of the studies included did not specifically exclude subjects with hepatic diseases or alcohol abuse, which may have obscured the results. Moderate heterogeneity was observed in the meta-analysis of GGT and all-cause mortality. Different compositions of cause-specific mortality might be the reason. However, subgroup analysis could only be performed on cardiovascular death because of insufficient information. GGT, even at physiologic high levels, predicted mortality, especially cardiovascular mortality and cancer mortality. The underlining mechanism and potential effects of GGT-targeted intervention on health warrant further investigation.

The role of chronic inflammation in obesity-associated cancers

There is a strong relationship between metabolism and immunity, which can become deleterious under conditions of metabolic stress. Obesity, considered a chronic inflammatory disease, is one example of this link. Chronic inflammation is increasingly being recognized as an etiology in several cancers, particularly those of epithelial origin, and therefore a potential link between obesity and cancer. In this review, the connection between the different factors that can lead to the chronic inflammatory state in the obese individual, as well as their effect in tumorigenesis, is addressed. Furthermore, the association between obesity, inflammation, and esophageal, liver, colon, postmenopausal breast, and endometrial cancers is discussed.

Contribution of uric acid to cancer risk, recurrence, and mortality

Two risk factors for the development and progression of cancers that are amenable to life style modification are chronic inflammation and the metabolic syndrome. This review proposes two new targets that may mechanistically integrate inflammation and metabolic syndrome, have been largely ignored, and are known to be druggable. Recent evidence has demonstrated that elevated serum uric acid (hyperuricemia) is associated with excess cancer risk, recurrence, and mortality. Although uric acid (UA) can function as a systemic antioxidant, its pro-inflammatory properties have been postulated to play an important role in the pathogenesis of cancer. Furthermore, obesity, Type 2 Diabetes Mellitus (T2DM), and the metabolic syndrome (MetS) are also associated with excess cancer, chronic inflammation, and with hyperuricemia, suggesting that UA may represent an important link between these disorders and the development of cancer. While pharmacological modulation of hyperuricemia could in principal augment anti-cancer therapeutic strategies, some cancer cells express low intracellular levels of the enzyme Xanthine Oxidoreductase (XOR) that are associated with increased cancer aggressiveness and poor clinical outcome. Thus, systemic pharmacological inhibition of XOR may worsen clinical outcome, and specific strategies that target serum uric acid (SUA) without inhibiting tumor cell XOR may create new therapeutic opportunities for cancer associated with hyperuricemia. This review will summarize the evidence that elevated SUA may be a true risk factor for cancer incidence and mortality, and mechanisms by which UA may contribute to cancer pathogenesis will be discussed in the hope that these will identify new opportunities for cancer management.

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).

Metabolic syndrome and leptin are associated with adverse pathological features in male colorectal cancer patients

AIM

Metabolic syndrome (MetS) describes a clustering of factors including central obesity, hypertension and raised plasma glucose, triglycerides and high-density lipoprotein (HDL) cholesterol. Central obesity is associated with a risk for colorectal cancer, but the impact of MetS on colorectal cancer biology and outcomes is unclear.

METHOD

A prospective observational study of colorectal cancer patients was carried out in an Irish population. Patients underwent metabolic and anthropometric assessment before treatment, including measurement of serum hormones and adipokines and CT measurement of visceral fat. MetS was defined according to the International Diabetes Federation definition(3) .

RESULTS

One-hundred and thirty consecutive colorectal cancer patients (66 men and 64 women) were recruited. MetS was diagnosed in 38% patients compared with the population norms reported at 21%(21) . Male patients had a significantly greater visceral fat area compared with female patients. MetS was associated with node-positive disease (P = 0.026), percentage nodal involvement (P = 0.033) and extramural vascular invasion (P = 0.049) in male patients but no significant association was observed in female patients. HDL cholesterol was also significantly associated with a more advanced pathological stage (P = 0.014) and node-positive disease (P = 0.028). Leptin was associated with nodal status (P = 0.036), microvascular invasion (P = 0.054), advanced pathological stage (P = 0.046) and more advanced Dukes stage (P = 0.042).

CONCLUSION

We report a high prevalence of MetS and visceral obesity in a colorectal cancer population. MetS and plasma leptin are associated with a more aggressive tumour phenotype in male patients only.

Uric acid is not an independent predictor of cardiovascular mortality in type 2 diabetes: a population-based study

OBJECTIVE

Although some studies have suggested that uric acid is a risk factor for mortality, this relationship is still uncertain in people with type 2 diabetes.

METHODS

The study base was the population-based cohort of 1540 diabetic subjects (median age 68.9 years) of the Casale Monferrato Study. The role of serum uric acid on 15-years all-cause, cardiovascular and non-cardiovascular mortality was assessed by multivariate Cox proportional hazards modeling.

RESULTS

Baseline levels of serum uric acid were negatively correlated with HbA1c, were higher in men and in the elderly and were independently associated with components of the metabolic syndrome. Out of 14,179 person-years, 1000 deaths (514 due to cardiovascular diseases) were observed. Compared to the lower quartile of uric acid, HRs (95% CI) in the upper quartile were 1.47 (1.22-1.76) for all-cause mortality; 1.40 (1.09-1.80) for cardiovascular mortality and 1.50 (1.15-1.96) for non-cardiovascular mortality. In multiple adjusted models, however, HRs were 1.30 (1.06-1.60) for all-cause mortality, 1.13 (0.85-1.50) for cardiovascular mortality and 1.50 (1.11-2.02) for non-cardiovascular mortality (men 1.87, 1.19-2.95; women 1.20, 0.80-1.80); the latter appeared to be due to neoplastic diseases (HR in all combined quartiles vs. lower quartile: both sexes 1.59, 1.05-2.40; men 1.54, 0.83-2.84, women 1.68, 0.95-2.92).

CONCLUSIONS

In diabetic people, uric acid is associated with components of the metabolic syndrome but it may not be accounted as an independent risk factor for cardiovascular mortality. The increased all-cause mortality risk with higher levels of uric acid might be due to increased neoplastic mortality and deserves future studies.

Insulin resistance: an independent risk factor for lung cancer?

Insulin resistance is closely associated with numerous metabolic disorders. Although studies have supported the importance of insulin resistance in carcinogenesis, the existing data have not established its relevance in the context of lung cancer. The aim of the present case-control study was to evaluate the association between insulin resistance and lung cancer after adjusting for possible confounders. Homeostasis model assessment of insulin resistance (HOMA-IR) and serum leptin and adiponectin levels were determined in 81 lung cancer cases and 162 age- and sex-matched controls; anthropometric and lifestyle variables were recorded. Mean HOMA-IR in the cases was more than 2-fold higher compared with the mean value of controls (P < .001). Among controls, HOMA-IR correlated positively with serum leptin (r = 0.16; P = .04), body mass index (r = 0.43; P = .0001), and waist-to-hip ratio (r = 0.21; P = .01) but negatively with serum adiponectin (r = -0.29; P = .0002). As expected, smoking was associated with an approximately 10-fold increase in lung cancer risk in multiple logistic regression models. A positive association between HOMA-IR, treated as continuous variable, and lung cancer (odds ratio [OR] = 1.52, 95% confidence interval [CI]: 1.16-1.99, P = .002, model 1) was demonstrated, which persisted after adjustment for somatometric and lifestyle variables (OR = 2.36, 95% CI: 1.00-5.55, P = .05, model 2). When serum adiponectin was also taken into account, the association seemed fairly robust (OR = 2.58, 95% CI: 1.11-6.01, P = .03, model 3); on the contrary, when serum leptin was added, the association remained positive, but lost its statistical significance (OR = 1.76, 95% CI: 0.78-3.98, P = .17, model 4). In the fully adjusted model, HOMA-IR was still positively, but only marginally, associated with lung cancer risk (OR = 2.02, 95% CI: 0.88-4.65, P = .10, model 5). Insulin resistance may represent a meaningful risk factor for lung cancer.