Association between prediagnostic glucose, triglycerides, cholesterol and meningioma, and reverse causality

Effect of Different Glucose Levels and Glycation on Meningioma Cell Migration and Invasion

Meningiomas are predominantly benign tumors, but there are also malignant forms that are associated with a poor prognosis. Like almost all tumors, meningiomas metabolize glucose as part of aerobic glycolysis (Warburg effect) for energy supply, so there are attempts to influence the prognosis of tumor diseases using a glucose-reduced diet. This altered metabolism leads to so called hallmarks of cancer, such as glycation and glycosylation. In this study, we investigated the influence of low (3 mM), normal (5.5 mM) and high glucose (15 mM) on a malignant meningioma cell line (IOMM-Lee, WHO grade 3). In addition, the influence of methylglyoxal, a by-product of glycolysis and a precursor for glycation, was investigated. Impedance-based methods (ECIS and RTCA) were used to study migration and invasion, and immunoblotting was used to analyze the expression of proteins relevant to these processes, such as focal adhesion kinase (FAK), merlin or integrin ß1. We were able to show that low glucose reduced the invasive potential of the cells, which was associated with a reduced amount of sialic acid. Under high glucose, barrier function was impaired and adhesion decreased, which correlated with a decreased expression of FAK.

Lifestyle and metabolic factors affect risk for meningioma in women: a prospective population-based study (The Cohort of Norway)

Background

Meningioma is the most common primary brain tumor, with a clear preponderance in women. Obesity is considered a risk factor for the development of meningioma. Obesity is also the clinical hallmark of metabolic syndrome, characterized by glucose intolerance, dyslipidemia, and hypertension. Lifestyle and metabolic factors directly impact overweight and obesity and are therefore potential risk factors for meningioma development. The aim of this study is to assess lifestyle and metabolic factors for meningioma risk in women.

Methods

The Cohort of Norway (CONOR) is a nationwide health survey, conducted between 1994 and 2003, including anthropometric measures, blood tests, and health questionnaires. Linkage to the National Cancer Registry enabled the identification of intracranial meningioma during follow-up until December 2018.

Results

A total of 81,652 women were followed for a combined total of 1.5 million years, and 238 intracranial meningiomas were identified. Increasing levels of physical activity (HR 0.81; 95% CI 0.68-0.96; p trend <0.02) and parity (HR 0.83; 95% CI 0.71-0.97; p trend <0.03) were negatively associated with meningioma risk. Diabetes mellitus or glucose intolerance increased the risk for meningioma (HR 2.54; 95% CI 1.60-4.05). Overweight and obesity were not associated with meningioma risk, nor was metabolic syndrome. However, participants without metabolic dysfunction had a reduced meningioma risk, while participants with all five metabolic factors present had a 4-fold risk increase for meningioma (HR 4.28; 95% CI 1.34-13.68).

Conclusion

Lifestyle factors seem to significantly influence meningioma risk. However, disentangling the complex associations and interactions between factors for meningioma risk will be a challenging task for future studies.

Role of Mediterranean diet in the development and recurrence of meningiomas: a narrative review

Several studies through the years have proven how an unhealthy nutrition, physical inactivity, sedentary lifestyle, obesity, and smoking represent relevant risk factors in cancer genesis. This study aims to provide an overview about the relationship between meningiomas and food assumption in the Mediterranean diet and whether it can be useful in meningioma prevention or it, somehow, can prevent their recurrence. The authors performed a wide literature search in PubMed and Scopus databases investigating the presence of a correlation between Mediterranean diet and meningiomas. The following MeSH and free text terms were used: "Meningiomas" AND "Diet" and "Brain tumors" AND "diet." Databases' search yielded a total of 749 articles. After duplicate removal, an abstract screening according to the eligibility criteria has been performed and 40 articles were selected. Thirty-one articles were excluded because they do not meet the inclusion criteria. Finally, a total of 9 articles were included in this review. It is widely established the key and protective role that a healthy lifestyle and a balanced diet can have against tumorigenesis. Nevertheless, studies focusing exclusively on the Mediterranean diet are still lacking. Thus, multicentric and/or prospective, randomized studies are mandatory to better assess and determine the impact of food assumptions in meningioma involvement.

The causal relationship between genetically determined telomere length and meningiomas risk

Background

Studies have shown that longer leukocyte telomere length (LTL) is significantly associated with increased risk of meningioma. However, there is limited evidence concerning the causal association of LTL with benign and malignant meningiomas or with the location of benign tumors.

Methods

We used three LTL datasets from different sources, designated by name and sample size as LTL-78592, LTL-9190, and LTL-472174. The linkage disequilibrium score (LDSC) was used to explore the association between LTL and meningioma. We utilized two-sample bidirectional Mendelian randomization (TSMR) to evaluate whether LTL is causally related to meningioma risk. We adjusted for confounders by conducting multivariable Mendelian randomization (MVMR).

Results

In the LTL-78592, longer LTL was significantly associated with increased risk of malignant [odds ratio (OR) = 5.14, p = 1.04 × 10-5], benign (OR = 4.81, p < 0.05), benign cerebral (OR = 5.36, p < 0.05), and benign unspecified meningioma (OR = 8.26, p < 0.05). The same results were obtained for the LTL-9190. In the LTL-472174, longer LTL was significantly associated with increased risk of malignant (OR = 4.94, p < 0.05), benign (OR = 3.14, p < 0.05), and benign cerebral meningioma (OR = 3.59, p < 0.05). Similar results were obtained in the MVMR. In contrast, only benign cerebral meningioma displayed a possible association with longer LTL (OR = 1.01, p < 0.05). No heterogeneity or horizontal pleiotropy was detected.

Conclusion

In brief, genetically predicted longer LTL may increase the risk of benign, malignant, and benign cerebral meningiomas, regardless of the LTL measure, in European populations.

Incidental Meningiomas: Potential Predictors of Growth and Current State of Management

The rise in availability of neuroimaging has led to an increase in incidentally discovered meningiomas. These tumors are typically asymptomatic and tend to display slow growth. Treatment options include observation with serial monitoring, radiation, and surgery. Although optimal management is unclear, clinicians recommend a conservative approach, which preserves quality of life and limits unnecessary intervention. Several risk factors have been investigated for their potential utility in the development of prognostic models for risk assessment. Herein, the authors review the current literature on incidental meningiomas, focusing their discussion on potential predictive factors for tumor growth and appropriate management practices.

Characterization of volumetric growth of intracranial meningiomas in Māori and Pasifika populations in New Zealand

BACKGROUND

Māori and Pasifika populations in New Zealand have a higher incidence and prevalence of intracranial meningioma (IM). We sought to evaluate the volumetric growth rate of meningiomas under surveillance in these populations.

METHODS

From July 2002 to October 2020, 336 patients with a total of 408 IM underwent conservative management with serial radiological surveillance at Auckland City Hospital and met the criteria for the study. Inclusion criteria included: age >16 at diagnosis, ≥2 appropriate scans one or more years apart. Exclusion criteria included previous cranial irradiation, a diagnosis of Neurofibromatosis and prior treatment of meningioma. Demographic and clinical data were obtained from the electronic medical records. Imaging data were recorded from the first and last scans. We utilized open-source image processing software (3D Slicer) for semi-automated segmentation and volume calculation. Consistent with previous literature, we calculated the relative growth rate (RGR, %/year) and annual volume change (AVC, cm3 /year) over time.

RESULTS

Four hundred and eight meningiomas were volumetrically characterized for a mean duration of 6.2 years. The Māori and Pasifika populations (n = 134/393) demonstrated a higher RGR (31.41 versus 14.33%/year) (P = 0.026) and AVC (2.05 versus 0.95 cm3 ) (P = 0.025) compared to the control population. They also presented at a younger age and had a higher rate of tumour multiplicity. Males represented only 17.6% of the cohort but exhibited a higher growth rate (AVC = 2.52 cm3 /year) than females (AVC = 0.99 cm3 /year) (P = 0034).

CONCLUSIONS

Māori and Pasifika populations in New Zealand have a higher incidence and volumetric growth rate of IM compared to a control population. This warrants further clinical, histopathological and genomic analysis.

Glycation Interferes with the Expression of Sialyltransferases in Meningiomas

Meningiomas are the most common non-malignant intracranial tumors and prefer, like most tumors, anaerobic glycolysis for energy production (Warburg effect). This anaerobic glycolysis leads to an increased synthesis of the metabolite methylglyoxal (MGO) or glyoxal (GO), which is known to react with amino groups of proteins. This reaction is called glycation, thereby building advanced glycation end products (AGEs). In this study, we investigated the influence of glycation on sialylation in two meningioma cell lines, representing the WHO grade I (BEN-MEN-1) and the WHO grade III (IOMM-Lee). In the benign meningioma cell line, glycation led to differences in expression of sialyltransferases (ST3GAL1/2/3/5/6, ST6GAL1/2, ST6GALNAC2/6, and ST8SIA1/2), which are known to play a role in tumor progression. We could show that glycation of BEN-MEN-1 cells led to decreased expression of ST3Gal5. This resulted in decreased synthesis of the ganglioside GM3, the product of ST3Gal5. In the malignant meningioma cell line, we observed changes in expression of sialyltransferases (ST3GAL1/2/3, ST6GALNAC5, and ST8SIA1) after glycation, which correlates with less aggressive behavior.

Diabetes increases the risk of meningioma: A systematic review and meta-analysis of observational studies

BACKGROUND

Increasing epidemiological evidence suggests that diabetes may be associated with meningioma risk, but the evidence supporting this association is still inconclusive. Therefore, we performed a meta-analysis of all eligible observational studies to evaluate the potential association of diabetes with meningioma risk.

METHODS

A comprehensive literature search was performed in the PubMed, Web of Science and Cochrane Library databases up to November 30, 2020. A random-effects model was applied to calculate the pooled effect size (ES) and its 95 % confidence interval (CI).

RESULTS

Eight studies were included in this study. In a random-effects pooled analysis, the results showed that DM (diabetes mellitus) increased the risk of meningioma (ES 1.17, 95 % CI: 1.02-1.35, P = 0.027). In subgroup analyses, DM increased the risk of meningioma in women (ES: 1.19, 95 % CI: 1.02-1.40, P = 0.027) and men (ES: 1.53, 95 % CI: 1.25-1.88, P = 0.000). This effect was not observed in the postmenopausal group (ES: 1.18, 95 % CI: 0.64-2.18, P = 0.597).

CONCLUSION

Our meta-analysis showed that DM increases the risk of meningioma, but the association was only present in some subgroups. This conclusion should be further confirmed.

Glycation of benign meningioma cells leads to increased invasion

Meningiomas are the most common non-malignant intracranial tumors. Like most tumors, meningiomas prefer anaerobic glycolysis for energy production (Warburg effect). This leads to an increased synthesis of the metabolite methylglyoxal (MGO). This metabolite is known to react with amino groups of proteins. This reaction is called glycation, thereby building advanced glycation endproducts (AGEs). In this study, we investigated the influence of glycation on two meningioma cell lines, representing the WHO grade I (BEN-MEN-1) and the WHO grade III (IOMM-Lee). Increasing MGO concentrations led to the formation of AGEs and decreased growth in both cell lines. When analyzing the influence of glycation on adhesion, chemotaxis and invasion, we could show that the glycation of meningioma cells resulted in increased invasive potential of the benign meningioma cell line, whereas the invasive potential of the malignant cell line was reduced. In addition, glycation increased the E-cadherin- and decreased the N-cadherin-expression in BEN-MEN-1 cells, but did not affect the cadherin-expression in IOMM-Lee cells.

Height as a risk factor in meningioma: a study of 2 million Israeli adolescents

BACKGROUND

Meningiomas are the most common primary central nervous system tumors. Potential risk factors include obesity, height, history of allergy/atopy, and autoimmune diseases, but findings are conflicting. This study sought to assess the role of the different risk factors in the development of meningioma in adolescents/young adults.

METHODS

The cohort included 2,035,915 Jewish men and women who had undergone compulsory physical examination between 1967 and 2011, at age 16 to 19 years, prior to and independent of actual military enlistment. To determine the incidence of meningioma, the military database was matched with the Israel National Cancer Registry. Cox proportional hazard models were used to estimate the hazard ratios for meningioma according to sex, body mass index (BMI), height, and history of allergic or autoimmune disease.

RESULTS

A total of 480 subjects (328 females) were diagnosed with meningioma during a follow-up of 40,304,078 person-years. Median age at diagnosis was 42.1 ± 9.4 years (range 17.4-62.6). On univariate analysis, female sex (p < 0.01) and height (p < 0.01) were associated with risk of meningioma. When the data were stratified by sex, height remained a significant factor only in men. Spline analysis of the male subjects showed that a height of 1.62 m was associated with a minimum disease risk and a height of 1.85+ meters, with a significant risk.

CONCLUSIONS

This large population study showed that sex and adolescent height in males (> 1.85 m) were associated with an increased risk of meningioma in adulthood.

Body mass index, comorbidities, and hormonal factors in relation to meningioma in an ethnically diverse population: the Multiethnic Cohort

BACKGROUND

Meningioma is the most common intracranial tumor in the US and its etiology remains poorly understood. Meningioma has been predominantly studied among white populations. The aim of this study was to evaluate the associations of anthropometric, comorbidity, and hormonal factors with meningioma in an ethnically diverse population.

METHODS

A nested case-control analysis was performed within the Multiethnic Cohort (MEC). Meningioma cases were identified via linkage with Medicare and the California Office of Statewide Health Planning and Development Hospital Discharge data and were matched to up to 10 controls. Anthropometric, comorbidities, physical activity level, and hormonal factors at baseline based on questionnaires were evaluated for association with meningioma.

RESULTS

A total of 894 cases and 8918 matched controls were included in this study. Increasing body mass index (BMI) (P-trend = 0.041) and weight increases since age 21 (P-trend = 0.0052) were positively associated with meningioma. Hormonal factors including oral contraceptive use (odds ratio [OR]: 1.24; 95% CI: 1.01-1.51) and estrogen hormonal therapy use (per 5 years, OR: 1.07; 95% CI: 1.01-1.15) were associated with meningioma risk. Hypertension was positively associated with meningioma (OR: 1.26; 95% CI: 1.09-1.47), with individuals who reported a history of both hypertension and diabetes showing a stronger association (OR: 1.54; 95% CI: 1.17-2.03). The tests for heterogeneity across race/ethnicity were not statistically significant (P heterogeneity ≥ 0.17); however, the association of BMI with meningioma was mainly observed in Japanese Americans (P-trend = 0.0036) and hypertension in Japanese Americans (OR: 1.63; 95% CI: 1.17-2.27) and Native Hawaiians (OR: 1.86; 95% CI: 1.02-3.40).

CONCLUSION

Obesity, hormonal factors, and hypertension were associated with meningioma in an ethnically diverse population.

HbA1c in patients with intracranial meningiomas WHO grades I and II: A preliminary study

Meningiomas are among the most common primary brain tumors. There is a growing need for novel ways of differentiating between benign (World Health Organization [WHO] grade I) and atypical (WHO grade II) meningiomas as well as for novel markers of the tumor's future behavior. A difference between glucose metabolism in atypical and benign meningiomas is well known. However, a significant correlation between the systemic metabolic status of the patient and the meningioma WHO grade has not yet been established. Our aim was to compare the WHO grades of intracranial meningiomas with the patient's HbA1c levels as a more reliable marker of the chronic systemic metabolic status than the fasting blood glucose value, which is usually looked at. We retrospectively analyzed 15 patients and compared their meningioma WHO grade with their preoperative HbA1c values. Our results show that patients with benign intracranial meningiomas have significantly lower HbA1c value. Conversely, patients with atypical intracranial meningiomas have higher HbA1c values. Furthermore, we showed that the proliferation factor Ki67 was statistically strongly correlated with the HbA1c value (p < .001. These results imply a possible positive correlation between meningioma cell proliferation and the chronic systemic glycemia. Further research in this area could not only lead to better understanding of meningiomas but could have significant clinical application.

Factors Associated With Meningioma Detected in a Population-Based Sample

OBJECTIVE

To determine the frequency of incidental meningioma and identify associated factors in a population-based sample of participants who systematically underwent brain imaging.

PATIENTS AND METHODS

We searched the Mayo Clinic Study of Aging, a population-based sample of Olmsted County, Minnesota, residents who underwent longitudinal magnetic resonance imaging of the brain. Using a text search of radiologists' notes for 2402 individuals (median age, 75.0 years) who underwent imaging between August 10, 2005, and July 31, 2014, we identified 52 patients (2.2%) who had at least one meningioma. We estimated the association of selected risk factors with the presence of meningioma using odds ratios and 95% CIs from logistic regression models adjusted for age and sex. Based on these results, we moved the most significant variables forward to a multivariable model.

RESULTS

Controlling for age and sex, significant associations with the presence of meningioma included higher body mass index (odds ratio [OR], 1.06; 95% CI, 1.01-1.12; P=.03), nonsteroidal anti-inflammatory drugs (OR, 2.11; 95% CI, 1.13-3.95; P=.02), aspirin (OR, 1.90; 95% CI, 1.05-3.46; P=.04), and blood pressure-lowering medication (OR, 2.06; 95% CI, 1.06-3.99; P=.03). Lower risk was associated with male sex (OR, 0.51; 95% CI, 0.29-0.90; P=.02), coronary artery disease (OR, 0.46; 95% CI, 0.22-0.97; P=.04), and higher self-reported anxiety (OR, 0.88; 95% CI, 0.78-0.98; P=.02). Simultaneous adjustment for all of these factors except aspirin in a multivariable model did not attenuate these associations (concordance, 0.71).

CONCLUSION

In a population-based sample of 2402 participants, 52 (2.2%) had an incidental meningioma. They were more likely to be female and have higher body mass index. Meningioma was also associated with certain medications (nonsteroidal anti-inflammatory drugs and blood pressure-lowering medications) and inversely with anxiety and coronary artery disease.

Mendelian randomization provides support for obesity as a risk factor for meningioma

Little is known about the causes of meningioma. Obesity and obesity-related traits have been reported in several epidemiological observational studies to be risk factors for meningioma. We performed an analysis of genetic variants associated with obesity-related traits to assess the relationship with meningioma risk using Mendelian randomization (MR), an approach unaffected by biases from temporal variability and reverse causation that might have affected earlier investigations. We considered 11 obesity-related traits, identified genetic instruments for these factors, and assessed their association with meningioma risk using data from a genome-wide association study comprising 1,606 meningioma patients and 9,823 controls. To evaluate the causal relationship between the obesity-related traits and meningioma risk, we consider the estimated odds ratio (OR) of meningioma for each genetic instrument. We identified positive associations between body mass index (odds ratio [OR_SD] = 1.27, 95% confidence interval [CI] = 1.03–1.56, P = 0.028) and body fat percentage (OR_SD = 1.28, 95% CI = 1.01–1.63, P = 0.042) with meningioma risk, albeit non-significant after correction for multiple testing. Associations for basal metabolic rate, diastolic blood pressure, fasting glucose, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, systolic blood pressure, total cholesterol, triglycerides and waist circumference with risk of meningioma were non-significant. Our analysis provides additional support for obesity being associated with an increased risk of meningioma.

Metabolic syndrome in relation to risk of meningioma

BACKGROUND

Meningioma is a frequent primary intracranial tumor, the etiology of which is potentially related to adiposity. Metabolic syndrome (MetS) is an increasingly common disease characterized by having at least three of the following conditions: central adiposity, arterial hypertension, dyslipidemia, and insulin resistance. Only one prior study investigated MetS in relation to meningioma risk and found a positive association between the two.

RESULTS

Among 2,027 cases and 20,269 controls, body mass index was positively associated with meningioma (p-value for trend < 0.0001). Arterial hypertension was also associated with an increased risk of meningioma (OR = 1.34; 95% CI = 1.20- 1.49). By comparison, high-density lipoprotein, triglycerides, fasting serum glucose, and use of ACE-inhibitors, AT-II inhibitors, beta-blockers, diuretics, calcium antagonists, nitrates, or statins were not associated with risk of meningioma.

MATERIALS AND METHODS

We conducted a matched case-control analysis using data from the U.K.-based Clinical Practice Research Datalink (CPRD) to analyse medical conditions and treatments related to MetS in cases with meningioma and meningioma-free controls. We identified all cases with an incident diagnosis of meningioma between 1995 and 2015 and matched each to ten controls on age, sex, calendar time, general practice, and number of years of active history in the CPRD prior to the index date. Exposures were assessed using computerised records. We conducted conditional logistic regression analysis to determine relative risks, estimated as odds ratios (ORs) with 95% confidence intervals (CIs), adjusted for confounding factors.

CONCLUSIONS

Obesity and arterial hypertension are positively associated with risk of meningioma. Further studies are needed to better understand potential underlying biologic mechanisms.

Association of serum lipids and severity of epithelial ovarian cancer: an observational cohort study of 349 Chinese patients

While obesity and fat intake have been associated with the risk and prognosis of epithelial ovarian cancer, the association between the lipid levels and epithelial ovarian cancer phenotype remains controversial. We conducted a retrospective study of 349 epithelial ovarian cancer patients who received treatment at Jiangsu Cancer Hospital, China between 2011 and 2017. We analyzed age at diagnosis, blood pressure, plasma glucose content, body mass index (BMI), lipid levels and clinical parameters. Severity of epithelial ovarian cancer was classified according to the International Federation of Gynecology and Obstetrics (FIGO) grading system. Univariate analysis of the clinical factors according to the severity of epithelial ovarian cancer was followed by logistic regression analysis to identify clinical factors significantly associated with epithelial ovarian cancer severity. Univariate analysis indicated that age, BMI, triglyceride (TG), and high density lipoproteins (HDL) differed significantly among different stages of epithelial ovarian cancer (P<0.05). In the logistic regression model, elevated TG (OR: 1.883; 95% CI= 1.207-2.937), and low HDL (OR: 0.497; 95% CI= 0.298-0.829) levels were significantly associated with the high severity epithelial ovarian cancer. Our data indicate that high TG and low HDL levels correlate with a high severity of epithelial ovarian cancer. These data provide important insight into the potential relationship between the lipid pathway and epithelial ovarian cancer phenotype and development.

Diabetes, use of metformin, and the risk of meningioma

BACKGROUND

Metformin is a commonly used oral antidiabetic agent that has been associated with decreased cancer risk. However, data regarding the association between metformin use and the risk of meningioma are unavailable.

METHODS

We conducted a matched case-control analysis using data from the U.K.-based Clinical Practice Research Datalink (CPRD) to analyse diabetes status, duration of diabetes, glycemic control, and use of metformin, sulfonylureas, and insulin in relation to the risk of meningioma. We conducted conditional logistic regression analyses to determine relative risks, estimated as odds ratios (ORs) with 95% confidence intervals (CIs) and adjusted for body mass index, smoking, history of arterial hypertension, myocardial infarction, and use of estrogens (among women).

RESULTS

We identified 2,027 meningioma cases and 20,269 controls. For diabetes there was the suggestion of an inverse association with meningioma (OR = 0.89; 95%CI = 0.74-1.07), which was driven by an inverse relation among women (OR = 0.78; 95%CI = 0.62-0.98), in whom we also noted a suggestive inverse association with duration of diabetes (p-value for trend = 0.071). For metformin there was a suggestive positive relation, particularly after matching on duration of diabetes and HbA1c level (OR = 1.64; 95%CI = 0.89-3.04). Sulfonylureas showed no clear association (OR = 0.91; 95%CI = 0.46-1.80). For insulin there was the suggestion of an inverse relation, in particular when comparing a high vs. low number of prescriptions (OR = 0.58; 95%CI = 0.18-1.83).

CONCLUSION

Further studies are needed to solidify a possible inverse association between diabetes and meningioma risk and to clarify the role of antidiabetics in this context.

Associations between prediagnostic blood glucose levels, diabetes, and glioma

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