Coffee and tea consumption and the risk of glioma: a systematic review and dose-response meta-analysis.

In this systematic review and dose-response meta-analysis, we aimed to assess whether coffee and tea consumption is related to the risk of glioma. We performed a systematic literature search using PubMed, Embase, Scopus and the EuropePMC from the inception of database up until 1 October 2020. Exposures in the present study were coffee and tea consumption, the main outcome was the incidence of glioma. The present study compares the association between the exposure of coffee and tea with the incidence of glioma, and the results are reported in relative risks (RR). There are 12 unique studies comprising of 1 960 731 participants with 2987 glioma cases. Higher coffee consumption was associated with a statistically non-significant trend towards lower risk of glioma (RR 0·77 (95 % CI 0·55, 1·03), P= 0·11; I2:75·27 %). Meta-regression showed that the association between coffee and glioma was reduced by smoking (P= 0·029). Higher tea consumption was associated with a lower risk of glioma (RR 0·84 (95 % CI 0·71, 0·98), P= 0·030; I2:16·42 %). Sensitivity analysis by removal of case-control studies showed that higher coffee consumption (RR 0·85 (95 % CI 0·72, 1·00), P= 0·046; I2:0 %) and higher tea consumption (RR 0·81 (95 % CI 0·70, 0·93), P= 0·004; I2:0 %, Pnon-linearity = 0·140) were associated with lower risk of glioma. Dose-response meta-analysis showed that every one cup of coffee per day decreases the risk of glioma by 3 % (RR 0·97 (95 % CI 0·94, 0·99), P= 0·016, Pnon-linearity = 0·054) and every one cup of tea per day decreases the risk of glioma by 3 % (RR 0·97 (95 % CI 0·94, 1·00), P= 0·048). This meta-analysis showed apparent association between coffee and tea intake and risk of glioma.

High prevalence of developmental venous anomaly in adult patients with midline thalamic diffuse gliomas.

OBJECTIVE: This study aimed to assess the prevalence of developmental venous anomaly (DVA) in patients with thalamic glioma. Furthermore, we explored the association between DVA and some important biomarkers, such as IDH1 mutation, and H3K27M mutation. PATIENTS AND METHODS: Patients who received tumor resection in West China Hospital between August 2009 and October 2017 were enrolled. Propensity score matching was conducted based on a logistic regression model and 1:1 matching for case and control was used to generate a new cohort from patients with meningioma. Chi-square test, t-test, univariate and multivariate analyses were employed to assess the prevalence of DVA in thalamic glioma and meningioma and to identify risk factors associated with DVA. RESULTS: Ninety-nine patients with thalamic glioma were enrolled in the current study (male, n = 54; female, n = 45). The mean age was 42.9 ± 15.3 years old. We identified a higher prevalence of DVA in 99 patients with thalamic glioma when compared with 99 patients with meningioma (18.18% vs. 7.07%), which was slightly lower than the prevalence of DVA in glioma reported in previous studies. Furthermore, the distribution of gender, age, and tumor grade in DVA did not reach statistical significance. Chi-square test, univariate and multivariate analyses showed that IDH1 mutation, ATRX mutation, MGMT promoter methylation, p53 mutation, MMP9, EGFR, and Top II positive expression, TERT mutation, and H3K27M mutation were not associated with the development of DVA in thalamic glioma. CONCLUSION: A higher prevalence of DVA was found in thalamic glioma compared with meningioma.

Antibodies Against Hypothalamus and Pituitary Gland in Childhood-Onset Brain Tumors and Pituitary Dysfunction.

Purpose: To detect the presence of antipituitary (APA) and antihypothalamus antibodies (AHA) in subjects treated for brain cancers, and to evaluate their potential association with pituitary dysfunction. Methods: We evaluated 63 patients with craniopharyngioma, glioma, and germinoma treated with surgery and/or radiotherapy and/or chemotherapy at a median age of 13 years. Forty-one had multiple pituitary hormone deficiencies (MPHD), six had a single pituitary defect. GH was the most common defect (65.1%), followed by AVP (61.9%), TSH (57.1%), ACTH (49.2%), and gonadotropin (38.1%). APA and AHA were evaluated by simple indirect immunofluorescence method indirect immunofluorescence in patients and in 50 healthy controls. Results: Circulating APA and/or AHA were found in 31 subjects (49.2%) and in none of the healthy controls. In particular, 25 subjects out of 31 were APA (80.6%), 26 were AHA (83.90%), and 20 were both APA and AHA (64.5%). Nine patients APA and/or AHA have craniopharyngioma (29%), seven (22.6%) have glioma, and 15 (48.4%) have germinoma. Patients with craniopharyngioma were positive for at least one antibody in 39.1% compared to 33.3% of patients with glioma and to 78.9% of those with germinoma with an analogous distribution for APA and AHA between the three tumors. The presence of APA or AHA and of both APA and AHA was significantly increased in patients with germinoma. The presence of APA (P = 0.001) and their titers (P = 0.001) was significantly associated with the type of tumor in the following order: germinomas, craniopharyngiomas, and gliomas; an analogous distribution was observed for the presence of AHA (P = 0.002) and their titers (P = 0.012). In addition, we found a significant association between radiotherapy and APA (P = 0.03). Conclusions: Brain tumors especially germinoma are associated with the development of hypothalamic-pituitary antibodies and pituitary defects. The correct interpretation of APA/AHA antibodies is essential to avoid a misdiagnosis of an autoimmune infundibulo-neurohypophysitis or pituitary hypophysitis in patients with germinoma.

A prospective study of coffee and tea consumption and the risk of glioma in the UK Biobank.

BACKGROUND: Coffee and tea have been hypothesised to reduce the risk of some cancers; however, their impact on glioma is less well studied. METHODS: We examined associations between self-reported intake of tea and coffee in relation to glioma risk in the UK Biobank. We identified 487 incident glioma cases among 379,259 participants. Hazard ratios (HR) and 95% confidence intervals (CI) for glioma according to caffeinated beverage consumption were calculated using Cox proportional hazards regression with adjustment for age, gender, race and education; daily cups of tea or coffee were included in models considering the other beverage. RESULTS: Consuming 4 or more cups of tea was associated with reduced risk of glioma when compared to no tea consumption (HR = 0.69; 95% CI, 0.51-0.94). A significant inverse association was observed for glioblastoma (HR = 0.93 per 1 cup/d increment; 95% CI, 0.89-0.98) and among males for all gliomas combined (HR = 0.95 per 1 cup/d increment; 95% CI, 0.90-1.00). A suggestive inverse association was also observed with greater consumption of coffee (HR = 0.71; 95% CI, 0.49-1.05 for >4 versus 0 cups/d). Results were not materially changed with further adjustment for smoking, alcohol and body mass index. Associations were similar in 2-year and 3-year lagged analyses. CONCLUSIONS: In this prospective study, we found a significant inverse association between tea consumption and the risk of developing glioma, and a suggestive inverse association for the consumption of coffee. Further investigation on the possible preventive role of caffeine in glioma is warranted.

A prospective study of tea and coffee intake and risk of glioma.

Tea and coffee have antioxidant and neuroprotective effects. Observational studies suggest that tea and coffee intake may reduce cancer risk, but data on glioma risk are inconclusive. We evaluated the association between tea, coffee and caffeine intake and glioma risk in the female Nurses' Health Study (NHS) and Nurses' Health Study II (NHSII) and the male Health Professionals Follow-Up Study (HPFS). Cumulative intake was derived from validated quadrennial food frequency questionnaires. Glioma cases were confirmed by medical record review. Multivariable-adjusted hazard ratios of glioma by beverage intake category were estimated using Cox proportional hazards models. We documented 554 incident cases of glioma (256 in NHS, 87 in NHSII and 211 in HPFS). Compared to <1 cup/week, higher tea consumption was borderline inversely associated with glioma risk in pooled cohorts (hazard ratio [HR] = 0.73, 95% confidence interval [CI]: 0.49-1.10 for >2 cups/day, p-trend = 0.05), but not in women (HR = 0.74, 95% CI: 0.47-1.18 for >2 cups/day, p-trend = 0.11) or men (HR = 0.70, 95% CI: 0.30-1.60 for >2 cups/day, p-trend = 0.30) separately. Overall, we observed no significant associations between caffeinated, decaffeinated or total coffee intake and glioma risk. There were no material differences in the results with baseline values, 8-year lagged responses, or when limited to glioblastoma (n = 362). In three large prospective cohort studies, tea intake was borderline inversely associated with glioma risk. No significant associations were observed for coffee intake and glioma risk. These results merit further exploration in prospective studies.

Tea and coffee consumption in relation to glioma: a case-control study.

PURPOSE: Data on the link between tea and coffee consumption and risk of glioma are controversial. We aimed to examine the association between tea and coffee consumption and glioma in Iranian adults. METHODS: In this hospital-based case-control study, we enrolled 128 pathologically confirmed new cases of glioma and 256 age- and sex-matched controls. Dietary intakes of study participants including tea and coffee consumption was assessed using the validated Block-format 123-item semi-quantitative FFQ. Participants were categorized based on tertiles of tea and coffee consumption. Data on potential confounders were also collected through the use of pre-tested questionnaire. RESULTS: Individuals with the greatest tea consumption were less likely to have glioma compared with those with the lowest consumption (0.36; 0.20-0.68). This inverse association was not changed after controlling for energy intake. The association remained statistically significant even after taking other potential confounders, including dietary intakes of red and processed meats, legumes and nuts, fruits, salt and mutual effects of tea and coffee consumption, into account (0.33; 0.13-0.86). Additional adjustments for BMI did not alter the association. After controlling for potential confounders, including dietary intakes and BMI, coffee consumption was inversely associated with odds of glioma; such that individuals in the top category of coffee consumption were 91% less likely to have glioma compared with those in the bottom category (0.09; 0.03-0.24). Considering coffee and tea intake combined, those in the highest tertile were 65% less likely to have glioma compared with those in the lowest tertile (0.35; 0.15-0.83). CONCLUSION: We found an inverse association between tea and coffee consumption and odds of glioma, even after controlling for a wide range of confounders.

Mobile phone radiation causes brain tumors and should be classified as a probable human carcinogen (2A) (review).

Quickly changing technologies and intensive uses of radiofrequency electromagnetic field (RF-EMF)­emitting phones pose a challenge to public health. Mobile phone users and uses and exposures to other wireless transmitting devices (WTDs) have increased in the past few years. We consider that CERENAT, a French national study, provides an important addition to the literature evaluating the use of mobile phones and risk of brain tumors. The CERENAT finding of increased risk of glioma is consistent with studies that evaluated use of mobile phones for a decade or longer and corroborate those that have shown a risk of meningioma from mobile phone use. In CERENAT, exposure to RF­EMF from digitally enhanced cordless telephones (DECTs), used by over half the population of France during the period of this study, was not evaluated. If exposures to DECT phones could have been taken into account, the risks of glioma from mobile phone use in CERENAT are likely to be higher than published. We conclude that radiofrequency fields should be classified as a Group 2A ̔probable̓ human carcinogen under the criteria used by the International Agency for Research on Cancer (Lyon, France). Additional data should be gathered on exposures to mobile and cordless phones, other WTDs, mobile phone base stations and Wi­Fi routers to evaluate their impact on public health. We advise that the as low as reasonable achievable (ALARA) principle be adopted for uses of this technology, while a major cross­disciplinary effort is generated to train researchers in bioelectromagnetics and provide monitoring of potential health impacts of RF­EMF.

Vitamin E intake is not associated with glioma risk: evidence from a meta-analysis.

BACKGROUND: Epidemiological studies evaluating the association between vitamin E intake and glioma risk have produced inconsistent results. Thus, we conducted a meta-analysis to summarize the evidence from epidemiological studies of vitamin E intake with the risk of glioma. METHODS: Pertinent studies were identified by a search in pubmed and web of knowledge up to August 2014. The random-effect model was used to combine the results. Publication bias was estimated using the Egger's regression asymmetry test. RESULTS: Twelve studies including 3180 glioma cases about vitamin E intake with the risk of glioma were included in this meta-analysis. The combined relative risk (RR) of glioma associated with vitamin E intake was 0.88 (95% CI = 0.69-1.12). The association was significant neither in the case-control studies nor in the cohort studies. No publication biases were found. CONCLUSIONS: Our analysis indicated that vitamin E intake is not associated with the risk of glioma.

A meta-analysis of coffee and tea consumption and the risk of glioma in adults.

BACKGROUND: Coffee contains many compounds, including antioxidants, which could prevent cancerogenesis, and coffee has been related with lower incidence of cancer at several sites. Tea is also rich in antioxidants, mainly polyphenols. To provide a quantitative overall estimate on the relation between coffee and tea consumption and glioma, we combined all published data, using a meta-analytic approach. METHODS: In September 2012, a bibliography search was carried out in both PubMed and Embase to identify observational studies providing quantitative estimates on the issue. Pooled estimates of the relative risks (RR) and the corresponding 95 % confidence intervals (CI) were calculated using random-effects models. RESULTS: Six studies (four cohort and two case-control studies) were available for meta-analysis, for a total of about 2100 cases. The summary RRs and 95 % CIs of glioma for drinkers versus non/occasional drinkers were 0.96 (95 % CI: 0.81-1.13) for coffee and 0.86 (95 % CI: 0.78-0.94) for tea, with no heterogeneity between studies. When we compared the highest versus the lowest categories of consumption, the RRs were 1.01 (95 % CI: 0.83-1.22) for coffee, 0.88 (95 % CI: 0.69-1.12) for tea, and 0.75 (95 % CI: 0.54-1.05) for coffee plus tea. CONCLUSIONS: This meta-analysis, although based on few studies, suggests a lack of association between coffee intake and glioma risk, and a tendency, if any, to a lower risk for tea and coffee plus tea drinkers.

Coffee, tea, soda, and caffeine intake in relation to risk of adult glioma in the NIH-AARP Diet and Health Study.

PURPOSE: We utilized the large, prospective NIH-AARP Diet and Health Study to further explore the hypothesis, suggested by two recent prospective cohort studies, that increased intake of coffee, tea, soda, and/or caffeine is associated with reduced adult glioma risk. METHODS: At baseline in 1995-1996, dietary intake, including coffee, tea, and soda, was assessed with a food frequency questionnaire. We used Cox proportional hazards models to calculate adjusted hazard ratios (HR) and 95 % confidence intervals (CI) for glioma risk in relation to beverage intake. RESULTS: During follow-up of 545,771 participants through 2006, 904 participants were diagnosed with glioma. We found no trends of decreasing glioma risk with increasing intake of specific beverages or total caffeine. HR patterns for consumption of the caffeinated versus decaffeinated form of each beverage were inconsistent with a specific caffeine effect. HR patterns of reduced glioma risk for most categories of beverage intake greater than "none" prompted a post hoc analysis that revealed borderline-significant inverse associations for any versus no intake of tea (HR = 0.84; 95 % CI, 0.69-1.03), total coffee plus tea (HR = 0.70; 95 % CI, 0.48-1.03), and soda (HR = 0.82; 95 % CI, 0.67-1.01). CONCLUSIONS: The borderline-significant inverse associations could be explained by a threshold effect in which any beverage intake above a low level confers a beneficial effect, most likely due to beverage constituents other than caffeine. They could also be explained by non-drinkers of these beverages sharing unknown extraneous characteristics associated with increased glioma risk, or by chance.

Coffee, tea, caffeine intake, and risk of adult glioma in three prospective cohort studies.

Current data suggest that caffeinated beverages may be associated with lower risk of glioma. Caffeine has different effects on the brain, some of which could play a role in brain carcinogenesis, and coffee has been consistently associated with reduced risk of liver cancer, thus suggesting a potential anticarcinogenic effect. A total of 335 incident cases of gliomas (men, 133; women, 202) were available from three independent cohort studies. Dietary intake was assessed by food frequency questionnaires obtained at baseline and during follow-up. Cox proportional hazard models were used to estimate incidence rate ratios (RR) and 95% confidence intervals (CI) between consumption of coffee, tea, carbonated beverages, caffeine, and glioma risk adjusting for age and total caloric intake. Estimates from each cohort were pooled using a random-effects model. Consumption of five or more cups of coffee and tea daily compared with no consumption was associated with a decrease risk of glioma (RR, 0.60; 95% CI, 0.41-0.87; P(trend) = 0.04). Inverse, although weaker, associations were also observed between coffee, caffeinated coffee, tea, and carbonated beverages and glioma risk. No association was observed between decaffeinated coffee and glioma risk. Among men, a statistically significant inverse association was observed between caffeine consumption and risk of glioma (RR, 0.46; 95% CI, 0.26-0.81; P(trend) = 0.03); the association was weaker among women. Our findings suggest that consumption of caffeinated beverages, including coffee and tea, may reduce the risk of adult glioma, but further research is warranted to confirm these findings in other populations.

IgE, allergy, and risk of glioma: update from the San Francisco Bay Area Adult Glioma Study in the temozolomide era.

The consistently observed inverse relationship of allergic conditions with glioma risk and our previous demonstration that immunoglobulin E (IgE) levels also were lower in glioma patients than controls suggest that atopic allergy may be related to a mechanism that inhibits or prevents glioma. We sought to extend these results with a new and larger series of patients (n = 535 with questionnaire data; 393 with IgE measures) and controls (n = 532 with questionnaire data; 470 with IgE measures). As expected, glioma cases were less likely than controls to report history of allergies [among self-reported cases, Odds ratios (OR) = 0.59, 95% confidence interval (CI): 0.41-0.85]. IgE levels also were lower in glioma cases versus controls (OR per unit log IgE = 0.89, 95% CI (0.82-0.98). However, this inverse relationship was only apparent among cases receiving temozolomide, a treatment which became part of the "standard of care" for glioblastoma patients during the study period. Among patients receiving temozolomide, IgE levels in cases whose blood samples were obtained within 30 days of diagnosis were slightly higher than controls, whereas IgE levels in cases whose blood sample was obtained >60 days after diagnosis were significantly lower than controls (OR = 0.80; 95% CI: 0.71-0.89). Thus, although our results robustly confirm the inverse association between allergy and glioma, the results for IgE are affected by temozolomide treatments which may have influenced IgE levels. These results have implications for the study of immunologic factors in glioma as well as for immunotherapy protocols for treating glioma.

Dietary zinc intake and brain cancer in adults: a case-control study.

Little is known about the aetiology of brain tumours. One putative factor suggested from animal models is a protective effect of dietary Zn. We tested the hypothesis that increased compared with low dietary Zn intake is protective against brain tumour development. We conducted a population-based case-control study in the UK, of adults aged 18-69 years, between 2001 and 2004 aiming to identify possible risk factors. Dietary information was collected from 637 cases diagnosed with a glioma or meningioma, and 876 controls. Data were obtained from a self-completed FFQ. Multivariate logistic regression analysis was conducted, adjusting for socio-demographic factors, season of questionnaire return, multivitamin supplementation and energy intake. Although a weak protective effect was observed for the third quartile of intake (normal compared with low intake) in the meningioma group, this was limited to the specific brain tumour subtype and quartile, and was not significant after also adjusting for intake of other elements. Overall there was no significant effect of Zn intake. No association or dose-response relationship was observed between increased compared with low Zn intake and risk of glioma or meningioma.

Inverse association of antioxidant and phytoestrogen nutrient intake with adult glioma in the San Francisco Bay Area: a case-control study.

BACKGROUND: Increasing evidence from epidemiologic studies suggest that oxidative stress may play a role in adult glioma. In addition to dietary antioxidants, antioxidant and weak estrogenic properties of dietary phytoestrogens may attenuate oxidative stress. Our hypothesis is that long-term consumption of dietary antioxidants and phytoestrogens such as genistein, daidzein, biochanin A, formononetin, matairesinol, secoisolariciresinol and coumestrol, may reduce the risk of adult glioma. METHODS: Using unconditional logistic regression models, we compared quartiles of consumption for several specific antioxidants and phytoestrogens among 802 adult glioma cases and 846 controls from two study series from the San Francisco Bay Area Adult Glioma Study, 1991-2000, controlling for vitamin supplement usage, age, socioeconomic status, gender, ethnicity and total daily calories. For cases, dietary information was either self-reported or reported by a proxy. For controls, dietary information was self-reported. Gender- and series-specific quartiles of average daily nutrient intake, estimated from food-frequency questionnaires, were computed from controls. RESULTS: Significant p-values (trend test) were evaluated using significance levels of either 0.05 or 0.003 (the Bonferroni corrected significance level equivalent to 0.05 adjusting for 16 comparisons). For all cases compared to controls, statistically significant inverse associations were observed for antioxidant index (p < 0.003), carotenoids (alpha- and beta-carotene combined, p < 0.05), daidzein (p = 0.003), matairesinol (p < 0.05), secoisolariciresinol (p < 0.003), and coumestrol (p < 0.003). For self-reported cases compared to controls, statistically significant inverse associations were observed for antioxidant index (p < 0.05) and daidzein (p < 0.05). CONCLUSION: Our results support inverse associations of glioma with higher dietary antioxidant index and with higher intake of certain phytoestrogens, especially daidzein.

Brain cancer in a residential area bordering on an oil refinery.

Both in response to community concerns about brain cancer related to an oil refinery and in order to more fully understand the etiology of primary site brain cancer (glioma), a highly focused cancer cluster investigation was conducted. The components included: (1) a literature review of occupational exposures in the petroleum refining and petrochemical industries, (2) comparisons between observed and expected cases, (3) comparisons between mean age at diagnosis and median survival time and (4) interviews concerning exposures of cases. Evidence from the literature review revealed little, if any, effect of petroleum refinery or petrochemical exposure on the risk for brain cancer. There was no statistically significant increase in the number of brain cancer cases in the community (observed = 12, expected = 9.46, standardized mortality ratio = 1.27). There was no statistically significant decrease in mean age at diagnosis or median survival time among those most exposed. Reports of exposure from the case interviews were highest for eating processed meats (98.5%), dental X-rays (96.6%), dog ownership (91.2%) and swimming (80.3%). There were no major occupational exposures identified. It seems unlikely that petrochemicals are involved in any significant way in the etiology of most brain cancers (gliomas). A follow-up case-control study should focus primarily on those risk factors mentioned frequently by the cases.

Diet and risk of adult glioma in eastern Nebraska, United States.

OBJECTIVE: To investigate potential associations between diet and adult glioma. METHODS: We conducted a population-based case-control study of adult glioma in eastern Nebraska. Nutrient and food group intakes were estimated for 236 glioma cases and 449 controls using information obtained from a food-frequency questionnaire. RESULTS: After adjusting for potential confounders, inverse associations with risk of adult glioma were observed for intakes of dark yellow vegetables (highest quartile versus lowest: OR = 0.6, Ptrend = 0.03) and beans (OR = 0.4, Ptrend = 0.0003), but no associations were seen for dietary sources of preformed nitrosamines or high-nitrate vegetables. Our nutrient analysis revealed significant inverse associations between risk of adult glioma and dietary intake of pro-vitamin A carotenoids (highest quartile versus lowest: OR = 0.5, Ptrend = 0.005), a-carotene (OR = 0.5, Ptrend = 001), beta-carotene (OR = 0.5, Ptrend = 0.01), dietary fiber (OR=0.6, Ptrend = 0.048) and fiber from beans (OR = 0.5, Ptrend = 0.0002). We observed no significant associations with risk of adult glioma for intakes of other nutrients or compounds including nitrate, nitrite, vitamin C, vitamin E, saturated fat, cholesterol, dietary fiber from grain products, or fiber from fruit and vegetables. CONCLUSION: Our study does not support the N-nitroso compound hypothesis, but suggests potential roles for carotenoids and possibly other phytochemicals in reducing risk of adult glioma.

Case-control study of intracranial tumors among employees at a petrochemical research facility.

This case-control study evaluated the relation between potential exposure to chemical and physical agents and the occurrence of intracranial tumors among employees at a petrochemical research facility. Cases were employees with glioma (n = 6) or benign intracranial tumors (n = 6). Controls (n = 119) were individually matched to cases on gender and birth year, and they were alive and did not have an intracranial tumor at the case's diagnosis date. Exposure information came from interviews with subjects or surrogates and from corporate records on agents used in research projects. Analyses computed matched odds ratios (ORs) and corresponding 95% confidence intervals (CIs) for self-reported exposure to 15 agents and project-based estimates of exposure to 29 agents. For gliomas, the OR was elevated for self-reported exposure to ionizing radiation (OR, 15.7; CI, 1.4 to 179.4), n-hexane (OR, infinity; CI, 1.4 to infinity), organometallics (OR, 9.4; CI, 1.5 to 59.7), and amines other than nitrosamines (OR, 6.0; CI, 1.0 to 35.7). The OR also was elevated for project-based potential use of ionizing radiation (OR, 9.6; CI, 1.7 to 55.2) and for potential use of n-hexane lasting at least 4 years (OR, 16.2; CI, 1.1 to 227.6). For benign intracranial tumors, the OR was elevated only for self-reported exposure to ionizing radiation (OR, 5.4; CI, 1.7 to 43.1) and other amines (OR, 5.2; CI, 0.9 to 29.5). Occupational exposure may have contributed to the glioma excess, but the specific causal agents remain unknown. The study indicated that benign intracranial tumors were unlikely to be work-related.

Dietary and other lifestyle factors of women with brain gliomas in Los Angeles County (California, USA)

A population-based interview study in Los Angeles County (California, USA) of 94 women with intracranial gliomas and 94 individually matched neighborhood controls investigated the relationship to various sources of exposure to N-nitroso compounds and their precursors and to vitamins which inhibit the endogenous formation of these compounds. The study offers some support for the hypothesis that dietary sources of nitroso exposure relate to risk. Risk increased with increasing consumption of cured meats, most notably of bacon (odds ratio [OR] for the third tertile of intake = 6.6, 95 percent confidence interval [CI] = 1.9-22.5, P trend < 0.001). Risk was reduced with increasing intake of vegetables such as bell peppers (OR for third tertile = 0.2, CI = 0.1-0.7, P trend < 0.01). In addition, use of vitamin supplements appeared protective, and there was some suggestion that eating cured meats in combination with foods which inhibit endogenous nitrosation mitigates risk. Other potential sources of nitroso exposure such as smoking, cosmetics, and drinking water did not relate to risk. Despite the limitations of data on usual adult diet, it appears that dietary sources of nitroso compounds may be important in the development of gliomas.

Dietary and tobacco risk factors for adult onset glioma in the San Francisco Bay Area (California, USA)

The roles of diet and tobacco in the etiology of primary brain cancer are controversial. In this report, we compare dietary and cigarette smoking histories among 434 adults newly diagnosed with glioma in the San Francisco Bay Area (California, USA) between 1991 and 1994 with frequency age, gender, and ethnicity-matched population-based controls. Data were obtained on use of vitamin supplements and mean weekly consumption of each of 24 food groups. Adjusted for age, family income, and education, for both men and women, cases had higher mean weekly consumption of cured meats and other cured foods, lower consumption of high vitamin A and C fruits and vegetables, and higher average intakes of beer and other alcohol than controls. Men with brain cancer were twice as likely as control men to report high consumption of cured foods and low consumption of foods rich in vitamin C (odds ratio [OR] = 2.0, 95 percent confidence interval [CI] = 1.2-3.5). This association was less pronounced and not statistically significant in women (OR = 1.5, CI = 0.8-2.7). Similarly, men with brain cancer were twice as likely as controls to have high nitrite and low vitamin C consumption. Among men only, cases were 1.8 times more likely than controls to report smoking unfiltered cigarettes (CI = 0.9-3.4). Moreover, among smokers cases smoked unfiltered cigarettes almost twice as long as controls (P = 0.04) and cases' average total pack-years also significantly exceeded controls. Although these findings support the hypothesis that N-nitroso compounds might be a factor in adult glioma, they are compatible with other dietary hypotheses. In particular, these results also favor the hypothesis that total body burden of oxidants may play a role in brain cancer causation.

Risk factors for gliomas and meningiomas in males in Los Angeles County.

Detailed job histories and information about other suspected risk factors were obtained during interviews with 272 men aged 25-69 with a primary brain tumor first diagnosed during 1980-1984 and with 272 individually matched neighbor controls. Separate analyses were conducted for the 202 glioma pairs and the 70 meningioma pairs. Meningioma, but not glioma, was related to having a serious head injury 20 or more years before diagnosis [odds ratio (OR) = 2.3; 95% confidence interval (CI) = 1.1-5.4], and a clear dose-response effect was observed relating meningioma risk to number of serious head injuries (P for trend = 0.01; OR for greater than or equal to 3 injuries = 6.2; CI = 1.2-31.7). Frequency of full-mouth dental X-ray examinations after age 25 related to both glioma (P for trend = 0.04) and meningioma risk (P for trend = 0.06). Glioma, but not meningioma risk, related to duration of prior employment in jobs likely to involve high exposure to electric and magnetic fields (P for trend = 0.05). This risk was greatest for astrocytoma (OR for employment in such jobs for greater than 5 years = 4.3; CI = 1.2-15.6). More glioma cases had worked in the rubber industry (discordant pairs 6/1) and more worked in hot processes using plastics (9/1). More meningioma cases had jobs that involved exposure to metal dusts and fumes (discordant pairs 13/5), and six of these cases and two controls worked as machinists. Finally, there was a protective effect among glioma pairs relating to frequency of use of vitamin C and other vitamin supplements (P for trend = 0.004); the OR for use at least twice a day was 0.4 (CI = 0.2-0.8).