Nitrosyl-Heme and Heme Iron Intake from Processed Meats in Subjects from the EPIC-Spain Cohort.

BACKGROUND: The consumption of processed meats (PMs) and red meats are linked to the likelihood of developing colorectal cancer. Various theories have been proposed to explain this connection, focusing on nitrosyl-heme and heme iron intake. We hypothesized that differences in nitrosyl-heme and heme iron intakes will be associated with various sociodemographic and lifestyle factors. METHODS: The study included 38,471 healthy volunteers (62% females) from five Spanish regions within the EPIC-Spain cohort. High-Performance Liquid Chromatography (HPLC) determined nitrosyl-heme and heme iron levels in the 39 most consumed PMs. Food intake was assessed using validated questionnaires in interviews. Nitrosyl-heme and heme iron intakes, adjusted for sex, age, body mass index (BMI), center, and energy intake, were expressed as geometric means due to their skewed distribution. Variance analysis identified foods explaining the variability of nitrosyl-heme and heme iron intakes. RESULTS: The estimated intakes were 528.6 µg/day for nitrosyl-heme and 1676.2 µg/day for heme iron. Significant differences in nitrosyl-heme intake were found by sex, center, energy, and education level. Heme iron intake varied significantly by sex, center, energy, and smoking status. "Jamón serrano" and "jamón cocido/jamón de York" had the highest intake values, while "morcilla asturiana" and "sangrecilla" were key sources of nitrosyl-heme and heme iron. CONCLUSIONS: This is the first study to estimate levels of nitrosyl-heme intake directly in PMs for a large sample, revealing variations based on sex, BMI, smoking, and activity. Its data aids future exposure estimations in diverse populations.

Exposure to bacterial products lipopolysaccharide and flagellin and hepatocellular carcinoma: a nested case-control study.

BACKGROUND: Leakage of bacterial products across the gut barrier may play a role in liver diseases which often precede the development of liver cancer. However, human studies, particularly from prospective settings, are lacking. METHODS: We used a case-control study design nested within a large prospective cohort to assess the association between circulating levels of anti-lipopolysaccharide (LPS) and anti-flagellin immunoglobulin A (IgA) and G (IgG) (reflecting long-term exposures to LPS and flagellin, respectively) and risk of hepatocellular carcinoma. A total of 139 men and women diagnosed with hepatocellular carcinoma between 1992 and 2010 were matched to 139 control subjects. Multivariable rate ratios (RRs), including adjustment for potential confounders, hepatitis B/C positivity, and degree of liver dysfunction, were calculated with conditional logistic regression. RESULTS: Antibody response to LPS and flagellin was associated with a statistically significant increase in the risk of hepatocellular carcinoma (highest vs. lowest quartile: RR = 11.76, 95% confidence interval = 1.70-81.40; P trend = 0.021). This finding did not vary substantially by time from enrollment to diagnosis, and did not change after adjustment for chronic infection with hepatitis B and C viruses. CONCLUSIONS: These novel findings, based on exposures up to several years prior to diagnosis, support a role for gut-derived bacterial products in hepatocellular carcinoma development. Further study into the role of gut barrier failure and exposure to bacterial products in liver diseases is warranted.

Dietary and lifestyle determinants of acrylamide and glycidamide hemoglobin adducts in non-smoking postmenopausal women from the EPIC cohort.

PURPOSE: Acrylamide was classified as 'probably carcinogenic' to humans in 1994 by the International Agency for Research on Cancer. In 2002, public health concern increased when acrylamide was identified in starchy, plant-based foods, processed at high temperatures. The purpose of this study was to identify which food groups and lifestyle variables were determinants of hemoglobin adduct concentrations of acrylamide (HbAA) and glycidamide (HbGA) in 801 non-smoking postmenopausal women from eight countries in the European Prospective Investigation into Cancer and Nutrition (EPIC) cohort. METHODS: Biomarkers of internal exposure were measured in red blood cells (collected at baseline) by high-performance liquid chromatography/tandem mass spectrometry (HPLC/MS/MS) . In this cross-sectional analysis, four dependent variables were evaluated: HbAA, HbGA, sum of total adducts (HbAA + HbGA), and their ratio (HbGA/HbAA). Simple and multiple regression analyses were used to identify determinants of the four outcome variables. All dependent variables (except HbGA/HbAA) and all independent variables were log-transformed (log2) to improve normality. Median (25th-75th percentile) HbAA and HbGA adduct levels were 41.3 (32.8-53.1) pmol/g Hb and 34.2 (25.4-46.9) pmol/g Hb, respectively. RESULTS: The main food group determinants of HbAA, HbGA, and HbAA + HbGA were biscuits, crackers, and dry cakes. Alcohol intake and body mass index were identified as the principal determinants of HbGA/HbAA. The total percent variation in HbAA, HbGA, HbAA + HbGA, and HbGA/HbAA explained in this study was 30, 26, 29, and 13 %, respectively. CONCLUSIONS: Dietary and lifestyle factors explain a moderate proportion of acrylamide adduct variation in non-smoking postmenopausal women from the EPIC cohort.

Serum Endotoxins and Flagellin and Risk of Colorectal Cancer in the European Prospective Investigation into Cancer and Nutrition (EPIC) Cohort.

BACKGROUND: Chronic inflammation and oxidative stress are thought to be involved in colorectal cancer development. These processes may contribute to leakage of bacterial products, such as lipopolysaccharide (LPS) and flagellin, across the gut barrier. The objective of this study, nested within a prospective cohort, was to examine associations between circulating LPS and flagellin serum antibody levels and colorectal cancer risk. METHODS: A total of 1,065 incident colorectal cancer cases (colon, n = 667; rectal, n = 398) were matched (1:1) to control subjects. Serum flagellin- and LPS-specific IgA and IgG levels were quantitated by ELISA. Multivariable conditional logistic regression models were used to calculate ORs and 95% confidence intervals (CI), adjusting for multiple relevant confouding factors. RESULTS: Overall, elevated anti-LPS and anti-flagellin biomarker levels were not associated with colorectal cancer risk. After testing potential interactions by various factors relevant for colorectal cancer risk and anti-LPS and anti-flagellin, sex was identified as a statistically significant interaction factor (Pinteraction < 0.05 for all the biomarkers). Analyses stratified by sex showed a statistically significant positive colorectal cancer risk association for men (fully-adjusted OR for highest vs. lowest quartile for total anti-LPS + flagellin, 1.66; 95% CI, 1.10-2.51; Ptrend, 0.049), whereas a borderline statistically significant inverse association was observed for women (fully-adjusted OR, 0.70; 95% CI, 0.47-1.02; Ptrend, 0.18). CONCLUSION: In this prospective study on European populations, we found bacterial exposure levels to be positively associated to colorectal cancer risk among men, whereas in women, a possible inverse association may exist. IMPACT: Further studies are warranted to better clarify these preliminary observations.

Acrylamide and Glycidamide Hemoglobin Adducts and Epithelial Ovarian Cancer: A Nested Case-Control Study in Nonsmoking Postmenopausal Women from the EPIC Cohort.

BACKGROUND: Acrylamide was classified as "probably carcinogenic to humans (group 2A)" by the International Agency for Research on Cancer. Epithelial ovarian cancer (EOC) is the fourth cause of cancer mortality in women. Five epidemiological studies have evaluated the association between EOC risk and dietary acrylamide intake assessed using food frequency questionnaires, and one nested case-control study evaluated hemoglobin adducts of acrylamide (HbAA) and its metabolite glycidamide (HbGA) and EOC risk; the results of these studies were inconsistent. METHODS: A nested case-control study in nonsmoking postmenopausal women (334 cases, 417 controls) was conducted within the European Prospective Investigation into Cancer and Nutrition (EPIC) cohort. Unconditional logistic regression models were used to estimate ORs and 95% confidence intervals (CI) for the association between HbAA, HbGA, HbAA+HbGA, and HbGA/HbAA and EOC and invasive serous EOC risk. RESULTS: No overall associations were observed between biomarkers of acrylamide exposure analyzed in quintiles and EOC risk; however, positive associations were observed between some middle quintiles of HbGA and HbAA+HbGA. Elevated but nonstatistically significant ORs for serous EOC were observed for HbGA and HbAA+HbGA (ORQ5vsQ1, 1.91; 95% CI, 0.96-3.81 and ORQ5vsQ1, 1.90; 95% CI, 0.94-3.83, respectively); however, no linear dose-response trends were observed. CONCLUSION: This EPIC nested case-control study failed to observe a clear association between biomarkers of acrylamide exposure and the risk of EOC or invasive serous EOC. IMPACT: It is unlikely that dietary acrylamide exposure increases ovarian cancer risk; however, additional studies with larger sample size should be performed to exclude any possible association with EOC risk.

Inflammatory Markers and Risk of Epithelial Ovarian Cancer by Tumor Subtypes: The EPIC Cohort.

BACKGROUND: Evidence suggests an etiologic role for inflammation in ovarian carcinogenesis and heterogeneity between tumor subtypes and anthropometric indices. Prospective studies on circulating inflammatory markers and epithelial invasive ovarian cancer (EOC) have predominantly investigated overall risk; data characterizing risk by tumor characteristics (histology, grade, stage, dualistic model of ovarian carcinogenesis) and anthropometric indices are sparse. METHODS: We conducted a nested case-control study in the European Prospective Investigation into Cancer and Nutrition (EPIC) cohort to evaluate C-reactive protein (CRP), IL6, and EOC risk by tumor characteristics. A total of 754 eligible EOC cases were identified; two controls (n = 1,497) were matched per case. We used multivariable conditional logistic regression to assess associations. RESULTS: CRP and IL6 were not associated with overall EOC risk. However, consistent with prior research, CRP >10 versus CRP ≤1 mg/L was associated with higher overall EOC risk [OR, 1.67 (1.03-2.70)]. We did not observe significant associations or heterogeneity in analyses by tumor characteristics. In analyses stratified by waist circumference, inflammatory markers were associated with higher risk among women with higher waist circumference; no association was observed for women with normal waist circumference [e.g., IL6: waist ≤80: ORlog2, 0.97 (0.81-1.16); waist >88: ORlog2, 1.78 (1.28-2.48), Pheterogeneity ≤ 0.01]. CONCLUSIONS: Our data suggest that high CRP is associated with increased risk of overall EOC, and that IL6 and CRP may be associated with EOC risk among women with higher adiposity. IMPACT: Our data add to global evidence that ovarian carcinogenesis may be promoted by an inflammatory milieu.

Plasma carotenoids, vitamin C, retinol and tocopherols levels and pancreatic cancer risk within the European Prospective Investigation into Cancer and Nutrition: a nested case-control study: plasma micronutrients and pancreatic cancer risk.

Evidence of a protective effect of several antioxidants and other nutrients on pancreatic cancer risk is inconsistent. The aim of this study was to investigate the association for prediagnostic plasma levels of carotenoids, vitamin C, retinol and tocopherols with risk of pancreatic cancer in a case-control study nested within the European Prospective Investigation into Cancer and Nutrition (EPIC). 446 incident exocrine pancreatic cancer cases were matched to 446 controls by age at blood collection, study center, sex, date and time of blood collection, fasting status and hormone use. Plasma carotenoids (α- and ß-carotene, lycopene, ß-cryptoxanthin, canthaxanthin, zeaxanthin and lutein), α- and γ-tocopherol and retinol were measured by reverse phase high-performance liquid chromatography and plasma vitamin C by a colorimetric assay. Incidence rate ratios (IRRs) with 95% confidence intervals (95%CIs) for pancreatic cancer risk were estimated using a conditional logistic regression analysis, adjusted for smoking status, smoking duration and intensity, waist circumference, cotinine levels and diabetes status. Inverse associations with pancreatic cancer risk were found for plasma ß-carotene (IRR highest vs. lowest quartile 0.52, 95%CI 0.31-0.88, p for trend = 0.02), zeaxanthin (IRR highest vs. lowest quartile 0.53, 95%CI 0.30-0.94, p for trend = 0.06) and α-tocopherol (IRR highest vs. lowest quartile 0.62, 95%CI 0.39-0.99, p for trend = 0.08. For α- and ß-carotene, lutein, sum of carotenoids and γ-tocopherol, heterogeneity between geographical regions was observed. In conclusion, our results show that higher plasma concentrations of ß-carotene, zeaxanthin and α-tocopherol may be inversely associated with risk of pancreatic cancer, but further studies are warranted.

Prolactin determinants in healthy women: A large cross-sectional study within the EPIC cohort.

BACKGROUND: Experimental and epidemiologic data suggest that higher circulating prolactin is associated with breast cancer risk; however, how various risk factors for breast cancer influence prolactin levels in healthy women is not clear. METHODS: We analyzed cross-sectional associations between several suggested reproductive and lifestyle risk factors for breast cancer and circulating prolactin among pre- and postmenopausal women, taking into account the use of current postmenopausal hormone therapy, among 2,560 controls from a breast cancer nested case-control study within the EPIC cohort. RESULTS: Adjusted geometric mean prolactin levels were significantly higher among premenopausal women, and among postmenopausal women using hormone therapy compared with nonusers (8.2, 7.0, and 6.3 ng/mL, respectively; Pcat = <0.0001). Furthermore, prolactin levels were significantly higher among users of combined estrogen-progestin hormone therapy compared with users of estrogen-alone hormone therapy (6.66 vs. 5.90 ng/mL; Pcat = 0.001). Prolactin levels were lower among parous women compared with nulliparous women (8.61 vs. 10.95 ng/mL; Pcat = 0.0002, premenopausal women); the magnitude of this difference depended on the number of full-term pregnancies (22.1% lower, ≥3 vs. 1 pregnancy, Ptrend = 0.01). Results for parity were similar but lower in magnitude among postmenopausal women. Prolactin did not vary by other studied factors, with the exception of lower levels among postmenopausal smokers compared with never smokers. CONCLUSIONS: Our study shows that current hormone therapy use, especially the use of combined hormone therapy, is associated with higher circulating prolactin levels in postmenopausal women, and confirms prior findings of lower circulating prolactin in parous women. IMPACT: Our study extends the knowledge linking various breast cancer risk factors with circulating prolactin.

Cross-sectional associations of objectively measured physical activity, cardiorespiratory fitness and anthropometry in European adults.

OBJECTIVE: To quantify the independent associations between objectively measured physical activity (PA), cardiorespiratory fitness (CRF), and anthropometry in European men and women. METHODS: 2,056 volunteers from 12 centers across Europe were fitted with a heart rate and movement sensor at 2 visits 4 months apart for a total of 8 days. CRF (ml/kg/min) was estimated from an 8 minute ramped step test. A cross-sectional analysis of the independent associations between objectively measured PA (m/s(2)/d), moderate and vigorous physical activity (MVPA) (%time/d), sedentary time (%time/d), CRF, and anthropometry using sex stratified multiple linear regression was performed. RESULTS: In mutually adjusted models, CRF, PA, and MVPA were inversely associated with all anthropometric markers in women. In men, CRF, PA, and MVPA were inversely associated with BMI, whereas only CRF was significantly associated with the other anthropometric markers. Sedentary time was positively associated with all anthropometric markers, however, after adjustment for CRF significant in women only. CONCLUSION: CRF, PA, MVPA, and sedentary time are differently associated with anthropometric markers in men and women. CRF appears to attenuate associations between PA, MVPA, and sedentary time. These observations may have implications for prevention of obesity.

A structural equation modelling approach to explore the role of B vitamins and immune markers in lung cancer risk.

The one-carbon metabolism (OCM) is considered key in maintaining DNA integrity and regulating gene expression, and may be involved in the process of carcinogenesis. Several B-vitamins and amino acids have been implicated in lung cancer risk, via the OCM directly as well as immune system activation. However it is unclear whether these factors act independently or through complex mechanisms. The current study applies structural equations modelling (SEM) to further disentangle the mechanisms involved in lung carcinogenesis. SEM allows simultaneous estimation of linear relations where a variable can be the outcome in one equation and the predictor in another, as well as allowing estimation using latent variables (factors estimated by correlation matrix). A large number of biomarkers have been analysed from 891 lung cancer cases and 1,747 controls nested within the European Prospective Investigation into Cancer and Nutrition (EPIC) cohort. Four putative mechanisms in the OCM and immunity were investigated in relation to lung cancer risk: methionine-homocysteine metabolism, folate cycle, transsulfuration, and mechanisms involved in inflammation and immune activation, all adjusted for tobacco exposure. The hypothesized SEM model confirmed a direct and protective effect for factors representing methionine-homocysteine metabolism (p = 0.020) and immune activation (p = 0.021), and an indirect protective effect of folate cycle (p = 0.019), after adjustment for tobacco smoking. In conclusion, our results show that in the investigation of the involvement of the OCM, the folate cycle and immune system in lung carcinogenesis, it is important to consider complex pathways (by applying SEM) rather than the effects of single vitamins or nutrients (e.g. using traditional multiple regression). In our study SEM were able to suggest a greater role of the methionine-homocysteine metabolism and immune activation over other potential mechanisms.

Physical Activity and Mortality in Individuals With Diabetes Mellitus: A Prospective Study and Meta-analysis.

BACKGROUND Physical activity (PA) is considered a cornerstone of diabetes mellitus management to prevent complications, but conclusive evidence is lacking. METHODS This prospective cohort study and meta-analysis of existing studies investigated the association between PA and mortality in individuals with diabetes. In the EPIC study (European Prospective Investigation Into Cancer and Nutrition), a cohort was defined of 5859 individuals with diabetes at baseline. Associations of leisure-time and total PA and walking with cardiovascular disease (CVD) and total mortality were studied using multivariable Cox proportional hazards regression models. Fixed- and random-effects meta-analyses of prospective studies published up to December 2010 were pooled with inverse variance weighting. RESULTS In the prospective analysis, total PA was associated with lower risk of CVD and total mortality. Compared with physically inactive persons, the lowest mortality risk was observed in moderately active persons: hazard ratios were 0.62 (95% CI, 0.49-0.78) for total mortality and 0.51 (95% CI, 0.32-0.81) for CVD mortality. Leisure-time PA was associated with lower total mortality risk, and walking was associated with lower CVD mortality risk. In the meta-analysis, the pooled random-effects hazard ratio from 5 studies for high vs low total PA and all-cause mortality was 0.60 (95% CI, 0.49-0.73). CONCLUSIONS Higher levels of PA were associated with lower mortality risk in individuals with diabetes. Even those undertaking moderate amounts of activity were at appreciably lower risk for early death compared with inactive persons. These findings provide empirical evidence supporting the widely shared view that persons with diabetes should engage in regular PA.

Prediagnostic concentrations of plasma genistein and prostate cancer risk in 1,605 men with prostate cancer and 1,697 matched control participants in EPIC.

PURPOSE: Data from prospective epidemiological studies in Asian populations and from experimental studies in animals and cell lines suggest a possible protective association between dietary isoflavones and the development of prostate cancer. We examined the association between circulating concentrations of genistein and prostate cancer risk in a case-control study nested in the European Prospective Investigation into Cancer and Nutrition. METHODS: Concentrations of the isoflavone genistein were measured in prediagnostic plasma samples for 1,605 prostate cancer cases and 1,697 matched control participants. Relative risks (RRs) for prostate cancer in relation to plasma concentrations of genistein were estimated by conditional logistic regression. RESULTS: Plasma genistein concentrations were not associated with prostate cancer risk; the multivariate relative risk for men in the highest fifth of genistein compared with men in the lowest fifth was 1.00 (95 % confidence interval: 0.79, 1.27; p linear trend = 0.82). There was no evidence of heterogeneity in this association by age at blood collection, country of recruitment, or cancer stage or histological grade. CONCLUSION: Plasma genistein concentration was not associated with prostate cancer risk in this large cohort of European men.

Plasma cotinine levels and pancreatic cancer in the EPIC cohort study.

Smoking is an established risk factor for pancreatic cancer, previously investigated by the means of questionnaires. Using cotinine as a biomarker for tobacco exposure allows more accurate quantitative analyses to be performed. This study on pancreatic cancer, nested within the European Prospective Investigation into Cancer and Nutrition (EPIC cohort), included 146 cases and 146 matched controls. Using liquid chromatography-mass spectrometry, plasma cotinine levels were analyzed on average 8.0 years before cancer onset (5-95% range: 2.8-12.0 years). The relation between plasma cotinine levels and pancreatic cancer was analyzed with conditional logistic regression for different levels of cotinine in a population of never and current smokers. This was also done for the self-reported number of smoked cigarettes per day at baseline. Every increase of 350 nmol/L of plasma cotinine was found to significantly elevate risk of pancreatic cancer [odds ratio (OR): 1.33, 95% confidence interval (CI): 1.11-1.60]. People with a cotinine level over 1187.8 nmol/L, a level comparable to smoking 17 cigarettes per day, have an elevated risk of pancreatic cancer, compared to people with cotinine levels below 55 nmol/L (OR: 3.66, 95% CI: 1.44-9.26). The results for self-reported smoking at baseline also show an increased risk of pancreatic cancer from cigarette smoking based on questionnaire information. People who smoke more than 30 cigarettes per day showed the highest risk compared to never smokers (OR: 4.15, 95% CI: 1.02-16.42). This study is the first to show that plasma cotinine levels are strongly related to pancreatic cancer.

Smoking, secondhand smoke, and cotinine levels in a subset of EPIC cohort.

BACKGROUND: Several countries are discussing new legislation regarding the ban on smoking in public places, based on the growing evidence of the hazards of secondhand smoke (SHS) exposure. The objective of the present study is to quantitatively assess the relationship between smoking, SHS, and serum cotinine levels in the European Prospective Investigation into Cancer and Nutrition (EPIC) cohort. METHODS: From a study on lung cancer in the EPIC cohort, questionnaire information on smoking was collected at enrolment, and cotinine was measured in serum. Three statistical models were applied by using samples available in a cross-section design: (i) cotinine levels by categories combining smoking and SHS (n = 859); (ii) the effect of hours of passive smoking exposure in nonsmokers only (n = 107); (iii) the effect of the number of cigarettes consumed per day in current smokers only (n = 832). All models were adjusted for country, sex, age, and body mass index. RESULTS: Among nonsmokers, passive smokers presented significant differences in cotinine compared with nonexposed, with a marked (but not significant) difference among former-smokers. A one hour per day increment of SHS gave rise to a significant 2.58 nmol/L (0.45 ng/mL) increase in mean serum cotinine (P < 0.001). In current smokers, a one cigarette per day increment gave rise to a significant 22.44 nmol/L (3.95 ng/mL) increase in cotinine mean (P < 0.001). CONCLUSIONS: There is clear evidence that not only tobacco smoking but also involuntary exposure increases cotinine levels. IMPACT: This study strengthens the evidence for the benefits of a smoking ban in public places.