| 1. |
- Baltar, Valéria Troncoso, et al.
(author)
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A structural equation modelling approach to explore the role of B vitamins and immune markers in lung cancer risk
- 2013
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In: European Journal of Epidemiology. - : Springer Science and Business Media LLC. - 0393-2990 .- 1573-7284. ; 28:8, s. 677-688
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Journal article (peer-reviewed)abstract
- 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.
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| 2. |
- Baltar, Valéria Troncoso, et al.
(author)
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Smoking, secondhand smoke, and cotinine levels in a subset of EPIC cohort
- 2011
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In: Cancer Epidemiology, Biomarkers and Prevention. - : American Association for Cancer Research. - 1055-9965 .- 1538-7755. ; 20:5, s. 869-875
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Journal article (peer-reviewed)abstract
- 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.
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| 3. |
- Chuang, Shu-Chun, et al.
(author)
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A U-shaped relationship between plasma folate and pancreatic cancer risk in the European Prospective Investigation into Cancer and Nutrition
- 2011
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In: European Journal of Cancer. - Oxford : Pergamon. - 0959-8049 .- 1879-0852. ; 47:12, s. 1808-1816
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Journal article (peer-reviewed)abstract
- Folate intake has shown an inverse association with pancreatic cancer; nevertheless, results from plasma measurements were inconsistent. The aim of this study is to examine the association between plasma total homocysteine, methionine, folate, cobalamin, pyridoxal 5'-phosphate, riboflavin, flavin mononucleotide and pancreatic cancer risk in the European Prospective Investigation into Cancer and Nutrition (EPIC). We conducted a nested case-control study in the EPIC cohort, which has an average of 9.6 years of follow-up (1992-2006), using 463 incident pancreatic cancer cases. Controls were matched to each case by center, sex, age (+/- 1 year), date (+/- 1 year) and time (+/- 3 h) at blood collection and fasting status. Conditional logistic regression was used to calculate the odds ratios (OR) and 95% confidence intervals (CI), adjusting for education, smoking status, plasma cotinine concentration, alcohol drinking, body mass index and diabetes status. We observed a U-shaped association between plasma folate and pancreatic cancer risk. The ORs for plasma folate <= 5, 5-10, 10-15 (reference), 15-20, and > 20 nmol/L were 1.58 (95% CI = 0.72-3.46), 1.39 (0.93-2.08), 1.0 (reference), 0.79 (0.52-1.21), and 1.34 (0.89-2.02), respectively. Methionine was associated with an increased risk in men (per quintile increment: OR = 1.17, 95% CI = 1.00-1.38) but not in women (OR = 0.91, 95% CI = 0.78-1.07; p for heterogeneity < 0.01). Our results suggest a U-shaped association between plasma folate and pancreatic cancer risk in both men and women. The positive association that we observed between methionine and pancreatic cancer may be sex dependent and may differ by time of follow-up. However, the mechanisms behind the observed associations warrant further investigation.
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| 4. |
- Leenders, Max, et al.
(author)
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Plasma cotinine levels and pancreatic cancer in the EPIC cohort study
- 2012
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In: International Journal of Cancer. - : Wiley. - 0020-7136 .- 1097-0215. ; 131:4, s. 997-1002
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Journal article (peer-reviewed)abstract
- 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 (595% range: 2.812.0 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): 1.111.60]. 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: 1.449.26). 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: 1.0216.42). This study is the first to show that plasma cotinine levels are strongly related to pancreatic cancer.
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| 5. |
- McKay, James D., et al.
(author)
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A Genome-Wide Association Study of Upper Aerodigestive Tract Cancers Conducted within the INHANCE Consortium
- 2011
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In: PLOS Genetics. - : Public Library of Science (PLoS). - 1553-7390 .- 1553-7404. ; 7:3
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Journal article (peer-reviewed)abstract
- Genome-wide association studies (GWAS) have been successful in identifying common genetic variation involved in susceptibility to etiologically complex disease. We conducted a GWAS to identify common genetic variation involved in susceptibility to upper aero-digestive tract (UADT) cancers. Genome-wide genotyping was carried out using the Illumina HumanHap300 beadchips in 2,091 UADT cancer cases and 3,513 controls from two large European multi-centre UADT cancer studies, as well as 4,821 generic controls. The 19 top-ranked variants were investigated further in an additional 6,514 UADT cancer cases and 7,892 controls of European descent from an additional 13 UADT cancer studies participating in the INHANCE consortium. Five common variants presented evidence for significant association in the combined analysis (p <= 5 x 10(-7)). Two novel variants were identified, a 4q21 variant (rs1494961, p = 1 x 10(-8)) located near DNA repair related genes HEL308 and FAM175A (or Abraxas) and a 12q24 variant (rs4767364, p = 2 x 10(-8)) located in an extended linkage disequilibrium region that contains multiple genes including the aldehyde dehydrogenase 2 (ALDH2) gene. Three remaining variants are located in the ADH gene cluster and were identified previously in a candidate gene study involving some of these samples. The association between these three variants and UADT cancers was independently replicated in 5,092 UADT cancer cases and 6,794 controls non-overlapping samples presented here (rs1573496-ADH7, p = 5 x 10(-8); rs1229984-ADH1B, p = 7 x 10(-9); and rs698-ADH1C, p = 0.02). These results implicate two variants at 4q21 and 12q24 and further highlight three ADH variants in UADT cancer susceptibility.
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| 6. |
- Zuo, Hui, et al.
(author)
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Results from the European Prospective Investigation into Cancer and Nutrition Link Vitamin B6 Catabolism and Lung Cancer Risk
- 2018
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In: Cancer Research. - 0008-5472 .- 1538-7445. ; 78:1, s. 302-308
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Journal article (peer-reviewed)abstract
- Circulating pyridoxal-5′-phosphate (PLP) has been linked to lung cancer risk. The PAr index, defined as the ratio 4-pyridoxic acid/(pyridoxal + PLP), reflects increased vitamin B6 catabolism during inflammation. PAr has been defined as a marker of lung cancer risk in a prospective cohort study, but analysis of a larger numbers of cases are needed to deepen the significance of this study. Here, we conducted a nested case–control study within the European Prospective Investigation into Cancer and Nutrition (EPIC, n = 521,330), which included 892 incident lung cancer cases and 1,748 controls matched by center, gender, date of blood collection, and date of birth. The association of PAr with risk of lung cancer was evaluated by using conditional logistic regression. Study participants with elevated PAr experienced higher risk of lung cancer in a dose–response fashion, with a doubling in PAr levels associated with 52% higher odds of lung cancer after adjustment for tobacco smoking, serum cotinine levels, educational attainment, and BMI [OR, 1.52; 95% confidence interval (CI) 1.27–1.81; P < 0.001]. Additional adjustment for intake of vegetables and fruits and physical activity did not materially affect risk association. The association of PAr with lung cancer risk was similar in both genders but slightly stronger in former smokers and in participants diagnosed with squamous cell carcinoma. This study provides robust evidence that increased vitamin B6 catabolism is independently associated with a higher risk of future lung cancer.
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