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Pre-diagnostic copper and zinc biomarkers and colorectal cancer risk in the European Prospective Investigation into Cancer and Nutrition cohort.Adequate intake of copper and zinc, two essential micronutrients, are important for antioxidant functions. Their imbalance may have implications for development of diseases like colorectal cancer (CRC), where oxidative stress is thought to be etiologically involved. As evidence from prospective epidemiologic studies is lacking, we conducted a case-control study nested within the European Prospective Investigation into Cancer and Nutrition (EPIC) cohort to investigate the association between circulating levels of copper and zinc, and their calculated ratio, with risk of CRC development. Copper and zinc levels were measured by reflection X-ray fluorescence spectrometer in 966 cases and 966 matched controls. Multivariable adjusted odds ratios (OR) and 95% confidence intervals (CI) were calculated using conditional logistic regression and are presented for the fifth versus first quintile. Higher circulating concentration of copper was associated with a raised CRC risk (OR = 1.50; 95% CI: 1.06, 2.13; P-trend = 0.02) whereas an inverse association with cancer risk was observed for higher zinc levels (OR = 0.65; 95% CI: 0.43, 0.97; P-trend = 0.07). Consequently, the ratio of copper/zinc was positively associated with CRC (OR = 1.70; 95% CI: 1.20, 2.40; P-trend = 0.0005). In subgroup analyses by follow-up time, the associations remained statistically significant only in those diagnosed within 2 years of blood collection. In conclusion, these data suggest that copper or copper levels in relation to zinc (copper to zinc ratio) become imbalanced in the process of CRC development. Mechanistic studies into the underlying mechanisms of regulation and action are required to further examine a possible role for higher copper and copper/zinc ratio levels in CRC development and progression.
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Measured Adiposity in Relation to Head and Neck Cancer Risk in the European Prospective Investigation into Cancer and Nutrition.Background: Emerging evidence from cohort studies indicates that adiposity is associated with greater incidence of head and neck cancer. However, most studies have used self-reported anthropometry which is prone to error.Methods: Among 363,094 participants in the European Prospective Investigation into Cancer and Nutrition study (EPIC) with measured anthropometry, there were 837 incident cases of head and neck cancer. Head and neck cancer risk was examined in relation to body mass index (BMI) [lean: <22.5 kg/m2, normal weight (reference): 22.5-24.9 kg/m2, overweight 25-29.9 kg/m2, obese: ≥30 kg/m2], waist circumference (WC), hip circumference (HC), and waist-to-hip ratio (WHR) using Cox proportional hazards models.Results: Among men, a BMI < 22.5 kg/m2 was associated with higher head and neck cancer risk [HR 1.62; 95% confidence interval (CI), 1.23-2.12)]; BMI was not associated with head and neck cancer among women. WC and WHR were associated with greater risk of head and neck cancer among women (WC per 5 cm: HR, 1.08; 95% CI, 1.02-1.15; WHR per 0.1 unit: HR, 1.64; 95% CI, 1.38-1.93). After stratification by smoking status, the association for WHR was present only among smokers (Pinteraction = 0.004). Among men, WC and WHR were associated with head and neck cancer only upon additional adjustment for BMI (WC per 5 cm: HR 1.16; 95% CI, 1.07-1.26; WHR per 0.1 unit: HR, 1.42; 95% CI, 1.21-1.65).Conclusions: Central adiposity, particularly among women, may have a stronger association with head and neck cancer risk than previously estimated.Impact: Strategies to reduce obesity may beneficially impact head and neck cancer incidence. Cancer Epidemiol Biomarkers Prev; 26(6); 895-904. ©2017 AACR.
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Metabolic Mediators of the Association Between Adult Weight Gain and Colorectal Cancer: Data From the European Prospective Investigation into Cancer and Nutrition (EPIC) Cohort.Evidence indicates that gaining weight in adult life is associated with an elevated risk of colorectal cancer; however, biological mechanisms that may explain this association remain unclear. We evaluated the mediation effect of 20 different biomarkers on the relationship between adult weight gain and colorectal cancer, using data from a prospective nested case-control study of 452 incident cases diagnosed between 1992 and 2003 and matched within risk sets to 452 controls within the European Prospective Investigation into Cancer and Nutrition (EPIC) cohort. The proportions of mediated effects (%) were estimated on the basis of differences in percent effect changes in conditional logistic regression models with and without additional adjustment for individual biomarkers. Greater adult weight gain (≥300 g/year vs. <300 g/year) was associated with a higher risk of colon cancer (multivariable-adjusted relative risk = 1.54, 95% confidence interval: 1.07, 2.24) but not rectal cancer (relative risk = 1.07, 95% confidence interval: 0.68, 1.66). This association was accounted for mostly by attained waist circumference (reduction of 61%) and by the biomarkers soluble leptin receptor (reduction of 43%) and glycated hemoglobin (reduction of 28%). These novel data suggest that the observed association between adult weight gain and colon cancer could be primarily explained by attained abdominal fatness and biomarkers of metabolic dysfunction.