| 1. |
- Agudo, Antonio, et al.
(author)
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Impact of Cigarette Smoking on Cancer Risk in the European Prospective Investigation into Cancer and Nutrition Study
- 2012
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In: Journal of Clinical Oncology. - 0732-183X .- 1527-7755. ; 30:36, s. 4550-4557
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Journal article (peer-reviewed)abstract
- Purpose Our aim was to assess the impact of cigarette smoking on the risk of the tumors classified by the International Agency for Research on Cancer as causally associated with smoking, referred to as tobacco-related cancers (TRC). Methods The study population included 441,211 participants (133,018 men and 308,193 women) from the European Prospective Investigation Into Cancer and Nutrition. We investigated 14,563 participants who developed a TRC during an average follow-up of 11 years. The impact of smoking cigarettes on cancer risk was assessed by the population attributable fraction (AF(p)), calculated using the adjusted hazard ratios and 95% CI for current and former smokers, plus either the prevalence of smoking among cancer cases or estimates from surveys in representative samples of the population in each country. Results The proportion of all TRC attributable to cigarette smoking was 34.9% (95% CI, 32.5 to 37.4) using the smoking prevalence among cases and 36.2% (95% CI, 33.7 to 38.6) using the smoking prevalence from the population. The AF(p) were above 80% for cancers of the lung and larynx, between 20% and 50% for most respiratory and digestive cancers and tumors from the lower urinary tract, and below 20% for the remaining TRC. Conclusion Using data on cancer incidence for 2008 and our AF(p) estimates, about 270,000 new cancer diagnoses per year can be considered attributable to cigarette smoking in the eight European countries with available data for both men and women (Italy, Spain, United Kingdom, the Netherlands, Greece, Germany, Sweden, Denmark).
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| 2. |
- Aleksandrova, Krasimira, et al.
(author)
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A prospective study of the immune system activation biomarker neopterin and colorectal cancer risk
- 2015
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In: Journal of the National Cancer Institute. - : Oxford University Press. - 0027-8874 .- 1460-2105. ; 107:4
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Journal article (peer-reviewed)abstract
- Background: Neopterin may be relevant for colorectal cancer (CRC) development, as a biomarker of cellular immune activity exerting pleiotropic effects on cellular ageing, oxidative stress, and inflammation. So far, the association between prediagnostic neopterin and colon and rectal cancer risk has not been evaluated in human populations. Methods: A nested case-control study was conducted within the European Prospective Investigation into Cancer and Nutrition cohort using data on plasma concentrations of total neopterin (T-N, sum of neopterin and 7,8-dihydroneopterin) in 830 incident CRC case patients (561 colon and 269 rectal) matched within risk sets to 830 control participants. A subsequent replication study used data from the Hordaland Health Study, where 173 CRC case patients have been diagnosed among 6594 healthy participants over 12 years of follow-up. Results: After multivariable adjustment for a priori chosen CRC risk factors, a "U-shaped" association of T-N with CRC was revealed. Compared with the second quintile of the T-N distribution, the relative risks for the first, third, fourth, and fifth quintiles were 2.37 (95% CI = 1.66 to 3.39), 1.24 (95% CI = 0.87 to 1.77), 1.55 (95% CI = 1.08 to 2.22), and 2.31 (95% CI = 1.63 to 3.27), respectively. Replication of these associations within the Hordaland Health Study yielded similar results. No differences have been observed when the associations were explored by colon and rectal cancer site (two-sided P-difference = .87) and after excluding case patients diagnosed within the first four follow-up years. Conclusions: These novel findings provide evidence of the role of both suppressed and activated cell-mediated immunity as reflected by prediagnostic T-N concentrations in the development of CRC.
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| 3. |
- Aleksandrova, Krasimira, et al.
(author)
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Circulating C-reactive protein concentrations and risks of colon and rectal cancer : a nested case-control study within the European Prospective Investigation into Cancer and Nutrition
- 2010
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In: American Journal of Epidemiology. - : Oxford University Press (OUP). - 0002-9262 .- 1476-6256. ; 172:4, s. 407-418
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Journal article (peer-reviewed)abstract
- The authors investigated associations between serum C-reactive protein (CRP) concentrations and colon and rectal cancer risk in a nested case-control study within the European Prospective Investigation into Cancer and Nutrition (1992-2003) among 1,096 incident cases and 1,096 controls selected using risk-set sampling and matched on study center, age, sex, time of blood collection, fasting status, menopausal status, menstrual cycle phase, and hormone replacement therapy. In conditional logistic regression with adjustment for education, smoking, nutritional factors, body mass index, and waist circumference, CRP showed a significant nonlinear association with colon cancer risk but not rectal cancer risk. Multivariable-adjusted relative risks for CRP concentrations of > or = 3.0 mg/L versus <1.0 mg/L were 1.36 (95% confidence interval (CI): 1.00, 1.85; P-trend = 0.01) for colon cancer and 1.02 (95% CI: 0.67, 1.57; P-trend = 0.65) for rectal cancer. Colon cancer risk was significantly increased in men (relative risk = 1.74, 95% CI: 1.11, 2.73; P-trend = 0.01) but not in women (relative risk = 1.06, 95% CI: 0.67, 1.68; P-trend = 0.13). Additional adjustment for C-peptide, glycated hemoglobin, and high density lipoprotein cholesterol did not attenuate these results. These data provide evidence that elevated CRP concentrations are related to a higher risk of colon cancer but not rectal cancer, predominantly among men and independently of obesity, insulin resistance, and dyslipidemia.
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| 4. |
- Aleksandrova, Krasimira, et al.
(author)
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Combined impact of healthy lifestyle factors on colorectal cancer : a large European cohort study
- 2014
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In: BMC Medicine. - : BioMed Central. - 1741-7015. ; 12:1, s. 168-
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Journal article (peer-reviewed)abstract
- BACKGROUND: Excess body weight, physical activity, smoking, alcohol consumption and certain dietary factors are individually related to colorectal cancer (CRC) risk; however, little is known about their joint effects. The aim of this study was to develop a healthy lifestyle index (HLI) composed of five potentially modifiable lifestyle factors - healthy weight, physical activity, non-smoking, limited alcohol consumption and a healthy diet, and to explore the association of this index with CRC incidence using data collected within the European Prospective Investigation into Cancer and Nutrition (EPIC) cohort. METHODS: In the EPIC cohort, a total of 347,237 men and women, 25- to 70-years old, provided dietary and lifestyle information at study baseline (1992 to 2000). Over a median follow-up time of 12 years, 3,759 incident CRC cases were identified. The association between a HLI and CRC risk was evaluated using Cox proportional hazards regression models and population attributable risks (PARs) have been calculated. RESULTS: After accounting for study centre, age, sex and education, compared with 0 or 1 healthy lifestyle factors, the hazard ratio (HR) for CRC was 0.87 (95% confidence interval (CI): 0.44 to 0.77) for two factors, 0.79 (95% CI: 0.70 to 0.89) for three factors, 0.66 (95% CI: 0.58 to 0.75) for four factors and 0.63 (95% CI: 0.54 to 0.74) for five factors; P-trend <0.0001. The associations were present for both colon and rectal cancers, HRs, 0.61 (95% CI: 0.50 to 0.74; P for trend <0.0001) for colon cancer and 0.68 (95% CI: 0.53 to 0.88; P-trend <0.0001) for rectal cancer, respectively (P-difference by cancer sub-site = 0.10). Overall, 16% of the new CRC cases (22% in men and 11% in women) were attributable to not adhering to a combination of all five healthy lifestyle behaviours included in the index. CONCLUSIONS: Combined lifestyle factors are associated with a lower incidence of CRC in European populations characterized by western lifestyles. Prevention strategies considering complex targeting of multiple lifestyle factors may provide practical means for improved CRC prevention.
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| 5. |
- Aleksandrova, Krasimira, et al.
(author)
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Inflammatory and metabolic biomarkers and risk of liver and bilary tract cancer
- 2014
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In: Hepatology. - : Wiley-Blackwell. - 0270-9139 .- 1527-3350. ; 60:3, s. 858-871
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Journal article (peer-reviewed)abstract
- Obesity and associated metabolic disorders have been implicated in liver carcinogenesis; however there is little data on the role of obesity-related biomarkers on liver cancer risk. We studied prospectively the association of inflammatory and metabolic biomarkers with risks of hepatocellular carcinoma (HCC), intra-hepatic bile duct (IBD) and gallbladder and bilary tract cancers outside of the liver (GBTC) in a nested case-control study within the European Prospective Investigation into Cancer and Nutrition (EPIC). Over an average of 7.7 years, 296 participants developed HCC (n=125), GBTC (n=137) or IBD (n=34). Using risk set sampling, controls were selected in a 2:1 ratio and matched for recruitment center, age, sex, fasting status, time of blood collection. Baseline serum concentrations of C-reactive protein (CRP), interleukin-6 (IL-6), C-peptide, total, high-molecular-weight (HMW) adiponectin, leptin, fetuin-a, and glutamatdehydrogenase (GLDH) were measured and incidence rate ratios (IRRs) and 95% confidence intervals (CI-s) estimated using conditional logistic regression. After adjustment for lifestyle factors, diabetes, hepatitis infection and adiposity measures, higher concentrations of CRP, IL-6, C-peptide and non-HMW adiponectin were associated with higher risk of HCC (IRR per doubling of concentrations = 1.22; 95%CI = 1.02-1.46, P=0.03; 1.90; 95%CI = 1.30-2.77, P=0.001; 2.25; 95%CI = 1.43-3.54, P=0.0005 and 2.09; 95%CI = 1.19-3.67, P=0.01, respectively). CRP was associated also with risk of GBTC (IRR = 1.22; 95%CI = 1.05-1.42, P=0.01). GLDH was associated with risks of HCC (IRR = 1.62; 95%CI = 1.25-2.11, P=0.0003) and IBD (IRR = 10.5; 95%CI = 2.20-50.90, P=0.003). The continuous net reclassification index was 0.63 for CRP, IL-6, C-peptide and non-HMW adiponectin, and 0.46 for GLDH indicating good predictive ability of these biomarkers. Conclusion: Elevated levels of biomarkers of inflammation and hyperinsulinemia are associated with a higher risk of HCC, independent of obesity and established liver cancer risk factors.
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| 6. |
- Aleksandrova, Krasimira, et al.
(author)
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Leptin and soluble leptin receptor in risk of colorectal cancer in the European prospective investigation into Cancer and nutrition cohort
- 2012
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In: Cancer Research. - Philadelphia, USA : American Association for Cancer Research. - 0008-5472 .- 1538-7445. ; 72:20, s. 5328-5337
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Journal article (peer-reviewed)abstract
- Leptin, a peptide hormone produced primarily by the adipocytes, is hypothesized to play a role in the pathogenesis of colorectal cancer (CRC). Soluble leptin receptor (sOB-R) may regulate leptin's physiologic functions; however its relation to CRC risk is unknown. This study explored the association of leptin and sOB-R with risk of CRC in a prospective nested case-control study within the European Prospective Investigation into Cancer and Nutrition (EPIC) cohort. A total of 1,129 incident CRC cases (713 colon, 416 rectal) were matched within risk sets to 1,129 controls. Conditional logistic regression was used to calculate relative risks (RR) and 95% confidence intervals (CI). After multivariable adjustment including body mass index (BMI), waist circumference, and baseline leptin concentrations, sOB-R was strongly inversely associated with CRC (RR comparing the highest quintile vs. the lowest, 0.55; 95% CI, 0.40-0.76; P-trend = 0.0004) and colon cancer (RR, 0.42; 95% CI, 0.28-0.63, P-trend = 0.0001); whereas no association was seen for rectal cancer (RR adjusted for BMI and waist circumference, 0.83; 95% CI, 0.48-1.44, P-trend = 0.38). In contrast, leptin was not associated with risk of CRC (RR adjusted for BMI and waist circumference, 0.85; 95% CI, 0.56-1.29, P-trend = 0.23). Additional adjustments for circulating metabolic biomarkers did not attenuate these results. These novel findings suggest a strong inverse association between circulating sOB-R and CRC risk, independent of obesity measures, leptin concentrations, and other metabolic biomarkers. Further research is needed to confirm the potentially important role of sOB-R in CRC pathogenesis. Cancer Res; 72(20); 5328-37. (C) 2012 AACR.
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| 7. |
- Aleksandrova, Krasimira, et al.
(author)
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Physical activity, mediating factors and risk of colon cancer : insights into adiposity and circulating biomarkers from the EPIC cohort
- 2017
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In: International Journal of Epidemiology. - : Oxford University Press. - 0300-5771 .- 1464-3685. ; 46:6, s. 1823-1835
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Journal article (peer-reviewed)abstract
- There is convincing evidence that high physical activity lowers the risk of colon cancer; however, the underlying biological mechanisms remain largely unknown. We aimed to determine the extent to which body fatness and biomarkers of various biologically plausible pathways account for the association between physical activity and colon cancer. We conducted a nested case-control study in a cohort of 519 978 men and women aged 25 to 70 years followed from 1992 to 2003. A total of 713 incident colon cancer cases were matched, using risk-set sampling, to 713 controls on age, sex, study centre, fasting status and hormonal therapy use. The amount of total physical activity during the past year was expressed in metabolic equivalent of task [MET]-h/week. Anthropometric measurements and blood samples were collected at study baseline. High physical activity was associated with a lower risk of colon cancer: relative risk a parts per thousand91 MET-h/week vs < 91 MET-h/week = 0.75 [95% confidence interval (CI): 0.57 to 0.96]. In mediation analyses, this association was accounted for by waist circumference: proportion explained effect (PEE) = 17%; CI: 4% to 52%; and the biomarkers soluble leptin receptor (sOB-R): PEE = 15%; 95% CI: 1% to 50% and 5-hydroxyvitamin D (25[OH]D): PEE = 30%; 95% CI: 12% to 88%. In combination, these factors explained 45% (95% CI: 20% to 125%) of the association. Beyond waist circumference, sOB-R and 25[OH]D additionally explained 10% (95% CI: 1%; 56%) and 23% (95% CI: 6%; 111%) of the association, respectively. Promoting physical activity, particularly outdoors, and maintaining metabolic health and adequate vitamin D levels could represent a promising strategy for colon cancer prevention.
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| 8. |
- Aleksandrova, Krasimira, et al.
(author)
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The association of coffee intake with liver cancer risk is mediated by biomarkers of inflammation and hepatocellular injury : data from the European Prospective Investigation into Cancer and Nutrition
- 2015
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In: American Journal of Clinical Nutrition. - : American Society for Nutrition. - 0002-9165 .- 1938-3207. ; 102:6, s. 1498-1508
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Journal article (peer-reviewed)abstract
- Background: Higher coffee intake has been purportedly related to a lower risk of liver cancer. However, it remains unclear whether this association may be accounted for by specific biological mechanisms. Objective: We aimed to evaluate the potential mediating roles of inflammatory, metabolic, liver injury, and iron metabolism biomarkers on the association between coffee intake and the primary form of liver cancer-hepatocellular carcinoma (HCC). Design: We conducted a prospective nested case-control study within the European Prospective Investigation into Cancer and Nutrition among 125 incident HCC cases matched to 250 controls using an incidence-density sampling procedure. The association of coffee intake with HCC risk was evaluated by using multivariable-adjusted conditional logistic regression that accounted for smoking, alcohol consumption, hepatitis infection, and other established liver cancer risk factors. The mediating effects of 21 biomarkers were evaluated on the basis of percentage changes and associated 95% CIs in the estimated regression coefficients of models with and without adjustment for biomarkers individually and in combination. Results: The multivariable-adjusted RR of having >= 4 cups (600mL) coffee/d compared with <2 cups (300 mL)/d was 0.25 (95% CI: 0.11, 0.62; P-trend = 0.006). A statistically significant attenuation of the association between coffee intake and HCC risk and thereby suspected mediation was confirmed for the inflammatory biomarker IL-6 and for the biomarkers of hepatocellular injury glutamate dehydrogenase, alanine aminotransferase, aspartate aminotransferase (AST), gamma-glutamyltransferase (GGT), and total bilirubin, which-in combination-attenuated the regression coefficients by 72% (95% CI: 7%, 239%). Of the investigated biomarkers, IL-6, AST, and GGT produced the highest change in the regression coefficients: 40%, 56%, and 60%, respectively. Conclusion: These data suggest that the inverse association of coffee intake with HCC risk was partly accounted for by biomarkers of inflammation and hepatocellular injury.
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| 9. |
- Aleksandrova, Krasimira, et al.
(author)
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Total and high-molecular-weight adiponectin and risk of colorectal cancer : the European prospective investigation into cancer and nutrition study
- 2012
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In: Carcinogenesis. - : Oxford University Press (OUP). - 0143-3334 .- 1460-2180. ; 33:6, s. 1211-1218
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Journal article (peer-reviewed)abstract
- Adiponectin - an adipose-tissue-derived protein may provide a molecular link between obesity and colorectal cancer (CRC), but evidence from large prospective studies is limited. In particular, no epidemiological study explored high-molecular-weight (HMW) and non-HMW adiponectin fractions in relation to CRC risk, despite they were hypothesised to have differential biological activities, i.e. regulating insulin sensitivity (HMW-adiponectin) versus inflammatory response (non-HMW-adiponectin). In a prospective nested case-control study we investigated whether pre-diagnostic serum concentrations of total, HMW and non-HMW-adiponectin are associated with risk of CRC, independent of obesity and other known CRC risk factors. A total of 1206 incident cases (755 colon, 451 rectal) were matched to 1206 controls using incidence density sampling. In conditional logistic regression, adjusted for dietary and lifestyle factors, total adiponectin and non-HMW-adiponectin concentrations were inversely associated with risk of CRC [relative risk (RR) comparing highest versus lowest quintile = 0.71, 95% confidence interval (CI) = 0.53-0.95, P (trend)=0.03 for total adiponectin and 0.45, 95%CI=0.34-0.61, P (trend)<0.0001 for non-HMW-adiponectin]. HMW-adiponectin concentrations were not associated with CRC risk (RR=0.91, 95%CI=0.68-1.22, P (trend)=0.55). Non-HMW-adiponectin was associated with CRC risk even after adjustment for body mass index and waist circumference (RR=0.39, 95%CI=0.26-0.60, P (trend)<0.0001); whereas the association with total adiponectin was no longer significant (RR=0.81, 95%CI=0.60-1.09, P (trend)=0.23). When stratified by cancer site, non-HMW-adiponectin was inversely associated with both colon and rectal cancer. These findings suggest an important role of the relative proportion of non-HMW-adiponectin in CRC pathogenesis. Future studies are warranted to confirm these results and to elucidate the underlying mechanisms.
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