Mazda Jenab

Association between Pre-Diagnostic Circulating Vitamin D Concentration and Risk of Colorectal Cancer in European Populations: a Nested Case-Control Study

Objective To examine the association between pre-diagnostic circulating vitamin D concentration, dietary intake of vitamin D and calcium, and the risk of colorectal cancer in European populations. Design Nested case-control study. Setting The study was conducted within the EPIC study, a cohort of more than 520u2009000 participants from 10 western European countries. Participants 1248 cases of incident colorectal cancer, which developed after enrolment into the cohort, were matched to 1248 controls Main outcome measures Circulating vitamin D concentration (25-hydroxy-vitamin-D, 25-(OH)D) was measured by enzyme immunoassay. Dietary and lifestyle data were obtained from questionnaires. Incidence rate ratios and 95% confidence intervals for the risk of colorectal cancer by 25-(OH)D concentration and levels of dietary calcium and vitamin D intake were estimated from multivariate conditional logistic regression models, with adjustment for potential dietary and other confounders. Results 25-(OH)D concentration showed a strong inverse linear dose-response association with risk of colorectal cancer (P for trend <0.001). Compared with a pre-defined mid-level concentration of 25-(OH)D (50.0-75.0 nmol/l), lower levels were associated with higher colorectal cancer risk (<25.0 nmol/l: incidence rate ratio 1.32 (95% confidence interval 0.87 to 2.01); 25.0-49.9 nmol/l: 1.28 (1.05 to 1.56), and higher concentrations associated with lower risk (75.0-99.9 nmol/l: 0.88 (0.68 to 1.13); ≥100.0 nmol/l: 0.77 (0.56 to 1.06)). In analyses by quintile of 25-(OH)D concentration, patients in the highest quintile had a 40% lower risk of colorectal cancer than did those in the lowest quintile (P<0.001). Subgroup analyses showed a strong association for colon but not rectal cancer (P for heterogeneity=0.048). Greater dietary intake of calcium was associated with a lower colorectal cancer risk. Dietary vitamin D was not associated with disease risk. Findings did not vary by sex and were not altered by corrections for season or month of blood donation. Conclusions The results of this large observational study indicate a strong inverse association between levels of pre-diagnostic 25-(OH)D concentration and risk of colorectal cancer in western European populations. Further randomised trials are needed to assess whether increases in circulating 25-(OH)D concentration can effectively decrease the risk of colorectal cancer.

Biomarkers in nutritional epidemiology: applications, needs and new horizons

Modern epidemiology suggests a potential interactive association between diet, lifestyle, genetics and the risk of many chronic diseases. As such, many epidemiologic studies attempt to consider assessment of dietary intake alongside genetic measures and other variables of interest. However, given the multi-factorial complexities of dietary exposures, all dietary intake assessment methods are associated with measurement errors which affect dietary estimates and may obscure disease risk associations. For this reason, dietary biomarkers measured in biological specimens are being increasingly used as additional or substitute estimates of dietary intake and nutrient status. Genetic variation may influence dietary intake and nutrient metabolism and may affect the utility of a dietary biomarker to properly reflect dietary exposures. Although there are many functional dietary biomarkers that, if utilized appropriately, can be very informative, a better understanding of the interactions between diet and genes as potentially determining factors in the validity, application and interpretation of dietary biomarkers is necessary. It is the aim of this review to highlight how some important biomarkers are being applied in nutrition epidemiology and to address some associated questions and limitations. This review also emphasizes the need to identify new dietary biomarkers and highlights the emerging field of nutritional metabonomics as an analytical method to assess metabolic profiles as measures of dietary exposures and indicators of dietary patterns, dietary changes or effectiveness of dietary interventions. The review will also touch upon new statistical methodologies for the combination of dietary questionnaire and biomarker data for disease risk assessment. It is clear that dietary biomarkers require much further research in order to be better applied and interpreted. Future priorities should be to integrate high quality dietary intake information, measurements of dietary biomarkers, metabolic profiles of specific dietary patterns, genetics and novel statistical methodology in order to provide important new insights into gene-diet-lifestyle-disease risk associations.

Serum C-peptide, IGFBP-1 and IGFBP-2 and risk of colon and rectal cancers in the European Prospective Investigation into Cancer and Nutrition

Western style diets and lifestyles are associated with increasing rates of obesity, diabetes and insulin resistance. Higher circulating insulin levels may modulate cell proliferation and apoptosis either directly or indirectly by increasing the bioactivity of IGF‐I and decreasing the bioactivity of some of its binding proteins. The objective of this study was to determine the association of increasing levels of serum C‐peptide, a biomarker of pancreatic insulin secretion, and IGF binding proteins (IGFBP) ‐1 and ‐2 with colorectal cancer risk in a case–control study nested within the European Prospective Investigation into Cancer and Nutrition (EPIC), a large cohort involving 10 Western European countries. A total of 1,078 colorectal cancer cases were matched (age, date of blood donation, fasting status, gender, study center) to an equal number of control subjects. Relative cancer risks were estimated using conditional logistic regression models. Serum C‐peptide concentration was positively associated with an increased colorectal cancer risk for the highest versus the lowest quintile (OR = 1.56, 95% CI = 1.16–2.09, ptrend < 0.01), which was slightly attenuated after adjustment for BMI and physical activity (OR = 1.37, 95% CI = 1.00–1.88, ptrend = 0.10). When stratified by anatomical site, the cancer risk was stronger in the colon (OR = 1.67, 95% CI = 1.14–2.46, ptrend < 0.01) than in the rectum (OR = 1.42, 95% CI = 0.90–2.25, ptrend = 0.35). The cancer risk estimates were not heterogeneous by gender or fasting status. No clear colorectal cancer risk associations were observed for IGFBP‐1 or ‐2. This large prospective study confirms that hyperinsulinemia, as determined by C‐peptide levels, is associated with an increased colorectal cancer risk.

Plasma and dietary carotenoid, retinol and tocopherol levels and the risk of gastric adenocarcinomas in the European prospective investigation into cancer and nutrition

Despite declining incidence rates, gastric cancer (GC) is a major cause of death worldwide. Its aetiology may involve dietary antioxidant micronutrients such as carotenoids and tocopherols. The objective of this study was to determine the association of plasma levels of seven common carotenoids, their total plasma concentration, retinol and α- and γ-tocopherol, with the risk of gastric adenocarcinoma in a case–control study nested within the European Prospective Investigation into Cancer and Nutrition (EPIC), a large cohort involving 10 countries. A secondary objective was to determine the association of total sum of carotenoids, retinol and α-tocopherol on GCs by anatomical subsite (cardia/noncardia) and histological subtype (diffuse/intestinal). Analytes were measured by high-performance liquid chromatography in prediagnostic plasma from 244 GC cases and 645 controls matched by age, gender, study centre and date of blood donation. Conditional logistic regression models adjusted by body mass index, total energy intake, smoking and Helicobacter pylori infection status were used to estimate relative cancer risks. After an average 3.2 years of follow-up, a negative association with GC risk was observed in the highest vs the lowest quartiles of plasma β-cryptoxanthin (odds ratio (OR)=0.53, 95% confidence intervals (CI)=0.30–0.94, Ptrend=0.006), zeaxanthin (OR=0.39, 95% CI=0.22–0.69, Ptrend=0.005), retinol (OR=0.55, 95% CI=0.33–0.93, Ptrend=0.005) and lipid-unadjusted α-tocopherol (OR=0.59, 95% CI=0.37–0.94, Ptrend=0.022). For all analytes, no heterogeneity of risk estimates or significant associations were observed by anatomical subsite. In the diffuse histological subtype, an inverse association was observed with the highest vs lowest quartile of lipid-unadjusted α-tocopherol (OR=0.26, 95% CI=0.11–0.65, Ptrend=0.003). These results show that higher plasma concentrations of some carotenoids, retinol and α-tocopherol are associated with reduced risk of GC.

Vitamin D Receptor and Calcium Sensing Receptor Polymorphisms and the Risk of Colorectal Cancer in European Populations

Increased levels of vitamin D and calcium may play a protective role in colorectal cancer (CRC) risk. It has been suggested that these effects may be mediated by genetic variants of the vitamin D receptor (VDR) and the calcium sensing receptor (CASR). However, current epidemiologic evidence from European populations for a role of these genes in CRC risk is scarce. In addition, it is not clear whether these genes may modulate CRC risk independently or by interaction with blood vitamin D concentration and level of dietary calcium intake. A case-control study was conducted nested within the European Prospective Investigation into Cancer and Nutrition. CRC cases (1,248) were identified and matched to 1,248 control subjects. Genotyping for the VDR (BsmI: rs1544410; Fok1: rs2228570) and CASR (rs1801725) genes was done by Taqman, and serum vitamin D (25OHD) concentrations were measured. Conditional logistic regression was used to estimate the incidence rate ratio (RR). Compared with the wild-type bb, the BB genotype of the VDR BsmI polymorphism was associated with a reduced risk of CRC [RR, 0.76; 95% confidence interval (CI), 0.59-0.98). The association was observed for colon cancer (RR, 0.69; 95% CI, 0.45-0.95) but not rectal cancer (RR, 0.97; 95% CI, 0.62-1.49). The Fok1 and CASR genotypes were not associated with CRC risk in this study. No interactions were noted for any of the polymorphisms with serum 25OHD concentration or level of dietary calcium. These results confirm a role for the BsmI polymorphism of the VDR gene in CRC risk, independent of serum 25OHD concentration and dietary calcium intake. (Cancer Epidemiol Biomarkers Prev 2009;18(9):2485‐91)

Consumption and portion sizes of tree nuts, peanuts and seeds in the European Prospective Investigation into Cancer and Nutrition (EPIC) cohorts from 10 European countries

Tree nuts, peanuts and seeds are nutrient dense foods whose intake has been shown to be associated with reduced risk of some chronic diseases. They are regularly consumed in European diets either as whole, in spreads or from hidden sources (e.g. commercial products). However, little is known about their intake profiles or differences in consumption between European countries or geographic regions. The objective of this study was to analyse the population mean intake and average portion sizes in subjects reporting intake of nuts and seeds consumed as whole, derived from hidden sources or from spreads. Data was obtained from standardised 24-hour dietary recalls collected from 36 994 subjects in 10 different countries that are part of the European Prospective Investigation into Cancer and Nutrition (EPIC). Overall, for nuts and seeds consumed as whole, the percentage of subjects reporting intake on the day of the recall was: tree nuts = 4. 4%, peanuts = 2.3 % and seeds = 1.3 %. The data show a clear northern (Sweden: mean intake = 0.15 g/d, average portion size = 15.1 g/d) to southern (Spain: mean intake = 2.99 g/d, average portion size = 34.7 g/d) European gradient of whole tree nut intake. The three most popular tree nuts were walnuts, almonds and hazelnuts, respectively. In general, tree nuts were more widely consumed than peanuts or seeds. In subjects reporting intake, men consumed a significantly higher average portion size of tree nuts (28.5 v. 23.1 g/d, P<0.01) and peanuts (46.1 v. 35.1 g/d, P<0.01) per day than women. These data may be useful in devising research initiatives and health policy strategies based on the intake of this food group.

Dietary intakes of retinol, beta-carotene, vitamin D and vitamin E in the European Prospective Investigation into Cancer and Nutrition cohort

Objectives:To describe the intake of the fat-soluble nutrients retinol, β-carotene, vitamin E and vitamin D and their food sources among 27 redefined centres in 10 countries participating in the European Prospective Investigation into Cancer and Nutrition (EPIC) study.Methods:Between 1995 and 2000, 36u2009034 subjects (age range: 35–74 years) completed a single standardized 24-h dietary recall using a computerized interview software program (EPIC-SOFT). Intakes of the fat-soluble nutrients were estimated using the standardized EPIC Nutrient Database.Results:For all the nutrients, in most centres, men had a higher level of intake than did women, even after adjustments for total energy intake and anthropometric confounders. Distinct regional gradients from northern to southern European countries were observed for all nutrients. The level intake of β-carotene and vitamin E also showed some differences by level of education, smoking status and physical activity. No meaningful differences in the nutrient intake were observed by age range.Conclusions:These results show differences by study centre, gender, age and various lifestyle variables in the intake of retinol, β-carotene, vitamin E and vitamin D between 10 European countries.

CDH1 gene polymorphisms, smoking, Helicobacter pylori infection and the risk of gastric cancer in the European Prospective Investigation into Cancer and Nutrition (EPIC-EURGAST).

Despite declining incidence rates, gastric cancer (GC) is a major cause of death worldwide. E-Cadherin is an adhesion molecule that is thought to be involved in GC. Germline mutations in the E-Cadherin gene (CDH1) have been identified in hereditary diffuse GC. Also, a promoter polymorphism at position -160 C/A has been suggested to lead to transcriptional down regulation and has been shown to affect GC risk in some studies. However, very little information exists on the GC risk association of other CDH1 polymorphisms and it is unclear whether any associations may be different by GC anatomical sites or histological types. Thus, a case-control study (cases=245/controls=950) nested within the European Prospective Investigation into Cancer and Nutrition (EPIC) cohort was conducted to assess the GC risk association of eight CDH1 gene polymorphisms. None of the CDH1 polymorphisms or haplotypes analysed were associated with GC risk and no differences of effect were observed by Helicobacter pylori infection status. However, three CDH1 polymorphisms in the same haplotype block, including the CDH1-160C/A, interacted with smoking to increase GC risk in smokers but not in never smokers. These findings should be confirmed in larger independent studies.

Long-term Cryoconservation and Stability of Vitamin C in Serum Samples of the European Prospective Investigation into Cancer and Nutrition

Plasma vitamin C level may be associated with risk of some chronic diseases. The rapid degradability of vitamin C in biological samples necessitates its stabilization with metaphosphoric acid or similar agents. However, in most cohort studies, prospectively collected biological samples are not treated with stabilizing agents before long-term frozen storage and it is not known whether vitamin C can be properly measured in such samples. The objective of this study was to determine the degree of vitamin C degradation in plasma samples stored without stabilization for 7 to 11 years at −196°C. Spearmans correlation coefficients indicate a moderate correlation between baseline and final plasma vitamin C levels in both men (r = 0.57, P < 0.0001) and women (r = 0.52, P < 0.0001). Samples were also categorized based on low or high baseline levels of plasma vitamin C, with the latter category showing the highest rate of loss per year of frozen storage in men (1.96 μmol/L, P value for difference <0.0001; percent loss 24.6%) and women (2.35 μmol/L, P value for difference <0.0001; percent loss 24.2%), as determined by multiple regression analysis adjusted for smoking status, age, and body mass index. In men, both baseline and final plasma vitamin C values were lower in smokers than never smokers, but for both men and women the rate of vitamin C loss during storage was not significantly different between smokers and never smokers. The results of this study show that vitamin C can be measured with reasonable reliability in plasma samples frozen for long periods of time without addition of any stabilizing agents.