Compilation of a standardised international folate database for EPIC

Dietary fatty acids and endometrial cancer risk within the European Prospective Investigation into Cancer and Nutrition

BACKGROUND

Diet may impact important risk factors for endometrial cancer such as obesity and inflammation. However, evidence on the role of specific dietary factors is limited. We investigated associations between dietary fatty acids and endometrial cancer risk in the European Prospective Investigation into Cancer and Nutrition (EPIC).

METHODS

This analysis includes 1,886 incident endometrial cancer cases and 297,432 non-cases. All participants were followed up for a mean of 8.8 years. Multivariable Cox proportional hazard models were used to estimate hazard ratios (HR) and 95% confidence intervals (CI) of endometrial cancer across quintiles of individual fatty acids estimated from various food sources quantified through food frequency questionnaires in the entire EPIC cohort. The false discovery rate (q-values) was computed to control for multiple comparisons.

RESULTS

Consumption of n-6 γ-linolenic acid was inversely associated with endometrial cancer risk (HR comparing 5th with 1st quintileQ5-Q1=0.77, 95% CI = 0.64; 0.92, ptrend=0.01, q-value = 0.15). This association was mainly driven by γ-linolenic acid derived from plant sources (HRper unit increment=0.94, 95%CI= (0.90;0.98), p = 0.01) but not from animal sources (HRper unit increment= 1.00, 95%CI = (0.92; 1.07), p = 0.92). In addition, an inverse association was found between consumption of n-3 α-linolenic acid from vegetable sources and endometrial cancer risk (HRper unit increment= 0.93, 95%CI = (0.87; 0.99), p = 0.04). No significant association was found between any other fatty acids (individual or grouped) and endometrial cancer risk.

CONCLUSION

Our results suggest that higher consumption of γ-linolenic acid and α-linoleic acid from plant sources may be associated with lower risk of endometrial cancer.

Dietary Advanced Glycation End-Products and Colorectal Cancer Risk in the European Prospective Investigation into Cancer and Nutrition (EPIC) Study

Dietary advanced glycation end-products (dAGEs) have been hypothesized to be associated with a higher risk of colorectal cancer (CRC) by promoting inflammation, metabolic dysfunction, and oxidative stress in the colonic epithelium. However, evidence from prospective cohort studies is scarce and inconclusive. We evaluated CRC risk associated with the intake of dAGEs in the European Prospective Investigation into Cancer and Nutrition (EPIC) study. Dietary intakes of three major dAGEs: Nε-carboxy-methyllysine (CML), Nε-carboxyethyllysine (CEL), and Nδ-(5-hydro-5-methyl-4-imidazolon-2-yl)-ornithine (MG-H1) were estimated in 450,111 participants (median follow-up = 13 years, with 6162 CRC cases) by matching to a detailed published European food composition database. Hazard ratios (HRs) and 95% confidence intervals (CIs) for the associations of dAGEs with CRC were computed using multivariable-adjusted Cox regression models. Inverse CRC risk associations were observed for CML (HR comparing extreme quintiles: HRQ5vs.Q1 = 0.92, 95% CI = 0.85-1.00) and MG-H1 (HRQ5vs.Q1 = 0.92, 95% CI = 0.85-1.00), but not for CEL (HRQ5vs.Q1 = 0.97, 95% CI = 0.89-1.05). The associations did not differ by sex or anatomical location of the tumor. Contrary to the initial hypothesis, our findings suggest an inverse association between dAGEs and CRC risk. More research is required to verify these findings and better differentiate the role of dAGEs from that of endogenously produced AGEs and their precursor compounds in CRC development.

Dietary Methyl-Group Donor Intake and Breast Cancer Risk in the European Prospective Investigation into Cancer and Nutrition (EPIC)

(1) Background: Methyl-group donors (MGDs), including folate, choline, betaine, and methionine, may influence breast cancer (BC) risk through their role in one-carbon metabolism; (2) Methods: We studied the relationship between dietary intakes of MGDs and BC risk, adopting data from the European Prospective Investigation into Cancer and Nutrition (EPIC) cohort; (3) Results: 318,686 pre- and postmenopausal women were followed between enrolment in 1992-2000 and December 2013-December 2015. Dietary MGD intakes were estimated at baseline through food-frequency questionnaires. Multivariable Cox proportional hazards regression models were used to quantify the association between dietary intake of MGDs, measured both as a calculated score based on their sum and individually, and BC risk. Subgroup analyses were performed by hormone receptor status, menopausal status, and level of alcohol intake. During a mean follow-up time of 14.1 years, 13,320 women with malignant BC were identified. No associations were found between dietary intakes of the MGD score or individual MGDs and BC risk. However, a potential U-shaped relationship was observed between dietary folate intake and overall BC risk, suggesting an inverse association for intakes up to 350 µg/day compared to a reference intake of 205 µg/day. No statistically significant differences in the associations were observed by hormone receptor status, menopausal status, or level of alcohol intake; (4) Conclusions: There was no strong evidence for an association between MGDs involved in one-carbon metabolism and BC risk. However, a potential U-shaped trend was suggested for dietary folate intake and BC risk. Further research is needed to clarify this association.

Dietary intake of trans fatty acids and breast cancer risk in 9 European countries

BACKGROUND

Trans fatty acids (TFAs) have been hypothesised to influence breast cancer risk. However, relatively few prospective studies have examined this relationship, and well-powered analyses according to hormone receptor-defined molecular subtypes, menopausal status, and body size have rarely been conducted.

METHODS

In the European Prospective Investigation into Cancer and Nutrition (EPIC), we investigated the associations between dietary intakes of TFAs (industrial trans fatty acids [ITFAs] and ruminant trans fatty acids [RTFAs]) and breast cancer risk among 318,607 women. Multivariable hazard ratios (HRs) and 95% confidence intervals (CIs) were estimated using Cox proportional hazards models, adjusted for other breast cancer risk factors.

RESULTS

After a median follow-up of 8.1 years, 13,241 breast cancer cases occurred. In the multivariable-adjusted model, higher total ITFA intake was associated with elevated breast cancer risk (HR for highest vs lowest quintile, 1.14, 95% CI 1.06-1.23; P trend = 0.001). A similar positive association was found between intake of elaidic acid, the predominant ITFA, and breast cancer risk (HR for highest vs lowest quintile, 1.14, 95% CI 1.06-1.23; P trend = 0.001). Intake of total RTFAs was also associated with higher breast cancer risk (HR for highest vs lowest quintile, 1.09, 95% CI 1.01-1.17; P trend = 0.015). For individual RTFAs, we found positive associations with breast cancer risk for dietary intakes of two strongly correlated fatty acids (Spearman correlation r = 0.77), conjugated linoleic acid (HR for highest vs lowest quintile, 1.11, 95% CI 1.03-1.20; P trend = 0.001) and palmitelaidic acid (HR for highest vs lowest quintile, 1.08, 95% CI 1.01-1.16; P trend = 0.028). Similar associations were found for total ITFAs and RTFAs with breast cancer risk according to menopausal status, body mass index, and breast cancer subtypes.

CONCLUSIONS

These results support the hypothesis that higher dietary intakes of ITFAs, in particular elaidic acid, are associated with elevated breast cancer risk. Due to the high correlation between conjugated linoleic acid and palmitelaidic acid, we were unable to disentangle the positive associations found for these fatty acids with breast cancer risk. Further mechanistic studies are needed to identify biological pathways that may underlie these associations.

Methodological approaches to compile and validate a food composition database for methyl-group carriers in the European Prospective Investigation into Cancer and Nutrition (EPIC) study

A standardised methodology was used to compile and validate a methyl-group carrier database (MGDB) including folate, choline, betaine and methionine, for use in the European Prospective Investigation into Cancer and Nutrition (EPIC) study. Compilation was performed by following structured guidelines to match the EPIC dietary intake data to food items from four food composition databases, according to their assigned priority of use. To assess relative validity, calculated dietary folate intakes were compared between the MGDB and the EPIC nutrient database (ENDB), used as the reference database. Folate intakes based on the MGDB and those generated using the ENDB showed good agreement (weighted κ = 0.63) and were strongly correlated (r = 0.81). This MGDB can be used for investigating potential associations between methyl-group carrier intakes and risk or prognosis of cancer and other diseases in the EPIC study population.

Schulze M, Johansson I, María Huerta J, Oliverio A, Ricceri F, Halkjær J, Amiano Etxezarreta P, Van Herck K, Weiderpass E, J. Gunter M, Huybrechts I. Comparing Calculated Nutrient Intakes Using Different Food Composition Databases: Results from the European Prospective Investigation into Cancer and Nutrition (EPIC) Cohort

This study aimed to compare calculated nutrient intakes from two different food composition databases using data from the European prospective investigation into cancer and nutrition (EPIC) cohort. Dietary intake data of the EPIC cohort was recently matched to 150 food components from the U.S. nutrient database (USNDB). Twenty-eight of these nutrients were already included in the EPIC nutrient database (ENDB-based upon country specific food composition tables), and used for comparison. Paired sample t-tests, Pearson's correlations (r), weighted kappa's (κ) and Bland-Altman plots were used to compare the dietary intake of 28 nutrients estimated by the USNDB and the ENDB for 476,768 participants. Small but significant differences were shown between the USNDB and the ENDB for energy and macronutrient intakes. Moderate to very strong correlations (r = 0.60-1.00) were found for all macro- and micronutrients. A strong agreement (κ > 0.80) was found for energy, water, total fat, carbohydrates, sugar, alcohol, potassium and vitamin C, whereas a weak agreement (κ < 0.60) was found for starch, vitamin D and vitamin E. Dietary intakes estimated via the USNDB compare adequately with those obtained via the ENDB for most macro- and micronutrients, although the agreement was weak for starch, vitamin D and vitamin E. The USNDB will allow exposure assessments for 150 nutrients to investigate associations with disease outcomes within the EPIC cohort.

Dietary and Circulating Fatty Acids and Ovarian Cancer Risk in the European Prospective Investigation into Cancer and Nutrition

BACKGROUND

Fatty acids impact obesity, estrogens, and inflammation, which are risk factors for ovarian cancer. Few epidemiologic studies have investigated the association of fatty acids with ovarian cancer.

METHODS

Within the European Prospective Investigation into Cancer and Nutrition (EPIC), 1,486 incident ovarian cancer cases were identified. Cox proportional hazard models with adjustment for ovarian cancer risk factors were used to estimate HRs of ovarian cancer across quintiles of intake of fatty acids. False discovery rate was computed to control for multiple testing. Multivariable conditional logistic regression models were used to estimate ORs of ovarian cancer across tertiles of plasma fatty acids among 633 cases and two matched controls in a nested case-control analysis.

RESULTS

A positive association was found between ovarian cancer and intake of industrial trans elaidic acid [HR comparing fifth with first quintileQ5-Q1 = 1.29; 95% confidence interval (CI) = 1.03-1.62; P trend = 0.02, q-value = 0.06]. Dietary intakes of n-6 linoleic acid (HRQ5-Q1 = 1.10; 95% CI = 1.01-1.21; P trend = 0.03) and n-3 α-linolenic acid (HRQ5-Q1 = 1.18; 95% CI = 1.05-1.34; P trend = 0.007) from deep-frying fats were also positively associated with ovarian cancer. Suggestive associations were reported for circulating elaidic (OR comparing third with first tertileT3-T1 = 1.39; 95% CI = 0.99-1.94; P trend = 0.06) and α-linolenic acids (ORT3-T1 = 1.30; 95% CI = 0.98-1.72; P trend = 0.06).

CONCLUSIONS

Our results suggest that higher intakes and circulating levels of industrial trans elaidic acid, and higher intakes of linoleic acid and α-linolenic acid from deep-frying fat, may be associated with greater risk of ovarian cancer.

IMPACT

If causal, eliminating industrial trans-fatty acids could offer a straightforward public health action for reducing ovarian cancer risk.

Dietary folate intake and pancreatic cancer risk: Results from the European prospective investigation into cancer and nutrition

Pancreatic cancer (PC) has an exceptionally low survival rate and primary prevention strategies are limited. Folate plays an important role in one-carbon metabolism and has been associated with the risk of several cancers, but not consistently with PC risk. We aimed to investigate the association between dietary folate intake and PC risk, using the standardised folate database across 10 European countries. A total of 477,206 participants were followed up for 11 years, during which 865 incident primary PC cases were recorded. Folate intake was energy-adjusted using the residual method. Hazard ratios (HRs) and 95% confidence intervals (CIs) were estimated using Cox proportional hazards models. In multivariable analyses stratified by age, sex, study centre and adjusted for energy intake, smoking status, BMI, educational level, diabetes status, supplement use and dietary fibre intake, we found no significant association between folate intake and PC risk: the HR of PC risk for those in the highest quartile of folate intake (≥353 μg/day) compared to the lowest (<241 μg/day) was 0.81 (95% CI: 0.51, 1.31; ptrend = 0.38). In current smokers, a positive trend was observed in PC risk across folate quartiles [HR = 4.42 (95% CI: 1.05, 18.62) for ≥353 μg/day vs. <241 μg/day, ptrend = 0.01]. Nonetheless, there was no significant interaction between smoking and dietary folate intake (pinteraction = 0.99). We found no association between dietary folate intake and PC risk in this large European study.

A new food-composition database for 437 polyphenols in 19,899 raw and prepared foods used to estimate polyphenol intakes in adults from 10 European countries

BACKGROUND

Accurate assessment of polyphenol intakes is needed in epidemiologic research in order to study their health effects, and this can be particularly challenging in international study settings.

OBJECTIVE

The purpose of this work is to describe the procedures to prepare a comprehensive polyphenol food-composition database that was used to calculate standardized polyphenol intakes from 24-h diet recalls (24HDRs) and dietary questionnaires (DQs) in the European Prospective Investigation into Cancer and Nutrition (EPIC).

Design

With the use of the comparable food classification and facet-descriptor system of the computerized 24HDR program EPIC-Soft (renamed GloboDiet), foods reported in the 24HDR (n = 74,626) were first aggregated following a stepwise process. Multi-ingredient and generic foods were broken down into ingredients or more-specific foods with consideration of regional consumption habits before matching to foods in the Phenol-Explorer database. Food-composition data were adjusted by using selected retention factors curated in Phenol-Explorer. DQ foods (n = 13,946) were matched to a generated EPIC 24HDR polyphenol-composition database before calculation of daily intakes from the 24HDR and DQ.

RESULTS

Food matching yielded 2.0% and 2.7% of foods with missing polyphenol content in the 24HDR and DQ food data sets, respectively. Process-specific retention factors for 42 different polyphenol compounds were applied to adjust the polyphenol content in 35 prioritized Phenol-Explorer foods, thereby adjusting the polyphenol content in 70% of all of the prepared 24 food occurrences. A detailed food-composition database was finally generated for 437 polyphenols in 19,899 aggregated raw and prepared foods reported by 10 EPIC countries in the 24HDR.

Conclusions

An efficient procedure was developed to build the most-comprehensive food-composition database for polyphenols, thereby standardizing the calculations of dietary polyphenol intakes obtained from different dietary assessment methods and European populations. The whole database is accessible online. This procedure could equally be used for other food constituents and in other cohorts.

Voluntary Folic Acid Fortification Levels and Nutrient Composition of Food Products from the Spanish Market: A 2011-2015 Update

INTRODUCTION

Folic acid (FA) is a synthetic compound commonly added for voluntary fortification of food products in many European countries. In our country, food composition databases (FCDB) lack comprehensive data on FA fortification practices and this is considered a priority research need when undergoing nutritional assessment of the population.

METHODS

A product inventory was collected and updated by visiting retail stores in Madrid Region, conducting online supermarket searches, and by the provision of food label information by manufacturers. Euro-FIR FCDB guidelines for data compilation and harmonization were used.

RESULTS

The FCDB, compiled between 2011 and 2015, includes FA as well as macro and micronutrient data from 338 fortified foodstuffs. As compared to previous FCDB updates (May 2010), 37 products have ceased to declare added FA in their labels, mainly yogurt and fermented milk products. The main food subgroup is 'breakfast cereals' (n = 95, 34% of total). However, the highest average FA fortification levels per recommended serving were observed in the 'milk, milk products, and milk substitutes' group at ≥35% FA Nutrient Reference Values (NRV, 200 µg, EU Regulation 1169 of 2011) (60-76.3 µg FA per 200 mL). Average contribution to the FA NRV per food group and serving ranged between 16%-35%.

CONCLUSION

Our data show a minor decrease in the number of FA fortified products, but vitamin levels added by manufacturers are stable in most food groups and subgroups. This representative product inventory comprises the main FA food source from voluntary fortification in our country. It is therefore a unique compilation tool with valuable data for the assessment of dietary intakes for the vitamin.

Main nutrient patterns and colorectal cancer risk in the European Prospective Investigation into Cancer and Nutrition study

BACKGROUND

Much of the current literature on diet-colorectal cancer (CRC) associations focused on studies of single foods/nutrients, whereas less is known about nutrient patterns. We investigated the association between major nutrient patterns and CRC risk in participants of the European Prospective Investigation into Cancer and Nutrition (EPIC) study.

METHODS

Among 477 312 participants, intakes of 23 nutrients were estimated from validated dietary questionnaires. Using results from a previous principal component (PC) analysis, four major nutrient patterns were identified. Hazard ratios (HRs) and 95% confidence intervals (CIs) were computed for the association of each of the four patterns and CRC incidence using multivariate Cox proportional hazards models with adjustment for established CRC risk factors.

RESULTS

During an average of 11 years of follow-up, 4517 incident cases of CRC were documented. A nutrient pattern characterised by high intakes of vitamins and minerals was inversely associated with CRC (HR per 1 s.d.=0.94, 95% CI: 0.92-0.98) as was a pattern characterised by total protein, riboflavin, phosphorus and calcium (HR (1 s.d.)=0.96, 95% CI: 0.93-0.99). The remaining two patterns were not significantly associated with CRC risk.

CONCLUSIONS

Analysing nutrient patterns may improve our understanding of how groups of nutrients relate to CRC.