Nutritional Epidemiology Group
Current Research Topics
The European Prospective Investigation into Cancer and Nutrition (EPIC)
The Nutritional Epidemiology Group is active in cancer site-specific EPIC working groups, in particular for cancers of the breast, colorectum, and liver. For breast cancer, major recent publications include inverse associations of higher dietary fibre intake, dietary folate intake (among people with higher alcohol consumption), and a healthy lifestyle with breast cancer risk. Investigation of the role of industrial fatty acids, as well as exploration of their potential epigenetic interactions, is in progress. For colorectal cancer, the roles of gut barrier function, advanced glycation end-products, and microRNA are being investigated. For liver cancer, comprehensive analyses of dietary, nutritional, and metabolic risk factors are being undertaken. In addition, the Group is active in researching determinants of weight gain, a potential risk factor for several cancers, and has recently shown a positive association of risk of weight gain with higher circulating markers of industrial trans-fatty acids during a 5-year follow-up.
The European Code Against Cancer
The Group led the review of recommendations for the fourth edition of the European Code Against Cancer regarding diet, obesity, physical activity, alcohol consumption, and breastfeeding (see http://cancer-code-europe.iarc.fr).
The Group is applying modern, multiplatform metabolomics techniques in efforts to identify new dietary biomarkers, and is leading a large collaboration to explore metabolic profiles specific to dietary patterns and lifestyle habits, particularly those thought to be associated with cancer development. The Group also develops analytical strategies for metabolomics data to explore cancer etiology and diagnostic biomarker profiles, particularly for cancers of the liver, pancreas, and colorectum.
Exploration of gene-nutrient interactions is of interest to the Group. Recent activities include involvement in the Micronutrient Genomics Project, an international collaboration on micronutrient genomic studies. Studies are currently under way exploring potential genetic interactions with iron, selenium, and other nutrients in colorectal cancer etiology. Also, the Group is exploring the interaction of folate and other B vitamins with alcohol and folate metabolism genes, particularly for breast cancer. Another area of active study is the interaction between fatty acids and fatty acid metabolism genes in relation to breast and pancreatic cancers.
Alcohol and cancer
The Group is continuing its contribution to the understanding of the association of alcohol consumption with cancer at several anatomical sites. Recent publications pertain to the role of alcohol in breast cancer subtypes, colorectal cancer, and total and cause-specific mortality in a competing risks framework. Research is currently focusing on specific research challenges, such as the evaluation of the role of alcohol in combination with lifestyle determinants such as smoking and specific dietary factors (folate, dietary fibre), and the investigation of the differential associations observed in men and women.
Determinants of healthy ageing and cancer risk factors in elderly populations
Because populations worldwide are living longer, potential risk factors for cancers in elderly populations are of increasing interest. The Group is involved in a large European project called Consortium on Health and Ageing Network of Cohorts in Europe and the United States (CHANCES), where it leads the cancer work package. The project brings together 13 international cohorts and aims to conduct pooled analyses of determinants of cancer risk and survival in elderly populations. Major themes of research in the project include obesity, alcohol, diabetes, and social determinants. The Group is also developing its own consortia on the topic and leading applications for further funding.
The Group has invested resources to develop and adapt methods to integrate information of a diverse nature (lifestyle, diet, biomarkers, and metabolites) into statistical models for the investigation of cancer etiology. This entails the use of novel multivariate statistical techniques for dietary pattern discovery, or the investigation of sources of variation in high-dimensional data (metabolomics, epigenetics). Measurement errors in self-reported dietary assessments are a major limitation in modern epidemiology. The Group leads research into advanced methods for measurement error correction, including linear regression calibration, and the use of Bayesian modelling to integrate questionnaire and biomarker measurements into a disease model.
Studies in low- and middle-Income settings
Breast cancer is the most common cancer among women in developed countries and is increasing dramatically in both incidence and mortality in lower-income countries. The Group is using large cohorts and multicentre case-control studies to identify the roles and mechanisms by which diet, physical activity, obesity, and metabolic disorders affect breast cancer incidence and survival.
Lifestyle, metabolic, and hormonal determinants of breast cancer and mammographic density in Mexican women
The Group is collaborating with the National Institute of Public Health (INSP) and the National Institute of Cancerology (INCAN) in Mexico on a breast cancer case-control study (CAMA) of 2000 Mexican women and a large cohort of Mexican teachers (EsMaestras) selected in 9 Mexican states including close to 85 000 women aged 25-70 years. As a first approach, the association of nutritional, metabolic, inflammatory, and hormonal factors with mammographic density, a strong breast cancer risk factor, are being evaluated.
IARC multicentre population-based case-control study (PRECAMA): Molecular Subtypes of Premenopausal Breast Cancer in Latin American Women (http://precama.iarc.fr)
One major activity of the Group is the development of a multicentre population-based case-control study, currently including four Latin American countries (Chile, Colombia, Costa Rica, and Mexico), on the molecular subtypes of premenopausal breast cancer in Latin American women. The group is currently collaborating with the National Institute of Public Health (INSP), Mexico; la Fundación Guanacaste, Costa Rica; the University of Antioquia, Colombia; the University of Chile; and the Fred Hutchinson Cancer Research Center, USA. New countries are expected to join the study. The objective is to evaluate the distribution of specific molecular cancer subtypes and identify the roles/mechanisms of diet, physical activity, obesity, and metabolic disorders in breast cancer incidence/survival. The goal is to recruit close to 2000 cases and controls in various Latin American countries. A standard protocol has been developed for collection of data and biological and tumour samples. The pilot phase has been completed (200 cases and controls), and recruitment is continuing. Knowledge of specific risk factors for breast cancer subtypes will enable the targeting of prevention measures.
Influence of diet, physical activity, and body size on breast cancer in South Africa: a study in African women in transition
A population-based case-control study of breast cancer is being conducted in black South African women in Soweto, Johannesburg, in collaboration with the University of the Witwatersrand, South Africa. The study will enrol 500 cases and controls over 2.5 years and obtain dietary and lifestyle questionnaire data and biological and tumour samples. Recruitment is in progress. This study will be the largest study to date on breast cancer risk among women in South Africa and will provide extremely valuable information on the distribution of molecular subtypes of breast tumours and nutritional risk factors, to support preventive actions.
Nutritional transition in sub-Saharan Africa and its relationship with obesity and cancer: a study in the General Population Cohort in Uganda
The integration of highly specific biomarkers of industrial trans-fatty acids will make it possible to provide a better understanding of the nutritional transition in sub-Saharan Africa and its impact on obesity and cancer. The General Population Cohort (GPC) set up in Uganda by MRC/UVRI, Uganda and the Department of Health Sciences, University of York, United Kingdom, provides a unique framework for building on a large-scale prospective cohort in a sub-Saharan African population. A cross-sectional analysis nested within the GPC in Uganda will be designed to monitor changes of biomarkers of fatty acids over the past 20 years and their impact on obesity and markers of cancer.
Nutritional transition in Lebanon and its relationship with obesity and cancer: a study in the cohort in Greater Beirut
The integration of biomarkers of industrial trans-fatty acids will make it possible to evaluate the exposure to trans-fatty acids among the adult Lebanese population in the Greater Beirut area, Lebanon and to determine related sociodemographic and lifestyle correlations associated with their consumption, as well as to evaluate the association between the levels of trans-fatty acids and risk of various chronic diseases. This study is being developed in collaboration with the American University of Beirut, Lebanon.
Early life and metabolic disorders
Fetal/early life appears to be one of the major determinants of health in later life. The Group is collaborating with National Institute of Public Health (INSP), Mexico and Emory University, USA to evaluate in a birth cohort the effects of maternal and infant nutrition and its interaction with environmental and genetic factors on growth, metabolic, and hormonal profiles. Recent work has been related to docosahexaenoic acid (DHA) supplementation during pregnancy and epigenetic markers.