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Zugna D, Popovic M, Fasanelli F, Heude B, Scelo G, Richiardi L. Applied causal inference methods for sequential mediators. BMC Med Res Methodol 2022; 22:301. [PMID: 36424556 PMCID: PMC9686042 DOI: 10.1186/s12874-022-01764-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2022] [Accepted: 10/19/2022] [Indexed: 11/25/2022] Open
Abstract
BACKGROUND Mediation analysis aims at estimating to what extent the effect of an exposure on an outcome is explained by a set of mediators on the causal pathway between the exposure and the outcome. The total effect of the exposure on the outcome can be decomposed into an indirect effect, i.e. the effect explained by the mediators jointly, and a direct effect, i.e. the effect unexplained by the mediators. However finer decompositions are possible in presence of independent or sequential mediators. METHODS We review four statistical methods to analyse multiple sequential mediators, the inverse odds ratio weighting approach, the inverse probability weighting approach, the imputation approach and the extended imputation approach. These approaches are compared and implemented using a case-study with the aim to investigate the mediating role of adverse reproductive outcomes and infant respiratory infections in the effect of maternal pregnancy mental health on infant wheezing in the Ninfea birth cohort. RESULTS Using the inverse odds ratio weighting approach, the direct effect of maternal depression or anxiety in pregnancy is equal to a 59% (95% CI: 27%,94%) increased prevalence of infant wheezing and the mediated effect through adverse reproductive outcomes is equal to a 3% (95% CI: -6%,12%) increased prevalence of infant wheezing. When including infant lower respiratory infections in the mediation pathway, the direct effect decreases to 57% (95% CI: 25%,92%) and the indirect effect increases to 5% (95% CI: -5%,15%). The estimates of the effects obtained using the weighting and the imputation approaches are similar. The extended imputation approach suggests that the small joint indirect effect through adverse reproductive outcomes and lower respiratory infections is due entirely to the contribution of infant lower respiratory infections, and not to an increased prevalence of adverse reproductive outcomes. CONCLUSIONS The four methods revealed similar results of small mediating role of adverse reproductive outcomes and early respiratory tract infections in the effect of maternal pregnancy mental health on infant wheezing. The choice of the method depends on what is the effect of main interest, the type of the variables involved in the analysis (binary, categorical, count or continuous) and the confidence in specifying the models for the exposure, the mediators and the outcome.
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Affiliation(s)
- D Zugna
- grid.7605.40000 0001 2336 6580Cancer Epidemiology Unit, Department of Medical Sciences, University of Turin, Via Santena 7, 10126 Turin, Italy
| | - M Popovic
- grid.7605.40000 0001 2336 6580Cancer Epidemiology Unit, Department of Medical Sciences, University of Turin, Via Santena 7, 10126 Turin, Italy
| | - F Fasanelli
- grid.7605.40000 0001 2336 6580Cancer Epidemiology Unit, Department of Medical Sciences, University of Turin, Via Santena 7, 10126 Turin, Italy
| | - B Heude
- grid.513249.80000 0004 8513 0030Université de Paris Cité, Inserm, INRAE, Centre of Research in Epidemiology and StatisticS (CRESS), F-75004 Paris, France
| | - G Scelo
- grid.7605.40000 0001 2336 6580Cancer Epidemiology Unit, Department of Medical Sciences, University of Turin, Via Santena 7, 10126 Turin, Italy
| | - L Richiardi
- grid.7605.40000 0001 2336 6580Cancer Epidemiology Unit, Department of Medical Sciences, University of Turin, Via Santena 7, 10126 Turin, Italy
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Perrier F, Viallon V, Ambatipudi S, Ghantous A, Cuenin C, Hernandez-Vargas H, Chajès V, Baglietto L, Matejcic M, Moreno-Macias H, Kühn T, Boeing H, Karakatsani A, Kotanidou A, Trichopoulou A, Sieri S, Panico S, Fasanelli F, Dolle M, Onland-Moret C, Sluijs I, Weiderpass E, Quirós JR, Agudo A, Huerta JM, Ardanaz E, Dorronsoro M, Tong TYN, Tsilidis K, Riboli E, Gunter MJ, Herceg Z, Ferrari P, Romieu I. Association of leukocyte DNA methylation changes with dietary folate and alcohol intake in the EPIC study. Clin Epigenetics 2019; 11:57. [PMID: 30940212 PMCID: PMC6444439 DOI: 10.1186/s13148-019-0637-x] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2018] [Accepted: 02/20/2019] [Indexed: 12/14/2022] Open
Abstract
Background There is increasing evidence that folate, an important component of one-carbon metabolism, modulates the epigenome. Alcohol, which can disrupt folate absorption, is also known to affect the epigenome. We investigated the association of dietary folate and alcohol intake on leukocyte DNA methylation levels in the European Prospective Investigation into Cancer and Nutrition (EPIC) study. Leukocyte genome-wide DNA methylation profiles on approximately 450,000 CpG sites were acquired with Illumina HumanMethylation 450K BeadChip measured among 450 women control participants of a case-control study on breast cancer nested within the EPIC cohort. After data preprocessing using surrogate variable analysis to reduce systematic variation, associations of DNA methylation with dietary folate and alcohol intake, assessed with dietary questionnaires, were investigated using CpG site-specific linear models. Specific regions of the methylome were explored using differentially methylated region (DMR) analysis and fused lasso (FL) regressions. The DMR analysis combined results from the feature-specific analysis for a specific chromosome and using distances between features as weights whereas FL regression combined two penalties to encourage sparsity of single features and the difference between two consecutive features. Results After correction for multiple testing, intake of dietary folate was not associated with methylation level at any DNA methylation site, while weak associations were observed between alcohol intake and methylation level at CpG sites cg03199996 and cg07382687, with qval = 0.029 and qval = 0.048, respectively. Interestingly, the DMR analysis revealed a total of 24 and 90 regions associated with dietary folate and alcohol, respectively. For alcohol intake, 6 of the 15 most significant DMRs were identified through FL. Conclusions Alcohol intake was associated with methylation levels at two CpG sites. Evidence from DMR and FL analyses indicated that dietary folate and alcohol intake may be associated with genomic regions with tumor suppressor activity such as the GSDMD and HOXA5 genes. These results were in line with the hypothesis that epigenetic mechanisms play a role in the association between folate and alcohol, although further studies are warranted to clarify the importance of these mechanisms in cancer. Electronic supplementary material The online version of this article (10.1186/s13148-019-0637-x) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- F Perrier
- Nutritional Methodology and Biostatistics Group, International Agency for Research on Cancer (IARC), World Health Organization, 150, cours Albert Thomas, 69372, Lyon CEDEX 08, France
| | - V Viallon
- Nutritional Methodology and Biostatistics Group, International Agency for Research on Cancer (IARC), World Health Organization, 150, cours Albert Thomas, 69372, Lyon CEDEX 08, France
| | - S Ambatipudi
- Epigenetics Group, IARC, Lyon, France.,MRC Integrative Epidemiology Unit, Bristol Medical School, University of Bristol, Bristol, UK
| | | | - C Cuenin
- Epigenetics Group, IARC, Lyon, France
| | | | - V Chajès
- Nutritional Epidemiology Group, IARC, Lyon, France
| | - L Baglietto
- Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy
| | - M Matejcic
- Nutritional Epidemiology Group, IARC, Lyon, France.,Department of Preventive Medicine, Keck School of Medicine, University of Southern California/Norris Comprehensive Cancer Center, Los Angeles, CA, USA
| | | | - T Kühn
- Division of Cancer Epidemiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - H Boeing
- Department of Epidemiology, German Institute of Human Nutrition (DIfE), Potsdam-Rehbrücke, Germany
| | - A Karakatsani
- Hellenic Health Foundation, Athens, Greece.,2nd Pulmonary Medicine Department, School of Medicine, National and Kapodistrian University of Athens, "ATTIKON" University Hospital, Haidari, Greece
| | - A Kotanidou
- Hellenic Health Foundation, Athens, Greece.,1st Department of Critical Care Medicine and Pulmonary Services, University of Athens Medical School, Evangelismos Hospital, Athens, Greece
| | | | - S Sieri
- Epidemiology and Prevention Unit, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy
| | - S Panico
- Dipartimento di Medicina Clinica e Chirurgia, Federico II University, Naples, Italy
| | - F Fasanelli
- Cancer Epidemiology Unit, Department of Medical Sciences, University of Turin, Via Santena 7, Turin, Italy
| | - M Dolle
- National Institute of Public Health and the Environment (RIVM), Centre for Health Protection (pb12), Bilthoven, The Netherlands
| | - C Onland-Moret
- Department of Epidemiology, Julius Center Research Program Cardiovascular Epidemiology, Utrecht, The Netherlands
| | - I Sluijs
- Department of Epidemiology, Julius Center Research Program Cardiovascular Epidemiology, Utrecht, The Netherlands
| | - E Weiderpass
- Department of Research, Cancer Registry of Norway, Institute of Population-Based Cancer Research, Oslo, Norway.,Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Stockholm, Sweden.,Genetic Epidemiology Group, Folkhälsan Research Center and Faculty of Medicine, University of Helsinki, Helsinki, Finland.,Department of Community Medicine, University of Tromsø, The Arctic University of Norway, Tromsø, Norway
| | - J R Quirós
- Public Health Directorate, Asturias, Spain
| | - A Agudo
- Unit of Nutrition and Cancer, Cancer Epidemiology Research Program, Catalan Institute of Oncology-IDIBELL, L'Hospitalet de Llobregat, Barcelona, Spain
| | - J M Huerta
- Department of Epidemiology, Murcia Regional Health Council, IMIB-Arrixaca, Murcia, Spain.,CIBER Epidemiology and Public Health CIBERESP, Madrid, Spain
| | - E Ardanaz
- Department of Epidemiology, Murcia Regional Health Council, IMIB-Arrixaca, Murcia, Spain.,CIBER Epidemiology and Public Health CIBERESP, Madrid, Spain.,Navarra Public Health Institute, Pamplona, Spain.,IdiSNA, Navarra Institute for Health Research, Pamplona, Spain
| | - M Dorronsoro
- Public Health Direction and Biodonostia Research Institute and CIBERESP, Basque Regional Health Department, San Sebastian, Spain
| | - T Y N Tong
- Cancer Epidemiology Unit, Nuffield Department of Population Health, University of Oxford, Oxford, UK
| | - K Tsilidis
- Department of Epidemiology and Biostatistics, School of Public Health, Imperial College London, London, UK
| | - E Riboli
- Department of Epidemiology and Biostatistics, School of Public Health, Imperial College London, London, UK
| | - M J Gunter
- Nutritional Epidemiology Group, IARC, Lyon, France
| | - Z Herceg
- Epigenetics Group, IARC, Lyon, France
| | - P Ferrari
- Nutritional Methodology and Biostatistics Group, International Agency for Research on Cancer (IARC), World Health Organization, 150, cours Albert Thomas, 69372, Lyon CEDEX 08, France.
| | - I Romieu
- Nutritional Epidemiology Group, IARC, Lyon, France
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Sieri S, Agnoli C, Pala V, Grioni S, Brighenti F, Pellegrini N, Masala G, Palli D, Mattiello A, Panico S, Ricceri F, Fasanelli F, Frasca G, Tumino R, Krogh V. Dietary glycemic index, glycemic load, and cancer risk: results from the EPIC-Italy study. Sci Rep 2017; 7:9757. [PMID: 28851931 PMCID: PMC5575161 DOI: 10.1038/s41598-017-09498-2] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2017] [Accepted: 07/27/2017] [Indexed: 12/21/2022] Open
Abstract
Factors linked to glucose metabolism are involved in the etiology of several cancers. High glycemic index (GI) or high glycemic load (GL) diets, which chronically raise postprandial blood glucose, may increase cancer risk by affecting insulin-like growth factor. We prospectively investigated cancer risk and dietary GI/GL in the EPIC-Italy cohort. After a median 14.9 years, 5112 incident cancers and 2460 deaths were identified among 45,148 recruited adults. High GI was associated with increased risk of colon and bladder cancer. High GL was associated with: increased risk of colon cancer; increased risk of diabetes-related cancers; and decreased risk of rectal cancer. High intake of carbohydrate from high GI foods was significantly associated with increased risk of colon and diabetes-related cancers, but decreased risk of stomach cancer; whereas high intake of carbohydrates from low GI foods was associated with reduced colon cancer risk. In a Mediterranean population with high and varied carbohydrate intake, carbohydrates that strongly raise postprandial blood glucose may increase colon and bladder cancer risk, while the quantity of carbohydrate consumed may be involved in diabetes-related cancers. Further studies are needed to confirm the opposing effects of high dietary GL on risks of colon and rectal cancers.
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Affiliation(s)
- S Sieri
- Epidemiology and Prevention Unit, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy
| | - C Agnoli
- Epidemiology and Prevention Unit, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy
| | - V Pala
- Epidemiology and Prevention Unit, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy
| | - S Grioni
- Epidemiology and Prevention Unit, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy
| | - F Brighenti
- Department of Public Health, University of Parma, Parma, Italy
| | - N Pellegrini
- Department of Public Health, University of Parma, Parma, Italy
| | - G Masala
- Molecular and Nutritional Epidemiology Unit, ISPO-Cancer Research and Prevention Institute, Florence, Italy
| | - D Palli
- Molecular and Nutritional Epidemiology Unit, ISPO-Cancer Research and Prevention Institute, Florence, Italy
| | - A Mattiello
- Department of Clinical and Experimental Medicine, Federico II University, Naples, Italy
| | - S Panico
- Department of Clinical and Experimental Medicine, Federico II University, Naples, Italy
| | - F Ricceri
- Department of Clinical and Biological Sciences, University of Turin, Turin, Italy.,Unit of Epidemiology, Regional Health Service ASL TO3, Grugliasco, Turin, Italy
| | - F Fasanelli
- Unit of Cancer Epidemiology, Department of Medical Sciences, University of Turin, Turin, Italy
| | - G Frasca
- Cancer Registry, Department of Medical Prevention, ASP Ragusa, Italy
| | - R Tumino
- Cancer Registry, Department of Medical Prevention, ASP Ragusa, Italy
| | - V Krogh
- Epidemiology and Prevention Unit, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy.
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