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Food intake, serum biomarkers of folate, vitamins B6 and B12, polymorphism of gene MTHFR and the effects on homocysteine levels in the ISA-Capital study: disentangling multiple relations with structural equation models

Grant number: 11/10628-1
Support type:Scholarships in Brazil - Post-Doctorate
Effective date (Start): November 01, 2011
Effective date (End): February 28, 2013
Field of knowledge:Health Sciences - Nutrition
Principal researcher:Dirce Maria Lobo Marchioni
Grantee:Valéria Troncoso Baltar
Home Institution: Faculdade de Saúde Pública (FSP). Universidade de São Paulo (USP). São Paulo , SP, Brazil


Homocysteine (hcy) is considered a biomarker of cardiovascular diseases (CVD), and its blood levels elevation may be associated with vitamins B6, B12 and/or folate deficiency. However, studies' results regarding these relationships are conflictive. Food and nutrient intake, usually estimated through reports, presents characteristics (such as high intrapersonal variability, zero inflated and asymmetric distribution) that result in the mitigation of association measures, making the identification of the association between diet and disease very difficult. This project proposes to develop and apply a new statistical methodology to estimated more accurately folate, vitamin B6 and B12 usual intake considering such characteristics to then, investigate the relation between usual intake of these vitamins and serum levels of folate, vitamins B6 and B12, which, in turn, have effect on plasma hcy levels, considering polymorphisms in the MTHFR gene. It will be considered diet information collected in the population-based ISA-Capital health survey (24-hour recall applied in duplicate) and mixed models (with fix and random effects and zero inflated generalized Gamma distribution). The simultaneous relations among diet, serum vitamins levels and plasma hcy levels will be estimated through structural equation modelling, allowing the estimation of latent variables (not directly estimated), indirect effects, in which, one variable can be independent in one equation and response in another. It is not from our knowledge any study that takes into account all these relationships simultaneously.

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Scientific publications
(References retrieved automatically from Web of Science and SciELO through information on FAPESP grants and their corresponding numbers as mentioned in the publications by the authors)
RODRIGUES-MOTTA, MARIANA; GALVIS SOTO, DIANA MILENA; LACHOS, VICTOR H.; VILCA, FILIDOR; BALTAR, VALERIA TRONCOSO; VERLY JUNIOR, ELISEU; FISBERG, REGINA MARA; LOBO MARCHIONI, DIRCE MARIA. A mixed-effect model for positive responses augmented by zeros. STATISTICS IN MEDICINE, v. 34, n. 10, p. 1761-1778, MAY 10 2015. Web of Science Citations: 3.

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