A Quantile Regression Approach Can Reveal the Effect of Fruit and Vegetable Consumption on Plasma Homocysteine Levels

Autor(es)

Verly-, Jr., Eliseu ^[1] ; Steluti, Josiane ^[2] ; Fisberg, Regina Mara ^[2] ; Marchioni, Dirce Maria Lobo ^[2]

Afiliação do(s) autor(es)

^[1] Univ Estado Rio De Janeiro, Inst Social Med, Dept Epidemiol, Rio De Janeiro - Brazil

^[2] Univ Sao Paulo, Sch Publ Hlth, Dept Nutr, Sao Paulo - Brazil

• Tipo de documento: Artigo Científico
• Fonte: PLoS One; v. 9, n. 11 NOV 3 2014.
• Citações Web of Science: 13

Resumo

Introduction: A reduction in homocysteine concentration due to the use of supplemental folic acid is well recognized, although evidence of the same effect for natural folate sources, such as fruits and vegetables (FV), is lacking. The traditional statistical analysis approaches do not provide further information. As an alternative, quantile regression allows for the exploration of the effects of covariates through percentiles of the conditional distribution of the dependent variable. Objective: To investigate how the associations of FV intake with plasma total homocysteine (tHcy) differ through percentiles in the distribution using quantile regression. Materials and Methods: A cross-sectional population-based survey was conducted among 499 residents of Sao Paulo City, Brazil. The participants provided food intake and fasting blood samples. Fruit and vegetable intake was predicted by adjusting for day-to-day variation using a proper measurement error model. We performed a quantile regression to verify the association between tHcy and the predicted FV intake. The predicted values of tHcy for each percentile model were calculated considering an increase of 200 g in the FV intake for each percentile. Results: The results showed that tHcy was inversely associated with FV intake when assessed by linear regression whereas, the association was different when using quantile regression. The relationship with FV consumption was inverse and significant for almost all percentiles of tHcy. The coefficients increased as the percentile of tHcy increased. A simulated increase of 200 g in the FV intake could decrease the tHcy levels in the overall percentiles, but the higher percentiles of tHcy benefited more. Conclusions: This study confirms that the effect of FV intake on lowering the tHcy levels is dependent on the level of tHcy using an innovative statistical approach. From a public health point of view, encouraging people to increase FV intake would benefit people with high levels of tHcy. (AU)

• Processo FAPESP: 09/15831-0 - Fatores dietéticos, homocisteína, polimorfismos do gene MTHFR e risco cardiovascular em adultos e idosos: estudo de base populacional - ISA - capital
• Beneficiário: Regina Mara Fisberg
• Modalidade de apoio: Auxílio à Pesquisa - Regular
• Processo FAPESP: 11/19788-1 - Avaliação da deficiência de folato após a fortificação mandatória de ácido fólico e consequências à saúde: estudo de base populacional no município de São Paulo
• Beneficiário: Dirce Maria Lobo Marchioni
• Modalidade de apoio: Auxílio à Pesquisa - Regular
• Processo FAPESP: 10/19899-5 - Consumo dietético, variantes genéticas e relação com os níveis sanguíneos de folato, ácido fólico não metabolizado e homocisteína após a fortificação mandatória de ácido fólico: estudo de base populacional - ISA-Capital.
• Beneficiário: Josiane Steluti
• Modalidade de apoio: Bolsas no Brasil - Doutorado