RESUMO
INTRODUCTION: Concentrations of inorganic arsenic (iAs) metabolites in urine present intra- and interindividual variations, which are determined not only by the magnitude of exposure to iAs, but also by differences in genetic, environmental and dietary factors. OBJECTIVE: To evaluate whether differences in dietary intake of selected micronutrients are associated with the metabolism of iAs. METHODS: The intake of 21 micronutrients was estimated for 1027 women living in northern Mexico using a food frequency questionnaire. Concentration of urinary metabolites of iAs was determined by high performance liquid chromatography inductively coupled plasma mass spectrometry (HPLC-ICP-MS) and the proportion of iAs metabolites was calculated (%iAs, monomethylarsonic acid [%MMA] and dimethylarsinic acid [%DMA]), as well as ratios corresponding to the first (MMA/iAs), second (DMA/MMA) and total methylation (DMA/iAs). RESULTS: After adjustment for covariates, it was found that methionine, choline, folate, vitamin B12, Zn, Se and vitamin C favor elimination of iAs mainly by decreasing the %MMA and/or increasing %DMA in urine. CONCLUSIONS: Our results confirm that diet contributes to the efficiency of iAs elimination. Further studies are needed to assess the feasibility of dietary interventions that modulate the metabolism of iAs and the consequent risk of diseases related to its exposure.
Assuntos
Arsênio/metabolismo , Micronutrientes/administração & dosagem , Adulto , Idoso , Estudos Transversais , Feminino , Humanos , México , Pessoa de Meia-IdadeRESUMO
Exposure to environmental contaminants, dietary factors and lifestyles may explain worldwide different breast cancer (BC) incidence. Inorganic arsenic (iAs) in the drinking water is a concern in many regions, such as northern Mexico. Studies in several countries have associated the proportion of urinary monomethylarsenic (%MMA) with increased risks for many As-related diseases, including cancer. To investigate the potential relationships between the risk of BC and the capacity to methylate iAs, a hospital-based case-control study (1016 cases/1028 controls) was performed in northern Mexico. Women were directly interviewed about their reproductive histories. The profile of As metabolites in urine was determined by HPLC-ICP-MS and methylation capacity was assessed by metabolite percentages and indexes. Total urinary As, excluding arsenobetaine (TAs-AsB), ranged from 0.26 to 303.29µg/L. Most women (86%) had TAs-AsB levels below As biological exposure index (35µg/L). Women with higher %MMA and/or primary methylation index (PMI) had an increased BC risk (%MMA ORQ5vs.Q1=2.63; 95%CI 1.89,3.66; p for trend <0.001; PMI ORQ5vs.Q1=1.90; 95%CI 1.39,2.59, p for trend <0.001). In contrast, women with higher proportion of urinary dimethylarsenic (%DMA) and/or secondary methylation index (SMI) had a reduced BC risk (%DMA ORQ5vs.Q1=0.63; 95%CI 0.45,0.87, p for trend 0.006; SMI ORQ5vsQ1=0.42, 95%CI 0.31,0.59, p for trend <0.001). Neither %iAs nor total methylation index was associated to BC risk. Inter-individual variations in iAs metabolism may play a role in BC carcinogenesis. Women with higher capacity to methylate iAs to MMA and/or a lower capacity to further methylate MMA to DMA were at higher BC risk.
Assuntos
Arsênio/urina , Neoplasias da Mama/epidemiologia , Neoplasias da Mama/urina , Água Potável/efeitos adversos , Poluentes Químicos da Água/urina , Neoplasias da Mama/diagnóstico , Estudos de Casos e Controles , Feminino , Humanos , Metilação , México/epidemiologia , Pessoa de Meia-Idade , Poluentes Químicos da Água/efeitos adversosRESUMO
OBJECTIVE: To evaluate the reproducibility and validity of folate intake (FI) estimated from a food frequency questionnaire (FFQ), taking into account the retention factor (RF) associated with meal preparation processes. MATERIAL AND METHODS: A total of 497 healthy adult participants were interviewed with a FFQ. A second interview was performed one year later of a sample of 100 randomly selected individuals who had not modified their diet during the previous year. In addition,serum folate (SF) concentrations were measured by radioimmunoassay to evaluate the validity of FI. RESULTS: Reproducibility of IF was 0.36 and 0.34 for folate without FR and with FR, respectively. SF concentration significantly correlated with FI (0.18 with RF; 0.21 without RF, p<0.05). CONCLUSION: Incorporating the folate RF in estimates of FI does not improve the reproducibility and validity of those estimates.
Assuntos
Dieta/estatística & dados numéricos , Comportamento Alimentar , Ácido Fólico , Inquéritos e Questionários , Adulto , Idoso , Consumo de Bebidas Alcoólicas/epidemiologia , Algoritmos , Antropometria , Escolaridade , Feminino , Ácido Fólico/sangue , Deficiência de Ácido Fólico/epidemiologia , Humanos , Masculino , México/epidemiologia , Pessoa de Meia-Idade , Reprodutibilidade dos Testes , Estudos de Amostragem , Fatores Sexuais , Fumar/epidemiologiaRESUMO
OBJETIVO: Evaluar la reproducibilidad y validez de la ingestión de folato (IF),estimada a partir de un cuestionario de frecuencia de consumo (CFC), considerando el factor de retención (FR) correspondiente al método de preparación empleado. MATERIAL Y MÉTODOS: Al inicio del estudio se entrevistó a 497 adultos sanos; un año después se realizó una segunda entrevista a una muestra de 100 individuos seleccionados aleatoriamente,quenohubieran modificadosudietadurante el año previo; adicionalmente, para evaluar la validez de la IF, mediante radioinmunoensayo,se determinaron los niveles de folato sérico (FS). RESULTADOS: La reproducibilidad de la IF fue de 0.36 y 0.34 para el folato sin y con FR,respectivamente. Se observó una correlación significativa entre la IF y el FS de 0.18 con FR y 0.21 sin FR (p<0.05, respectivamente). CONCLUSIONES: Incorporar el FR en las estimaciones de la IF no mejora la reproducibilidad ni la validez de las mismas.
OBJECTIVE: To evaluate the reproducibility and validity of folate intake (FI) estimated from a food frequency questionnaire (FFQ), taking into account the retention factor (RF) associated with meal preparation processes. MATERIAL AND METHODS: A total of 497 healthy adult participants were interviewed with a FFQ.A second interview was performed one year later of a sample of 100 randomly selected individuals who had not modified their diet during the previous year. In addition,serum folate (SF) concentrations were measured by radioimmunoassay to evaluate the validity of FI. RESULTS: Reproducibility of IF was 0.36 and 0.34 for folate without FR and with FR, respectively. SF concentration significantly correlated with FI (0.18 with RF; 0.21 without RF, p<0.05). CONCLUSION: Incorporating the folate RF in estimates of FI does not improve the reproducibility and validity of those estimates.