Prevalence of vitamin B12 deficiency in type 2 diabetic patients using metformin: a cross-sectional study / Prevalência de deficiência de vitamina B12 em pacientes diabéticos do tipo 2 usando metformina: um estudo transversal

ABSTRACT: CONTEXT AND OBJECTIVE: The prevalence of vitamin B12 deficiency varies from 5.8% to 30% among patients undergoing long-term treatment with metformin. Because of the paucity of data on Brazilian patients, this study aimed to determine the frequency of B12 deficiency and related factors among Brazilian patients with type 2 diabetes mellitus (T2DM) using metformin. DESIGN AND SETTING: Cross-sectional study at a public university hospital. METHODS: Patients with T2DM and a control group of non-diabetics were included. Serum B12 levels were measured and biochemical B12 deficiency was defined as serum levels < 180 pg/ml. Associations between B12 deficiency and age, duration of T2DM, duration of use and dosage of metformin, and use of proton pump inhibitors (PPIs) or histamine H2 antagonists were determined. RESULTS: 231 T2DM patients using metformin (T2DM-met) and 231 controls were included. No difference in the frequency of PPI or H2-antagonist use was seen between the groups. B12 deficiency was more frequent in the T2DM-met group (22.5% versus 7.4%) and this difference persisted after excluding PPI/H2-antagonist users (17.9% versus 5.6%). The factors that interfered with serum B12 levels were PPI/H2-antagonist use and duration of metformin use ≥ 10 years. Use of PPI/H2-antagonists was associated with B12 deficiency, with an odds ratio of 2.60 (95% confidence interval, 1.34-5.04). CONCLUSIONS: Among T2DM patients, treatment with metformin and concomitant use of PPI/H2-antagonists are associated with a higher chance of developing B12 deficiency than among non-diabetics.

RESUMO: CONTEXTO E OBJETIVO: A prevalência de deficiência de vitamina B12 varia de 5,8% a 30% nos pacientes em tratamento a longo prazo com metformina. Devido à escassez de dados em pacientes brasileiros, este estudo determinou a frequência de deficiência de B12 e fatores relacionados em pacientes brasileiros com diabetes mellitus tipo 2 (DM2) usando metformina. TIPO DE ESTUDO E LOCAL: Estudo transversal em hospital público universitário. MÉTODOS: Pacientes com DM2 e um grupo controle de não diabéticos foram incluídos. Os níveis séricos de vitamina B12 foram dosados e deficiência bioquímica de B12 foi definida como níveis séricos < 180 pg/ml. Foi investigada a associação entre deficiência de B12 e idade, duração do DM2, duração do uso e dose de metformina, uso de inibidores de bomba de prótons (IBP) ou antagonistas dos receptores histamínicos H2 (antagonistas-H2). RESULTADOS: 231 pacientes DM2 usando metformina (DM2-met) e 231 controles foram incluídos. Não houve diferença na frequência de uso de IBP/antagonistas-H2 entre os grupos. Deficiência de B12 foi mais frequente no grupo DM2-met (22,5% versus 7,4%) e essa diferença persistiu após exclusão dos usuários de IBP/antagonistas-H2 (17,9% versus 5,6%). Fatores que interferiram nos níveis séricos de B12 foram: uso de IBP/antagonistas-H2 e duração do uso de metformina ≥ 10 anos. O uso de IBP/antagonistas-H2 associou-se com deficiência de B12, com um risco relativo de 2,60 (95% intervalo de confiança, 1,34-5,04). CONCLUSÕES: Considerando pacientes com DM2, o tratamento com metformina e uso concomitante de IBP/antagonistas-H2 estão associados com maior chance de desenvolver deficiência de B12 quando comparado aos não diabéticos.

Nutritional status of iron, vitamin B12, folate, retinol and anemia in children 1 to 11 years old: Results of the Ensanut 2012 / Estado nutricional de hierro, vitamina B12, folato, retinol y anemia en niños de 1 a 11 años: Resultados de la Ensanut 2012

Objective. To describe the frequency of anemia, iron, vitamin B12, folate, retinol and predictors of anemia among Mexican children from Ensanut 2012. Materials and methods. Hemoglobin, ferritin, CRP, vitamin B12, retinol and folate concentrations were measured in 2 678 children aged 1-4 y and 4 275 children aged 5-11 y. Adjusted logistic regression models were constructed to assess the risk for anemia and micronutrient deficiencies. Results. In preschoolers and scholars, the overall prevalence of anemia was 20.4 and 9.7%, iron deficiency 14 and 9.3%, low vitamin B12 (LB12S) 1.9 and 2.6%; Folate 0.30 and 0%, and retinol depletion (VADp) 15.7 and 2.3%, respectively. ID and VADp were negatively associated with Hb (coefficient: -0.38 and -0.45, p<0.05); a higher log-CRP was associated with higher risk for anemia and VADp (OR=1.13 and OR=2.1, p<0.05, respectively). Conclusions. Iron deficiency, anemia and VADp are some of the main nutritional problems among Mexican infants.

Objetivo. Describir la frecuencia de anemia, deficiencia de hierro, vitamina B12, folato, retinol y predictores de la anemia en niños mexicanos de la Ensanut 2012. Material y métodos. Se midieron las concentraciones de hemoglobina, ferritina, PCR, vitamina B12, retinol y folato en 2 678 niños de 1-4 años y 4 275 niños de 5-11 años. Se construyeron modelos de regresión logística para evaluar el riesgo de anemia y deficiencias de micronutrientes. Resultados. La prevalencia de anemia en preescolares y escolares fue 20.4 y 9.7%; deficiencia de hierro (DH) 14 y 9.3%; baja concentración de vitamina B12 (BCB12) 1.9 y 2.6%; folato 0.30 y 0%, y depleción de vitamina A (DpVA), 15.7 y 2.3%, respectivamente. La DH y DpVA se asociaron negativamente con la Hb (coeficiente: -0.38 y -0.45, p<0.05); a mayor log-PCR, mayor riesgo de anemia y DpVA (OR=1.13 y OR=2.1, p<0.05, respectivamente). Conclusiones. DH, anemia y DpVA son algunos de los principales problemas de nutrición en niños mexicanos.

Prevalence of iron, folate, and vitamin B12 deficiencies in 20 to 49 years old women: Ensanut 2012 / Prevalencia de deficiencias de hierro, folato y vitamina B12 en mujeres de 20 a 49 años: Ensanut 2012

Objective. To describe the prevalence of iron, folate, and B12 deficiencies in Mexican women of reproductive age from the National Health and Nutrition Survey (Ensanut) 2012. Materials and methods. Data came from a national probabilistic survey, representative from rural and urban areas, and different age groups. Blood samples were obtained from 4 263, 20 to 49 years old women for serum ferritin, vitamin B12 and serum folate concentrations. The prevalence of deficiencies, was assessed using adjusted logistic regression models. Results. The deficiency of folate was 1.9% (95%CI 1.3-2.8), B12 deficiency was 8.5% (95%CI 6.7-10.1) and iron deficiency was 29.4% (95%CI 26.5-32.2). No differences were found when compared with 2006, 24.8% (95%CI 22.3-27.2). Conclusions. The vitamin B12 deficiency is still a problem for women of reproductive age and their offspring in Mexico, while folate deficiency disappeared as a problem. Iron deficiency needs prevention and fortification strategies.

Objetivo. Describir las prevalencias de deficiencias de hierro, folato y B12 en mujeres mexicanas en edad reproductiva de la Encuesta Nacional de Salud y Nutrición (Ensanut) 2012. Material y métodos. Datos derivados de una encuesta probabilística nacional, representativa del área rural y urbana por grupos de edad. Se obtuvo una submuestra de sangre en 4 263 mujeres de 20 a 49 años de edad para medir las concentraciones séricas de ferritina, vitamina B12 y folato. Las deficiencias fueron evaluadas mediante regresiones logísticas múltiples ajustadas. Resultados. La prevalencia de deficiencias de folatos fue de 1.9% (IC95% 1.3-2.8) y vitamina B12 de 8.5% (IC95% 6.7-10.1). La deficiencia de hierro no fue diferente a la de 2006: 29.4% (IC95% 26.5-32.2) vs 24.8% (IC95% 22.3-27.2). Conclusiones. La prevalencia de deficiencias de hierro y vitamina B12 todavía representan un problema en mujeres mexicanas (20-49), mientras que la deficiencia de folato ha dejado de ser un problema de salud pública. Aún se requieren estrategias de prevención en México.