Fabiana Viegas Raimundo

Vitamin B12 in metformin-treated diabetic patients: a cross-sectional study in Brazil

OBJECTIVE The objective of this study was to evaluate the presence of vitamin B12 deficiency and the factors associated with serum vitamin B12 levels in a sample of metformin-treated Brazilian diabetic patients. METHOD Cross-sectional study. RESULTS 144 patients were included. Serum vitamin B12 levels were low (< 125 pmol/L) in 10 patients (6.9%) and possibly low (125 - 250 pmol/L) in 53 patients (36.8%). Serum vitamin B12 levels were negatively associated with age (B = -3.17; β= -0.171; p = 0.037) and duration of metformin use (B= -33.36; β= -0.161; p = 0.048), and positively associated with the estimated intake of vitamin B12 (B= 67.96; β= 0.249; p = 0.002). CONCLUSION The present findings suggest a high prevalence of vitamin B12 deficiency in metformin-treated diabetic patients. Older patients, patients in long term treatment with metformin and low vitamin B12 intake are probably more prone to this deficiency.

Effect of High- versus Low-Fat Meal on Serum 25-Hydroxyvitamin D Levels after a Single Oral Dose of Vitamin D: A Single-Blind, Parallel, Randomized Trial

Background/Aims. Vitamin D3 is liposoluble, so dietary fat could increase its oral absorption. Our aim was to compare serum 25-hydroxyvitamin D [25(OH)D] after the oral intake of cholecalciferol with a high- or low-fat meal. Methods. In a single-blind, parallel clinical trial, 32 healthy physicians were divided into two groups. In the same day, they ingested 50,000 IU (1.25 mg) of vitamin D3 with food: group 1 (G1): lipids: 25.6 g and group 2 (G2) lipids: 1.7 g. Serum 25(OH)D (0, 7, and 14 days), and parathyroid hormone (PTH), and calcium (0 and 14 days) were measured. Results. Baseline mean serum 25(OH)D levels were 42.7 ± 19.0 nmol/L in G1 and 36.4 ± 19.0 nmol/L in G2 (P = 0.38). After cholecalciferol, mean serum 25(OH)D was higher in G1 (P < 0.001): 7 days: G1 = 46.2 (38.4–53.9) nmol/L and G2 = 33.7 (25.4–40.1) nmol/L; 14 days: G1 = 53.7 (45.2–62.1) nmol/L and G2 = 33.7 (25.2–42.2) nmol/L. Serum PTH and 25(OH)D were negatively correlated before and after the intake of vitamin D3, respectively, r = −0.42 (P = 0.02) and r = −0.52 (P = 0.003). Conclusions. A high-fat meal increased the absorption of vitamin D3, as measured by serum 25(OH)D.

Calcium and vitamin D intake and biochemical tests in short-stature children and adolescents

Background:Growth is highly dependent on the absorption of nutrients. Inadequate calcium and vitamin D intake may compromise bone mineralization and growth. There is a great deal of concern regarding calcium and vitamin D intake, as well as biochemical changes in children and adolescents, which led us to investigate calcium and vitamin D levels during growth.Methods:Fifty-eight children and adolescents with short stature (z-score <3 s.d.) were evaluated from September 2005 to February 2007. Blood biochemical analyses and 24-h urine tests were performed and were used to evaluate calcium, phosphorus, creatinine, sodium, alkaline phosphatase, parathyroid hormone (PTH) and 25(OH)D levels. Dietary inquiries, repeated three times, were used to estimate the actual intake of these substances.Results:A reduced calcium (608.6 mg/day) and vitamin D (72.5 IU/day) intake was observed. Calcium excretion in 24-h urine (56 mg/24 h) and calcium excretion by weight (2.0 mg/24 h/kg) showed scores that were below normal. A negative correlation between PTH and both dietary vitamin D (r=−0.46; P<0.01) and calcium intake (r =−0.41; P<0.001) was observed.Conclusions:The low calcium and vitamin D intake observed in short-stature children and adolescents was associated with biochemical results, and suggested that PTH and calcium excretion may be useful screening tests for evaluating dietary calcium and vitamin D.

Prevalence of low bone mineral density in adolescents and adults with cystic fibrosis

OBJECTIVE The aim of this cross-sectional study was to evaluate the prevalence of low bone mass density in cystic fibrosis patients as well as to evaluate the factors associated with bone mass in such patients. METHODS Bone mass density was measured by dual-photon X-ray absorptiometry of lumbar spine (L1-L4), in patients ≤19 years old, or lumbar spine and femur (total and neck) in patients ≥20 years old. Evaluations of nutritional status, biochemical parameters, and lung function were performed. Medication data were obtained from medical records. RESULTS Fifty-eight patients were included in the study (25 males/ 33 females), mean age 23.9 years (16-53 years). The prevalence of bone mass below the expected range for age at any site was 20.7%. None of the subjects had history of fracture. Lumbar spine Z-score in cystic fibrosis patients correlated positively with body mass index (r= 0.3, p=0.001), and forced expiratory volume in the first second (% predicted) (r=0.415, p=0.022). Mean lumbar spine Z-score was higher in women (p=0.001), in patients with no pancreatic insufficiency (p=0.032), and in patients with no hospitalization in the last 3 months (p=0.02). After multivariate analysis, body mass index (p= 0.001) and sex (p=0.001) were independently associated with Z-score in lumbar spine. CONCLUSION Low bone mass is a frequent problem in patients with CF, being independently associated with body mass index, and male sex.

Hypovitaminosis D in patients with cystic fibrosis: a cross-section study in South Brazil.

Cystic fibrosis (CF) patients have a susceptibility to vitamin D deficiency because of nutrient malabsorption.