Reproducibility and Validity of Capillary Dried Blood Spot for Diagnosis of Vitamin A Deficiency and Anemia in Children <5 Years Old.

BACKGROUND: Vitamin A deficiency (VAD) and anemia are the most prevalent nutritional deficiency in children globally. The dried blood spot (DBS) method has been used in prevalence studies of VAD and anemia in different age groups. However, it has not yet been validated for children. OBJECTIVES: This study aimed to assess the reproducibility and validity of DBS in the diagnosis of VAD and anemia in preschoolers. METHODS: Venous and capillary blood samples were collected from a representative sample of children <5 y old who attended the public health system in Rio de Janeiro. Serum retinol and hemoglobin were measured in 235 and 182 children, respectively. Serum retinol was measured with HPLC and hemoglobin was measured with spectrophotometry in samples of venous (gold standard) and capillary blood (test method, DBS). DBS reproducibility was assessed with the intraclass correlation coefficient (ICC), κ, and prevalence-adjusted and bias-adjusted κ (PABAK). DBS validity was assessed with sensitivity, specificity, accuracy index (AI), positive predictive value (PPV), and negative predictive value (NPV). RESULTS: DBS showed very good reproducibility for serum retinol (ICC = 0.94, κ = 0.83, PABAK = 0.76) and very good/good reproducibility for hemoglobin (ICC = 0.86, κ = 0.69, PABAK = 0.69). Prevalence rates for VAD by the reference and test methods were 11.5% and 11.9%, respectively, whereas the anemia rates were 19.2% and 46.2%. The test method showed low sensitivity (33%) and PPV (32%) and high specificity (91%) and NPV (92%) for serum retinol. For hemoglobin, the test method showed fair sensitivity (71%), low PPV (30%), fair specificity (60%), and high NPV (90%). AI was 83% for VAD and 62% for anemia. CONCLUSIONS: The results suggest that DBS is adequate for the diagnosis of VAD in preschool children, but not for anemia.

Short-term effects of low-dose estradiol on endothelial function and blood viscosity in nondiabetic postmenopausal overweight women: a double-blind, placebo-controlled study.

OBJECTIVE: The beneficial effects of estrogen on endothelial function depend on its integrity. This study evaluates the short-term effects of low-dose transdermal estradiol on endothelial function, insulin sensitivity, and blood viscosity in nondiabetic overweight/obese women. METHODS: Forty-four nondiabetic overweight/obese women with a history of recent menopause were randomly allocated, in a double-blind fashion, to receive transdermal estradiol (1 mg/d, n = 22) or placebo (n = 22). The following parameters were assessed: endothelial reactivity (venous occlusion plethysmography and nailfold videocapillaroscopy), plasma levels of soluble adhesion molecules, insulin sensitivity (homeostasis model assessment of insulin resistance and areas under the curve of insulin and glucose during an oral glucose tolerance test), and blood and plasma viscosity. Data were expressed as means ±â€ŠSD or medians [first to third quartiles]. RESULTS: Participants were aged 51.8 ±â€Š2.3 years with a body mass index of 31.5 ±â€Š2.5 kg/m and time since menopause was 3 [2-5] years. At baseline, no differences between the groups were observed; however, after 3 months of treatment, the following changes were observed in the estradiol group compared with the placebo group: a decrease in the forearm vascular resistance at baseline (36.37 [24.9-51.27] vs 51.3 [40.88-70.03] mm Hg/mL per min 100 mL tissue, P < 0.01) and during the postocclusive reactive hyperemia response (15.93 [11.32-22.29] vs 22.13 [16.46-29.7] mm Hg/mL per min 100 mL tissue, P < 0.01), and an increase in red blood cell velocity at rest (0.316 [0.309-0.326] vs 0.303 [0.293-0.308] mm/s, P < 0.001) and during postocclusive reactive hyperemia response (0.374 [0.353-0.376] vs 0.341 [0.333-0.355] mm/s, P < 0.001). Furthermore, blood viscosity was lower in the estradiol group than in the placebo group (3.57 ±â€Š0.12 vs 3.76 ±â€Š0.22 mPa.s; P < 0.01). CONCLUSIONS: Short-term use of low-dose transdermal estradiol in nondiabetic overweight/obese women with a history of recent menopause improved endothelial function and decreased blood viscosity compared with placebo.