AimsHeart failure (HF) is common in geriatric patients. Clinicians face diagnostic challenges primarily due to comorbidity and limited access to echocardiography. The purpose of this study was to identify independent determinants of the presence of HF in geriatric outpatients and to determine the optimal diagnostic strategy. Methods and resultsGeriatric outpatients [mean age 82 (+6) years, 30% men] with suspected HF underwent an extensive standardized diagnostic work-up. An expert consensus panel determined the presence of HF. Heart failure was present in 94 of 206 participants (46%). Male sex [odds ratio (OR) 2.0], age per 10 years (OR 1.6), nocturnal dyspnoea (OR 1.7), absence of wheezing (OR 2.1), loss of appetite (OR 1.7), and lower body mass index (BMI; OR 0.9) were independently associated with the presence of HF: the c-statistic of the model containing these items was 0.75. Of all additional tests, N-terminal pro-B-type natriuretic peptide (NT-proBNP) improved the diagnostic accuracy the most (OR ln NT-proBNP 2.8; c-statistic 0.92). A diagnostic rule, consisting of six clinical variables and NT-proBNP, showed good negative and positive predictive values. ConclusionHalf of geriatric patients suspected of HF actually have HF. Apart from age, gender, and nocturnal dyspnoea, absence of wheezing, loss of appetite, and lower BMI were independently associated with the presence of HF. Symptoms and signs in combination with NT-proBNP reliably identified the presence or absence of HF in the vast majority of patients. Additional diagnostic tests, in particular echocardiography, can be targeted at those in whom the presence of HF remains uncertain and to ascertain the cause of HF.--

BackgroundAsymptomatic carriage of Giardia intestinalis is highly prevalent among children in developing countries, and evidence regarding its role as a diarrhea-causing agent in these settings is controversial. Impaired linear growth and cognition have been associated with giardiasis, presumably mediated by malabsorption of nutrients. In a prospective cohort study, we aim to compare diarrhea rates in pre-school children with and without Giardia infection. Because the study was conducted in the context of an intervention trial assessing the effects of multi-nutrients on morbidity, we also assessed how supplementation influenced the relationship between Giardia and diarrhoea rates, and to what extent Giardia modifies the intervention effect on nutritional status.Methods and FindingsData were collected in the context of a randomized placebo-controlled efficacy trial with 2×2 factorial design assessing the effects of zinc and/or multi-micronutrients on morbidity (n = 612; height-for-age z-score <−1.5 SD). Outcomes measures were episodes of diarrhea (any reported, or with ≥3 stools in the last 24 h) and fever without localizing signs, as detected with health-facility based surveillance. Giardia was detected in stool by enzyme-linked immunosorbent assay. Among children who did not receive multi-nutrients, asymptomatic Giardia infection at baseline was associated with a substantial reduction in the rate of diarrhea (HR 0.32; 0.15–0.66) and fever without localizing signs (HR 0.56; 0.36–0.87), whereas no such effect was observed among children who received multi-nutrients (p-values for interaction 0.03 for both outcomes). This interaction was independent of age, HAZ-scores and distance to the research dispensary. There was no evidence that Giardia modified the intervention effect on nutritional status.ConclusionAlthough causality of the Giardia-associated reduction in morbidity cannot be established, multi-nutrient supplementation results in a loss of this protection and thus seems to influence the proliferation or virulence of Giardia or associated intestinal pathogens.

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In view of increasing interest in vitamin D, the New York Times recently suggested that it might become "the nutrient of the decade" (1 ). Vitamin D plays a major role in calcium and bone metabolism and is an essential (pre)hormone involved in cell maturation and proliferation (2 ). Vitamin D deficiency is linked to an increased risk of breast, colon, and prostate cancer as well as autoimmune diseases like juvenile diabetes (2 ). Analysis and method standardization of the key indicator of vitamin D homeostasis, 25(OH)-vitamin D 3 , has been studied (3, 4 ). Information about preanalytical stability of 25(OH)-vitamin D 3 in human blood is hard to find, however, especially for "on the bench" conditions. One older study is incomplete and another focuses on freeze-thaw cycles (5,6 ). Medical laboratory sample-handling guidelines currently require freezing the sample and protecting it from artificial light and repeated freezethaw cycles. On the other hand, food industries report very good stability of vitamin D in natural matrices like milk or fat. We tested the stability of 25(OH)-vitamin D 3 in 8 different human blood samples under several sets of routine laboratory conditions.Because dietary supplementation of vitamin D in the Netherlands is confined to vitamin D 3 , we studied only 25(OH)-vitamin D 3 stability. This restriction is a potential limitation of our study, but our aim was to investigate the natural form in human samples. Based on the close resemblance in structures of vitamin D 2 and D 3 and previous but limited experience with 25(OH)-vitamin D 2 stability (5 ), we expected the stabilities for 25(OH)-vitamin D 2 and D 3 to be similar under the conditions of our study.We performed the study with leftover samples from 8 anonymous outpatients. Our study was approved by the hospital's ethics committee. Samples were collected in BD plastic blood collection containers free of anticoagulant. The original 25(OH)-vitamin D 3 concentrations ranged from 35-110 nmol/L. The baseline concentration values for our experiment (time ϭ 0) were the means of quintuplicate analyses, and for subsequent measurements they were the means of triplicate analyses. After exposure to the specified conditions in the original BD container, serum sample aliquots in stoppered plastic tubes were frozen immediately at Ϫ20°C until analysis. Storage conditions examined were extended common routine laboratory conditions: storage of serum at 6°C and at room temperature (about 20°C) in the dark and on the RT, room temperature. 55:8 1584-1595 (2009) This small increase can be attributed to evaporation or freeze-drying processes, but we believe there is also a small positive effect due to increased turbidity of the samples after freeze-thawing cycles. A 4.0% decrease in the mean concentration was seen following storage at Ϫ20°C for up to 2 months. Clinical ChemistryMean 25(OH)-vitamin D 3 concentrations (n ϭ 8) during storage under these common laboratory conditions are presented in Fig. 1. A mean decrease of 2.3% was noted after 72 h stora...

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SummaryObjective Because vitamin D synthesis is lower in a heavily pigmented skin than in a lighter skin, the relative contribution of determinants to the vitamin D concentration might differ between ethnic groups. The aim of this study was to assess the prevalence of vitamin D deficiency and the relative contribution of vitamin D consumption and exposure to sunlight to the vitamin D concentration in a multiethnic population. Design Cross-sectional study. Modifiable, significant determinants (standardized regression coefficients) for serum 25(OH)D concentration were: consumption of fatty fish (0·160), use of vitamin D supplements (0·142), area of uncovered skin (highest category 0·136; middle category 0·028), use of tanning bed (0·103), consumption of margarine (0·093) and preference for sun (0·089). We found no significant modification of ethnic group on the effect of sunlight determinants. ConclusionOf the modifiable determinants, fatty fish and supplements are the greatest contributors to the serum 25(OH)D concentration in a multiethnic population.

As melatonin amplitude and melatonin rhythm decreased with advancing renal dysfunction, follow-up research into circadian rhythms in patients with CKD is warranted.

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