1.
Adapting iron dose supplementation in pregnancy for greater effectiveness on mother and child health: protocol of the ECLIPSES randomized clinical trial.
Arija, V, Fargas, F, March, G, Abajo, S, Basora, J, Canals, J, Ribot, B, Aparicio, E, Serrat, N, Hernández-MartÃnez, C, et al
BMC pregnancy and childbirth. 2014;14:33
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Currently there is no consensus on the best practice for meeting the differing iron needs of pregnant women during the gestational period. Iron needs during pregnancy are influenced by many factors including initial iron status, genetic alterations and dietary intake, and these individual characteristics should be considered when prescribing an iron supplement. The aim of this protocol is to determine a trial design that assesses the effectiveness of iron supplementation adapted to haemoglobin levels at the start of pregnancy relative to the usually prescribed dose. Women in the first trimester will be divided into two groups based on their initial haemoglobin levels and will be randomised to receive either a low or high dose iron supplement. If this protocol is carried out, outcomes should elucidate the optimal iron supplementation dose required to promote maternal and infant health, based on initial haemoglobin levels. These findings would contribute to developing guidelines for good clinical practice.
Abstract
BACKGROUND Currently, there is no consensus regarding iron supplementation dose that is most beneficial for maternal and offspring health during gestation. Recommended iron supplementation dose does not preempt anemia in around 20% of the pregnancies, nor the risk of hemoconcentration in 15%. This deficit, or excess, of iron prejudices the mother-child wellbeing. Therefore the aims of the study are to determine the highest level of effectiveness of iron supplementation adapted to hemoglobin (Hb) levels in early pregnancy, which would be optimum for mother-child health. METHODS/DESIGN DESIGN Randomized Clinical Trial (RCT) triple-blindedSetting: 10 Primary Care Centers from Catalunya (Spain)Study subjects: 878 non-anemic pregnant women at early gestation stage, and their subsequent newborns METHODS The study is structured as a RCT with 2 strata, depending on the Hb levels before week 12 of gestation. Stratum #1: If Hb from 110 to 130 g/L, randomly assigned at week 12 to receive iron supplement of 40 or 80 mg/d. Stratum #2: If Hb >130 g/L, randomly assigned at week 12 to receive iron supplement of 40 or 20 mg/d. MEASUREMENTS In the mother: socio-economic data, clinical history, food item frequency, lifestyle and emotional state, and adherence to iron supplement prescription. Biochemical measurements include: Hb, serum ferritin, C reactive protein, cortisol, and alterations in the HFE gene (C282Y, H63D). In children: ultrasound fetal biometry, anthropometric measurements, and temperament development.Statistical analyses, using the SPSS program for Windows, will include bivariate and multivariate analyses adjusted for variables associated with the relationship under study. DISCUSSION Should conclusive outcomes be reached, the study would indicate the optimal iron supplementation dose required to promote maternal and infant health. These results would contribute towards developing guidelines for good clinical practice.
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A nutrient-wide association study on blood pressure.
Tzoulaki, I, Patel, CJ, Okamura, T, Chan, Q, Brown, IJ, Miura, K, Ueshima, H, Zhao, L, Van Horn, L, Daviglus, ML, et al
Circulation. 2012;126(21):2456-64
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Elevated blood pressure (BP) is a major risk factor for coronary heart disease and stroke. This study aims to examine the association between a wide range of nutrients and BP using a systematic nutrient-wide association study (NWAS) approach. Data obtained from the cross-sectional International Study of Macro/Micro-nutrients and Blood Pressure (INTERMAP) were analysed. All foods and drinks, including supplements, from 24-hours dietary recalls as well as analytes from urine collection were recorded. Statistical analyses were then performed for the associations of 82 nutrients from food only, 73 nutrients from foods plus supplements, as well as 3 urinary electrolytes/electrolyte ratios with systolic and diastolic BP. The study found: direct associations between alcohol and urinary sodium/potassium ratio with systolic BP; inverse associations between dietary phosphorus, magnesium, non-heme iron, thiamin, folacin, and riboflavin with systolic BP; inverse associations between dietary folacin and riboflavin with diastolic BP; and inclusion of nutrients from supplements intake decreased the associations of folacin, thiamin and riboflavin intake with BP. Authors emphasised the importance of NWAS approach to identify the complex array of nutritional correlates of systolic and diastolic BP. Findings have a potential to represent causative relations that need to be further examined in observational and interventional studies.
Abstract
BACKGROUND A nutrient-wide approach may be useful to comprehensively test and validate associations between nutrients (derived from foods and supplements) and blood pressure (BP) in an unbiased manner. METHODS AND RESULTS Data from 4680 participants aged 40 to 59 years in the cross-sectional International Study of Macro/Micronutrients and Blood Pressure (INTERMAP) were stratified randomly into training and testing sets. US National Health and Nutrition Examination Survey (NHANES) four cross-sectional cohorts (1999-2000, 2001-2002, 2003-2004, 2005-2006) were used for external validation. We performed multiple linear regression analyses associating each of 82 nutrients and 3 urine electrolytes with systolic and diastolic BP in the INTERMAP training set. Significant findings were validated in the INTERMAP testing set and further in the NHANES cohorts (false discovery rate <5% in training, P<0.05 for internal and external validation). Among the validated nutrients, alcohol and urinary sodium-to-potassium ratio were directly associated with systolic BP, and dietary phosphorus, magnesium, iron, thiamin, folacin, and riboflavin were inversely associated with systolic BP. In addition, dietary folacin and riboflavin were inversely associated with diastolic BP. The absolute effect sizes in the validation data (NHANES) ranged from 0.97 mm Hg lower systolic BP (phosphorus) to 0.39 mm Hg lower systolic BP (thiamin) per 1-SD difference in nutrient variable. Inclusion of nutrient intake from supplements in addition to foods gave similar results for some nutrients, though it attenuated the associations of folacin, thiamin, and riboflavin intake with BP. CONCLUSIONS We identified significant inverse associations between B vitamins and BP, relationships hitherto poorly investigated. Our analyses represent a systematic unbiased approach to the evaluation and validation of nutrient-BP associations.