Predicted vitamin D status during pregnancy in relation to offspring forearm fractures in childhood: a study from the Danish National Birth Cohort

In a prospective cohort study, the association between maternal vitamin D status during pregnancy and offspring forearm fractures during childhood and adolescence was analysed in 30 132 mother and child pairs recruited to the Danish National Birth Cohort between 1996 and 2002. Data on characteristics, dietary factors and lifestyle factors were collected on several occasions during pregnancy. We analysed the association between predicted vitamin D status, based on a subsample with 25-hydroxyvitamin D (25(OH)D) biomarker measurements (n 1497) from gestation week 25, and first-time forearm fractures among offspring between birth and end of follow-up. Diagnoses were extracted from the Danish National Patient Register. Multivariable Cox regression models using age as the underlying time scale indicated no overall association between predicted vitamin D status (based on smoking, season, dietary and supplementary vitamin D intake, tanning bed use and outdoor physical activity) in pregnancy and offspring forearm fractures. Likewise, measured 25(OH)D, tanning bed use and dietary vitamin D intake were not associated with offspring forearm fractures. In mid-pregnancy, 91 % of the women reported intake of vitamin D from dietary supplements. Offspring of women who took >10 µg/d in mid-pregnancy had a significantly increased risk for fractures compared with the reference level of zero intake (hazard ratios (HR) 1·31; 95 % CI 1·06, 1·62), but this was solely among girls (HR 1·48; 95 % CI 1·10, 2·00). Supplement use in the peri-conceptional period exhibited similar pattern, although not statistically significant. In conclusion, our data indicated no protective effect of maternal vitamin D status with respect to offspring forearm fractures

Bioimpedance index for measurement of total body water in severely malnourished children: Assessing the effect of nutritional oedema

Restoration of body composition indicates successful management of severe acute malnutrition (SAM). Bioimpedance (BI) index (height(2)/resistance) is used to predict total body water (TBW) but its performance in SAM, especially with oedema, requires further investigation

Gradient-based wind farm layout optimization with inclusion and exclusion zones

Wind farm layout optimization is usually subjected to boundary constraints of irregular shapes. The analytical expressions of these shapes are rarely available, and, consequently, it can be challenging to include them in the mathematical formulation of the problem. This paper presents a new methodology to integrate multiple disconnected and irregular domain boundaries in wind farm layout optimization problems. The method relies on the analytical gradients of the distances between wind turbine locations and boundaries, which are represented by polygons. This parameterized representation of boundary locations allows for a continuous optimization formulation. A limitation of the method, if combined with gradient-based solvers, is that wind turbines are placed within the nearest polygons when the optimization is started in order to satisfy the boundary constraints; thus the allocation of wind turbines per polygon is highly dependent on the initial guess. To overcome this and improve the quality of the solutions, two independent strategies are proposed. A case study is presented to demonstrate the applicability of the method and the proposed strategies. In this study, a wind farm layout is optimized in order to maximize the annual energy production (AEP) in a non-uniform wind resource site. The problem is constrained by the minimum distance between wind turbines and five irregular polygon boundaries, defined as inclusion zones. Initial guesses are used to instantiate the optimization problem, which is solved following three independent approaches: (1) a baseline approach that uses a gradient-based solver; (2) approach 1 combined with the relaxation of the boundaries, which allows for a better design space exploration; and (3) the application of a heuristic algorithm, “smart-start”, prior to the gradient-based optimization, improving the allocation of wind turbines within the inclusion polygons based on the potential wind resource and the available area. The results show that the relaxation of boundaries combined with a gradient-based solver achieves on average +10.2 % of AEP over the baseline, whilst the smart-start algorithm, combined with a gradient-based solver, finds on average +20.5 % of AEP with respect to the baseline and +9.4 % of AEP with respect to the relaxation strategy.</p

Guillain-Barré syndrome and adjuvanted pandemic influenza A (H1N1) 2009 vaccines: A multinational self-controlled case series in Europe

BACKGROUND: The risk of Guillain-Barré syndrome (GBS) following the United States' 1976 swine flu vaccination campaign in the USA led to enhanced active surveillance during the pandemic influenza (A(H1N1)pdm09) immunization campaign. This study aimed to estimate the risk of GBS following influenza A(H1N1)pdm09 vaccination. METHODS: A self-controlled case series (SCCS) analysis was performed in Denmark, Finland, France, Netherlands, Norway, Sweden, and the United Kingdom. Information was collected according to a common protocol and standardised procedures. Cases classified at levels 1-4a of the Brighton Collaboration case definition were included. The risk window was 42 days starting the day after vaccination. Conditional Poisson regression and pooled random effects models estimated adjusted relative incidences (RI). Pseudo likelihood and vaccinated-only methods addressed the potential contraindication for vaccination following GBS. RESULTS: Three hundred and three (303) GBS and Miller Fisher syndrome cases were included. Ninety-nine (99) were exposed to A(H1N1)pdm09 vaccination, which was most frequently adjuvanted (Pandemrix and Focetria). The unadjusted pooled RI for A(H1N1)pdm09 vaccination and GBS was 3.5 (95% Confidence Interval (CI): 2.2-5.5), based on all countries. This lowered to 2.0 (95% CI: 1.2-3.1) after adjustment for calendartime and to 1.9 (95% CI: 1.1-3.2) when we accounted for contra-indications. In a subset (Netherlands, Norway, and United Kingdom) we further adjusted for other confounders and there the RI decreased from 1.7 (adjusted for calendar month) to 1.4 (95% CI: 0.7-2.8), which is the main finding. CONCLUSION: This study illustrates the potential of conducting European collaborative vaccine safety studies. The main, fully adjusted analysis, showed that the RI of GBS was not significantly elevated after influenza A(H1N1)pdm09 vaccination (RI = 1.4 (95% CI: 0.7-2.8). Based on the upper limits of the pooled estimate we can rule out with 95% certainty that the number of excess GBS cases after influenza A(H1N1)pdm09 vaccination would be more than 3 per million vaccinated

Guillain-Barré syndrome and adjuvanted pandemic influenza A (H1N1) 2009 vaccines: A multinational self-controlled case series in Europe

Background: The risk of Guillain-Barré syndrome (GBS) following the United States' 1976 swine flu vaccination campaign in the USA led to enhanced active surveillance during the pandemic influenza (A(H1N1)pdm09) immunization campaign. This study aimed to estimate the risk