Inflammation Adjustment by Two Methods Decreases the Estimated Prevalence of Zinc Deficiency in Malawi.

Serum zinc concentration (SZC) is used widely to assess population-level zinc status. Its concentration decreases during inflammatory responses, which can affect the interpretation of the results. This study aimed to re-estimate the prevalence of zinc deficiency in Malawi based on the 2015-2016 Malawi Micronutrient Survey (MNS) data, by adjusting SZC measures with markers of inflammation. SZC and inflammation data from 2760 participants were analysed. Adjustments were made using: (1) The Internal Correction Factor (ICF) method which used geometric means, and (2) The Biomarkers Reflecting Inflammation and Nutritional Determinants of Anemia (BRINDA) method, which used linear regression. Mean SZC values increased significantly when adjustments were made by either ICF or BRINDA (p < 0.001). The national prevalence of zinc deficiency decreased from 62% to 59%, after ICF adjustment, and to 52% after BRINDA adjustment. ICF and BRINDA values of SZC were highly correlated (p < 0.001, r = 0.99), but a Bland-Altman plot showed a lack of agreement between the two methods (bias of 2.07 µg/dL). There was no association between the adjusted SZC and stunting, which is a proxy indicator for zinc deficiency. Inflammation adjustment of SZC, using ICF or BRINDA, produces lower estimates of zinc deficiency prevalence, but the lack of agreement between the adjustment methods warrants further research. Furthermore, the lack of association between SZC and stunting highlights the need to explore other biomarkers and proxies of population zinc assessment. This study demonstrates the importance of considering inflammatory confounders when reporting SZC, to ensure accuracy and to support policy decision making

Joint modelling of multivariate longitudinal clinical laboratory safety outcomes, concomitant medication and clinical adverse events: application to artemisinin-based treatment during pregnancy clinical trial

Background In drug trials, clinical adverse events (AEs), concomitant medication and laboratory safety outcomes are repeatedly collected to support drug safety evidence. Despite the potential correlation of these outcomes, they are typically analysed separately, potentially leading to misinformation and inefficient estimates due to partial assessment of safety data. Using joint modelling, we investigated whether clinical AEs vary by treatment and how laboratory outcomes (alanine amino-transferase, total bilirubin) and concomitant medication are associated with clinical AEs over time following artemisinin-based antimalarial therapy. Methods We used data from a trial of artemisinin-based treatments for malaria during pregnancy that randomized 870 women to receive artemether-lumefantrine (AL), amodiaquine-artesunate (ASAQ) and dihydroartemisinin-piperaquine (DHAPQ). We fitted a joint model containing four sub-models from four outcomes: longitudinal sub-model for alanine aminotransferase, longitudinal sub-model for total bilirubin, Poisson sub-model for concomitant medication and Poisson sub-model for clinical AEs. Since the clinical AEs was our primary outcome, the longitudinal sub-models and concomitant medication sub-model were linked to the clinical AEs sub-model via current value and random effects association structures respectively. We fitted a conventional Poisson model for clinical AEs to assess if the effect of treatment on clinical AEs (i.e. incidence rate ratio (IRR)) estimates differed between the conventional Poisson and the joint models, where AL was reference treatment.ResultsOut of the 870 women, 564 (65%) experienced at least one AE. Using joint model, AEs were associated with the concomitant medication (log IRR 1.7487; 95% CI: 1.5471, 1.9503; p ConclusionWe demonstrated that although the AEs did not vary across the treatments, the joint model yielded efficient AE incidence estimates compared to the Poisson model. The joint model showed a positive relationship between the AEs and concomitant medication but not with laboratory outcomes. Trial registration ClinicalTrials.gov: NCT00852423

The choice of reference chart affects the strength of the association between malaria in pregnancy and small for gestational age: an individual participant data meta-analysis comparing the Intergrowth-21 with a Tanzanian birthweight chart

Background: The prevalence of small for gestational age (SGA) may vary depending on the chosen weight-for-gestational-age reference chart. An individual participant data meta-analysis was conducted to assess the implications of using a local reference (STOPPAM) instead of a universal reference (Intergrowth-21) on the association between malaria in pregnancy and SGA. Methods: Individual participant data of 6,236 newborns were pooled from seven conveniently identified studies conducted in Tanzania and Malawi from 2003–2018 with data on malaria in pregnancy, birthweight, and ultrasound estimated gestational age. Mixed-effects regression models were used to compare the association between malaria in pregnancy and SGA when using the STOPPAM and the Intergrowth-21 references, respectively. Results: The 10th percentile for birthweights-for-gestational age was lower for STOPPAM than for Intergrowth-21, leading to a prevalence of SGASTOPPAM of 14.2% and SGAIG21 of 18.0%, p < 0.001. The association between malaria in pregnancy and SGA was stronger for STOPPAM (adjusted odds ratio (aOR) 1.30 [1.09–1.56], p < 0.01) than for Intergrowth-21 (aOR 1.19 [1.00–1.40], p = 0.04), particularly among paucigravidae (SGASTOPPAM aOR 1.36 [1.09–1.71], p < 0.01 vs SGAIG21 aOR 1.21 [0.97–1.50], p = 0.08). Conclusions: The prevalence of SGA may be overestimated and the impact of malaria in pregnancy underestimated when using Intergrowth-21. Comparing local reference charts to global references when assessing and interpreting the impact of malaria in pregnancy may be appropriate

Number of repeating digits in base b expansion of fractions

Educação Superior::Ciências Exatas e da Terra::MatemáticaIn base 10 the fraction 1/3 has 1 repeating digit, 3, while 1/7 has 6 repeating digits: {1,4,2,8,5,7}. This plot shows the number of repeating digits in the base b representation of a fraction with a specified numerator and with denominators from 1 up to a specified size for bases b=2 to a specified siz

Equal InCircles along a line

Japanese mathematics flourished during Edo period 1603-1867 and was depicted on wooden tablets called Sangaku. There is a rich history of geometric theorems and problems recorded on these tablets. Consider the incircle C of radius r of any triangle (each side of the triangle is tangent to the circle) and the extended line L along one side of the triangle. Construct a triangle with base common to L and an incircle of radius r on either side of the triangle. Continue this process on either side of the group of triangles until n triangles are constructed, n>2. The incircle of the triangle formed by the combination of any a, 2≤

Prime walk

Take a prime walk in 2 or 3 dimensions by walking straight ahead for each non-prime step and turning in the next direction out of a selected set of directions for each prime step. The path is colored various hues along the way from beginning to end. You can select the number of possible directions and choose permutations of the directions when there are less than 9. If 3D is selected so that a three-dimensional representation is presented then the "3D method for directions" pull-down menu allows for a choice of two ways of determining the set of possible directions in 3D. Usually the default of "SpringEmbedding" is the best choice, but for some bases, such as 9, 15 and 21 "SpringElectricalEmbedding" gives a better representation. When the base is less than 9 then permutations of the canonical ordering of the directions can be made with the "permutation of directions" slider. Choosing different permuations or directions when the number of steps is more than 10000 will take longer to render

Generalized digit parity

This Demonstration shows fractal patterns in the generalized digit parity of natural numbers. The concept of binary parity can be generalized for non-negative integers n and for all positive integer bases b>2 by the definition: sum of digits of n in base b(mod b). Plotting these results in two dimensions (n,b) produces beautiful fractal patterns. This Demonstration explores a subset of these patterns by allowing the setting of starting values and ranges for n and bEducação Superior::Ciências Exatas e da Terra::Matemátic

Square matrix permutations

The demonstration is an interactive display that illustrates the connection between the permutations of square matrices and the Pisano sequence which is related to Fibonacci numbers. This approach is appealing to both kinaesthetic and visual learners. The initial discovery of the connection was first reported in: N. Patson 2007, Pisano period and permutations of n × n matrices, Australian Mathematical Society Gazette, Vol 34, Number 1, pp 39-43

Möbius Mu Function Walk

Take a walk guided by the Möbius function. Choose one of five sets of rules. The path is colored various hues to help distinguish overlapping parts. Choose the number of possible turns that could be taken at each step of the journey