scholarly journals Cross-validation Of Whole Body Sweat Sodium Prediction Equations

2020 ◽  
Vol 52 (7S) ◽  
pp. 969-969
Author(s):  
Lindsay B. Baker ◽  
Ryan P. Nuccio ◽  
Adam J. Reimel ◽  
Shyretha Brown ◽  
Corey T. Ungaro ◽  
...  
2020 ◽  
Vol 8 (15) ◽  
Author(s):  
Lindsay B. Baker ◽  
Ryan P. Nuccio ◽  
Adam J. Reimel ◽  
Shyretha D. Brown ◽  
Corey T. Ungaro ◽  
...  

2014 ◽  
Vol 9 (5) ◽  
pp. 832-838 ◽  
Author(s):  
Christine E. Dziedzic ◽  
Megan L. Ross ◽  
Gary J. Slater ◽  
Louise M. Burke

Context:There is interest in including recommendations for the replacement of the sodium lost in sweat in individualized hydration plans for athletes.Purpose:Although the regional absorbent-patch method provides a practical approach to measuring sweat sodium losses in field conditions, there is a need to understand the variability of estimates associated with this technique.Methods:Sweat samples were collected from the forearms, chest, scapula, and thigh of 12 cyclists during 2 standardized cycling time trials in the heat and 2 in temperate conditions. Single measure analysis of sodium concentration was conducted immediately by ion-selective electrodes (ISE). A subset of 30 samples was frozen for reanalysis of sodium concentration using ISE, flame photometry (FP), and conductivity (SC).Results:Sweat samples collected in hot conditions produced higher sweat sodium concentrations than those from the temperate environment (P= .0032). A significant difference (P= .0048) in estimates of sweat sodium concentration was evident when calculated from the forearm average (mean ± 95% CL; 64 ± 12 mmol/L) compared with using a 4-site equation (70 ± 12 mmol/L). There was a high correlation between the values produced using different analytical techniques (r2= .95), but mean values were different between treatments (frozen FP, frozen SC > immediate ISE > frozen ISE;P< .0001).Conclusion:Whole-body sweat sodium concentration estimates differed depending on the number of sites included in the calculation. Environmental testing conditions should be considered in the interpretation of results. The impact of sample freezing and subsequent analytical technique was small but statistically significant. Nevertheless, when undertaken using a standardized protocol, the regional absorbent-patch method appears to be a relatively robust field test.


2005 ◽  
Vol 22 (2) ◽  
pp. 198-206 ◽  
Author(s):  
Phillip C. Usera ◽  
John T. Foley ◽  
Joonkoo Yun

The purpose of this study was to cross-validate skinfold and anthropometric measurements for individuals with Down syndrome (DS). Estimated body fat of 14 individuals with DS and 13 individuals without DS was compared between criterion measurement (BOP POD®) and three prediction equations. Correlations between criterion and field-based tests for non-DS group and DS groups ranged from .81 – .94 and .11 – .54, respectively. Root-Mean-Squared-Error was employed to examine the amount of error on the field-based measurements. A MANOVA indicated significant differences in accuracy between groups for Jackson’s equation and Lohman’s equation. Based on the results, efforts should now be directed toward developing new equations that can assess the body composition of individuals with DS in a clinically feasible way.


1992 ◽  
Vol 72 (1) ◽  
pp. 366-373 ◽  
Author(s):  
L. B. Houtkooper ◽  
S. B. Going ◽  
T. G. Lohman ◽  
A. F. Roche ◽  
M. Van Loan

The purposes of this study were to develop and cross-validate the “best” prediction equations for estimating fat-free body mass (FFB) from bioelectrical impedance in children and youth. Predictor variables included height2/resistance (RI) and RI with anthropometric data. FFB was determined from body density (underwater weighing) and body water (deuterium dilution) (FFB-DW) and from age-corrected density equations, which account for variations in FFB water and bone content. Prediction equations were developed using multiple regression analyses in the validation sample (n = 94) and cross-validated in three other samples (n = 131). R2 and standard error of the estimate (SEE) values ranged from 0.80 to 0.95 and 1.3 to 3.7 kg, respectively. The four samples were then combined to develop a recommended equation for estimating FFB from three regression models. R2 and SEE values and coefficients of variation from these regression equations ranged from 0.91 to 0.95, 2.1 to 2.9 kg, and 5.1 to 7.0%, respectively. As a result of all cross-validation analyses, we recommend the equation FFB-DW = 0.61 RI + 0.25 body weight + 1.31, with a SEE of 2.1 kg and adjusted R2 of 0.95. This study demonstrated that RI with body weight can predict FFB with good accuracy in Whites 10–19 yr old.


2017 ◽  
Vol 42 (2) ◽  
pp. 157-165 ◽  
Author(s):  
Megumi Ohta ◽  
Taishi Midorikawa ◽  
Yuki Hikihara ◽  
Yoshihisa Masuo ◽  
Shizuo Sakamoto ◽  
...  

This study examined the validity of segmental bioelectrical impedance (BI) analysis for predicting the fat-free masses (FFMs) of whole-body and body segments in children including overweight individuals. The FFM and impedance (Z) values of arms, trunk, legs, and whole body were determined using a dual-energy X-ray absorptiometry and segmental BI analyses, respectively, in 149 boys and girls aged 6 to 12 years, who were divided into model-development (n = 74), cross-validation (n = 35), and overweight (n = 40) groups. Simple regression analysis was applied to (length)2/Z (BI index) for each of the whole-body and 3 segments to develop the prediction equations of the measured FFM of the related body part. In the model-development group, the BI index of each of the 3 segments and whole body was significantly correlated to the measured FFM (R2 = 0.867–0.932, standard error of estimation = 0.18–1.44 kg (5.9%–8.7%)). There was no significant difference between the measured and predicted FFM values without systematic error. The application of each equation derived in the model-development group to the cross-validation and overweight groups did not produce significant differences between the measured and predicted FFM values and systematic errors, with an exception that the arm FFM in the overweight group was overestimated. Segmental bioelectrical impedance analysis is useful for predicting the FFM of each of whole-body and body segments in children including overweight individuals, although the application for estimating arm FFM in overweight individuals requires a certain modification.


2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Dalmo Machado ◽  
Sérgio Oikawa ◽  
Valdir Barbanti

The aim of this study was to propose and cross-validate an anthropometric model for the simultaneous estimation of fat mass (FM), bone mineral content (BMC), and lean soft tissue (LST) using DXA as the reference method. A total of 408 boys (8–18 years) were included in this sample. Whole-body FM, BMC, and LST were measured by DXA and considered as dependent variables. Independent variables included thirty-two anthropometrics measurements and maturity offset determined by the Mirwald equation. From a multivariate regression model , a matrix analysis was performed resulting in a multicomponent anthropometric model. The cross-validation was executed through the sum of squares of residuals (PRESS) method. Five anthropometric variables predicted simultaneously FM, BMC, and LST. Cross-validation parameters indicated that the new model is accurate with high values ranging from 0.94 to 0.98 and standard error of estimate ranging from 0.01 to 0.09. The newly proposed model represents an alternative to accurately assess the body composition in male pediatric ages.


2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Yemei Liu ◽  
Pei Yang ◽  
Yong Pi ◽  
Lisha Jiang ◽  
Xiao Zhong ◽  
...  

Abstract Background We aimed to construct an artificial intelligence (AI) guided identification of suspicious bone metastatic lesions from the whole-body bone scintigraphy (WBS) images by convolutional neural networks (CNNs). Methods We retrospectively collected the 99mTc-MDP WBS images with confirmed bone lesions from 3352 patients with malignancy. 14,972 bone lesions were delineated manually by physicians and annotated as benign and malignant. The lesion-based differentiating performance of the proposed network was evaluated by fivefold cross validation, and compared with the other three popular CNN architectures for medical imaging. The average sensitivity, specificity, accuracy and the area under receiver operating characteristic curve (AUC) were calculated. To delve the outcomes of this study, we conducted subgroup analyses, including lesion burden number and tumor type for the classifying ability of the CNN. Results In the fivefold cross validation, our proposed network reached the best average accuracy (81.23%) in identifying suspicious bone lesions compared with InceptionV3 (80.61%), VGG16 (81.13%) and DenseNet169 (76.71%). Additionally, the CNN model's lesion-based average sensitivity and specificity were 81.30% and 81.14%, respectively. Based on the lesion burden numbers of each image, the area under the receiver operating characteristic curve (AUC) was 0.847 in the few group (lesion number n ≤ 3), 0.838 in the medium group (n = 4–6), and 0.862 in the extensive group (n > 6). For the three major primary tumor types, the CNN-based lesion identifying AUC value was 0.870 for lung cancer, 0.900 for prostate cancer, and 0.899 for breast cancer. Conclusion The CNN model suggests potential in identifying suspicious benign and malignant bone lesions from whole-body bone scintigraphic images.


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