Kuen-Chang Hsieh

The novel application of artificial neural network on bioelectrical impedance analysis to assess the body composition in elderly

BackgroundThis study aims to improve accuracy of Bioelectrical Impedance Analysis (BIA) prediction equations for estimating fat free mass (FFM) of the elderly by using non-linear Back Propagation Artificial Neural Network (BP-ANN) model and to compare the predictive accuracy with the linear regression model by using energy dual X-ray absorptiometry (DXA) as reference method.MethodsA total of 88 Taiwanese elderly adults were recruited in this study as subjects. Linear regression equations and BP-ANN prediction equation were developed using impedances and other anthropometrics for predicting the reference FFM measured by DXA (FFMDXA) in 36 male and 26 female Taiwanese elderly adults. The FFM estimated by BIA prediction equations using traditional linear regression model (FFMLR) and BP-ANN model (FFMANN) were compared to the FFMDXA. The measuring results of an additional 26 elderly adults were used to validate than accuracy of the predictive models.ResultsThe results showed the significant predictors were impedance, gender, age, height and weight in developed FFMLR linear model (LR) for predicting FFM (coefficient of determination, r2 = 0.940; standard error of estimate (SEE) = 2.729 kg; root mean square error (RMSE) = 2.571kg, P < 0.001). The above predictors were set as the variables of the input layer by using five neurons in the BP-ANN model (r2 = 0.987 with a SD = 1.192 kg and relatively lower RMSE = 1.183 kg), which had greater (improved) accuracy for estimating FFM when compared with linear model. The results showed a better agreement existed between FFMANN and FFMDXA than that between FFMLR and FFMDXA.ConclusionWhen compared the performance of developed prediction equations for estimating reference FFMDXA, the linear model has lower r2 with a larger SD in predictive results than that of BP-ANN model, which indicated ANN model is more suitable for estimating FFM.

Cross-mode bioelectrical impedance analysis in a standing position for estimating fat-free mass validated against dual-energy x-ray absorptiometry.

Bioelectrical impedance analysis (BIA) is commonly used to assess body composition. Cross-mode (left hand to right foot, Z(CR)) BIA presumably uses the longest current path in the human body, which may generate better results when estimating fat-free mass (FFM). We compared the cross-mode with the hand-to-foot mode (right hand to right foot, Z(HF)) using dual-energy x-ray absorptiometry (DXA) as the reference. We hypothesized that when comparing anthropometric parameters using stepwise regression analysis, the impedance value from the cross-mode analysis would have better prediction accuracy than that from the hand-to-foot mode analysis. We studied 264 men and 232 women (mean ages, 32.19 ± 14.95 and 34.51 ± 14.96 years, respectively; mean body mass indexes, 24.54 ± 3.74 and 23.44 ± 4.61 kg/m2, respectively). The DXA-measured FFMs in men and women were 58.85 ± 8.15 and 40.48 ± 5.64 kg, respectively. Multiple stepwise linear regression analyses were performed to construct sex-specific FFM equations. The correlations of FFM measured by DXA vs. FFM from hand-to-foot mode and estimated FFM by cross-mode were 0.85 and 0.86 in women, with standard errors of estimate of 2.96 and 2.92 kg, respectively. In men, they were 0.91 and 0.91, with standard errors of the estimates of 3.34 and 3.48 kg, respectively. Bland-Altman plots showed limits of agreement of -6.78 to 6.78 kg for FFM from hand-to-foot mode and -7.06 to 7.06 kg for estimated FFM by cross-mode for men, and -5.91 to 5.91 and -5.84 to 5.84 kg, respectively, for women. Paired t tests showed no significant differences between the 2 modes (P > .05). Hence, cross-mode BIA appears to represent a reasonable and practical application for assessing FFM in Chinese populations.

Validation of two portable bioelectrical impedance analyses for the assessment of body composition in school age children

Background Bioelectrical impedance analysis (BIA) is a convenient and child-friendly method for longitudinal analysis of changes in body composition. However, most validation studies of BIA have been performed on adult Caucasians. The present cross-sectional study investigated the validity of two portable BIA devices, the Inbody 230 (BIA8MF) and the Tanita BC-418 (BIA8SF), in healthy Taiwanese children. Methods Children aged 7–12 years (72 boys and 78 girls) were recruited. Body composition was measured by the BIA8SF and the BIA8MF. Dual X-ray absorptiometry (DXA) was used as the reference method. Results There were strong linear correlations in body composition measurements between the BIA8SF and DXA and between the BIA8MF and DXA. Both BIAs underestimated fat mass (FM) and percentage body fat (%BF) relative to DXA in both genders The degree of agreement in lean body mass (LBM), FM, and %BF estimates was higher between BIA8MF and DXA than between BIA8SF and DXA. The Lin’s concordance correlation coefficient (ρc) for LBM8MF met the criteria of substantial to perfect agreement whereas the ρc for FM8MF met the criteria of fair to substantial agreement. Bland-Altman analysis showed a clinically acceptable agreement between LBM measures by BIA8MF and DXA. The limit of agreement in %BF estimation by BIA and DXA were wide and the errors were clinically important. For the estimation of ALM, BIA8SF and BIA8MF both provided poor accuracy. Conclusions For all children, LBM measures were precise and accurate using the BIA8MF whereas clinically significant errors occurred in FM and %BF estimates. Both BIAs underestimated FM and %BF in children. Thus, the body composition results obtained using the inbuilt equations of the BIA8SF and BIA8MF should be interpreted with caution, and high quality validation studies for specific subgroups of children are required prior to field research.

The validity and accuracy in foot-to-foot bioelectrical impedance analysis measuring models referenced by dual-energy X-ray absorptiometry in body composition in standing position

The criterion validity of foot-to-foot (Z F-F ) by bioelectrical impedance analysis (BIA) in a standing position measuring models was referenced by dual-energy X-ray absorptiometry (DEXA) and hand-to-foot (Z H-F ). In order to cross match analysis, both of the Z H-F and Z F-F measuring by BIA were performed in the same event to the identical subject, simultaneously. 105 males (7 to 70 years old) and 108 females (7 to 67 years old) were measured by BIA and DEXA. The Z F-F value was 481.85 ± 63.37 ohm in male and 554.35 ± 74.97 ohm in female. The Z H-F value was 586.82 ± 81.56 ohm in male and 703.28 ± 97.70 ohm in female. Regression equations for Z F-F and Z H-F were Z F-F = 0.926 Z H-F - 63.093, (R = 0.85) in male and Z F-F = 0.909 Z H-F - 86.673 (R = 0.86) in female. The fat free mass (FFM), measured by DEXA was 49.42 ± 10.03 kg in male and 34.52 ± 4.45 kg in female. The correlation (R value) for Z F-F to DEXA was 0.93 and for Z H-F was 0.96 in male, and 0.85 and 0.87 in female, respectively. The high correlation between Z H-F and Z F-F vs. whole body DEXA in both male and female renders it applicable to develop the clinical instrument by foot-to-foot measuring models by BIA in standing position. Key words : Hand-to-foot bioimpedance analysis, foot-to-foot bioimpednace analysis, relative body fat (BF), fat free mass (FFM), dual-energy X-ray absorptiometry (DEXA).

MIDDLE-AGED SUBJECTS WITH HABITUAL LOW-SPEED CYCLING EXERCISE HAVE GREATER MONONUCLEAR CELL RESPONSIVENESS AGAINST HUMAN HEPATITIS B VIRUS SURFACE ANTIGEN

SUMMARY Background: Whether middle-aged people with habitual cycling exercise (HCE) at low intensity in the morning have higher immunity against hepatitis B virus than sedentary controls (SCs) is a health issue in the elderly. Methods: Conditioned media (CM) were prepared by stimulating isolated human peripheral blood mononu- clear cells (MNC) with phytohemagglutinin (PHA) or assessment of their inhibitory effects on hepatitis B surface antigen expression in human hepatoma Hep3B cells. Results: With the percent of maximal oxygen uptake at about 45.52% and percent of maximal heart rate at about 68.58% during a cycling exercise program in the present study, we considered HCE as an aerobic and a low to mod- erate exercise for the elderly. The concentrations of secreted cytokines such as interferon gamma, tumor necro- sis factor α and interferon alpha were higher in the MNC-CM from the HCE group than from the SC group. The inhibitory rates of MNC-CM of the HCE group against hepatitis B surface antigen expression were higher than that of the SC group. In the same stimulating concentration of PHA (10 μg/mL), the relative hepatitis B surface anti- gen expression in MNC-CM of the HCE group was 64.7% versus 81.5% of the SC group. The reduction in inhibitory rates in cytokine neutralization experiments suggests crucial roles of these cytokines for the inhibitory effect of HCE-PHA-MNC-CM against hepatitis B surface antigen expression. Conclusion: The results reveal that the immune response of MNC, which are stimulated by PHA to suppress hep- atitis B surface antigen expression, is greater in middle-aged subjects with low-speed HCE than in sedentary subjects. (International Journal of Gerontology 2010; 4(2): 82-88)

Comparison of Different Measurement Equations for Body Composition Estimation in Male Athletes

The purpose of this study was to compare the validity between three established prediction equations and our prediction equation referenced by DEXA (Dual-energy X-ray absorptiometry) on fat free mass (FFM) in Taiwan male soccer players. Methods: Twenty seven elite Taiwan soccer players were estimated by bioelectrical impedance analysis (BIA) and DEXA. The R2 value of FFM estimated by our prediction equation and DEXA was 0.918. The R2 values of FFM estimated by three different stablished prediction equations and DEXA were 0.725, 0.794 and 0.868, respectively. In summary, our specialized prediction equation shown the highest correlation among equations suggestion evaluating athletic body composition should use appropriate prediction equation rather than that of for general people.

Estimation of segmental fat free mass in Taiwanese elderly females by bioelectrical impedance analysis with new mathematical model

The aim of this study was to develop new predictive equations for evaluating the fat free mass (FFM) of body segments in Taiwan elderly female. Modified bioelectrical impedance analysis with eight electrodes (BIA 8 ) and referenced standard dual-energy x-ray absorptiometry (DXA) was applied to measure the segment body composition. The criterion of FFM values determined by DXA and predictive values by BIA were compared. After analyzing by linear regression, we obtained the FFM predictive equations by BIA 8 for segments. The Bland-Altman analysis was used to evaluate the differences of mean estimated segmental FFM from equations by BIA 8 and by DXA. The correlation coefficient (R) of FFM between values measured by DXA and estimated by BIA 8 in whole body, lower limbs, upper limbs and trunk were 0.89, 0.64, 0.60 and 0.81, respectively, and the differences of mean FFM were 2.39, 0.94, 0.27 and 2.02 kg, respectively. With the relatively higher weight coefficient of H 2 /Z (H, height; Z, impedance values), it plays a critical role in our new predictive equation. For the greater performance in prediction of fat free mass by our new BIA model, it provides potential in monitoring the body composition in female elderly by greater precision way. Key words: Dual-energy x-ray absorptiometry (DXA), prediction equation, body composition.

Hand-to-Hand Model for Bioelectrical Impedance Analysis to Estimate Fat Free Mass in a Healthy Population

This study aimed to establish a hand-to-hand (HH) model for bioelectrical impedance analysis (BIA) fat free mass (FFM) estimation by comparing with a standing position hand-to-foot (HF) BIA model and dual energy X-ray absorptiometry (DXA); we also verified the reliability of the newly developed model. A total of 704 healthy Chinese individuals (403 men and 301 women) participated. FFM (FFMDXA) reference variables were measured using DXA and segmental BIA. Further, regression analysis, Bland–Altman plots, and cross-validation (2/3 participants as the modeling group, 1/3 as the validation group; three turns were repeated for validation grouping) were conducted to compare tests of agreement with FFMDXA reference variables. In male participants, the hand-to-hand BIA model estimation equation was calculated as follows: FFMmHH = 0.537 h2/ZHH − 0.126 year + 0.217 weight + 18.235 (r2 = 0.919, standard estimate of error (SEE) = 2.164 kg, n = 269). The mean validated correlation coefficients and limits of agreement (LOAs) of the Bland–Altman analysis of the calculated values for FFMmHH and FFMDXA were 0.958 and −4.369–4.343 kg, respectively, for hand-to-foot BIA model measurements for men; the FFM (FFMmHF) and FFMDXA were 0.958 and −4.356–4.375 kg, respectively. The hand-to-hand BIA model estimating equation for female participants was FFMFHH = 0.615 h2/ZHH − 0.144 year + 0.132 weight + 16.507 (r2 = 0.870, SEE = 1.884 kg, n = 201); the three mean validated correlation coefficient and LOA for the hand-to-foot BIA model measurements for female participants (FFMFHH and FFMDXA) were 0.929 and −3.880–3.886 kg, respectively. The FFMHF and FFMDXA were 0.942 and −3.511–3.489 kg, respectively. The results of both hand-to-hand and hand-to-foot BIA models demonstrated similar reliability, and the hand-to-hand BIA models are practical for assessing FFM.

Discrepancies between leg-to-leg bioelectrical Impedance analysis and computerized tomography in abdominal visceral fat measurement

The aim of this study was to evaluate leg-to-leg bioelectrical impedance analysis (LBIA) using a four-contact electrode system for measuring abdominal visceral fat area (VFA). The present study recruited 381 (240 male and 141 female) Chinese participants to compare VFA measurements estimated by a standing LBIA system (VFALBIA) with computerized tomography (CT) scanned at the L4-L5 vertebrae (VFACT). The total mean body mass index (BMI) was 24.7 ± 4.2 kg/m2. Correlation analysis, regression analysis, Bland-Altman plot, and paired sample t-tests were used to analyze the accuracy of the VFALBIA. For the total subjects, the regression line was VFALBIA = 0.698 VFACT + 29.521, (correlation coefficient (r) = 0.789, standard estimate of error (SEE) = 24.470 cm2, p < 0.001), Lin’s correlation coefficient (CCC) was 0.785; and the limit of agreement (LOA; mean difference ±2 standard deviation) ranged from −43.950 to 67.951 cm2, LOA% (given as a percentage of mean value measured by the CT) was 48.2%. VFALBIA and VFACT showed significant difference (p < 0.001). Collectively, the current study indicates that LBIA has limited potential to accurately estimate visceral fat in a clinical setting.

Comparison of Standing Posture Bioelectrical Impedance Analysis with DXA for Body Composition in a Large, Healthy Chinese Population

Bioelectrical impedance analysis (BIA) is a common method for assessing body composition in research and clinical trials. BIA is convenient but when compared with other reference methods, the results have been inconclusive. The level of obesity degree in subjects is considered to be an important factor affecting the accuracy of the measurements. A total of 711 participants were recruited in Taiwan and were sub-grouped by gender and levels of adiposity. Regression analysis and Bland-Altman analysis were used to evaluate the agreement of the measured body fat percentage (BF%) between BIA and DXA. The BF% measured by the DXA and BIA methods (Tanita BC-418) were expressed as BF%DXA and BF%BIA8, respectively. A one-way ANOVA was used to test the differences in BF% measurements by gender and levels of adiposity. The estimated BF%BIA8 and BF%DXA in the all subjects, male and female groups were all highly correlated (r = 0.934, 0.901, 0.916, all P< 0.001). The average estimated BF%BIA8 (22.54 ± 9.48%) was significantly lower than the average BF%DXA (26.26 ± 11.18%). The BF%BIA8 was overestimated in the male subgroup (BF%DXA< 15%), compared to BF%DXA by 0.45%, respectively. In the other subgroups, the BF%BIA8 values were all underestimated. Standing BIA estimating body fat percentage in Chinese participants have a high correlation, but underestimated on normal and high obesity degree in both male and female subjects.