Browsing by Author "de Lanerolle-Dias, M."

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    Develepment and validation of a BIA prediction equation for 11-13 year old Sri Lankan girls
    (Sri Lanka Medical Association, 2018) Samaranayake, D.; Dabare, H. P. M.; de Lanerolle-Dias, M.; Waidyatilaka, I.; Jayawardena, R.; Hills, A. P.; Wickremasinghe, A.R.; Lanerolle, P.; Wickramasinghe, V.P.
    INTRODUCTION AND OBJECTIVES: Population-specific measures of body composition are important in management of childhood obesity. This study aimed to develop and validate a bioelectrical impedance analysis (BIA) equation to assess total body water (TBW) and fat mass (FM) in Sri Lankan girls aged 11-13 years. METHODS: Forty-six 11-13 year-old healthy school girls were purposively selected and randomly divided into model development (n=30) and model validation (n=l6) sub-samples. Weight, height and impedance using BIA were measured. TBW was determined and FM was derived through the criterion Deuterium-dilution technique. Prediction equations for TBW and FM were developed using impedance index (heightvimpedance; cm2/Q), weight and height as independent variables. Final equations were developed combining the two sub-samples. Validity was assessed using correlation coefficients, paired-samples T-test and Bland-Altman plots. RESULTS: In the validation sample, predicted TBW and FM showed significant correlations and did not significantly differ from reference values, Final prediction equation for TBW had a R2 of 92.3% and RMSE of l.035 while FM prediction equation had a R2 of 94.3% and RMSE of 1.38. TBW predicted from new equation (19.48± 3.45kg) was not significantly different from reference TBW (19.52±3.65kg) and the two measures were significantly correlated (r=0.975, p<0.001). Similarly, predicted FM (10.41±4.39kg) was not significantly different from reference FM (10.38±4.74kg) and predicted and reference values were significantly correlated (r=0.974, p<0.001). In both prediction equations, the majority ofresiduals were within mean± l.96SD. CONCLUSION: Newly developed prediction equations for BIA assessment of TBW and FM show high validity compared to reference technique.
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    Validity of BIA prediction equations in determining the fat mass of 11-13 year old Sri Lankan girls
    (Sri Lanka Medical Association, 2018) Samaranayake, D.; Dabare, H. P. M.; de Lanerolle-Dias, M.; Waidyatilaka, I.; Jayawardena, R.; Hills, A. P.; Wickremasinghe, A.R.; Wickramasinghe, V.P.; Lanerolle, P.
    INTRODUCTION AND OBJECTIVES: Bioelectrical impedance analysis (BIA) is a simple body composition assessment method, based on use of prediction equations. Validation of equations for the specific populations is important for accurate assessment. This study aimed to determine the validity of available BIA equations in assessing the fat mass (FM) in Sri Lankan girls aged 11-13 years. METHODS: Forty-six 11-13 year-old healthy school girls were purposively selected. Weight, height and impedance using BIA were measured. Total body water was determined and FM was derived through the criterion Deuterium dilution technique. Twelve BIA prediction equations applicable to the age and sex were identified from literature. Predicted FM calculated according to each equation was compared with reference FM (assessed through isotope dilution), and validity was assessed using correlation coefficients, paired samples T-test and Bland-Altman plots. RESULTS: FM predicted by all twelve equations was significantly correlated (r>0.93, p<0.05) with reference FM. Mean (±SD) bias of predicted FM ranged from -5.32 (±1.79) kg to 5.8 (±2.1 l) kg. Only four equations predicted mean FM values that were not significantly different from the mean reference FM values, the mean bias (±SD) ranging from -0.21 (±2.23) kg to 0.06 (±l.72) kg. Of these four prediction equations, only one had a symmetric, uniform distribution of error within the ±l .96 SD limits in the Bland-Altman analysis. CONCLUSION: Most available BIA prediction equations are unsatisfactory for use in the local context. Cross validation of existing prediction equations before use or development of BIA prediction equations to suit the local populations is recommended.