Human body surface area scales linearly with height and mass and is largely independent of body composition: A 3D laser scanning and body composition study

Indexing Estimates of GFR to Body Surface Area in Low-Resource Settings With a High Burden of Malnutrition: Evidence From Guatemala

Background: Creatinine and cystatin C concentrations are commonly used to estimate glomerular filtration rate (eGFR) in clinical practice and epidemiological studies. To estimate the influence of different body composition measures on eGFR from creatinine and cystatin C blood concentrations, we compared the associations of different anthropometric and body composition measures with eGFR derived from creatinine (eGFR creat ) and cystatin C (eGFR cystC ) blood concentrations. Methods: In a population-based cohort study among 4,305 children aged 6.0 years (95% range 5.7-8.0), we measured weight and height and calculated body mass index (BMI) and body surface area (BSA), and lean and fat mass using dual-energy X-ray absorptiometry. At the same age, we measured creatinine and cystatin C blood concentrations and estimated the GFR. Results: Correlation between eGFR based on creatinine and cystatin C concentrations was r = 0.40 ( p value cystC but not with eGFR creat . Higher BSA was associated with higher eGFR creat and lower eGFR cystC ( p value creat but not with eGFR cystC . Conclusion: Our findings suggest that both eGFR creat and eGFR cystC are influenced by BMI and BSA. eGFR creat is more strongly influenced by body composition than eGFR cystC .

Dilatation of the Ascending Aorta in Turner Syndrome: Influence of Bicuspid Aortic Valve Morphology and Body Composition

Utility of Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) Equations in Obese Diabetic Individuals Before and After Weight Loss

The Importance of Considering Metabolism When Indexing the GFR

An Endorsement of the Removal of Race From GFR Estimation Equations: A Position Statement From the National Kidney Foundation Kidney Disease Outcomes Quality Initiative

Should Estimated Glomerular Filtration Rate Be Adjusted for Race?

In Reply to ‘The Importance of Considering Metabolism When Indexing the GFR’

To examine the differences arising from indexing resting metabolic rate (RMR) against fat-free mass (FFM) determined using two-, three- and four-compartment body composition models. All RMR and body composition measurements were conducted on the same day for each subject following compliance with premeasurement protocols. Data were generated from measurements on 104 males (age 32.1+/-12.1 y (mean+/-s.d.); body mass 81.15+/-12.85 kg; height 179.5+/-6.5 cm; body fat 20.6+/-7.6%). Body density (BD), total body water (TBW) and bone mineral mass (BMM) were measured by hydrodensitometry, deuterium dilution and dual energy X-ray absorptiometry (DXA), respectively. These measures were used to determine two (hydrodensitometry: BD; hydrometry: TBW)-, three (BD and TBW)- and four- compartment (BD, TBW and BMM) FFM values. DXA also provided three compartment derived FFM values. RMR was measured using open circuit indirect calorimetry. Three (body fat group: lean, moderate, high) x five (body composition determination: hydrodensitometry, hydrometry, three-compartment, DXA, four-compartment) ANOVAs were conducted on FFM and RMR kJ.kg FFM(-1).d(-1). Within-group comparisons revealed that hydrodensitometry and DXA were associated with significant (P<0.001) overestimations and underestimations of FFM and RMR kJ.kg FFM(-1).d(-1), respectively, compared with four-compartment-derived criterion values. A significant interaction (P<0.001) resulted from DXA's greater deviations from criterion values in lean subjects. While hydrometric means were not significantly (P> or =0.68) different from criterion values intraindividual differences were large (FFM: -1.5 to 2.9 kg; RMR: -6.0 to 3.2 kJ.kg FFM(-1).d(-1)). The relationship between RMR kJ.kg FFM(-1).d(-1) and exercise status would best be investigated using three (BD, TBW)- or four (BD, TBW, BMM)-compartment body composition models to determine FFM. Other models either significantly underestimate indexed RMR (hydrodensitometry, DXA) or display large intraindividual differences (hydrometry) compared with four-compartment derived criterion values. Australian Research Council (small grants scheme).

BackgroundFat Free Mass (FFM) is an important and essential indicator in various sports populations, since greater muscle and bone mass generates greater strength, endurance and speed in athletes.ObjectiveThe purpose of the study was to validate Body Surface Area (BSA) as an anthropometric indicator to estimate FFM in young basketball players.MethodsA descriptive cross-sectional study was carried out in 105 male basketball players of the Brazilian Basketball Confederation of Sao Paulo (Campinas), Brazil. The age range was 11 to 15 years. Weight and height were evaluated. BSA, body mass index (BMI) and maturity status (MS) were calculated. Total body scanning was performed by dual X-ray absorptiometry (DXA). The components were extracted: Fat mass (FM), Fat free mass (FFM), percentage of fat mass (%FM) and bone mass (BM). The data were analyzed using the correlation coefficient of concordance (CCC) in terms of precision and accuracy.ResultsThree regression equations were generated: equation 1 had age and body weight as predictors [FFM= -30.059+(2.926*age)+(0.625*Weight)] (R2 = 92%, precision = 0.96 and accuracy = 0.99), equation 2 used age and BSA [FFM=-45.719+(1.934*age)+(39.388*BSA)] (R2 = 94%, precision = 0.97 and accuracy = 0.99) and equation 3 was based on APHV and BSA [FFM=-15.284+(1.765*APHV)+(37.610*(BSA)] (R2 = 94%, precision = 0.96 and accuracy = 0.99).ConclusionsThe results suggest the use of anthropometric equation using decimal age and BSA to estimate FFM in young basketball players. This new method developed can be used to design, evaluate and control training programs and monitor the weight status of athletes.

Background and Aims Glomerular filtration rate (GFR) is the main index of renal function in clinical practice and research. GFR is used to assess renal function at fixed points and to check the evolution of renal disease evolution over time, the response of the kidneys to diverse treatments, to adjust potentially toxic drugs and to establish risk for cardiovascular events and disease progression. Renal function is usually adjusted for body surface area (BSA) by Dubois-Dubois formula, a rudimentary and inexact method to estimate BSA. Also, the indexation of GFR for BSA was based on the hypothesis of the proportionality between metabolic rate and BSA, published at the end of 19th century. This assumption has no scientific basis since metabolic rate is linked to nutritional and maintenance fluid requirements rather that weight or BSA. Later, GFR started to be reported adjusted to a “standard” body surface area of 1.73 m2. Despite these limitations, indexing GFR by the Dubois–Dubois formula is widely used. Additionally, adjusting renal function for BSA has very little impact on GFR in individuals of normal body size, but a large impact by artificially adding or subtracting renal function in patients with extreme body surface areas very different (higher or lower) from 1.73 m2. Furthermore, the adjustment for BSA does not take gender into account, thus ignoring the differences between men and women in this regard. However, the difference between adjusted and unadjusted GFR by gender has been seldom evaluated in a wide cohort. The present study aimed to evaluate the impact of the adjustment of GFR by BSA in our whole cohort of patients with and without CKD. Method We evaluated renal function by the plasma clearance of iohexol using dried blood spot technique (iohexol-DBS) at the Renal Function Laboratory of the University of La Laguna in 2389 patients with CKD of diverse aetiologies. We reported measured GFR at Hospital Universitario de Canarias as unadjusted in ml/min. Then, we adjusted the result by applying the formula (GFR unadjusted = GFR adjusted × BSA/1.73). BSA was calculated by DuBois and DuBois formula (BSA = 0.007184 × Weight0.425 × Height0.725). We then analyzed the difference in adjusted GFR compared to the unadjusted GFR by gender. We analyzed the number of cases with a percent difference between both values using a cut-off of 15%. In addition, we analyzed subgroups of men and women with extreme BSAs far from the 1.73 m2 standard: &amp;gt;2.00 and &amp;lt;1.50, to evaluate how adjustment of GFR by BSA affects this subpopulation of patients. Results Of the total of 2389 patients, 1561 (65%) were men and 827 (35%) women: 20% had advanced CKD (pre-dialysis), 27% CKD of diverse causes, 19% diabetes, 9% were living kidney donors and 15% kidney transplant recipients and 10% had other causes i.e. non-renal transplantation, cirrhosis, heart failure, etc. In men the mean unadjusted GFR was 61 ± xx ml/min in men, while the BSA-adjusted GFR was 53 ± xx ml/min/1.73 m2. However, in women the adjusted and unadjusted GFR were similar 59 ± xx ml/min or ml/min/1.73 m2. Around half of the men (n = 743, 47%) while only 10% of women (80 of 827) BSA adjustment led to a reduction in GFR with differences &amp;lt; −15% between unadjusted and BSA-adjusted GFR. In men, the average reduction of GFR with BSA adjustment was –24%, distributed as follows: 34% from −15 to −20%; 45% from −20 to −30% and 21% greater than −30%. Only 5 of 1561 male while 53 of 827 women (6%) had an increment &amp;gt; 15%. Conclusion The BSA adjustment differentially penalizes male subjects with and without CKD, particularly in those with larger height and/or weight, both variables of the Dobois-Dubois formula used to adjust the GFR, with a false mean reduction of 24% of GFR observed in almost half of the cases. However, this does not occur in women because the latter's body surface area is more similar to the 1.73 m2 standard. Adjustment for renal function should be abandoned because there is no scientific basis for it, and it may overestimate the degree of renal function in almost half of male patients.

Association of body surface area with fat mass, free fat mass and total weight in healthy individuals, and implications for the dosage of cytotoxic drugs.

Measuring body composition and regional fat mass accurately

Interpretation of whole body dual energy X-ray absorptiometry measures in children: comparison with peripheral quantitative computed tomography

Calculation of cytostatic dose is typically based on body surface area (BSA) regardless of body composition. The aim of this study was to assess the discrepancy between BSA and low fat-free mass (FFM) by investigating the prevalence of low FFM with regard to BSA in 630 cancer patients. First, BSA was calculated according to DuBois and DuBois. Patients were divided into 6 categories with respect to their BSA. Each BSA category was further divided into 3 groups according to FFM: low (<−1 SD of mean FFM), normal (−0.99 and 0.99 SD of mean FFM) or high (>1 SD of mean FFM), which was derived through bioelectric impedance analysis. FFM was reduced in 15.7% of patients, 69% had normal and 15.2% had high FFM. In patients with low FFM (i.e., more than-1 SD lower than the mean FFM within their BSA group), body mass index and fatigue were higher whereas functional status was reduced. Moreover, in the subcohort of patients receiving chemotherapy, absolute FFM [Hazard ratio (HR) = 0.970, P = 0.026] as well as the allocation to the low FFM group (HR = 1.644, P = 0.025) emerged as predictors of increased 1-yr mortality. In conclusion, there was a large discrepancy between FFM and BSA. Particularly women were affected by low FFM.