Neighborhood Walkability Index and Its Association With Indices of Childhood Obesity in Bengaluru, Karnataka

Background: The prevalence of childhood obesity is increasing in low-middle income countries like India. Built environment features such as walkability can influence weight-related outcomes but data from developing countries are scanty. Objective: To develop population level walkability index in urban Bengaluru, and examine its association with indices of childhood obesity in school children. Study Design: Nested cross-sectional study based on a cohort. Participants: Normal healthy children aged 6 to 15 years from urban schools in Bengaluru. The children were stratified into different land use classification such as residential, commercial and open space based on residential address. Methods: Anthropometric data, body composition data, measured using air displacement plethysmography. Outcomes: Walkability index derived using residential density, street connectivity and land-use mix environment variables. Results: The mean (SD) of age, body mass index (BMI), BMI zscore and percentage body fat (% Body fat) of 292 (50% boys) children were 10.8 (2.9) year, 17.4 (3.3) kg/m2, -0.27 (1.35) and 20.9% (8.8), respectively. The mean (SD) walkability index was 16.5, which was negatively associated with BMI (slope -0.25 and -0.08) and percentage body fat (slope -0.47 and -0.21) for age 5 and 10 years, respectively in children, but the effects decreased with increasing age. Conclusions: The findings of this pilot study suggest that the neighborhood walkability may be associated with the obesity indices in younger children. Future longitudinal studies are needed to understand how built environment affects health and body composition of children in India and other low-middle income countries.

Clinical performance of 3-body fat measurements in obese adolescents 15 to 18 years-old / Medidas da gordura corporal em adolescentes obesos de 15 a 18 anos

There is a lack of information about the performance and clinical use of body fat measurements in children and adolescents, particularly in obese people. Objective: the purpose of this study was to compare percentage body fat (%BF) among 3 different methodologies, including hydrostatic weighing (HW), dual energy x-ray absorptiometry (DXA) and air displacement plethysmography (ADP), in obese adolescents. Subjects: A total of 36 obese adolescents were evaluated, which 15 males (16.00 + 0.9 yrs, 105.0 + 10.9 kg, 179.9 + 7.2 cm, 34.9 + 4.4 kg/m2) and 21 females (16.5 + 1.5 yrs, 91.1 + 10.5 kg, 163.6 + 4.2 cm, 34.1 + 3.7 kg/m2). All of them performed HW, total body DXA and ADP. Results: For males, the means of %BF regarding HW, DXA and ADP were 45.7 + 9.0, 42.3 + 5.2 and 35.6 + 7.9, respectively. For females, the means of %BF were 47.7 + 6.8, 50.7 + 4 and 42.4 + 5.3, respectively. No significant difference was found between HW and DXA. In general, the %BF values provided by ADP measurements were lower than other two methods. Conclusion: There was a good agreement between DXA and HW methods, but ADP measurements can underestimate the %BF in obese adolescents.

A 4-compartment model based validation of air displacement plethysmography, dual energy X-ray absorptiometry, skinfold technique & bio-electrical impedance for measuring body fat in Indian adults.

Background & objectives: Many methods are available for measuring body fat of an individual, each having its own advantages and limitations. The primary objective of the present study was to validate body fat estimates from individual methods using the 4-compartment (4C) model as reference. The second objective was to obtain estimates of hydration of fat free mass (FFM) using the 4C model. Methods: The body fat of 39 adults (19 men and 20 women) aged 20-40 yr was estimated using air displacement plethysmography (ADP), dual energy X-ray absorptiometry (DEXA), 4-skinfold technique and bio-electrical impedance (BIA). Total body water was estimated using isotope dilution method. Results: All the methods underestimated body fat when compared to 4C model, except for DEXA and the mean difference from the reference was lowest for DEXA and ADP. The precision of the fat mass estimated from 4C model using the propagation of error was 0.25 kg, while the mean hydration factor obtained by the 4C model was found to be 0.74 ± 0.02 in the whole group of men and women. Interpretations & conclusion: The results of the present study suggest that DEXA and ADP methods can provide reasonably accurate estimates of body fat, while skinfold and bio-electrical impedance methods require the use of population specific equations.

Comparative Study of Air Displacement Plethysmography,Bioelectrical Impedance Analysis and Skinfold Thickness in the Determination of Adult Body Fat Percentage / 中国运动医学杂志

Objective The purpose of this study was to compare the correlations of air displacement plethysmography (ADP, BOD-POD) with the bioelectrical impedance analysis (BIA, including TANITA and OMRON methods) and skinfold thickness (ST). Methods Six hundred and ninety-seven healthy Shanghai adults (471 male and 226 female), aged 20-to 59 year, were enrolled in this study. Measurement of body composition derived from ADP was used as the reference method. The validity of all of the other methods was assessed by comparison against the reference by one-way anova and bivariate correlations. Results Estimation of body fat percentage by BIA were highly correlated with that by ADP in both male and female subjects (r=0.702 to 0.760, P