Longitudinal concordance of body composition and anthropometric assessment by a novel smartphone application across a 12-week self-managed weight loss intervention.

Smartphone applications (SPA) now offer the ability to provide accessible in-home monitoring of relevant individual health biomarkers. Previous cross-sectional validations of similar technologies have reported acceptable accuracy with high-grade body composition assessments; this research assessed longitudinal agreement of a novel SPA across a self-managed weight loss intervention of thirty-eight participants (twenty-one males, seventeen females). Estimations of body mass (BM), body fat percentage (BF%), fat-free mass (FFM) and waist circumference (WC) from the SPA were compared with ground truth (GT) measures from a dual-energy X-ray absorptiometry scanner and expert technician measurement. Small mean differences (MD) and standard error of estimate (SEE) were observed between method deltas (ΔBM: MD = 0·12 kg, SEE = 2·82 kg; ΔBF%: MD = 0·06 %, SEE = 1·65 %; ΔFFM: MD = 0·17 kg, SEE = 1·65 kg; ΔWC: MD = 1·16 cm, SEE = 2·52 cm). Concordance correlation coefficient (CCC) assessed longitudinal agreement between the SPA and GT methods, with moderate concordance (CCC: 0·55-0·73) observed for all measures. The novel SPA may not be interchangeable with high-accuracy medical scanning methods yet offers significant benefits in cost, accessibility and user comfort, in conjunction with the ability to monitor body shape and composition estimates over time.

Obesity and visceral fat in Indonesia: An unseen epidemic? A study using iDXA and surrogate anthropometric measures.

OBJECTIVE: Indonesia's dramatic rise in chronic disease belies their relatively low obesity prevalence. This study provides normative iDXA and anthropometry measures in an Indonesian cohort. We also compare obesity prevalence determined by traditional measures. METHODS: 2623 Indonesian adults were measured by an iDXA and had waist and hip circumferences collected. Normative data were stratified by sex and age. Obesity prevalence was compared using body mass index (BMI) and body fat percentage (BF%). Specificity, sensitivity, and Youden's Index evaluated the ability of cut-off values to identify individuals with high visceral adipose tissue (VAT). RESULTS: Overweight and obese prevalence by BF% was 72 % for males and 63 % for females. BMI incorrectly categorized 40 % of obese individuals as normal/overweight. Waist circumference provided the highest Youden's Index (0.69-0.73), identifying 91 % of Indonesians with high VAT mass. CONCLUSIONS: Normative BF% and VAT mass are higher among Indonesians when compared with Caucasian populations. This highlights the rise of chronic disease is potentially due to high BF% and VAT mass. Compared with criterion iDXA BF%, obesity prevalence is severely underestimated by BMI. Measuring waist circumference is recommended in clinical settings due to its ability to identify participants with high VAT mass.

DXA reference values and anthropometric screening for visceral obesity in Western Australian adults.

Limited reference values exist for visceral adipose tissue (VAT) mass measured by DXA. The objectives of this study were to provide reference values for DXA-derived VAT mass and compare the association with anthropometry measures. The study cohort comprised 677 men and 738 women aged 18-65 years from Western Australia. Whole-body scans using a GE Lunar iDXA and anthropometry measures were collected. Reference percentile data were stratified by sex and age. Correlation analysis compared DXA-derived and anthropometry variables. Specificity, sensitivity, and Youden's Index were used to evaluate the ability of anthropometric thresholds to predict individuals with high VAT. In men, waist circumference (WC), waist-hip ratio, and waist-height ratio (WHtR) had 'high' correlations with VAT mass. In women, only WHtR was 'highly' correlated with VAT mass. Overweight thresholds for WC, along with a body mass index of 25.0 kg/m2 in women, had the highest combination of sensitivity and specificity when using anthropometry measures to identify individuals with high VAT mass. We provide the first reference data sets for DXA-derived VAT mass among Western Australians. Excessive VAT mass may be identified in men using the overweight WC threshold and in women using both the overweight BMI and WC thresholds.