Mehmet MİÇOOĞULLARI, Ayşe OKAN
Eurasian Journal of Medicine and Oncology - 2026;10(4):1-13
Introduction: Smartphone-based anthropometry offers a low-cost, high-throughput approach to body composition assessment, but agreement with established field methods requires careful evaluation. Objectives: We assessed agreement between an image-based mobile application (LeanScreen within PostureScreen Mobile) and a multi-frequency, segmental bioelectrical impedance analyzer (TANITA MC-180) under standardized pre-test conditions in sedentary young adults. Methods: In a cross-sectional study, 40 participants (57.5% women; aged 18-30 years) underwent same-day assessments by both methods following strict pre-analytic controls. Outcomes assessed included waist-to-hip ratio (WHR), body fat percentage (%BF), fat-free percentage (%FF), fat body mass (FBM), fat-free mass (FFM), and basal metabolic rate (BMR). Agreement was evaluated using paired t-tests, Pearson correlations (95% confidence intervals), Bland-Altman analyses, and intraclass correlation coefficients (ICCs) with a two-way mixed-effects absolute agreement model. Results: Mean paired differences were small and not statistically significant for all outcomes. Linear associations were very high (r = 0.943-0.995; p < 0.001), with the highest for BMR (r = 0.995) and FFM (r = 0.993). Bland-Altman analyses showed small mean biases and clinically acceptable limits of agreement (LoA) for WHR, %BF, %FF, FBM, and FFM, with no evidence of proportional bias. For BMR, bias was near-zero with acceptable LoA (-74.1 to 72.7 kcal/day), but a small proportional bias was detected (beta1 = 0.068; p < 0.001). Absolute agreement was excellent, as indicated by the ICC (3,1) values: BMR (0.993), FFM (0.990), FBM (0.989), %FF (0.967), %BF (0.967), and WHR (0.938). Conclusion: Under controlled conditions, LeanScreen and BIA TANITA showed high agreement for body composition estimates, supporting their use for population-level comparisons and screening. For individual-level decisions near clinical cut points, corroboration with repeated measures or a reference method is advisable. These findings support protocolized smartphone anthropometry as a practical, field-based approach for body composition assessment in young adults, while criterion-validation studies remain necessary to determine absolute accuracy.
