Reference values for bioelectrical impedance-derived phase angle: a cross-sectional study of 5,049 healthy...

Phase angle (PhA), derived from bioelectrical impedance analysis (BIA), is a noninvasive indicator of cellular integrity and body cell mass. PhA varies with age, sex, and population background; however, reference data from Latin American populations remain limited. This study therefore aimed to establish age- and sex-specific PhA reference values and percentile curves in a healthy Colombian population.

This cross-sectional study enrolled 5,049 individuals (3,113 females) aged 10-94 years. PhA was calculated directly from body resistance and reactance obtained from BIA. Smoothed centile curves and tables for the 3rd, 10th, 25th, 50th, 75th, 90th, and 97th percentiles were calculated using the Lambda-Mu-Sigma (LMS) method to develop sex- and age-specific norms.

PhA followed a non-linear pattern with age, increasing during adolescence and early adulthood, peaking around midlife (40-49 years), and declining thereafter. Males consistently exhibited higher PhA values than females across all age groups. Sex-specific percentile curves (P3-P97) were generated, illustrating the distribution of the PhA by age group and providing normative reference values for clinical and research applications.

This study provides the first age- and sex-specific phase angle reference values for a healthy Colombian population, addressing the lack of normative standards in Latin America. These population-specific curves offer clinically relevant benchmarks that may improve the assessment of cellular health and nutritional status in diverse settings.