Reference data for body composition parameters in normal-weight Polish adolescents: results from the population-based ADOPOLNOR study.

The aim of this study was to develop age- and sex-specific reference data for body composition parameters, including fat-free mass (FFM), body cell mass (BCM), fat mass (FM) and related indices, fat mass percentage (FM%), total body water (TBW) and muscle mass (MM) and to assess differences in these parameters between male and female adolescents. Bioelectrical impedance analysis (BIA) data were obtained from an ethnically homogeneous sub-sample of 4037 normal-weight participants selected on the basis of BMI from the total sample (2005 males and 2032 females aged 10-18 years) of the ADOPOLNOR study, a cross-sectional population-based survey conducted in western Poland. The LMS method and RefCurv version 0.4.2 software package were used to calculate centile values and plot smoothed centile curves. The results showed age-related changes in body composition parameters and a clear sexual dimorphism. From the age of 13 (for FFM) or 14 (for BCM, BCMI and MM) or throughout adolescence (for TBW and FFMI), boys had consistently higher values for these parameters than girls (p < 0.01 for each). However, they had significantly lower values for FM, FMI and FM% (1.3, 1.6 and 1.5 times lower at 18 years, respectively), indicating a lower proportion of body fat than girls (p < 0.01 for each). The centile values and curves were specific for boys and girls of all ages. Compared with other European adolescent cohorts, the data fit the normal-weight subsamples better than the population reference data.

conclusionThis study provides reference data for body composition in normal (healthy) weight Polish adolescents, providing a contextualised framework that takes into account the unique physiological and environmental factors of the region. These reference data may also be useful for other Central European adolescents. WHAT IS KNOWN: • Adolescence is a period of significant physical growth and increased susceptibility to nutritional problems due to factors such as suboptimal nutrition, unhealthy dietary choices, inadequate physical activity and psychosocial stressors related to body image concerns. • Body composition (BC) parameters, rather than BMI alone, are more effective in identifying nutritional abnormalities and health risks such as eating disorders, obesity and chronic diseases. Existing studies provide reference data for BC parameters, but often do not cover all relevant measures or specific regional populations. WHAT IS NEW: • This study provides new age- and sex-specific reference values for a comprehensive range of body composition parameters, including body cell mass (BCM), total body water (TBW) and muscle mass (MM), in addition to fat-free mass (FFM) and fat mass (FM), in a large, ethnically homogeneous, normal-weight population of Polish adolescents aged 10-18 years. • These reference values for the normalweight cohort reflect healthy adolescent growth and body composition patterns, minimising bias from abnormal weight status. In addition, they can be applied to other Central European adolescent populations.