Body composition references, sarcopenia cutoffs, and prevalence in youth using bioelectrical impedance analysis.

Muscle-related parameters increased during puberty in both sexes, with a more pronounced increase in males, followed by a plateau or gradual increase after adolescence.

• Parameters assessed included fat-free mass, fat-free mass index, appendicular skeletal muscle mass (ASM), and skeletal muscle mass index (SMI).
• The study population consisted of 1451 youth aged 10-25 years from a nationwide survey.
• The increase in muscle-related parameters was more pronounced in males than females.
• Reference values were established using the least mean squares (LMS) method, which estimates age-specific percentiles.

Fat-related parameters followed different trajectories by sex across the age range studied.

• In males, fat mass, fat mass index, and percentage body fat decreased until age 14 years before increasing.
• In females, fat-related parameters increased until adolescence and declined after early adulthood.
• Parameters assessed included fat mass, fat mass index, and percentage body fat.
• These patterns were identified in 1451 youth aged 10-25 years using BIA data from a nationwide survey.

Sarcopenia prevalence based on skeletal muscle mass index (SMI) was 2.05% in males and 1.04% in females.

• Sarcopenia cutoff values were age- and sex-specific.
• SMI-based sarcopenia prevalence was lower than prevalence estimates based on fat-to-muscle ratio measures.
• The cross-sectional study analyzed 1451 youth aged 10-25 years.
• Data were drawn from a nationwide survey using bioelectrical impedance analysis (BIA).

Sarcopenia prevalence based on fat-free mass-to-fat ratio (FFM-MFR) was 5.21% in males and 6.38% in females.

• FFM-MFR-based prevalence was higher than SMI-based prevalence in both sexes.
• FFM-MFR-based prevalence was slightly higher in females (6.38%) than in males (5.21%).
• Age- and sex-specific cutoff values were used to define sarcopenia.
• The sample comprised 1451 youth aged 10-25 years from a nationally representative dataset.

Sarcopenia prevalence based on appendicular skeletal muscle mass-to-fat ratio (ASM-MFR) was 5.06% in males and 5.79% in females.

• ASM-MFR-based prevalence was similar to FFM-MFR-based prevalence across both sexes.
• Prevalence was slightly higher in females (5.79%) than in males (5.06%) using ASM-MFR.
• Three distinct sarcopenia definitions were applied: SMI, FFM-MFR, and ASM-MFR.
• All cutoff points were age- and sex-specific, derived from a cross-sectional sample of 1451 youth aged 10-25 years.

BIA-based body composition reference values for youth were established using nationally representative cross-sectional data from 1451 individuals aged 10-25 years.

• The least mean squares (LMS) method was used to estimate age-specific percentiles for body composition parameters.
• The study is described as cross-sectional and based on data from a nationwide survey.
• Reference data for BIA parameters were noted to remain limited in youth prior to this study.
• The reference values are intended to serve as a resource for early identification and management of sarcopenia in youth.