Age- and sex-specific normative values for muscle mass parameters in 18,625 Brazilian adults.
Level 4 - case-series / case-control
Cross-sectional observational study establishing normative reference values
PubMed 38235157 · doi:10.3389/fpubh.2023.1287994
What was done
The authors analyzed cross-sectional data from 18,625 Brazilian adults (aged 18 and older) who attended a nutritional clinic between January 2018 and July 2022. Muscle mass parameters—including absolute muscle mass, height-adjusted relative muscle mass, and appendicular muscle mass (ASM)—were measured using a bioimpedance digital scale (InBody 230). Assessments were standardized by requiring participants to abstain from physical exercise for 96 hours and fast from food and water for 8 hours prior to testing.
What was found
In women, total muscle mass peaked between ages 40–49 and declined at an average rate of 5.7% per decade from the sixth decade onward, while ASM peaked during the third decade and began declining from ages 50–59. In men, both absolute muscle mass and ASM peaked at 40–49 years and declined from the sixth decade. Both sexes exhibited a slightly greater overall decline in ASM than in total muscle mass (13% vs. 12%).
Why it matters
This study provides large-scale, sex- and age-stratified normative reference values for muscle mass in Brazilian adults, establishing a baseline to help clinicians identify sarcopenia and track age-related muscle loss in this population.
Limits
Participants were recruited solely from a single nutritional clinic setting rather than a representative random population sample, introducing selection bias. Body composition was assessed via bioelectrical impedance rather than gold-standard methods like DXA or MRI. The cross-sectional design cannot directly establish individual longitudinal rates of muscle loss.
Cited by
- context Muscle mass begins to decline starting in a person's 30s if left unaddressed.