Muscle mass is associated with physical and functional performance across adulthood. Its reduction plays a crucial role in the development of age-related conditions such as frailty and sarcopenia. Genetic variations potentially impact muscle health, particularly in an aged population.

For this reason, we aimed to evaluate the association between genetic biomarkers and appendicular lean mass index (ALMI), a marker of muscle health, to identify possible risk factors for age-related sarcopenia in a population-based study.

We cross-sectionally analyzed data collected in 2015 from the São Paulo Epidemiologic Sleep Study (EPISONO). Participants underwent bioelectrical impedance and genetic evaluations.

After adjusting the data for age and sex, 12 single nucleotide polymorphisms (SNP) were significantly associated with ALMI. Among them, rs9928094 (beta=-0.031 p=0.029) and rs9930333 (beta=-0.030 p=0.035) are located in the FTO gene, which is related to obesity and fat gain and, rs16839632 (beta=0.038 p=0.029) located in the FMN2 gene, responsible for actin cytoskeleton and cell polarity.

Poor muscle health is a multifactorial condition and genetic biomarkers can support the stratification of the risk for adverse body composition states affecting muscle and physical performance across adulthood.