Associations between sarcopenia components with bone health in older women with obesity

Abstract Background Sarcopenia, characterized by reduced muscle mass and strength, can impair bone health in older adults, especially in those with obesity. However, it remains unclear how individual sarcopenia components, associate with bone health variables, in older adults with obesity, and whether their combined associations are stronger than either one alone. Objective To investigate the independent and combined associations of appendicular lean mass (ALM) and handgrip strength with bone health in older adults with obesity and compare bone outcomes among three distinct phenotypes: older women with obesity alone, obesity plus low ALM, and obesity plus low ALM and low muscle strength. Methods In this cross-sectional study, 190 older women with obesity were included. Femoral neck, total hip, and lumbar spine bone mineral density (BMD), hip-bone geometry and ALM were assessed by dual x-ray absorptiometry (DXA). Muscle strength was assessed by handgrip strength (HGS). Results ALM and HGS were both associated with BMD and hip geometry in models adjusted for age and BMI (p<0.05). However, when included in the same model, only ALM remained significantly associated with bone outcomes (all p<0.05). Generalized linear models showed that older women with sarcopenia or with low ALM alone showed lower BMD and impaired bone geometry compared to those with preserved ALM and strength. Conclusion ALM appears to be more strongly associated with bone health than HGS for bone health in older women with obesity. Therefore, older women with obesity and low ALM, independent of handgrip strength levels, have worse bone health than their counterparts with preserved appendicular lean mass.