(P17-26-26) Sarcopenia and Lean Soft Tissue Quantity in Relation to Bone Health in Postmenopausal Women

Objectives: The prevalence of sarcopenia among postmenopausal women (PW) in the US is unclear. Besides, the evidence related to the role of lean soft tissue, the best surrogate for skeletal muscle mass, on bone health is scarce. The present study aimed to evaluate the prevalence of sarcopenia and the association between lean soft tissue quantity and bone health in postmenopausal women.

Methods: PW (≤10 years postmenopausal) who were not receiving hormone therapy or pharmacological agents known to affect bone were recruited. Bone mineral density (BMD), lean soft tissue, and body fat (BF%) were measured by dual-energy X-ray absorptiometry. Fasting blood and 24-hour urine samples were collected to assess inflammation and bone biomarkers. Dietary intake and physical activity (PA) were assessed via the 7-day Modified Willett FFQ and the Five-City Project Physical Activity Recall, respectively. Sarcopenia was defined as an appendicular lean soft tissue index (ALSTI) < 5.5kg/m² (EWGSOP2 criteria). Multiple linear regression was used to estimate associations between ALSTI and bone health markers, adjusting for key covariates. The Mann-Whitney U test was used to evaluate differences between PW with and without sarcopenia.

Results: The prevalence of sarcopenia was 19.5% (24/123). PW with sarcopenia had significantly lower body mass (58.4kg [53.0, 62.6] vs. 67.8kg [60.5, 76.8], p< 0.001), BF% (36.4% [33.4, 39.6] vs. 41.2% [35.6, 45.9]; p=0.019) and reported PA (681kcal/day [492, 819] vs. 882kcal/day [640, 1023]; p=0.006), but no differences in age (p=0.757), inflammation (p=0.185), and total energy (p=0.831) and protein (p=0.645) intake. ALSTI was positively associated with lumbar spine (L2-L4) BMD (r=0.238; p=0.008) and remained significant after adjusting for BF%, PA, inflammation, and age, with a 0.04 g/cm² (SE=0.02) increase per 1-unit increase in ALSTI (p=0.013). Trends were noted for L3 BMD (1.06g/cm² [1.00, 1.19] vs. 1.11g/cm² [1.04, 1.21]; p=0.077) and bone-specific alkaline phosphatase (13.6U/L [12.0, 17.6] vs. 16.8U/L [13.3, 20.1]; p=0.061), with less favorable bone health in PW with sarcopenia.

Conclusions: Sarcopenia is highly prevalent in PW with osteopenia, and it is associated with poorer bone health.

Funding Sources: N/A