Research Focus

Pelvic floor disorders are common in women and often multifactorial. Sarcopenia—age-related loss of skeletal muscle mass and function—may be an underrecognized risk factor. In a retrospective review of 264 women undergoing MR defecography and high-resolution anorectal manometry, we examined whether lower muscle mass, indexed by the psoas muscle index (PMI), is associated with pelvic floor and anal sphincter dysfunction.

Sarcopenia was identified on MRI in 98 of 264 women (37.1%). Women with sarcopenia were older and had lower body mass index, with similar parity and prior pelvic surgery compared with non-sarcopenic peers. Lower PMI was significantly associated with diminished anal resting pressure (P < 0.001) and squeeze pressure (P < 0.001). Sarcopenia also correlated with adverse pelvic floor dynamics, including increased levator hiatus length (P = 0.004), greater pelvic floor descent (P = 0.01), and a wider anorectal angle (P = 0.002). Clinically, women with sarcopenia were more likely to have anal hypotension and hypocontractility (both P < 0.001), reported higher fecal incontinence symptom severity (median Wexner score 8 vs 4, P = 0.03). In multivariable analyses, sarcopenia remained an independent risk factor for anal hypotension/hypocontractility, levator enlargement, and exaggerated levator hiatus descent.

• These findings suggest that systemic muscle loss is linked to both weaker anal sphincter function and pelvic floor laxity in women. Routine, opportunistic estimation of muscle mass (PMI = psoas cross-sectional area at L4 normalized by height squared) from clinically acquired MRI may help identify at-risk patients. Incorporating sarcopenia screening and targeted interventions—such as resistance training and nutrition optimization—alongside pelvic floor rehabilitation could improve outcomes.