Association of Standing Sacral-Abdominal Wall Distance and Android/Gynoid Fat Distribution with Locomotive Syndrome...

Locomotive syndrome (LS) is a major cause of mobility impairment and loss of independence in older adults. Abdominal morphology and patterns of body fat distribution are thought to affect physical function; however, their relationships with the severity of LS in women with osteoporosis remain insufficiently characterized. Standing sacral-abdominal wall distance (SAD) is considered an indicator of compromised trunk support mechanisms, whereas the android/gynoid fat ratio (A/G ratio) primarily reflects body fat distribution patterns.

This retrospective cross-sectional study included 221 women aged 65 years or older attending an osteoporosis outpatient clinic. LS was assessed using the stand-up test, the two-step test, and the Locomo 25 questionnaire according to official criteria. The most severe stage among the three tests was defined as the overall LS stage, and participants were classified into LS stage 0-1 and LS stage ≥ 2 groups. Associations of SAD and the A/G ratio with LS were examined using multivariable logistic regression analysis adjusted for age, skeletal muscle mass index (SMI), femoral neck T-score, and the Controlling Nutritional Status (CONUT) score.

Among the participants, 93 (42.1%) were classified as having LS stage ≥ 2. The LS stage ≥ 2 group had a significantly greater SAD than the LS stage 0-1 group (median, 167.3 mm vs. 154.6 mm; p < 0.001), whereas no significant difference was observed in the A/G ratio (p = 0.054). In multivariable analyses (n = 208), SAD was independently associated with LS stage ≥ 2 (odds ratio per 1 mm increase, 1.035; 95% confidence interval, 1.016-1.054; p < 0.001), corresponding to an odds ratio of 1.41 per 10 mm increase. The A/G ratio also showed an independent association, while no significant interaction between SAD and the A/G ratio was observed.

In women with osteoporosis, SAD was independently associated with LS severity, reflecting mobility impairment from a perspective distinct from body fat distribution. SAD may serve as a simple and clinically useful indicator for assessing the risk of severe LS.