Abstract / Summary
Abstract Background Frailty is associated with impaired mobility in older adults, but whether greater deficit accumulation is reflected in plantar pressure-time loading and contact timing among older adults with type 2 diabetes remains unclear. We examined these associations and explored them across diabetic foot-risk strata. Methods This community-based cross-sectional study, conducted from September 2025 through March 2026, included 810 adults aged ≥ 60 years with type 2 diabetes. FI33 was used for descriptive stratification; FI30, excluding BMI, diabetes duration and HbA1c, was the continuous exposure. Dynamic plantar pressure was measured using Footscan. The primary outcome was total regional pressure-time integral (T-PTI), defined as the sum of PTI across 20 bilateral plantar regions. Timing outcomes were relative medial-heel, lateral-heel and midfoot contact times, foot-flat phase (FFP), and forefoot push-off phase (FFPOP). HC3-robust linear regression adjusted for age, sex, BMI, diabetes duration, HbA1c and loss of protective sensation. Benjamini-Hochberg correction was applied. Operational IWGDF-based foot-risk strata were evaluated using stratified and interaction analyses. Results Each 0.10 increase in FI30 was associated with 5.12% higher T-PTI (95% CI 1.01%–9.40%; q = 0.0171). Relative medial-heel, lateral-heel and midfoot contact times were 1.79, 1.55 and 1.58 percentage points longer, respectively (q = 0.0012, 0.0034 and 0.0045), whereas FFPOP was 1.51 percentage points shorter (q = 0.0036). FFP was 1.68 percentage points longer (q = 0.0232), but was less robust in sensitivity analyses. Associations were directionally consistent in risk 0 and risk ≥ 1, with generally larger estimates among participants with at-risk feet; interaction tests did not indicate clear heterogeneity. Conclusions Greater deficit accumulation was associated with higher plantar pressure-time exposure, prolonged relative heel and midfoot contact, and shorter forefoot push-off in community-dwelling older adults with type 2 diabetes. Frailty-related systemic vulnerability and diabetic foot risk may provide complementary information, while dynamic plantar loading may provide candidate outcomes for prospective gait and exercise studies.