Sarcopenia defined by lean mass has been inconsistently associated with disability in elders. Studies suggest that definitions should consider body size and additional influences of high fat mass (FM; sarcopenic-obesity). We examined sarcopenia accounting for body size, and sarcopenic-obesity, in relation to mobility limitations among 767 elderly men and women (mean age 79 years) from the Framingham Study. Whole-body dual-energy x-ray absorptiometry measured appendicular lean mass (ALM) and total FM in 1992–1995. Sarcopenia was defined in two ways: ALM/height squared (ALM/ht²) and ALM adjusted for height and FM (residuals). Sarcopenic-obesity categories (referent, obese, sarcopenic, and sarcopenic-obese) were defined by cross-classifying ALM/ht² and obesity (% body fat: more than 30 for men and more than 40 for women). Mobility limitation was defined as self-reported inability to walk one-half mile, climb stairs, or perform heavy housework. Sex-specific logistic regression calculated odds ratios (OR) and 95% confidence intervals (CI) for mobility limitation, adjusting for covariates. Sixteen percent of men and 30% of women had mobility limitation. Among men, both ALM/ht² (OR = 6.3, 95% CI = 2.5–16.1) and residuals (OR = 4.6, 95% CI = 2.0–10.5) sarcopenia were associated with increased limitation. For sarcopenic-obesity, odds of limitation was higher in sarcopenic (OR = 6.1, 95% CI = 2.2–16.9) and sarcopenic-obese categories (OR = 3.5, 95% CI = 1.0–12.7) but suggested no synergistic effect. In women, only residuals sarcopenia was associated with higher odds of limitation (OR = 1.8, 95% CI = 1.2–2.9). Low lean mass is associated with mobility limitations after accounting for body size and fat, and lean and FM have independent effects on mobility in elders. These findings support previous reports that sarcopenia definitions should consider body size and fat.

Objective To assess the cross‐sectional relation of planus foot morphology to ipsilateral knee pain and compartment‐specific knee cartilage damage in older adults. Methods In the Framingham Studies, we adapted the Staheli Arch Index (SAI) to quantify standing foot morphology from pedobarographic recordings. We inquired about knee pain and read 1.5 T magnetic resonance image (MRI) scans using the Whole‐Organ MRI Score. Logistic regression compared the odds of knee pain among the most planus feet to the odds among all other feet, and estimated odds within categories of increasing SAI. Similar methods estimated the odds of cartilage damage in each knee compartment. Generalized estimating equations adjusted for age, sex, body mass index, and nonindependent observations. Results Among 1,903 participants (56% women, mean ± SD age 65 ± 9 years), 22% of knees were painful most days. Cartilage damage was identified in 45% of medial tibiofemoral (TF), 27% of lateral TF, 58% of medial patellofemoral (PF), and 42% of lateral PF compartments. Compared with other feet, the most planus feet had 1.3 times (95% confidence interval [95% CI] 1.1–1.6) the odds of knee pain (P = 0.009), and 1.4 times (95% CI 1.1–1.8) the odds of medial TF cartilage damage (P = 0.002). Odds of pain (P for linear trend = 0.05) and medial TF cartilage damage (P for linear trend = 0.001) increased linearly across categories of increasing SAI. There was no association between foot morphology and cartilage damage in other knee compartments. Conclusion Planus foot morphology is associated with frequent knee pain and medial TF cartilage damage in older adults.

Foot disorders are common among older adults and may lead to outcomes such as falls and functional limitation. However, the associations of foot posture and foot function to specific foot disorders at the population level remain poorly understood. The purpose of this study was to assess the relation between specific foot disorders, foot posture, and foot function. Participants were from the population-based Framingham Foot Study. Quintiles of the modified arch index and center of pressure excursion index from plantar pressure scans were used to create foot posture and function subgroups. Adjusted odds ratios of having each specific disorder were calculated for foot posture and function subgroups relative to a referent 3 quintiles. Pes planus foot posture was associated with increased odds of hammer toes and overlapping toes. Cavus foot posture was not associated with the foot disorders evaluated. Odds of having hallux valgus and overlapping toes were significantly increased in those with pronated foot function, while odds of hallux valgus and hallux rigidus were significantly decreased in those with supinated function. Foot posture and foot function were associated with the presence of specific foot disorders.