Calf Circumference as a Predictive Biomarker for Falls in older Adults: A Retrospective Case– Control Study

Background Falls are a significant cause of injury, loss of independence, and mortality among older adults. While muscle weakness and balance impairment are well-established modifiable risk factors, simple anthropometric measures such as calf circumference (CC) have not been thoroughly evaluated for their predictive value regarding fall risk in community settings. Objective This study aims to determine whether CC independently predicts fall risk in community-dwelling older adults and to compare its predictive performance with other sociodemographic, clinical, functional, and lifestyle factors. Methods In this retrospective case–control study, we analyzed electronic health records from 1,064 adults aged 60 years and older registered in the Sina health information system between March 2017 and December 2023 (266 fallers and 798 non-fallers). CC was measured at the widest point of the relaxed dominant calf (using the mean of four readings) and dichotomized into < 31 cm versus ≥ 31 cm. Covariates included age, sex, body mass index (BMI), education, marital and employment status, regular physical activity, limb muscle strength, cerebellar signs, foot examination findings, comorbidities (including diabetes, hypertension, dyslipidemia, cardiovascular disease, and obesity), and the use of statins or aspirin. Univariable and multiple logistic regression models were employed to estimate odds ratios (ORs) with 95% confidence intervals (CIs), with significance set at p ≤ 0.05. Results We analyzed 1,064 older adults (266 fallers; 25.0%). Fallers were older and had lower BMI than non-fallers (both p < 0.001). In multipule logistic regression, larger calf circumference (CC ≥ 31 cm) was independently associated with reduced odds of falling (adjusted OR = 0.54, 95% CI: 0.33–0.90, p = 0.01), whereas physical inactivity increased the odds (adjusted OR = 3.57, 95% CI: 2.19–5.83, p < 0.001). Cerebellar dysfunction showed a borderline association with higher fall risk (adjusted OR = 4.16, 95% CI: 0.98–17.71, p = 0.05). Other demographic and clinical factors were not independently associated after adjustment (all p > 0.05). Conclusions Calf circumference < 31 cm is independently associated with increased odds of falls in older adults. Routine measurement of CC using a simple tape in primary care or community settings offers a low-cost, feasible screening tool for the early identification of high-risk individuals and may inform targeted interventions such as resistance and balance training. Prospective cohort studies and randomized trials are necessary to validate sex- and age-specific CC thresholds and to assess whether interventions aimed at increasing calf muscle mass or function can reduce the incidence of falls.