Subsystems contributing to the decline in ability to walk: Bridging the gap between epidemiology and geriatric practice in the InCHIANTI study

Background: Older patients are often referred to geriatricians because of complaints of progressive difficulties in walking. The diagnostic and therapeutic approach to these patients is complex. Multiple physiologic subsystems may influence the ability to walk, and no standard criteria are currently available to establish whether these subsystems are functioning within the normal range. To address this lack of knowledge we conducted the InCHIANTI study. Objective: To identify measures that clinicians can use to understand the causes of walking difficulties in older persons. Design: A population-based study of persons living in the Chianti geographic area (Tuscany, Italy). Participants: 1453 persons (age-range 20-102 years; 91.6% of the eligible) selected from city registry of Greve in Chianti and Bagno a Ripoli (Tuscany, Italy), using a multistage sampling method. Measurements: Factors that influence walking ability were classified into six main physiologic subsystems: central nervous system, perceptual system, peripheral nervous system, muscles, bone/joints, and energy production/delivery. Measures of the integrity and functioning of each of these proposed subsystems were identified and administered to all participants. Conclusions: Data collected in InCHIANTI will be used to identify the main risk factors that influence loss of the ability to walk in older persons, to define physiologic subsystems that are critical for walking, to select the best measures of their integrity, and to establish critical ranges in these measures that are compatible with "normal" walking ability. The final goal is to translate epidemiological research into a geriatric clinical tool that makes possible more precise diagnosis and more effective treatment in patients with walking dysfunction.