Risk Factors for Falls: A Central Role in Prevention

Falls are a common and complex geriatric syndrome causing considerable mortality, reduced functioning, and premature nursing home admission among older people (Rubenstein and Josephson, 2002). Falls have many precipitating causes and predisposing risk factors, which makes diagnosis, treatment, and particularly prevention a difficult clinical challenge. A fall may be the first indicator of an acute problem (infection, low blood pressure caused by a change in position, cardiac arrhythmia), or may indicate progression of a chronic disease (Parkinsonism, dementia, diabetic neuropathy), or simply may be a signal of the onset of "normal" age-related changes in vision, gait, and strength. Moreover, most falls experienced by older people have multifactorial and interacting causes (e.g., a gait disorder and poor vision both contribute to a trip over an electrical cord. This complex relationship between risk factors, underlying causes, precipitating events, and falls is alluded to in Figure I. Such multifactorial causality is typical of geriatric syndromes generally and necessitates a systematic, multidimensional evaluation. This article reviews the risk factors for falls and discusses how identification of these risk factors is the core of a multidimensional fall evaluation. RISK FACTORS Many studies have identified risk factors for falling. A risk factor is defined as a characteristic or situation found significantly more often among individuals who subsequently experience a certain adverse event than individuals not experiencing the event. While there are some differences in risk factors between community-living and institutionalized populations, most of the risk factors overlap both groups. A recent review (Rubenstein and Josephson, 2002) of these fall risk-factor studies analyzed the data from sixteen studies providing quantitative risk data and summarized the relative risk of falls for people with each identified risk factor. Eight of these studies were conducted among community-dwelling populations and eight among nursing home populations. The relative risk of the most commonly reported risk factors is discussed below. It should be noted that some of these risk factors are directly involved in causing falls (e.g., weakness, gait and balance disorder), while others are more markers of other underlying causes (e.g., prior falls, use of an assistive device, age 80-plus). In these studies, weakness in lower extremities (detected by either functional testing or manual muscle examination) was identified as the most potent risk factor associated with falls, increasing the odds of falling, on average, by more than four times. Leg weakness is very common in older people. As a whole, healthy older people score 20 percent to 40 percent lower on strength tests than do young adults (Murray et al., 1980), and the prevalence of detectable lower-extremity weakness ranges from 57 percent among residents of an intermediate-care facility (Tinetti, Williams, and Mayewski, 1986) to more than 80 percent among residents of a skilled nursing facility (Robbins et al., 1989). Weakness often stems from deconditioning due to limited physical activity or prolonged bed rest, together with chronic debilitating medical conditions, such as heart failure, stroke, or pulmonary disease. Individuals who have already fallen are three times as likely to fall as those who have not. While recurrent falls in an individual are frequently due to the same underlying cause, they can also be an indication of progression of a disease like Parkinsonism or dementia or a new acute problem like infection or dehydration. Gait and balance disorders are also common among older adults, affecting between 20 percent and 50 percent of people over the age of 65 years (e.g., Alexander, 1996). Among nursing home populations, nearly three quarters of residents require assistance with walking or are unable to walk (Sahyoun et al., 2001). Both gait and balance impairments were found to be a significant risk factor for falls, associated with about a three-fold increase in risk of falling, and use of an assistive device for walking was associated with a risk of falling increased by 2. …